Climate change is impacting climate sensitive rural livelihood systems. Exposure, sensitivity, and adaptive capacity of agricultural livelihoods to climate variability and change differ across agro-ecologies and these...Climate change is impacting climate sensitive rural livelihood systems. Exposure, sensitivity, and adaptive capacity of agricultural livelihoods to climate variability and change differ across agro-ecologies and these pose a challenge to climate resilient development strategy. This study assesses agro-ecology specific vulnerability of smallholder farmers to climate change and variability in the Dabus Watershed (North-west Ethiopia), based on a survey of 734 farm households complemented with focus group discussion and key informant interviews. Recognizing the physiographic and climatic diversity that exists across agro-ecologies in the study area, Livelihood Vulnerability Index (LVI) framed within the United Nations Intergovernmental Panel on Climate Change (IPCC) vulnerability framework (LVI-IPCC) is adapted to assess agro-ecology specific vulnerability in two local agro-ecologies, namely wet lowland and dry lowland. For each agro-ecology, exposure, sensitivity and adaptive capacity indices as well as LVI-IPCC vulnerability score was calculated. The result shows that the dry lowland agro-ecology has a relatively higher exposure and sensitivity to climate stresses with a comparatively limited adaptive capability. On the other hand, the wet lowland agro-ecology exhibits intermediate vulnerability with a relatively lower perceived exposure and higher adaptive capacity. Higher exposure relative to adaptive capacity resulted in a positive LVI-IPCC score in the dry lowland agro-ecology and positioned it in more vulnerable level than the wet lowland. A higher adaptive capacity relative to exposure unveils a negative LVI-IPCC score for the wet lowland agro-ecology and positioned it in a moderate vulnerability category. In line with the findings, there is a need to set agro-ecology specific priorities for intervention that is most needed to cop up with the effects of climate variability and change in each agro-ecology. Climate risk exposure levels can be reduced through timely provision of climate specific information and early warning systems aimed at enhancing preparedness of farm households to extreme events. It is also crucial to expand availability of infrastructural facilities such as market, health services, and veterinary services so as to enhance adaptive capacity. Supporting alternative livelihood options and enhancing water harvesting practices for supplementary irrigation also call policy attention.展开更多
In the recent past there has been concern to address the declining trends and deteriorating ecological elements and their functions in productive agricultural landscapes. The efforts to revive the ecological functions...In the recent past there has been concern to address the declining trends and deteriorating ecological elements and their functions in productive agricultural landscapes. The efforts to revive the ecological functions needs multiple scale approach, which include scientific understanding, time dependent restorative activities and incorporation of wisdom of the stakeholders. Conservation initiatives linked to precision farming is an apt mechanism to minimize the loss of natural resources of agricultural landscapes to maintain the complex stabilizers of ecological functions. Such an effort must address the scientific evaluation of the farm as “ecologically sustainable unit” with due consideration to social construct at local to regional level. Sustainability indices can be useful tools for evaluating the farms to isolate degradative factors and identify ecologically conservative practices. This review will analyze certain inter-linked concepts relevant to address the sustainability issues in agro-ecology at the interface of socio-ecological perspective.展开更多
Cultivation of pollinator-dependent crops has expanded globally, increasing our reliance on insect pollination. This essential ecosystem service is provided by a wide range of managed and wild pollinators whose abunda...Cultivation of pollinator-dependent crops has expanded globally, increasing our reliance on insect pollination. This essential ecosystem service is provided by a wide range of managed and wild pollinators whose abundance and diversity are thought to be in decline, threatening sustainable food production. In Cameroon, several studies on pollinator-dependent crops carried out in different agro-ecological zones (AEZ) have been published in national and international journals, in order to present the importance and impact of flowering insects on fruit and seed yields of plant species. We proposed to produce a review article highlighting the different flowering insects and their importance for different plants according to AEZ, without however focusing on the quality of the journal (predator or non-predator) and how the different insects were identified (scientific names given in the publications). Thus, from 1997 to 2020, we collected 116 published papers from which only 26 were kept for this review. The results show that Hymenoptera, including the Apidae, followed by Megachilidae, are the most excellent pollinators of plant species in Cameroon, and they are present in different agro-ecological zones. The majority of publications focused on bees, particularly the honeybee Apis mellifera.展开更多
