Cover crops can have beneficial effects on soil microbiology by increasing carbon （C） supply, but these beneficial effects can be modulated by precipitation conditions. The objective of this study was to compare a f...Cover crops can have beneficial effects on soil microbiology by increasing carbon （C） supply, but these beneficial effects can be modulated by precipitation conditions. The objective of this study was to compare a fallow-winter wheat （Triticum aestivum L.） rotation to several cover crop-winter wheat rotations under rainfed and irrigated conditions in the semiarid US High Plains. Experiments were carried out at two sites, Sidney in Nebraska, and Akron in Colorado, USA, with three times of soil sampling in 2012--2013 at cover crop termination, wheat planting, and wheat maturity. The experiments included four single-species cover crops, a 10-species mixture, and a fallow treatment. The variables measured were soil C and nitrogen （N）, soil community structure by fatty acid methyl ester （FAME） profiles, and soil β-glucosidase,β-glucosaminidase, and phosphodiesterase activities. The fallow treatment, devoid of living plants, reduced the concentrations of most FAMEs at cover crop termination. The total FAME concentration was correlated with cover crop biomass （R = 0.62 at Sidney and 0.44 at Akron）. By the time of wheat planting, there was a beneficial effect of irrigation, which caused an increase in myeorrhizal and protozoan markers. At wheat maturity, the cover crop and irrigation effects on soil FAMEs had subsided, but irrigation had a positive effect on the β-glucosidase and phosphodiesterase activities at Akron, which was the drier of the two sites. Cover crops and irrigation were slow to impact soil C concentration. Our results show that cover crops had a short-lived effect on soil microbial communities in semiarid wheat-based rotations and irrigation could enhance soil enzyme activity. In the semiarid environment, longer time spans may have been needed to see beneficial effects of cover crops on soil microbial community structure, soil enzyme activities, and soil C sequestration.展开更多
Rice-wheat cropping system (RWCS) is one of the most important cropping systems in South Asia. However, sustainability of this system is under threat owing to several factors, of which deficiency of micronutrients par...Rice-wheat cropping system (RWCS) is one of the most important cropping systems in South Asia. However, sustainability of this system is under threat owing to several factors, of which deficiency of micronutrients particularly zinc (Zn), boron (B) and manganese (Mn) is one of the major problems. Continuous rotation of rice and wheat, imbalanced fertilizer use and little/no use of micronutrient-enriched fertilizers induce deficiencies of Zn, B and Mn in the RWCS of South Asia. Here we review that (i) imbalanced fertilizer use and organic matter depletion deteriorate soil structure resulting in low efficiency of applied macro- and micro-nutrients in RWCS.(ii) The micronutrients (Zn, B and Mn) are essentially involved in metabolism of rice and wheat plants, including chlorophyll synthesis, photosynthesis, enzyme activation and membrane integrity.(iii) Availability and uptake of Zn, B and Mn from rhizosphere depend on the physico-chemical soil properties (which differ under aerobic and anaerobic conditions) including soil pH, soil organic matter, soil moisture and interaction of these micronutrients with other nutrients.(iv) Plant ability to uptake and utilize the nutrients is affected by several plant factors such as root architecture, root hairs, transport kinetics parameter and root exudates.(v) Crop management and application of these microelements can help correct the micronutrients deficiency and enhance their grain concentration.展开更多
Bemisia tabaci is a polyphagous herbivore that feeds on a wide range of horticultural and ornamental crops cultivated under diverse ecological zones. In Sierra Leone, B. tabaci is found to infest a wide range of veget...Bemisia tabaci is a polyphagous herbivore that feeds on a wide range of horticultural and ornamental crops cultivated under diverse ecological zones. In Sierra Leone, B. tabaci is found to infest a wide range of vegetable crops by directly feeding on phloem sap thereby inducing physiological disorders, and also serve as a vector to gemini viruses. Invariably the destructive feeding of B. tabaci affects the productivity and aesthetic values of vegetables and other horticultural crops and hence is considered a serious economic pest. A bioassay experiment was carried out by rearing B. tabaci populations on four vegetable crops under controlled laboratory conditions to determine its life table and demographic parameters. Results showed that the intrinsic rate of growth which measures the population size and growth pattern was highest for populations reared on tomato crops with the following values: rm 0.145 female female−1 day−1, the gross reproduction rate (Ro), and finite growth rate λ were highest for population reared on tomato, correspondingly the development period from egg-adult emergence was shortest with a value of 26 d. Conversely, the computed demographical parameters rm, λ and Ro for the population reared on sweet pepper were 0.106 female female−1 day−1 respectively, with a corresponding development period egg-adult emergence as 36d. The computed biological parameters for okra and garden egg varied with intermediary values between tomato and pepper host materials. The survivorship rates were quite significant for the smaller instars (Instars 1-III) with over 80% surviving to pre-pupa and pupa stage for the populations reared for all the test materials. High mortality was noticed for the pre-pupa and pupa stages as their survival rates were significantly low compared to the high survival rates of the smaller instars. Less than 50% of pupae failed to emerge to adults except for populations reared on tomato test materials where 52% emerged to adults. The study indicated tomato as the most suitable host among the four vegetable crops. Although life table and demographic parameters are invaluable information for forecasting pest populations and help in designing pest management efforts, further investigations such as the economic threshold and economic injury levels of B. tabaci population are requisite decision tools for sound pest management decisions of B. tabaci on these vegetable crops. The information obtained from this investigation would be quite relevant for extension service and pest management practitioners where mixed vegetable farming is a common practice.展开更多
Field experiments were conducted at the experimental farm Cocoa Re-search Institute of Nigeria (CRIN) Sub-Station, Ochaja, in the Southern Guinea Savannaagro ecological zone of Nigeria to examine uptake and use effici...Field experiments were conducted at the experimental farm Cocoa Re-search Institute of Nigeria (CRIN) Sub-Station, Ochaja, in the Southern Guinea Savannaagro ecological zone of Nigeria to examine uptake and use efficien-cies of nutrients by Sesame and Bambara nut alley crops as influenced by manuring in a Cashew-based intercropping system. Experimental treatments were based on responses of sole and intercrop mixtures of Sesame and Bam-bara nut alley crops to Cocoa Pod Husk (CPH), pelletized organic fertilizer and NPK fertilizer in a cashew-based intercropping system. Data were collected on the growth and yield variables of the alley crops. Highest nitrogen harvest in-dex (NHI) for seed and leaf of alley crops were obtained from un-manure treated plants. Cocoa pod husk (CPH) significantly enhanced P uptake com-pared with other fertilizers applied. CPH improved Na, Ca, Mg Zn, Cu, P, K and carbohydrate in the leaves and Ca, Mg, Zn, Fe, Cu, crude fibre and car-bohydrate contents of seeds of sole crops while Sesame + Bambara had en-hanced contents of N, Ca, Mg, Zn, Cu, P, N, K, moisture, protein, and crude fi-bre, crude protein, moisture content in leaves. The effects of NPK were signifi-cant for N, K Ca, Zn, Fe, Cu, P, moisture and crude fibre, while in the un-manure (control) plots influenced N, fat and protein and nitrogen harvest index (NHI) of leaf and seeds. CPH and NPK fertilizers enhanced nutrient up-take and nitrogen harvest index of alley crops. Nutrient uptake was similar for the varieties of Sesame and Bambara nut as affected by the application of 4.84 and 9.68 Kg pelletized organic fertilizer. Sole Bambara had higher N and K concentration in leaves compared with Bambara +Sesame. In addition, sole Bambara had higher values of Physiology efficiency (PE), and fertilizer use ef-ficiency (FAE) compared to the mixed crops of Bambara + sesame. However, physiology efficiency (PE), and fertilizer use efficiency (FAE) were significantly lower for Bambara + Sesame. The un-manure plants had enhanced N, P and K uptake. Varietal effects were pronounced for most of the resource use effi-ciency variables measured. The alley crop varieties responded differently to 4.84 and 9.68 kg pelletized fertilizer treatments (Agronomy Efficiency (AE), N-removed at harvest and Internal Utilization Efficiency (IE) and partial fac-tor productivity (PFP)). Sesame variety NCRIBen04E had enhanced AE, N-remove at harvest, IE and PFP while variety E8 had significantly higher ap-parent Recovery