In recent years, the world has faced rising global temperatures, accumulative pollution, and energy crises, stimulating scientists worldwide to strive for eco-friendly and cost-effective solutions. Biochar has materia...In recent years, the world has faced rising global temperatures, accumulative pollution, and energy crises, stimulating scientists worldwide to strive for eco-friendly and cost-effective solutions. Biochar has materialized as a favorable tool for environmental remediation, indicating efficacy as an efficient sorbent substance for both inorganic and organic pollutants in environmental field. These unique properties exclude improved surface functionality, porous morphology, large specific surface area (SSA), cation exchange capacity (CEC), robust adsorption capabilities, environmental stability, and embedded micronutrients. Biochar exhibited potential characteristics for environmental oversight, greenhouse gas (GHG) emission reduction, and soil fertility improvement. This review explores the impact of fundamental factors such as retention time, pyrolysis temperature, gas flow rate, and reactor design on biochar yield and properties. Collected data revealed the various applications of biochar, ranging from waste management and construction materials to the adsorptive removal of hydrocarbon lubricants from aqueous media, contaminant immobilization, and carbon sequestration. It has played mostly a significant share in climate change mitigation and an important role in soil amendments. Biochar improves soil improvement by increasing water retention (10%–30%), carbon sequestration, soil surface functionality, and providing high surface area with chemical stability. The assessment also reports the prospects and contests associated with biochar application uses in various agriculture cropping ecosystems. Inclusive, this review highlights the multifaceted characteristics of biochar as an adjustable on top of a sustainable solution addressing greenhouse gas emission, carbon sequestration, and environmental stresses. However, further research is needed to understand its long-term impacts and optimal applications fully.展开更多
In developing countries such as Ethiopia, research to develop and promote soil and water conservation practices rarely addressed regional diversity. Using a water-balance approach in this study, we used runoff plots f...In developing countries such as Ethiopia, research to develop and promote soil and water conservation practices rarely addressed regional diversity. Using a water-balance approach in this study, we used runoff plots from three sites, each representing a different agro-ecological environment, e.g., high, mid and low in both elevation and rainfall, in the Upper Blue Nile Basin of Ethiopia to examine the runoff response and runoff conservation efficiency of a range of different soil and water conservation measures and their impacts on soil moisture. The plots at each site represented common land use types（cultivated vs. non-agricultural land use types） and slopes（gentle and steep）. Seasonal runoff from control plots in the highlands ranged 214–560 versus 253–475 mm at midlands and 119–200 mm at lowlands. The three soil and water conservation techniques applied in cultivated land increased runoff conservation efficiency by 32% to 51%, depending on the site. At the moist subtropical site in a highland region, soil and water conservation increased soil moisture enough to potentially cause waterlogging, which was absent at the lowrainfall sites. Soil bunds combined with Vetiveria zizanioides grass in cultivated land and short trenches in grassland conserved the most runoff（51% and 55%, respectively）. Runoff responses showed high spatial variation within and between land use types, causing high variation in soil and water conservation efficiency. Our results highlight the need to understand the role of the agro-ecological environment in the success of soil and water conservation measures to control runoff and hydrological dynamics. This understanding will support policy development to promote the adoption of suitable techniques that can be tested at other locations with similar soil, climatic, and topographic conditions.展开更多
Rapid climate and cropland use changes in recent decades have posed major challenges to food security in China.Hainan Is-land is the only tropical island in China and is blessed with natural conditions for crop produc...Rapid climate and cropland use changes in recent decades have posed major challenges to food security in China.Hainan Is-land is the only tropical island in China and is blessed with natural conditions for crop production.This study first simulates the climate scenarios of Hainan Island for 2030,2040 and 2050 under the four Socio-economic Pathways(SSPs)based on the climate models in ScenarioMIP of Coupled Model Intercomparison Project Phase 6(CMIP6),and then simulates the land use scenarios of Hainan Island for 2030,2040 and 2050 based on the Cellular Automata(CA)-Markov model.Finally,based on the Global Agro-Ecological Zones(GAEZ)model,the rice potential yield in Hainan Island for 2030,2040 and 2050 are simulated,and the effects of future climate and cropland use changes on rice potential yields are investigated.The results show that:1)from 2020 to 2050,mean maximum temperature first decreases and then increases,while mean minimum temperature increase sharply followed by a leveling off under the four SSPs.Precipitation decreases and then increases under other three SSPs except SSP2-4.5.Net solar radiation increases continuously under SSP1-2.6,2-4.5,and 5-8.5,and has the lowest simulated values under SSP3-7.0.Mean wind speed increases continuously under SSP1-2.6,fluctuates more under SSP2-4.5 and SSP5-8.5,and increases slowly and then decreases sharply under SSP3-7.0.Relative humidity basically decreases continuously under the four SSPs.2)Areas of paddy field are 302.49 thousand,302.41 thousand and 302.71 thou-sand ha for 2030,2040 and 2050,respectively,all less than that in 2020.Paddy field is mainly converted into built-up land and wood-land.As for the conversion of other land types to paddy field,woodland is the main source.3)Under the effects of future climate and cropland use changes,the mean potential productions in Hainan Island under the four SSPs increase 1.17 million,1.13 million and 1.11 million t,respectively,and the mean potential yields increase 3873.21,3766.71 and 3672.38 kg/ha,respectively for the three periods.The largest increases in mean rice potential production and mean potential yield are 1.21 million t and 4008.00 kg/ha,1.16 million t and 3846.65 kg/ha,as well as 1.13 million t and 3732.75 kg/ha,respectively under SSP 3-7.0,indicating that SSP3-7.0 is the most suitable scenario for rice growth.This study could provide scientific basis for crop planting planning and agricultural policy adjustment.展开更多
North-East Trinidad is a low income, underutilized, agro-ecological significant and agricultural community with great potential for producing non-traditional crops for domestic usage and export. Diversification is cri...North-East Trinidad is a low income, underutilized, agro-ecological significant and agricultural community with great potential for producing non-traditional crops for domestic usage and export. Diversification is critical to agro-ecological transitions to ensure food security and nutrition while conserving, protecting and enhancing natural resources. The growing demand for agro-ecological and food security solutions suggest that efforts be made to utilize sustainable agriculture, and agro-ecological methods by utilizing available rural landscapes and communities in an effort to fulfill these demands. Surveys of sustainable agriculture, organic farmers and agro-ecological interests were conducted in the impoverished region of North-East Trinidad. Survey results reported over 180 farmers with >1 - 10 acres of available farmland supported a high agricultural production capacity. The highest average per capita for vegetables was tomato (2.3 acres), for tubers was yam (1.03 acres), and for tree crops was green fig (900 plants). Livestock production was limited with duck production being highest (165). There is an increasing earning potential for small farmers and leaseholders, from utilization of non-traditional export crops and expanding agro-ecological land usage, increasing sustainable agriculture production in the area.展开更多
Sustainable development, as a “hot topic”, concerns not only economic development but also environmental protection. Agriculture, the base of other economic activities, has faced many difficulties that include over ...Sustainable development, as a “hot topic”, concerns not only economic development but also environmental protection. Agriculture, the base of other economic activities, has faced many difficulties that include over growth population, land decrease, and land degradation and so on. Therefore, how to increase the food supply, to meet the over\|growth population demands, is the main task all over the world at present, especially in the developing countries, such as China, but we also must protect agricultural environment for medium\| and long\|term development simultaneously. Hence, sustainable development in agriculture is the most important estate that we must concern. Its sustainable development determines the sustainability of other economic development to a great extent. Despite Chinese government has paid much attention to develop agricultural production and obtained great successions, there are also many shortcomings in Chinese agriculture. Therefore, China must seek new approaches for its development and environmental protection that suit local conditions and are based on local resources. Agro ecological engineering, the application of ecological engineering in agriculture, is very thriving in China in recent decades. In this paper, the ecological, economic and social benefits of agro\|ecological engineering are analyzed. The principles are discussed. The results indicated that agro\|ecological engineering can meet the farmer′s short\|, medium\| and long\|term benefits. In the meanwhile, it also concerns not only economic benefits but ecological and social benefits. Therefore, agro\|ecological engineering is a way that leads to sustainable agriculture in the future in China.展开更多
Using the method of emergy analysis, we analyze the input and output of agroecological economic system, and select five indicators (net emergy yield ratio, emergy investment ratio, environmental loading ratio, emergy ...Using the method of emergy analysis, we analyze the input and output of agroecological economic system, and select five indicators (net emergy yield ratio, emergy investment ratio, environmental loading ratio, emergy sustainability index, and dominance of emergy yield system) for assessment. The results show that the emergy input-output in Wu'an City is in general on the rise; the emergy investment ratio rises constantly, but the net emergy yield ratio decreases, and the comparative advantage in the prices of agricultural products is gradually lost. At the same time, with increase in the non-renewable industrial support emergy, the environmental pressures are also mounting. In the future agricultural development, it is necessary to pay more attention to the coordination between agricultural development and ecological environment, achieving sustainable development of agriculture.展开更多
Establishing agro-ecological compensation mechanism is the objective requirement for protecting agricultural ecological environment on the prerequisite of stabilizing and benefiting farmers,to realize protection in th...Establishing agro-ecological compensation mechanism is the objective requirement for protecting agricultural ecological environment on the prerequisite of stabilizing and benefiting farmers,to realize protection in the process of development and promote development through protection.This study analyzed existing problems in the practice of establishing agro-ecological compensation mechanism in Jiangsu Province,including failure to form systematic compensation system due to limited technological reserve,failure to bring into play expected compensation effect due to scant attention,and failure to set up perfect input mechanism due to insufficient financing channel.In line with these problems,it came up with feasible policy recommendations,including strictly implementing top frame design for agro-ecological compensation and giving impetus to standardized and institutionalized work,building pilot demonstration area for agro-ecological compensation,setting up diversified agro-ecological compensation approaches,establishing long-term security mechanism for agro-ecological compensation,and strengthening propaganda and education of agro-ecological compensation.It is expected to provide reference for establishing agro-ecological compensation mechanism in Jiangsu Province,and also provide system guarantee for promoting ecological progress and agricultural modernization in Jiangsu Province.展开更多