Efficiency (RE), apparent Recovery Efficiency by difference (RE%), Physiology Efficiency (PE), Utilization Efficiency (UE), and internal Utilization Efficient (IE). Bambara variety TVSu999 had higher IUE, Agron-omy Efficiency (AE), Apparent Recovery Efficiency (RE), Physiology Effi-ciency (PE) and Fertilizer Agronomy using Efficiency respectively (FAE) com-pared to variety TVSu1166. The fertilizers affected most of the indicators of nutrient use efficiency (NUE) measured. The effects were significant on AE, agronomic N-use efficiency (ANUE), RE, UE and PFP. NPK fertilizer enhanced Physiology efficiency (PE) and Partial factor production. NPK fertilizer signifi-cantly enhanced NUE parameters compared to CPH and un-manure. CPH manure significantly influenced RE%, PE and IE. The Internal Utilization Effi-ciency and N-remove at harvest were compared with the un-manure plants (control). The effects of 9.68 kg/plot pelletized fertilizer, were pronounced on Agronomy Efficiency (AE), Apparent Recovery Efficiency by difference (RE%), Physiology Efficiency (PE), Utilization Efficiency (UE), N-removed at harvest and Internal Utilization Efficiency (IE). Similar trends were observed in the responses NUE of Sesame and Bambara manuring. The responses sole crops in terms of RE, PE UE PFP were similar while their intercrop combina-tions had significantly higher AE, RE, UE, PFP and N removed at harvest. Sole Sesame significantly influence Agronomy Efficiency (AE), Utilization Effi-ciency (UE), Internal Efficiency (IE) and Partial Fertilizer Production (PFP) and sole Bambara under NPK fertilizer had enhanced N-removed at harvest and apparent recovery by difference (RE%). Bambara + Sesame under cocoa pod husk (CPH) manure had enhanced apparent recovery efficiency by difference (RE%), fertilizer use efficiency (FAE) and internal utilization efficiency (IE). Sesame variety NCRIBen04E had enhanced Agronomy Efficiency (AE), N-removed at harvest and Internal Utilization Efficiency (IE) under 9.68 kg treatment while variety E8 had higher partial factor productivity (PFP) at 4.84 kg/plot pelletized organic fertilizer.展开更多
Soil water retention is a critical aspect of agricultural management, especially in areas such as the Lower Mississippi River Alluvial Valley that face potential water shortages in the near future. Previous studies ha...Soil water retention is a critical aspect of agricultural management, especially in areas such as the Lower Mississippi River Alluvial Valley that face potential water shortages in the near future. Previous studies have linked changes in soil water retention characteristics to agricultural management practices, especially as they affect the accumulation of soil organic matter (SOM). Therefore, the objective of this study was to determine the relationship between soil water potential and gravimetric soil water content in the top 7.5 cm as affected by nitrogen (N) fertilization/residue level (high and low), residue burning (burning and non-burning), tillage (conventional and no-tillage), and irrigation (irrigated and non-irrigated) after 12 complete cropping cycles in a wheat (Triticum aestivum L.)-soybean [Glycine max (L.) Merr.], double-crop production system in the Delta region of eastern Arkansas using soil wetting curves. The soil investigated was a Calloway silt loam (fine silty, mixed, active, thermic Glossaquic Fraglossudalf). The slope characterizing the relationship between the natural logarithm of the soil water potential and the gravimetric soil water content was only affected (P < 0.05) by the N-fertilization/residue-level treatment, while the intercept was unaffected by any field treatment. Averaged across tillage, burning, and irrigation, soil water contents under the high-exceeded those under low-N-fertilization/residue-level treatment at the same water potential, with the greatest differences observed at water contents > 0.12 g·g-1. Understanding the ways in which alternative residue management practices affect soil water retention characteristics is an important component of conserving irrigation water resources.展开更多
Wheat is one of the most important cereals in the world, serving as a staple for millions globally. In the wake of the geopolitical crisis between Russia and Ukraine, it has become incumbent for many countries to inve...Wheat is one of the most important cereals in the world, serving as a staple for millions globally. In the wake of the geopolitical crisis between Russia and Ukraine, it has become incumbent for many countries to invest in wheat production. Improving cropping systems for wheat production is paramount. Intercropping cereals with legumes has tremendous advantages. Therefore, this study was designed to optimize wheat production by intercropping it with soybean at different densities. Between March and August 2023, a randomized complete block design trial was conducted in Bambili, North West of Cameroon with treatments T1 (wheat monocrop at 200,000 plants ha<sup>−</sup><sup>1</sup>), T2 (soybean monocrop at 250,000 plants ha<sup>−</sup><sup>1</sup>), T3 (200,000 wheat and 125,000 soybean ha<sup>−</sup><sup>1</sup>), T4 (100,000 wheat and 250,000 soybean ha<sup>−</sup><sup>1</sup>), T5 (200,000 wheat and 250,000 soybean ha<sup>−</sup><sup>1</sup>) and T6 (100,000 wheat and 125,000 soybean ha<sup>−</sup><sup>1</sup>). Results revealed that growth parameters of wheat were not significantly influenced by monocrop or intercrop. The yield of wheat was significantly higher in the monocrop than the intercrop treatments, with slight variation amongst the intercrop treatments. Soybean yield was higher in the monocrop than in the intercrop, with no variations amongst the intercrop treatments. Only the land equivalence ratio (LER) for T5 was greater than 1.0. The competitive ratio for T5 was 0.54 for wheat and 1.90 for soybean, comparatively lower than the other monocrop treatments. Intercropping wheat and soybean at 200,000:250,000 ratio is recommended.展开更多
The North China Plain,where summer corn(Zea mays L.)and winter wheat(Triticum aestivum L.)are the major crops grown,is a major agricultural area in China.Permeable soils make the region susceptible to groundwater poll...The North China Plain,where summer corn(Zea mays L.)and winter wheat(Triticum aestivum L.)are the major crops grown,is a major agricultural area in China.Permeable soils make the region susceptible to groundwater pollution by NO_3-N,which is applied to fields in large amounts of more than 400 kg NO_3-N ha^(-1)as fertilizer.A field experiment was established in 2002 to examine the relationship among N fertilization rate,soil NO_3-N,and NO_3-N groundwater contamination.Two adjacent fields were fertilized with local farmers' N fertilization rate(LN)and double the normal application rate(HN),respectively,and managed under otherwise identical conditions.The fields were under a traditional summer corn/winter wheat rotation.Over a 22-month period,we monitored NO_3-N concentrations in both bulk soil and soil pore water in 20-40 cm increments up to 180 cm depth.We also monitored NO_3-N concentrations in groundwater and the depth of the groundwater table.No significant differences in soil NO_3-N were observed between the LN and HN treatment.We identified NO_3-N plumes moving downward through the soil profile.The HN treatment resulted in significantly higher groundwater NO_3-N,relative to the LN treatment,with groundwater NO_3-N consistently exceeding the maximum safe level of 10 mg L^(-1),but groundwater NO_3-N above the maximum safe level was also observed in the LN treatment after heavy rain.Heavy rain in June,July,and August 2003 caused increased NO_3-N leaching through the soil and elevated NO_3-N concentrations in the groundwater.Concurrent rise of the groundwater table into NO_3-N- rich soil layers also contributed to the increased NO_3-N concentrations in the groundwater.Our results indicate that under conditions of average rainfall,soil NO_3-N was accumulated in the soil profile.The subsequent significantly higher- than-average rainfalls continuously flushed the soil NO_3-N into deeper layers and raised the groundwater table,which caused continuous groundwater contamination with NO_3-N.The results suggest that under common farming practices in the North China Plain,groundwater contamination with NO_3-N was likely,especially during heavy rainfalls,and the degree of groundwater contamination appeared to be proportional to the N application rates.Decreasing fertilization rates, splitting fertilizer inputs,and optimizing irrigation scheduling had potential to reduce groundwater NO_3-N contamination.展开更多
Reduced early crop growth and limited branching are amongst yield limiting factors of linola. Field response of seed priming treatments viz. 50 mmol L^-1 salicylic acid （SA）, 2.2% CaCl2 and 3.3% moringa leaf extract...Reduced early crop growth and limited branching are amongst yield limiting factors of linola. Field response of seed priming treatments viz. 50 mmol L^-1 salicylic acid （SA）, 2.2% CaCl2 and 3.3% moringa leaf extract （MLE） including untreated dry and hydropriming controls was evaluated on early crop growth and yield performance of linola. Osmopriming with CaCl2 reduced emergence time and produced the highest seedling fresh and dry weights including Chl. a contents. Osmopriming with CaCl2 reduced crop branching and flowering and maturity times and had the maximum plant height, number of branches, tillers, pods and seeds per pod followed by MLE. Increase in seed weight, biological and seed yields was 9.30, 34.16 and 39.49%, harvest index （4.12%） and oil contents （13.39%） for CaCl2 osmopriming. Positive relationship between emergence and seedling vigor traits, 100-seed weight, seed yield with maturity time, 100-seed weight and seed yield were found. The study concludes that seed osmopriming with CaC12 or MLE can play significant role to improve early crop growth and seed yields of linola.展开更多