Rainfall variability plays an important role in many socio-economic activities such as food security, livelihood and farming in Ghana. Rainfall impact studies are thus very crucial for proper management of these key s...Rainfall variability plays an important role in many socio-economic activities such as food security, livelihood and farming in Ghana. Rainfall impact studies are thus very crucial for proper management of these key sectors of the country. This paper examines the seasonal and annual rainfall variability in the four agro-ecological zones of Ghana from the CHIRPS V2 rainfall time series spanning a period of 1981-2015. The rainfall indices were computed with the aid of the FClimDex package whereas the trends of these indices were further tested using the Mann Kendall trend test. The results show good agreement (r ≥ 0.7) between CHIRPS V2 and gauge in almost all portions of country although high biases were observed especially in DJF season over parts of the Northeastern (NE) portions of the country. The mean seasonal rainfall climatology over the country is observed to be in the range of 20 - 80 mm, 60 - 200 mm, 100 - 220 mm and 40 - 180 mm in DJF, MAM, JJA and SON seasons respectively with high intensities of rainfall dominating Southwestern portions of the country. The trend analysis revealed positive trends of consecutive dry days in the Transition, Forest and Coastal zones and negative trends in the Savannah zone of the country. Decreasing trends of consecutive wet days are observed over the Savannah, Transition and Coastal zones whereas increasing trends dominate the Forest zone. Savannah, Forest and Transition zones show weak increasing trends of the number of heavy rainfall days whilst weak decreasing trends are observed over the Coastal zone of the country. Similarly, weak increasing trends of the number of very heavy rainfall days are observed over all the agro-ecological zones except in the Transition zone. It is observed that the annual wet day rainfall total has increasing trend in the Savannah and Forest zones of the country whereas decreasing trends cover the remainder of the zones. The trends of these indices in the agro-ecological zones were all significant at a significant value of 0.05. This paper assessed the performance of the CHIRPS V2 rainfall data over the region and reports on the biases in seasonal rainfall amounts which are limited in previous studies. These findings have adverse impacts on rain-fed agricultural practices, water resource management and food security over the country.展开更多
Dried fish are susceptible to bacteria and fungi attack and are liable to chemical changes which cause losses in quality and reduction of shelf-life. It is important therefore to maintain the quality of fish because c...Dried fish are susceptible to bacteria and fungi attack and are liable to chemical changes which cause losses in quality and reduction of shelf-life. It is important therefore to maintain the quality of fish because continuous consumption of contaminated fish and their products may predispose consumers to health hazards. Maintenance of high quality fish therefore calls for adequate and effective preservation techniques. The study examined the effectiveness of essential oils of Ocimum basilicum and Ocimum gratissimum from two Agro-ecological zones of Cameroon in limiting the microbial proliferation and preserving the quality of smoke-dried Oreochromis niloticus fish stored at 25˚C for two months. The plant materials were harvested from the Western Highlands and Monomodal Humid Forest agroecological zones of Cameroon. Extraction of the essential oil from the plants was done by hydro-distillation. The fish species (Oreochromis niloticus) used in this study was chosen based on a survey study on the most consumed species of freshwater smoke-dried fish in the Western Highlands and Monomodal Humid Forest Agro-ecological zones of Cameroon. Heterotrophic bacteria counts, fungi counts and Enterobacteriaceae counts were used to assess the level heterotrophic bacteria, fungi and Enterobacteriaceae respectively in the fish samples during storage and were done by culture techniques using total plate count agar, potato dextrose agar and violet red bile glucose agar respectively. Total volatile basic nitrogen, peroxide value, and thiobarbituric acid reactive substance assays were used as spoilage indices to assess the nutritional quality of the fish during storage. From the survey study, Oreochromis niloticus was the most consumed smoke-dried fish in the Western Highlands (35.45%) and Monomodal Humid Forest (34.55%) agroecological zones. All the EOs caused a significant reduction in the microbial loads, total volatile basic nitrogen, peroxide value, and thiobarbituric acid reactive substance of smoke-dried Oreochromis niloticus as storage progressed. However, the reduction in these values was more pronounced in samples treated with essential oils of O. gratissimum from the Western Highlands, with heterotrophic bacteria, fungi and Enterobacteriaceae counts being 5.89, 6.97 and 4.59 log<sub>10</sub> cfu/g respectively at the end of the storage period. This was followed by essential oils of O. gratissimum from the Monomodal Humid Forest with heterotrophic bacteria, fungi and Enterobacteriaceae counts being 