A 12-year cover crops study on the effects on SOC sequestration, storage, retention and loss and corn and soybean yields was conducted in southern Illinois. The use of cover crops for the maintenance and restoration o...A 12-year cover crops study on the effects on SOC sequestration, storage, retention and loss and corn and soybean yields was conducted in southern Illinois. The use of cover crops for the maintenance and restoration of soil organic carbon (SOC) and soil productivity of previously eroded soils were evaluated. No-till (NT), chisel plow (CP), and moldboard plow (MP) treatment plots with and without cover crops were established in 2001. The plot area was on sloping with a moderately well drained, eroded soil. The average annual corn and soybean yields were statistically the same for NT, CP, and MP systems with and without cover crops. By 2012, the cover crop treatments had more SOC stock than that without cover crops for the same soil layer and tillage treatment. The NT, CP, and MP treatments all sequestered SOC with cover crops. A pre-treatment SOC stock baseline for rooting zone was used to validate the finding that cover crops sequestered SOC in the topsoil, subsoil and root zone of the NT, CP and MP treatments during the 12-year study. Additional sequestered SOC was lost as a result of being transported off of the plots and retained in lower slopes, transported to the stream or released to atmosphere.展开更多
Utilization of nitrogen(N)element is a common practice used to reach profitable yields in horticultural crops and N supply can be used as a tool to manipulate the enhancement of phytochemicals and minerals in vegetabl...Utilization of nitrogen(N)element is a common practice used to reach profitable yields in horticultural crops and N supply can be used as a tool to manipulate the enhancement of phytochemicals and minerals in vegetable crops to address consumer-oriented quality production.Hence the study was aimed to investigate the effect of N application on leaf morphology,ascorbic acid content,phenolic acids,flavonoids,mineral content,and nitrate residues in three lettuce varieties(two green leafy lettuce,Multigreen 1 and Multigreen 3;one red leafy lettuce,Multired 4)grown in a closed hydroponic system(grave^-film)at harvest.Nitrogen was applied as ammonium nitrate(NH4NO3)at six different concentrations of 0,60,90,120,150 and 180 mg L^-1.The results obtained during 2015 and 2016 seasons were similar and demonstrated variety dependent responses with respect to different N application rates.Multigreen 3 was more sensitive to N supply and showed higher amount of nitrate residue at harvest.Variety Multired 4 was less sensitive to N supply followed by Multigreen 11 Although N supply at 120 mg L^-1 improved the yield and the number of leaves in Multigreen 3,overall 90 mg L^-1 can be recommended for these lettuce varieties to improve the yield and the accumulation of ascorbic acid content,phenolic acids mainly caffeic,caftaric acids,quercetin(the important flavonoid in lettuce),and Fe and Mn contents.Furthermore,the concentration of 90 mg L^-1 improved the antioxidant property(FRAP and ABTS^+)and reduced the nitrate accumulation,ensuring safe food for consumers.展开更多
Background:The prediction of biogeographical patterns from a large number of driving factors with complex interactions,correlations and non-linear dependences require advanced analytical methods and modeling tools.Thi...Background:The prediction of biogeographical patterns from a large number of driving factors with complex interactions,correlations and non-linear dependences require advanced analytical methods and modeling tools.This study compares different statistical and machine learning-based models for predicting fungal productivity biogeographical patterns as a case study for the thorough assessment of the performance of alternative modeling approaches to provide accurate and ecologically-consistent predictions.Methods:We evaluated and compared the performance of two statistical modeling techniques,namely,generalized linear mixed models and geographically weighted regression,and four techniques based on different machine learning algorithms,namely,random forest,extreme gradient boosting,support vector machine and artificial neural network to predict fungal productivity.Model evaluation was conducted using a systematic methodology combining random,spatial and environmental blocking together with the assessment of the ecological consistency of spatially-explicit model predictions according to scientific knowledge.Results:Fungal productivity predictions were sensitive to the modeling approach and the number of predictors used.Moreover,the importance assigned to different predictors varied between machine learning modeling approaches.Decision tree-based models increased prediction accuracy by more than 10%compared to other machine learning approaches,and by more than 20%compared to statistical models,and resulted in higher ecological consistence of the predicted biogeographical patterns of fungal productivity.Conclusions:Decision tree-based models were the best approach for prediction both in sampling-like environments as well as in extrapolation beyond the spatial and climatic range of the modeling data.In this study,we show that proper variable selection is crucial to create robust models for extrapolation in biophysically differentiated areas.This allows for reducing the dimensions of the ecosystem space described by the predictors of the models,resulting in higher similarity between the modeling data and the environmental conditions over the whole study area.When dealing with spatial-temporal data in the analysis of biogeographical patterns,environmental blocking is postulated as a highly informative technique to be used in cross-validation to assess the prediction error over larger scales.展开更多
Subsurface flow is a prominent runoff process in sloping lands of purple soil in the upper Yangtze River basin.However,it remains difficult to identify and quantify.In this study,in situ runoff experimental plots were...Subsurface flow is a prominent runoff process in sloping lands of purple soil in the upper Yangtze River basin.However,it remains difficult to identify and quantify.In this study,in situ runoff experimental plots were used to measure soil moisture dynamics using an array of time domain reflectometry(TDR) together with overland flow and subsurface flow using isolated collecting troughs.Frequency of preferential flow during rainfall events and the controls of subsurface flow processes were investigated through combined analysis of soil properties,topography,rainfall intensity,initial wetness,and tillage.Results showed that subsurface flow was ubiquitous in purple soil profiles due to welldeveloped macropores,especially in surface soils while frequency of preferential flow occurrence was very low(only 2 cases in plot C) during all 22 rainfall events.Dry antecedent moisture conditions promoted the occurrence of preferential flow.However,consecutive real-time monitoring of soil moisture at different depths and various slope positions implied the possible occurrence of multiple subsurface lateral flows during intensive storms.Rainfall intensity,tillage operation,and soil properties were recognized as main controls of subsurface flow in the study area,which allows the optimization of management practices for alleviating adverse environmental effects of subsurface flow in the region.展开更多
Farmers in the highlands of Ethiopia often plant Eucalyptus on their farmlands. However, growing Eucalyptus, especially on farm- lands suitable for crop production has become a great concern due to its alleged long-te...Farmers in the highlands of Ethiopia often plant Eucalyptus on their farmlands. However, growing Eucalyptus, especially on farm- lands suitable for crop production has become a great concern due to its alleged long-term site effects. Our study was conducted at Koga water- shed, Mecha District, northwestern Ethiopia to investigate whether crop- lands afforested with Eucalyptus camaldulensis Dehnh. can be restored for annual crop production after tree harvest. We compared growth and yield of two agricultural crops, barley （Hordeum vulgate L.） and finger millet （Eleusine coracana （L.） Gaertn.）, grown in clear-felled stands of E. camaldulensis and continuously cultivated croplands at twelve paired farmlands under a conventional farming system. Plant height and dry matter production were evaluated as indices of crop growth, while grain weight was evaluated as an index of crop yield. Crop growth and yield measurements averaged over all farmlands differed between land-use types. For both crops, plants grown on clear-felled stands were taller than on croplands. Dry matter production and yield were also significantly greater in crops cultivated on clear-felled stands. Cropland aboveground and belowground dry matter productions were lower by 31.8 and 25.4% for barley and 32.8% and 37% for finger millet, respectively. Clear-felled stands gave an average yield of 2.91 t.ha-1 for barley and 3.27 t.ha-1 for finger millet while cropland gave a yield of 1.97 and 2.31 t.ha-1 for barley and finger millet, respectively. Farmers also responded that farm plots on former eucalypt plantations showed greater crop growth and yield thandid continuously cultivated croplands. Farmers perceived that Eucalyptus plantations improved soil fertility and they preferred clear-felled stands for crop production and wished to plant Eucalyptus on their farmlands. Our results suggest that conversion of agricultural lands to Eucalyptus plantations can increase post-felling yields of cereal crops.展开更多
Agriculture is an important source of economic survival of rural populations, and with great power for poverty reduction in the economy. For this reason farming systems that are most efficient have to be sought. This ...Agriculture is an important source of economic survival of rural populations, and with great power for poverty reduction in the economy. For this reason farming systems that are most efficient have to be sought. This paper explores crop-based and pastoralism farming systems under conflicting land use relations. Incidences of violent conflicts are highlighted, which usually assume a depoliticised expression as inter-group conflicts. Competition for resources (land and water) is an important reason for such conflict, but the role of the state in protection of property rights is also advocated to nurture rivalry. Very wide difference in conception, that to the pastoralists property is cattle, land is common property open to herds, while to crop farmers land is property, which is divided between households, complicates the conflict resolution. State bias exists in the protection of property rights. Mechanisms for the state bias arebriefly cited. This paper suggests a farming systems educational approach as a way to reduce environmentally stressful practice, and strengthen the study of administrative regulation that harmonizes equity in conflicting land use.展开更多
The present study, conducted during 2016 and 2017 seasons, aimed to investigate the effect of IBA on rooting of Piper betle L. stem cuttings (softwood and semi-hardwood). The experiment was undertaken in misting house...The present study, conducted during 2016 and 2017 seasons, aimed to investigate the effect of IBA on rooting of Piper betle L. stem cuttings (softwood and semi-hardwood). The experiment was undertaken in misting house field 2 UPM using the sand media to determine the adventitious roots initiation and development using the histological method. The cuttings were treated with different IBA concentrations (0, 500, 1000, 1500 and 2000 mg/L). The nodes explants were used in the development of a protocol for in vitro propagation of P. betle L., with different concentrations of Clorox with different times of immersion (20% Clorox 10 minutes, 30% Clorox 10 minutes, 20% Clorox 20 minutes, and 30% 20 minutes). In multiplication of the plantlets, Murashige and Skoog (MS) medium with different concentrations of BAP (0, 0.5, 1.0, 2.0 mg/L) were used to investigate the rooting of the explants. The results indicated that the types of the cuttings were different in the rooting capacity and the length of the roots. Moreover, it was found that in comparison with the control treatment, by a rise in the concentrations of the IBA, there was a significant upsurge in the rooting percentage, the root diameter, and the number of the roots. The results indicated that the types of cutting with 1000, 1500 and 2000 mg/L IBA perform better in the root percentage (100%) in the semi hardwood cuttings. The best results, however, were 2000 mg/L IBA in the semi hardwood cuttings, with the number of the roots to be 35.05, and the fresh weight of the roots to be 3.94 g, the dry weight of the roots to be 0.33 g, the length of the roots to be 391.88 cm, the roots diameter to be 1.21 mm, the surface area of the roots to be 121.83 cm2, and the root volume to be 2.99 cm3. Nonetheless, the optimal concentration of Clorox with the time immersion was 20% with the 20-minute immersion time, which produced a shoot induction percentage of 30% dead explants and a mean number of 70.00 shoots per explant and the optimal concentration of benzylaminopurine (BAP) at 1.0 mg/L. It is of note that a shoot induction percentage of 22.29% and a mean number of 4.1% number of auxiliary bud per treatment. P. betle shoots in MS medium without PGR MS (0.0) yielded a good rooting.展开更多
High tunnels have been used in the United States for more than 50 years, and growers are encouraged to use them more frequently through government cost-share programs. Research on fruits and vegetable production syste...High tunnels have been used in the United States for more than 50 years, and growers are encouraged to use them more frequently through government cost-share programs. Research on fruits and vegetable production systems has focused on high value crops such as tomato, salad greens, and several fruit crops. Maintaining soil quality and controlling insects and diseases are all issues that growers face. This review looks at current research on these issues as well as economic considerations addressed in the scientific literature. Global statistics and reports are also reviewed that complement the North American studies. Gaps in our understanding are identified, and directions for future research are suggested.展开更多
Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considere...Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considered a replacement for the current Indian production system.It is also suitable for mechanical harvesting,which reducing labour costs,increasing input use efficiency,timely harvesting timely,maintaining cotton quality,and offering the potential to increase productivity and profitability.This technology has become widespread in globally cotton growing regions.Water management is critical for the success of high density cotton planting.Due to the problem of freshwater availability,more crops should be produced per drop of water.In the high-density planting system,optimum water application is essential to control excessive vegetative growth and improve the translocation of photoassimilates to reproductive organs.Deficit irrigation is a tool to save water without compromising yield.At the same time,it consumes less water than the normal evapotranspiration of crops.This review comprehensively documents the importance of growing cotton under a high-density planting system with deficit irrigation.Based on the current research and combined with cotton production reality,this review discusses the application and future development of deficit irrigation,which may provide theoretical guidance for the sustainable advancement of cotton planting systems.展开更多
Fields experiments were conducted at the Department of Crop Protection, Faculty of Agriculture, University of Maiduguri Teaching and Research Farm, Maiduguri during 2010 and 2011 cropping seasons to investigate the ef...Fields experiments were conducted at the Department of Crop Protection, Faculty of Agriculture, University of Maiduguri Teaching and Research Farm, Maiduguri during 2010 and 2011 cropping seasons to investigate the effects of intercropping pattern on stem borer pest infestation in pearl millet (Pennisetum glaucum L.) intercropped with ground nut (Arachis hypogea L.). A split-plot design was used to test the intercrop pattern of 1:0 ratio (sole millet), 1:1 ratio (1 millet row to 1 ground nut row), 2:1 ratio (2 millet rows to 1 ground nut row) and 1:2 ratio (1 millet row to 2 ground nut rows). The results obtained showed that the intercrop pattern of 1:2 ratio and 1:1 ratio yielded less stem borer infestation and abundance in pearl millet, and as well supported high panicle weight and grain yield. In addition to recommending either of these two intercropping patterns to pearl millet farmers for more effective stem borer pest management, results further show the need for identification of effective intercropping patterns in other cropping systems.展开更多