6.11, 7.79 and 4.86 log<sub>10</sub> cfu/g respectively at the end of the storage period. Also, essential oils of O. gratissimum from the Western Highlands was more effective in preserving the fish quality as lowest total volatile basic nitrogen (12.29 mg/100g), peroxide value (2.79 mEq O<sub>2</sub>·Kg<sup>−1</sup>) and thiobabituric reactive substance (1.695 mg MDA/Kg) values were observed for fish samples treated with this extract at the end of the storage period. This was followed by essential oils of O. gratissimum from the Monomodal Humid Forest with total volatile basic nitrogen (14.95 mgN/100g), Peroxide value (3.23 mEq O<sub>2</sub>·Kg<sup>−1</sup>) and thiobabituric reactive substance (2.354 mg MDA/Kg) at the end of the storage period. From the results obtained, essential oils from O. gratissimum were more effective than that from O. basilicum in the two agroecological zones and should be considered as natural alternative to chemical preservatives for further application in food preservation.展开更多
Chemical insecticides have been considered as a means to combat crop pests. Although their effectiveness is evident, their impact on the environment is increasingly being discussed. The aim of this study is to determi...Chemical insecticides have been considered as a means to combat crop pests. Although their effectiveness is evident, their impact on the environment is increasingly being discussed. The aim of this study is to determine the agro-ecological potential of a biological insecticide (C<sub>25</sub>H<sub>32</sub>O<sub>12</sub>) based on Aloe barbadensis in a Sahelian context. For this purpose, a completely randomized block experimental design with 3 replications and 4 treatments was set up to experiment with Aloe barbadensis as a bioinsecticide against pests of Abelmoschus esculentus. However, data were collected using an observation and parameter monitoring grid. This includes the cultivation of Abelmoschus esculentus, soil preparation, seeding and watering, plot labeling, preparation of the bioinsecticide (selection and preparation of raw materials, grinding of Aloe barbadensis miller and extraction of the crude bioinsecticide, quantification of treatment doses and dilution, and obtaining the formulated bioinsecticide), plant watering, plant treatment, and finally parameter monitoring. The results obtained reveal that the level of damage is significantly high in the control treatment T0 (63%) compared to the other treatments, with 29% for treatment T1, 7% for T2, and 1% for T3, implying a strong action capability of this insecticide against pests of Abelmoschus esculentus. Therefore, it can be concluded that for a normal growing season of Abelmoschus esculentus, this biological insecticide should be sprayed 12 times. Furthermore, this biological insecticide is unique in that it does not inflict any gastric toxicity on the pests, which gives it the characteristic of being a repellent. It is a biological insecticide whose efficacy period has been tested, with a minimum duration of 21 days. In conclusion, this formulated bioinsecticide based on Aloe barbadensis demonstrates significant efficacy against pests of Abelmoschus esculentus. In the future, we will consider experimenting with its effectiveness against pests of other plants.展开更多
The evolvement of IPM has experienced several significant stages. IPM is an ecosystem as a governance unit. It allows the presence of low numbers of pests because a direct or indirect relationship between biological s...The evolvement of IPM has experienced several significant stages. IPM is an ecosystem as a governance unit. It allows the presence of low numbers of pests because a direct or indirect relationship between biological species and their associated environmental living conditions could keep a long-term ecological balance. IPM also emphasizes overall benefits; it is necessary to integrate all kinds of safe, effective, economic, and simple managements as far as possible. When synthesizing and coordinating various managements, effective control object, effective time limit, effective scope, and effective degree of the individual method should be analysed first. The ultimate goal of IPM is for the sustainable development of agriculture. In the future IPM system engineering, crop resistance, the role of natural enemies, agricultural control, and the application of biological control technologies will be greatly strengthened, and the role of chemical pesticides will be significantly reduced. Safe, effective, and long-lasting control of pest populations will be below the level of harm caused, which could protect the ecological environment and the health of people and livestock, and promote the development of production.展开更多
Regional agriculture is the basis of regional sustainable development, so sustainable regional agricultural development is essential to the sustainable development of the whole society and becomes the focus of global ...Regional agriculture is the basis of regional sustainable development, so sustainable regional agricultural development is essential to the sustainable development of the whole society and becomes the focus of global research. The classification of regional agricultural structure is the basic work of regional agriculture study. This paper constructs index system （27 indices） of regional agricultural structure types with the three big indices： natural resources, developmental level of the agro-economy, and agro-ecological conditions. This paper also endows weight to every sub-classification index by means of AHP and obtains the comprehensive evaluation value of the three types of indices with arithmetic average weight approach. The regional agricultural structure can be classified into eight types in accordance with this evaluation results. The empirical study of China shows that the 31 provinces （municipalities and autonomous regions） are of different agriculture structural types. Finally, countermeasures of sustainsable agricultural development are put forward for the different agriculture structure features.展开更多