Climate change has been a global pandemic with its adverse impacts affecting environments and livelihoods. This has been largely attributed to anthropogenic activities which generate large amounts of Green House Gases...Climate change has been a global pandemic with its adverse impacts affecting environments and livelihoods. This has been largely attributed to anthropogenic activities which generate large amounts of Green House Gases (GHGs), notably carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) among others. In the Upper East of Ghana, climate change manifests in erratic rainfalls, drought, high temperatures, high wind speeds, high intensity rainfall, windstorms, flooding, declining vegetation cover, perennial devastating bushfires etc. Practices such as burning farm residues, use of dung as fuel for cooking, excessive application of nitrogenous fertilizers, and deforestation that are prevalent in the region exacerbate the situation. Although, efforts made by governmental and none-governmental organizations to mitigate climate change through afforestation, agroforestry and promotion of less fuelwood consuming cook stoves, land management practices antagonize these efforts as more CO2 is generated than the carrying capacity of vegetation in the region. Research findings have established the role of trees and soil in carbon sequestration in mitigating climate. However, there is limited knowledge on how the vegetation and soil in agroforestry interplay in mitigation climate change. It is against this background that this review seeks to investigate how vegetation and soil in an agroforestry interact synergistically to sequester carbon and contribute to mitigating climate change in Upper East region of Ghana. In this review, it was discovered soil stored more carbon than vegetation in an agroforestry system and is much effective in mitigating climate change. It was found out that in order to make soil and vegetation in an agroforestry system interact synergistically to effectively mitigate climate change, Climate Smart Agriculture practice which integrates trees, and perennials crops effectively mitigates climate. The review concluded that tillage practices that ensure retention and storage of soil organic carbon (SOC) could be much effective in carbon sequestration in the Savannah zones and could be augmented with vegetation to synergistically mitigate climate change in the Upper East region of Ghana.展开更多
The root appears to be the most relevant organ for breeding drought stress tolerance.However, our knowledge about temporal and spatial regulation of drought-associated genes in the root remains fragmented, especially ...The root appears to be the most relevant organ for breeding drought stress tolerance.However, our knowledge about temporal and spatial regulation of drought-associated genes in the root remains fragmented, especially in crop plants. We performed a meta-analysis of expression divergence of essential drought-inducible genes and analyzed their association with cis-elements in model crops and major cereal crops. Our analysis of42 selected drought-inducible genes revealed that these are expressed primarily in roots,followed by shoot, leaf, and inflorescence tissues, especially in wheat. Quantitative real-time RT-PCR analysis confirmed higher expression of TaDREB2 and TaAQP7 in roots,correlated with extensive rooting and drought-stress tolerance in wheat. A promoter scan up to 2 kb upstream of the translation start site using phylogenetic footprinting revealed708 transcription factor binding sites, including drought response elements(DREs), auxin response elements(Aux REs), MYCREs/MYBREs, ABAREs, and ERD1 in 19 selected genes.Interestingly, these elements were organized into clusters of overlapping transcription factor binding sites known as homotypic clusters(HCTs), which modulate drought physiology in plants. Taken together, these results revealed the expression preeminence of major drought-inducible genes in the root, suggesting its crucial role in drought adaptation. The occurrence of HCTs in drought-inducible genes highlights the putative evolutionary modifications of crop plants in developing drought adaptation. We propose that these DNA motifs can be used as molecular markers for breeding drought-resilient cultivars, particularly in the cereal crops.展开更多
文摘Cover crops can have beneficial effects on soil microbiology by increasing carbon （C） supply, but these beneficial effects can be modulated by precipitation conditions. The objective of this study was to compare a fallow-winter wheat （Triticum aestivum L.） rotation to several cover crop-winter wheat rotations under rainfed and irrigated conditions in the semiarid US High Plains. Experiments were carried out at two sites, Sidney in Nebraska, and Akron in Colorado, USA, with three times of soil sampling in 2012--2013 at cover crop termination, wheat planting, and wheat maturity. The experiments included four single-species cover crops, a 10-species mixture, and a fallow treatment. The variables measured were soil C and nitrogen （N）, soil community structure by fatty acid methyl ester （FAME） profiles, and soil β-glucosidase,β-glucosaminidase, and phosphodiesterase activities. The fallow treatment, devoid of living plants, reduced the concentrations of most FAMEs at cover crop termination. The total FAME concentration was correlated with cover crop biomass （R = 0.62 at Sidney and 0.44 at Akron）. By the time of wheat planting, there was a beneficial effect of irrigation, which caused an increase in myeorrhizal and protozoan markers. At wheat maturity, the cover crop and irrigation effects on soil FAMEs had subsided, but irrigation had a positive effect on the β-glucosidase and phosphodiesterase activities at Akron, which was the drier of the two sites. Cover crops and irrigation were slow to impact soil C concentration. Our results show that cover crops had a short-lived effect on soil microbial communities in semiarid wheat-based rotations and irrigation could enhance soil enzyme activity. In the semiarid environment, longer time spans may have been needed to see beneficial effects of cover crops on soil microbial community structure, soil enzyme activities, and soil C sequestration.
文摘Rice-wheat cropping system (RWCS) is one of the most important cropping systems in South Asia. However, sustainability of this system is under threat owing to several factors, of which deficiency of micronutrients particularly zinc (Zn), boron (B) and manganese (Mn) is one of the major problems. Continuous rotation of rice and wheat, imbalanced fertilizer use and little/no use of micronutrient-enriched fertilizers induce deficiencies of Zn, B and Mn in the RWCS of South Asia. Here we review that (i) imbalanced fertilizer use and organic matter depletion deteriorate soil structure resulting in low efficiency of applied macro- and micro-nutrients in RWCS.(ii) The micronutrients (Zn, B and Mn) are essentially involved in metabolism of rice and wheat plants, including chlorophyll synthesis, photosynthesis, enzyme activation and membrane integrity.(iii) Availability and uptake of Zn, B and Mn from rhizosphere depend on the physico-chemical soil properties (which differ under aerobic and anaerobic conditions) including soil pH, soil organic matter, soil moisture and interaction of these micronutrients with other nutrients.(iv) Plant ability to uptake and utilize the nutrients is affected by several plant factors such as root architecture, root hairs, transport kinetics parameter and root exudates.(v) Crop management and application of these microelements can help correct the micronutrients deficiency and enhance their grain concentration.
文摘Bemisia tabaci is a polyphagous herbivore that feeds on a wide range of horticultural and ornamental crops cultivated under diverse ecological zones. In Sierra Leone, B. tabaci is found to infest a wide range of vegetable crops by directly feeding on phloem sap thereby inducing physiological disorders, and also serve as a vector to gemini viruses. Invariably the destructive feeding of B. tabaci affects the productivity and aesthetic values of vegetables and other horticultural crops and hence is considered a serious economic pest. A bioassay experiment was carried out by rearing B. tabaci populations on four vegetable crops under controlled laboratory conditions to determine its life table and demographic parameters. Results showed that the intrinsic rate of growth which measures the population size and growth pattern was highest for populations reared on tomato crops with the following values: rm 0.145 female female−1 day−1, the gross reproduction rate (Ro), and finite growth rate λ were highest for population reared on tomato, correspondingly the development period from egg-adult emergence was shortest with a value of 26 d. Conversely, the computed demographical parameters rm, λ and Ro for the population reared on sweet pepper were 0.106 female female−1 day−1 respectively, with a corresponding development period egg-adult emergence as 36d. The computed biological parameters for okra and garden egg varied with intermediary values between tomato and pepper host materials. The survivorship rates were quite significant for the smaller instars (Instars 1-III) with over 80% surviving to pre-pupa and pupa stage for the populations reared for all the test materials. High mortality was noticed for the pre-pupa and pupa stages as their survival rates were significantly low compared to the high survival rates of the smaller instars. Less than 50% of pupae failed to emerge to adults except for populations reared on tomato test materials where 52% emerged to adults. The study indicated tomato as the most suitable host among the four vegetable crops. Although life table and demographic parameters are invaluable information for forecasting pest populations and help in designing pest management efforts, further investigations such as the economic threshold and economic injury levels of B. tabaci population are requisite decision tools for sound pest management decisions of B. tabaci on these vegetable crops. The information obtained from this investigation would be quite relevant for extension service and pest management practitioners where mixed vegetable farming is a common practice.
文摘Field experiments were conducted at the experimental farm Cocoa Re-search Institute of Nigeria (CRIN) Sub-Station, Ochaja, in the Southern Guinea Savannaagro ecological zone of Nigeria to examine uptake and use efficien-cies of nutrients by Sesame and Bambara nut alley crops as influenced by manuring in a Cashew-based intercropping system. Experimental treatments were based on responses of sole and intercrop mixtures of Sesame and Bam-bara nut alley crops to Cocoa Pod Husk (CPH), pelletized organic fertilizer and NPK fertilizer in a cashew-based intercropping system. Data were collected on the growth and yield variables of the alley crops. Highest nitrogen harvest in-dex (NHI) for seed and leaf of alley crops were obtained from un-manure treated plants. Cocoa pod husk (CPH) significantly enhanced P uptake com-pared with other fertilizers applied. CPH improved Na, Ca, Mg Zn, Cu, P, K and carbohydrate in the leaves and Ca, Mg, Zn, Fe, Cu, crude fibre and car-bohydrate contents of seeds of sole crops while Sesame + Bambara had en-hanced contents of N, Ca, Mg, Zn, Cu, P, N, K, moisture, protein, and crude fi-bre, crude protein, moisture content in leaves. The effects of NPK were signifi-cant for N, K Ca, Zn, Fe, Cu, P, moisture and crude fibre, while in the un-manure (control) plots influenced N, fat and protein and nitrogen harvest index (NHI) of leaf and seeds. CPH and NPK fertilizers enhanced nutrient up-take and nitrogen harvest index of alley crops. Nutrient uptake was similar for the varieties of Sesame and Bambara nut as affected by the application of 4.84 and 9.68 Kg pelletized organic fertilizer. Sole Bambara had higher N and K concentration in leaves compared with Bambara +Sesame. In addition, sole Bambara had higher values of Physiology efficiency (PE), and fertilizer use ef-ficiency (FAE) compared to the mixed crops of Bambara + sesame. However, physiology efficiency (PE), and fertilizer use efficiency (FAE) were significantly lower for Bambara + Sesame. The un-manure plants had enhanced N, P and K uptake. Varietal effects were pronounced for most of the resource use effi-ciency variables measured. The alley crop varieties responded differently to 4.84 and 9.68 kg pelletized fertilizer treatments (Agronomy Efficiency (AE), N-removed at harvest and Internal Utilization Efficiency (IE) and partial fac-tor productivity (PFP)). Sesame variety NCRIBen04E had enhanced AE, N-remove at harvest, IE and PFP while variety E8 had significantly higher ap-parent Recovery Efficiency (RE), apparent Recovery Efficiency by difference (RE%), Physiology Efficiency (PE), Utilization Efficiency (UE), and internal Utilization Efficient (IE). Bambara variety TVSu999 had higher IUE, Agron-omy Efficiency (AE), Apparent Recovery Efficiency (RE), Physiology Effi-ciency (PE) and Fertilizer Agronomy using Efficiency respectively (FAE) com-pared to variety TVSu1166. The fertilizers affected most of the indicators of nutrient use efficiency (NUE) measured. The effects were significant on AE, agronomic N-use efficiency (ANUE), RE, UE and PFP. NPK fertilizer enhanced Physiology efficiency (PE) and Partial factor production. NPK fertilizer signifi-cantly enhanced NUE parameters compared to CPH and un-manure. CPH manure significantly influenced RE%, PE and IE. The Internal Utilization Effi-ciency and N-remove at harvest were compared with the un-manure plants (control). The effects of 9.68 kg/plot pelletized fertilizer, were pronounced on Agronomy Efficiency (AE), Apparent Recovery Efficiency by difference (RE%), Physiology Efficiency (PE), Utilization Efficiency (UE), N-removed at harvest and Internal Utilization Efficiency (IE). Similar trends were observed in the responses NUE of Sesame and Bambara manuring. The responses sole crops in terms of RE, PE UE PFP were similar while their intercrop combina-tions had significantly higher AE, RE, UE, PFP and N removed at harvest. Sole Sesame significantly influence Agronomy Efficiency (AE), Utilization Effi-ciency (UE), Internal Efficiency (IE) and Partial Fertilizer Production (PFP) and sole Bambara under NPK fertilizer had enhanced N-removed at harvest and apparent recovery by difference (RE%). Bambara + Sesame under cocoa pod husk (CPH) manure had enhanced apparent recovery efficiency by difference (RE%), fertilizer use efficiency (FAE) and internal utilization efficiency (IE). Sesame variety NCRIBen04E had enhanced Agronomy Efficiency (AE), N-removed at harvest and Internal Utilization Efficiency (IE) under 9.68 kg treatment while variety E8 had higher partial factor productivity (PFP) at 4.84 kg/plot pelletized organic fertilizer.
文摘Soil water retention is a critical aspect of agricultural management, especially in areas such as the Lower Mississippi River Alluvial Valley that face potential water shortages in the near future. Previous studies have linked changes in soil water retention characteristics to agricultural management practices, especially as they affect the accumulation of soil organic matter (SOM). Therefore, the objective of this study was to determine the relationship between soil water potential and gravimetric soil water content in the top 7.5 cm as affected by nitrogen (N) fertilization/residue level (high and low), residue burning (burning and non-burning), tillage (conventional and no-tillage), and irrigation (irrigated and non-irrigated) after 12 complete cropping cycles in a wheat (Triticum aestivum L.)-soybean [Glycine max (L.) Merr.], double-crop production system in the Delta region of eastern Arkansas using soil wetting curves. The soil investigated was a Calloway silt loam (fine silty, mixed, active, thermic Glossaquic Fraglossudalf). The slope characterizing the relationship between the natural logarithm of the soil water potential and the gravimetric soil water content was only affected (P < 0.05) by the N-fertilization/residue-level treatment, while the intercept was unaffected by any field treatment. Averaged across tillage, burning, and irrigation, soil water contents under the high-exceeded those under low-N-fertilization/residue-level treatment at the same water potential, with the greatest differences observed at water contents > 0.12 g·g-1. Understanding the ways in which alternative residue management practices affect soil water retention characteristics is an important component of conserving irrigation water resources.
文摘Wheat is one of the most important cereals in the world, serving as a staple for millions globally. In the wake of the geopolitical crisis between Russia and Ukraine, it has become incumbent for many countries to invest in wheat production. Improving cropping systems for wheat production is paramount. Intercropping cereals with legumes has tremendous advantages. Therefore, this study was designed to optimize wheat production by intercropping it with soybean at different densities. Between March and August 2023, a randomized complete block design trial was conducted in Bambili, North West of Cameroon with treatments T1 (wheat monocrop at 200,000 plants ha<sup>−</sup><sup>1</sup>), T2 (soybean monocrop at 250,000 plants ha<sup>−</sup><sup>1</sup>), T3 (200,000 wheat and 125,000 soybean ha<sup>−</sup><sup>1</sup>), T4 (100,000 wheat and 250,000 soybean ha<sup>−</sup><sup>1</sup>), T5 (200,000 wheat and 250,000 soybean ha<sup>−</sup><sup>1</sup>) and T6 (100,000 wheat and 125,000 soybean ha<sup>−</sup><sup>1</sup>). Results revealed that growth parameters of wheat were not significantly influenced by monocrop or intercrop. The yield of wheat was significantly higher in the monocrop than the intercrop treatments, with slight variation amongst the intercrop treatments. Soybean yield was higher in the monocrop than in the intercrop, with no variations amongst the intercrop treatments. Only the land equivalence ratio (LER) for T5 was greater than 1.0. The competitive ratio for T5 was 0.54 for wheat and 1.90 for soybean, comparatively lower than the other monocrop treatments. Intercropping wheat and soybean at 200,000:250,000 ratio is recommended.
基金Project supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(No.kzc x2-yw-406)the National Basic Research Program of China(No.2005CB121103).
文摘The North China Plain,where summer corn(Zea mays L.)and winter wheat(Triticum aestivum L.)are the major crops grown,is a major agricultural area in China.Permeable soils make the region susceptible to groundwater pollution by NO_3-N,which is applied to fields in large amounts of more than 400 kg NO_3-N ha^(-1)as fertilizer.A field experiment was established in 2002 to examine the relationship among N fertilization rate,soil NO_3-N,and NO_3-N groundwater contamination.Two adjacent fields were fertilized with local farmers' N fertilization rate(LN)and double the normal application rate(HN),respectively,and managed under otherwise identical conditions.The fields were under a traditional summer corn/winter wheat rotation.Over a 22-month period,we monitored NO_3-N concentrations in both bulk soil and soil pore water in 20-40 cm increments up to 180 cm depth.We also monitored NO_3-N concentrations in groundwater and the depth of the groundwater table.No significant differences in soil NO_3-N were observed between the LN and HN treatment.We identified NO_3-N plumes moving downward through the soil profile.The HN treatment resulted in significantly higher groundwater NO_3-N,relative to the LN treatment,with groundwater NO_3-N consistently exceeding the maximum safe level of 10 mg L^(-1),but groundwater NO_3-N above the maximum safe level was also observed in the LN treatment after heavy rain.Heavy rain in June,July,and August 2003 caused increased NO_3-N leaching through the soil and elevated NO_3-N concentrations in the groundwater.Concurrent rise of the groundwater table into NO_3-N- rich soil layers also contributed to the increased NO_3-N concentrations in the groundwater.Our results indicate that under conditions of average rainfall,soil NO_3-N was accumulated in the soil profile.The subsequent significantly higher- than-average rainfalls continuously flushed the soil NO_3-N into deeper layers and raised the groundwater table,which caused continuous groundwater contamination with NO_3-N.The results suggest that under common farming practices in the North China Plain,groundwater contamination with NO_3-N was likely,especially during heavy rainfalls,and the degree of groundwater contamination appeared to be proportional to the N application rates.Decreasing fertilization rates, splitting fertilizer inputs,and optimizing irrigation scheduling had potential to reduce groundwater NO_3-N contamination.