Azadirachta indica seed samples were collected from four different agro-ecological regions（AERs） viz.,AER-2,AER-4,AER-5A and AER-5B of Gujarat state,India during 2000 to 2002 with an aim to assess variability in aza...Azadirachta indica seed samples were collected from four different agro-ecological regions（AERs） viz.,AER-2,AER-4,AER-5A and AER-5B of Gujarat state,India during 2000 to 2002 with an aim to assess variability in azadirachtin,oil and fatty acids content of the seeds and assess correlation of these parameters with morphological characters.Azadirachtin,oil and fatty acids content indicated significant（p0.01） variations between years and AERs in Gujarat.The azadirachtin ranged from 142 to 9 527 μg·g-1 seed kernel with an average of 2 426 μg·g-1 for the state.AER-5B recorded highest azadirachtin and oil content.Fatty acid composition was found to be affected by environmental factors particularly varying degree of annual rainfall and temperature during fruit ripening period.Conclusively trees growing in AER-5B performed better in term of azadirachtin,oil and stearic acid content.Tree girth at breast height showed no significant relation with these biochemicals.展开更多
To determine the genetic diversity and population structure of sweet potato accessions cultivated in China, and to establish the genetic relationships among their germplasm types, a representative collection of 240 ac...To determine the genetic diversity and population structure of sweet potato accessions cultivated in China, and to establish the genetic relationships among their germplasm types, a representative collection of 240 accessions was analyzed using inter-simple sequence repeat （ISSR） markers. The mean genetic similarity coefifcient, Nei’s gene diversity, and shared allele distance of tested sweet potato accessions were 0.7302, 0.3167 and 0.2698, respectively. The 240 accessions could be divided into six subgroups and ifve subpopulations based on neighbor-joining （NJ） clustering and STRUCTURE results, and obvious genetic relationships among the tested sweet potato accessions were identiifed. The marker-based NJ clustering and population structure showed no distinct assignment pattern corresponding to lfesh color or geographical ecotype of the tested sweet potato germplasm. Analysis of molecular variance （AMOVA） revealed small but signiifcant difference between white and orange-lfeshed sweet potato accessions. Small but signiifcant difference were also observed among sweet potato accessions from the Southern summer-autumn sweet potato region, the Yellow River Basin spring and summer sweet potato region and the Yangtze River Basin summer sweet potato region. This study demonstrates that genetic diversity in the tested sweet potato germplasm collection in China is lower than that in some reported sweet potato germplasm collections from other regions. Pedigree investigations suggest that more diverse Chinese sweet potato varieties should be formed by broadening the selection scope of breeding parents and incorporating the introduced varieties into future breeding programs.展开更多
Soil samples from thirty sites representing four agro-ecological zones in the Western Usambara Mountains (WUM) of the Lushoto District in northern Tanzania were collected and analyzed for different nutrients. The resu...Soil samples from thirty sites representing four agro-ecological zones in the Western Usambara Mountains (WUM) of the Lushoto District in northern Tanzania were collected and analyzed for different nutrients. The results suggested that the major soil fertility constraint was P deficiency. On the basis of critical levels established in other areas, 90% of the soils were ranked as P deficient. This was followed by N, which was ranked as inadequate in 73% of the sites. Magnesium, K, and Ca also appeared limiting with 67%, 53% and 50% of the soils falling below the established critical values, respectively. A few soils (10%) were also found to contain exchangeable Al. The metallic micronutrients (Cu, Fe, and Zn) were adequate in all soils. Two sites had excessive Mn that could lead to toxicity in crops, and one was Mn deficient.展开更多
By using emergy analysis theory and methods, we conduct quantitative analysis on the input and output of emergy, and sustainable development of agro-ecological system in Poyang Lake Area. The results show that compare...By using emergy analysis theory and methods, we conduct quantitative analysis on the input and output of emergy, and sustainable development of agro-ecological system in Poyang Lake Area. The results show that compared with the national average, the environmental loading ratio is relatively low in this area; the net emergy yield rate is high; the sustainable development ability is strong. Finally according to the results of emergy analysis, corresponding countermeasures are put forward as follows: develop agriculture based on the existing rich natural resources; increase technological inputs; develop circular agriculture; promote sustainable agricultural development.展开更多
Acid Lime (Citrus aurantifolia Swingle) is one of the important commercial fruits cultivated from terai to high hill of Nepal. It is an important source of vitamin “C” (ascorbic acid) for human nutrition. Amount of ...Acid Lime (Citrus aurantifolia Swingle) is one of the important commercial fruits cultivated from terai to high hill of Nepal. It is an important source of vitamin “C” (ascorbic acid) for human nutrition. Amount of juice, TSS (Total soluble solids), TA (Titrable acid) and vitamin C are the determining factors of quality of acid lime fruits which may vary according to bearing sides of the trees. The main objective of this study is, to determine the variation of fruit quality at different sides of the tree. Total of 15 bearing trees were selected randomly (5 trees per site) from three different agro ecological domain representing terai (1200 m asl) and samples were collected from the selected trees. Randomly ten fruits (from east, west, centre, north and south sides) were collected from each tree and analyzed for amount of vitamin C, TSS, TA and juice. Highest ascorbic acid 79.6 mg and 69.9 mg was observed in south side fruits whereas lowest 62.8 mg and 55.1 mg was observed in centre fruits in the high and mid hills zone respectively, but in terai, highest ascorbic acid 58.7 mg was observed in north side and lowest 41.8 mg was observed in centre. Highest amount of juice 43.9% was observed in south side fruits and lowest 36.6% in centre fruits, but amount of TSS 8.2% and TA 7.2% was observed in south side fruits and lowest 7.3% TSS and 7.0% TA was observed in centre fruits in high hills. In terai highest TSS 8.3% and TA 7.4% was observed in north side fruits and lowest TSS 7.3% and TA 6.7% was observed in centre fruits. Variation of TSS, TA percent and ascorbic acids was observed according to the agro ecological zone.展开更多
文摘Climate change is impacting climate sensitive rural livelihood systems. Exposure, sensitivity, and adaptive capacity of agricultural livelihoods to climate variability and change differ across agro-ecologies and these pose a challenge to climate resilient development strategy. This study assesses agro-ecology specific vulnerability of smallholder farmers to climate change and variability in the Dabus Watershed (North-west Ethiopia), based on a survey of 734 farm households complemented with focus group discussion and key informant interviews. Recognizing the physiographic and climatic diversity that exists across agro-ecologies in the study area, Livelihood Vulnerability Index (LVI) framed within the United Nations Intergovernmental Panel on Climate Change (IPCC) vulnerability framework (LVI-IPCC) is adapted to assess agro-ecology specific vulnerability in two local agro-ecologies, namely wet lowland and dry lowland. For each agro-ecology, exposure, sensitivity and adaptive capacity indices as well as LVI-IPCC vulnerability score was calculated. The result shows that the dry lowland agro-ecology has a relatively higher exposure and sensitivity to climate stresses with a comparatively limited adaptive capability. On the other hand, the wet lowland agro-ecology exhibits intermediate vulnerability with a relatively lower perceived exposure and higher adaptive capacity. Higher exposure relative to adaptive capacity resulted in a positive LVI-IPCC score in the dry lowland agro-ecology and positioned it in more vulnerable level than the wet lowland. A higher adaptive capacity relative to exposure unveils a negative LVI-IPCC score for the wet lowland agro-ecology and positioned it in a moderate vulnerability category. In line with the findings, there is a need to set agro-ecology specific priorities for intervention that is most needed to cop up with the effects of climate variability and change in each agro-ecology. Climate risk exposure levels can be reduced through timely provision of climate specific information and early warning systems aimed at enhancing preparedness of farm households to extreme events. It is also crucial to expand availability of infrastructural facilities such as market, health services, and veterinary services so as to enhance adaptive capacity. Supporting alternative livelihood options and enhancing water harvesting practices for supplementary irrigation also call policy attention.
文摘In the recent past there has been concern to address the declining trends and deteriorating ecological elements and their functions in productive agricultural landscapes. The efforts to revive the ecological functions needs multiple scale approach, which include scientific understanding, time dependent restorative activities and incorporation of wisdom of the stakeholders. Conservation initiatives linked to precision farming is an apt mechanism to minimize the loss of natural resources of agricultural landscapes to maintain the complex stabilizers of ecological functions. Such an effort must address the scientific evaluation of the farm as “ecologically sustainable unit” with due consideration to social construct at local to regional level. Sustainability indices can be useful tools for evaluating the farms to isolate degradative factors and identify ecologically conservative practices. This review will analyze certain inter-linked concepts relevant to address the sustainability issues in agro-ecology at the interface of socio-ecological perspective.
文摘Cultivation of pollinator-dependent crops has expanded globally, increasing our reliance on insect pollination. This essential ecosystem service is provided by a wide range of managed and wild pollinators whose abundance and diversity are thought to be in decline, threatening sustainable food production. In Cameroon, several studies on pollinator-dependent crops carried out in different agro-ecological zones (AEZ) have been published in national and international journals, in order to present the importance and impact of flowering insects on fruit and seed yields of plant species. We proposed to produce a review article highlighting the different flowering insects and their importance for different plants according to AEZ, without however focusing on the quality of the journal (predator or non-predator) and how the different insects were identified (scientific names given in the publications). Thus, from 1997 to 2020, we collected 116 published papers from which only 26 were kept for this review. The results show that Hymenoptera, including the Apidae, followed by Megachilidae, are the most excellent pollinators of plant species in Cameroon, and they are present in different agro-ecological zones. The majority of publications focused on bees, particularly the honeybee Apis mellifera.
基金Deanship of Scientific Research(DSR)at King Faisal University,Saudi Arabia,under project number KFU241939.