文摘Reduced early crop growth and limited branching are amongst yield limiting factors of linola. Field response of seed priming treatments viz. 50 mmol L^-1 salicylic acid （SA）, 2.2% CaCl2 and 3.3% moringa leaf extract （MLE） including untreated dry and hydropriming controls was evaluated on early crop growth and yield performance of linola. Osmopriming with CaCl2 reduced emergence time and produced the highest seedling fresh and dry weights including Chl. a contents. Osmopriming with CaCl2 reduced crop branching and flowering and maturity times and had the maximum plant height, number of branches, tillers, pods and seeds per pod followed by MLE. Increase in seed weight, biological and seed yields was 9.30, 34.16 and 39.49%, harvest index （4.12%） and oil contents （13.39%） for CaCl2 osmopriming. Positive relationship between emergence and seedling vigor traits, 100-seed weight, seed yield with maturity time, 100-seed weight and seed yield were found. The study concludes that seed osmopriming with CaC12 or MLE can play significant role to improve early crop growth and seed yields of linola.
文摘A 12-year cover crops study on the effects on SOC sequestration, storage, retention and loss and corn and soybean yields was conducted in southern Illinois. The use of cover crops for the maintenance and restoration of soil organic carbon (SOC) and soil productivity of previously eroded soils were evaluated. No-till (NT), chisel plow (CP), and moldboard plow (MP) treatment plots with and without cover crops were established in 2001. The plot area was on sloping with a moderately well drained, eroded soil. The average annual corn and soybean yields were statistically the same for NT, CP, and MP systems with and without cover crops. By 2012, the cover crop treatments had more SOC stock than that without cover crops for the same soil layer and tillage treatment. The NT, CP, and MP treatments all sequestered SOC with cover crops. A pre-treatment SOC stock baseline for rooting zone was used to validate the finding that cover crops sequestered SOC in the topsoil, subsoil and root zone of the NT, CP and MP treatments during the 12-year study. Additional sequestered SOC was lost as a result of being transported off of the plots and retained in lower slopes, transported to the stream or released to atmosphere.
基金funding from the National Research Foundation Grant,South Africa(98352)for Phytochemical Food Network to Improve Nutritional Quality for Consumers
文摘Utilization of nitrogen(N)element is a common practice used to reach profitable yields in horticultural crops and N supply can be used as a tool to manipulate the enhancement of phytochemicals and minerals in vegetable crops to address consumer-oriented quality production.Hence the study was aimed to investigate the effect of N application on leaf morphology,ascorbic acid content,phenolic acids,flavonoids,mineral content,and nitrate residues in three lettuce varieties(two green leafy lettuce,Multigreen 1 and Multigreen 3;one red leafy lettuce,Multired 4)grown in a closed hydroponic system(grave^-film)at harvest.Nitrogen was applied as ammonium nitrate(NH4NO3)at six different concentrations of 0,60,90,120,150 and 180 mg L^-1.The results obtained during 2015 and 2016 seasons were similar and demonstrated variety dependent responses with respect to different N application rates.Multigreen 3 was more sensitive to N supply and showed higher amount of nitrate residue at harvest.Variety Multired 4 was less sensitive to N supply followed by Multigreen 11 Although N supply at 120 mg L^-1 improved the yield and the number of leaves in Multigreen 3,overall 90 mg L^-1 can be recommended for these lettuce varieties to improve the yield and the accumulation of ascorbic acid content,phenolic acids mainly caffeic,caftaric acids,quercetin(the important flavonoid in lettuce),and Fe and Mn contents.Furthermore,the concentration of 90 mg L^-1 improved the antioxidant property(FRAP and ABTS^+)and reduced the nitrate accumulation,ensuring safe food for consumers.
基金supported by the Secretariat for Universities and of the Ministry of BusinessKnowledge of the Government of Catalonia and the European Social Fund+2 种基金partially supported by the Spanish Ministry of ScienceInnovation and Universities(Grant No.RTI2018–099315-A-I00)J.A.B.benefitted from a Serra-Húnter Fellowship provided by the Government of Catalonia。
文摘Background:The prediction of biogeographical patterns from a large number of driving factors with complex interactions,correlations and non-linear dependences require advanced analytical methods and modeling tools.This study compares different statistical and machine learning-based models for predicting fungal productivity biogeographical patterns as a case study for the thorough assessment of the performance of alternative modeling approaches to provide accurate and ecologically-consistent predictions.Methods:We evaluated and compared the performance of two statistical modeling techniques,namely,generalized linear mixed models and geographically weighted regression,and four techniques based on different machine learning algorithms,namely,random forest,extreme gradient boosting,support vector machine and artificial neural network to predict fungal productivity.Model evaluation was conducted using a systematic methodology combining random,spatial and environmental blocking together with the assessment of the ecological consistency of spatially-explicit model predictions according to scientific knowledge.Results:Fungal productivity predictions were sensitive to the modeling approach and the number of predictors used.Moreover,the importance assigned to different predictors varied between machine learning modeling approaches.Decision tree-based models increased prediction accuracy by more than 10%compared to other machine learning approaches,and by more than 20%compared to statistical models,and resulted in higher ecological consistence of the predicted biogeographical patterns of fungal productivity.Conclusions:Decision tree-based models were the best approach for prediction both in sampling-like environments as well as in extrapolation beyond the spatial and climatic range of the modeling data.In this study,we show that proper variable selection is crucial to create robust models for extrapolation in biophysically differentiated areas.This allows for reducing the dimensions of the ecosystem space described by the predictors of the models,resulting in higher similarity between the modeling data and the environmental conditions over the whole study area.When dealing with spatial-temporal data in the analysis of biogeographical patterns,environmental blocking is postulated as a highly informative technique to be used in cross-validation to assess the prediction error over larger scales.
基金by the Natural Science Foundation of China (Grant No. 40801101)
文摘Subsurface flow is a prominent runoff process in sloping lands of purple soil in the upper Yangtze River basin.However,it remains difficult to identify and quantify.In this study,in situ runoff experimental plots were used to measure soil moisture dynamics using an array of time domain reflectometry(TDR) together with overland flow and subsurface flow using isolated collecting troughs.Frequency of preferential flow during rainfall events and the controls of subsurface flow processes were investigated through combined analysis of soil properties,topography,rainfall intensity,initial wetness,and tillage.Results showed that subsurface flow was ubiquitous in purple soil profiles due to welldeveloped macropores,especially in surface soils while frequency of preferential flow occurrence was very low(only 2 cases in plot C) during all 22 rainfall events.Dry antecedent moisture conditions promoted the occurrence of preferential flow.However,consecutive real-time monitoring of soil moisture at different depths and various slope positions implied the possible occurrence of multiple subsurface lateral flows during intensive storms.Rainfall intensity,tillage operation,and soil properties were recognized as main controls of subsurface flow in the study area,which allows the optimization of management practices for alleviating adverse environmental effects of subsurface flow in the region.
基金financially supported by Bahir Dar University Research and Community Service
文摘Farmers in the highlands of Ethiopia often plant Eucalyptus on their farmlands. However, growing Eucalyptus, especially on farm- lands suitable for crop production has become a great concern due to its alleged long-term site effects. Our study was conducted at Koga water- shed, Mecha District, northwestern Ethiopia to investigate whether crop- lands afforested with Eucalyptus camaldulensis Dehnh. can be restored for annual crop production after tree harvest. We compared growth and yield of two agricultural crops, barley （Hordeum vulgate L.） and finger millet （Eleusine coracana （L.） Gaertn.）, grown in clear-felled stands of E. camaldulensis and continuously cultivated croplands at twelve paired farmlands under a conventional farming system. Plant height and dry matter production were evaluated as indices of crop growth, while grain weight was evaluated as an index of crop yield. Crop growth and yield measurements averaged over all farmlands differed between land-use types. For both crops, plants grown on clear-felled stands were taller than on croplands. Dry matter production and yield were also significantly greater in crops cultivated on clear-felled stands. Cropland aboveground and belowground dry matter productions were lower by 31.8 and 25.4% for barley and 32.8% and 37% for finger millet, respectively. Clear-felled stands gave an average yield of 2.91 t.ha-1 for barley and 3.27 t.ha-1 for finger millet while cropland gave a yield of 1.97 and 2.31 t.ha-1 for barley and finger millet, respectively. Farmers also responded that farm plots on former eucalypt plantations showed greater crop growth and yield thandid continuously cultivated croplands. Farmers perceived that Eucalyptus plantations improved soil fertility and they preferred clear-felled stands for crop production and wished to plant Eucalyptus on their farmlands. Our results suggest that conversion of agricultural lands to Eucalyptus plantations can increase post-felling yields of cereal crops.
文摘Agriculture is an important source of economic survival of rural populations, and with great power for poverty reduction in the economy. For this reason farming systems that are most efficient have to be sought. This paper explores crop-based and pastoralism farming systems under conflicting land use relations. Incidences of violent conflicts are highlighted, which usually assume a depoliticised expression as inter-group conflicts. Competition for resources (land and water) is an important reason for such conflict, but the role of the state in protection of property rights is also advocated to nurture rivalry. Very wide difference in conception, that to the pastoralists property is cattle, land is common property open to herds, while to crop farmers land is property, which is divided between households, complicates the conflict resolution. State bias exists in the protection of property rights. Mechanisms for the state bias arebriefly cited. This paper suggests a farming systems educational approach as a way to reduce environmentally stressful practice, and strengthen the study of administrative regulation that harmonizes equity in conflicting land use.
文摘The present study, conducted during 2016 and 2017 seasons, aimed to investigate the effect of IBA on rooting of Piper betle L. stem cuttings (softwood and semi-hardwood). The experiment was undertaken in misting house field 2 UPM using the sand media to determine the adventitious roots initiation and development using the histological method. The cuttings were treated with different IBA concentrations (0, 500, 1000, 1500 and 2000 mg/L). The nodes explants were used in the development of a protocol for in vitro propagation of P. betle L., with different concentrations of Clorox with different times of immersion (20% Clorox 10 minutes, 30% Clorox 10 minutes, 20% Clorox 20 minutes, and 30% 20 minutes). In multiplication of the plantlets, Murashige and Skoog (MS) medium with different concentrations of BAP (0, 0.5, 1.0, 2.0 mg/L) were used to investigate the rooting of the explants. The results indicated that the types of the cuttings were different in the rooting capacity and the length of the roots. Moreover, it was found that in comparison with the control treatment, by a rise in the concentrations of the IBA, there was a significant upsurge in the rooting percentage, the root diameter, and the number of the roots. The results indicated that the types of cutting with 1000, 1500 and 2000 mg/L IBA perform better in the root percentage (100%) in the semi hardwood cuttings. The best results, however, were 2000 mg/L IBA in the semi hardwood cuttings, with the number of the roots to be 35.05, and the fresh weight of the roots to be 3.94 g, the dry weight of the roots to be 0.33 g, the length of the roots to be 391.88 cm, the roots diameter to be 1.21 mm, the surface area of the roots to be 121.83 cm2, and the root volume to be 2.99 cm3. Nonetheless, the optimal concentration of Clorox with the time immersion was 20% with the 20-minute immersion time, which produced a shoot induction percentage of 30% dead explants and a mean number of 70.00 shoots per explant and the optimal concentration of benzylaminopurine (BAP) at 1.0 mg/L. It is of note that a shoot induction percentage of 22.29% and a mean number of 4.1% number of auxiliary bud per treatment. P. betle shoots in MS medium without PGR MS (0.0) yielded a good rooting.
文摘High tunnels have been used in the United States for more than 50 years, and growers are encouraged to use them more frequently through government cost-share programs. Research on fruits and vegetable production systems has focused on high value crops such as tomato, salad greens, and several fruit crops. Maintaining soil quality and controlling insects and diseases are all issues that growers face. This review looks at current research on these issues as well as economic considerations addressed in the scientific literature. Global statistics and reports are also reviewed that complement the North American studies. Gaps in our understanding are identified, and directions for future research are suggested.
文摘Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considered a replacement for the current Indian production system.It is also suitable for mechanical harvesting,which reducing labour costs,increasing input use efficiency,timely harvesting timely,maintaining cotton quality,and offering the potential to increase productivity and profitability.This technology has become widespread in globally cotton growing regions.Water management is critical for the success of high density cotton planting.Due to the problem of freshwater availability,more crops should be produced per drop of water.In the high-density planting system,optimum water application is essential to control excessive vegetative growth and improve the translocation of photoassimilates to reproductive organs.Deficit irrigation is a tool to save water without compromising yield.At the same time,it consumes less water than the normal evapotranspiration of crops.This review comprehensively documents the importance of growing cotton under a high-density planting system with deficit irrigation.Based on the current research and combined with cotton production reality,this review discusses the application and future development of deficit irrigation,which may provide theoretical guidance for the sustainable advancement of cotton planting systems.
文摘Fields experiments were conducted at the Department of Crop Protection, Faculty of Agriculture, University of Maiduguri Teaching and Research Farm, Maiduguri during 2010 and 2011 cropping seasons to investigate the effects of intercropping pattern on stem borer pest infestation in pearl millet (Pennisetum glaucum L.) intercropped with ground nut (Arachis hypogea L.). A split-plot design was used to test the intercrop pattern of 1:0 ratio (sole millet), 1:1 ratio (1 millet row to 1 ground nut row), 2:1 ratio (2 millet rows to 1 ground nut row) and 1:2 ratio (1 millet row to 2 ground nut rows). The results obtained showed that the intercrop pattern of 1:2 ratio and 1:1 ratio yielded less stem borer infestation and abundance in pearl millet, and as well supported high panicle weight and grain yield. In addition to recommending either of these two intercropping patterns to pearl millet farmers for more effective stem borer pest management, results further show the need for identification of effective intercropping patterns in other cropping systems.
文摘Climate change has been a global pandemic with its adverse impacts affecting environments and livelihoods. This has been largely attributed to anthropogenic activities which generate large amounts of Green House Gases (GHGs), notably carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) among others. In the Upper East of Ghana, climate change manifests in erratic rainfalls, drought, high temperatures, high wind speeds, high intensity rainfall, windstorms, flooding, declining vegetation cover, perennial devastating bushfires etc. Practices such as burning farm residues, use of dung as fuel for cooking, excessive application of nitrogenous fertilizers, and deforestation that are prevalent in the region exacerbate the situation. Although, efforts made by governmental and none-governmental organizations to mitigate climate change through afforestation, agroforestry and promotion of less fuelwood consuming cook stoves, land management practices antagonize these efforts as more CO2 is generated than the carrying capacity of vegetation in the region. Research findings have established the role of trees and soil in carbon sequestration in mitigating climate. However, there is limited knowledge on how the vegetation and soil in agroforestry interplay in mitigation climate change. It is against this background that this review seeks to investigate how vegetation and soil in an agroforestry interact synergistically to sequester carbon and contribute to mitigating climate change in Upper East region of Ghana. In this review, it was discovered soil stored more carbon than vegetation in an agroforestry system and is much effective in mitigating climate change. It was found out that in order to make soil and vegetation in an agroforestry system interact synergistically to effectively mitigate climate change, Climate Smart Agriculture practice which integrates trees, and perennials crops effectively mitigates climate. The review concluded that tillage practices that ensure retention and storage of soil organic carbon (SOC) could be much effective in carbon sequestration in the Savannah zones and could be augmented with vegetation to synergistically mitigate climate change in the Upper East region of Ghana.
基金supported by German–Pakistani Research Cooperation(grant no.56453308)via German Academic Exchange Service(DAAD)to build German–Pakistani research and academic exchange and partnerships
文摘The root appears to be the most relevant organ for breeding drought stress tolerance.However, our knowledge about temporal and spatial regulation of drought-associated genes in the root remains fragmented, especially in crop plants. We performed a meta-analysis of expression divergence of essential drought-inducible genes and analyzed their association with cis-elements in model crops and major cereal crops. Our analysis of42 selected drought-inducible genes revealed that these are expressed primarily in roots,followed by shoot, leaf, and inflorescence tissues, especially in wheat. Quantitative real-time RT-PCR analysis confirmed higher expression of TaDREB2 and TaAQP7 in roots,correlated with extensive rooting and drought-stress tolerance in wheat. A promoter scan up to 2 kb upstream of the translation start site using phylogenetic footprinting revealed708 transcription factor binding sites, including drought response elements(DREs), auxin response elements(Aux REs), MYCREs/MYBREs, ABAREs, and ERD1 in 19 selected genes.Interestingly, these elements were organized into clusters of overlapping transcription factor binding sites known as homotypic clusters(HCTs), which modulate drought physiology in plants. Taken together, these results revealed the expression preeminence of major drought-inducible genes in the root, suggesting its crucial role in drought adaptation. The occurrence of HCTs in drought-inducible genes highlights the putative evolutionary modifications of crop plants in developing drought adaptation. We propose that these DNA motifs can be used as molecular markers for breeding drought-resilient cultivars, particularly in the cereal crops.