文摘In recent years, the world has faced rising global temperatures, accumulative pollution, and energy crises, stimulating scientists worldwide to strive for eco-friendly and cost-effective solutions. Biochar has materialized as a favorable tool for environmental remediation, indicating efficacy as an efficient sorbent substance for both inorganic and organic pollutants in environmental field. These unique properties exclude improved surface functionality, porous morphology, large specific surface area (SSA), cation exchange capacity (CEC), robust adsorption capabilities, environmental stability, and embedded micronutrients. Biochar exhibited potential characteristics for environmental oversight, greenhouse gas (GHG) emission reduction, and soil fertility improvement. This review explores the impact of fundamental factors such as retention time, pyrolysis temperature, gas flow rate, and reactor design on biochar yield and properties. Collected data revealed the various applications of biochar, ranging from waste management and construction materials to the adsorptive removal of hydrocarbon lubricants from aqueous media, contaminant immobilization, and carbon sequestration. It has played mostly a significant share in climate change mitigation and an important role in soil amendments. Biochar improves soil improvement by increasing water retention (10%–30%), carbon sequestration, soil surface functionality, and providing high surface area with chemical stability. The assessment also reports the prospects and contests associated with biochar application uses in various agriculture cropping ecosystems. Inclusive, this review highlights the multifaceted characteristics of biochar as an adjustable on top of a sustainable solution addressing greenhouse gas emission, carbon sequestration, and environmental stresses. However, further research is needed to understand its long-term impacts and optimal applications fully.
基金supported by Grants-in-Aid for Scientific Research (25257417) from Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology, Japan
文摘In developing countries such as Ethiopia, research to develop and promote soil and water conservation practices rarely addressed regional diversity. Using a water-balance approach in this study, we used runoff plots from three sites, each representing a different agro-ecological environment, e.g., high, mid and low in both elevation and rainfall, in the Upper Blue Nile Basin of Ethiopia to examine the runoff response and runoff conservation efficiency of a range of different soil and water conservation measures and their impacts on soil moisture. The plots at each site represented common land use types（cultivated vs. non-agricultural land use types） and slopes（gentle and steep）. Seasonal runoff from control plots in the highlands ranged 214–560 versus 253–475 mm at midlands and 119–200 mm at lowlands. The three soil and water conservation techniques applied in cultivated land increased runoff conservation efficiency by 32% to 51%, depending on the site. At the moist subtropical site in a highland region, soil and water conservation increased soil moisture enough to potentially cause waterlogging, which was absent at the lowrainfall sites. Soil bunds combined with Vetiveria zizanioides grass in cultivated land and short trenches in grassland conserved the most runoff（51% and 55%, respectively）. Runoff responses showed high spatial variation within and between land use types, causing high variation in soil and water conservation efficiency. Our results highlight the need to understand the role of the agro-ecological environment in the success of soil and water conservation measures to control runoff and hydrological dynamics. This understanding will support policy development to promote the adoption of suitable techniques that can be tested at other locations with similar soil, climatic, and topographic conditions.
基金Under the auspices of Hainan Provincial Natural Science Foundation of China(No.321QN187,723RC466)Scientific Research Foundation of Hainan University(No.kyqd(sk)2135)Young Scholars Support Program of Hainan University(No.24QNFC-05)。
文摘Rapid climate and cropland use changes in recent decades have posed major challenges to food security in China.Hainan Is-land is the only tropical island in China and is blessed with natural conditions for crop production.This study first simulates the climate scenarios of Hainan Island for 2030,2040 and 2050 under the four Socio-economic Pathways(SSPs)based on the climate models in ScenarioMIP of Coupled Model Intercomparison Project Phase 6(CMIP6),and then simulates the land use scenarios of Hainan Island for 2030,2040 and 2050 based on the Cellular Automata(CA)-Markov model.Finally,based on the Global Agro-Ecological Zones(GAEZ)model,the rice potential yield in Hainan Island for 2030,2040 and 2050 are simulated,and the effects of future climate and cropland use changes on rice potential yields are investigated.The results show that:1)from 2020 to 2050,mean maximum temperature first decreases and then increases,while mean minimum temperature increase sharply followed by a leveling off under the four SSPs.Precipitation decreases and then increases under other three SSPs except SSP2-4.5.Net solar radiation increases continuously under SSP1-2.6,2-4.5,and 5-8.5,and has the lowest simulated values under SSP3-7.0.Mean wind speed increases continuously under SSP1-2.6,fluctuates more under SSP2-4.5 and SSP5-8.5,and increases slowly and then decreases sharply under SSP3-7.0.Relative humidity basically decreases continuously under the four SSPs.2)Areas of paddy field are 302.49 thousand,302.41 thousand and 302.71 thou-sand ha for 2030,2040 and 2050,respectively,all less than that in 2020.Paddy field is mainly converted into built-up land and wood-land.As for the conversion of other land types to paddy field,woodland is the main source.3)Under the effects of future climate and cropland use changes,the mean potential productions in Hainan Island under the four SSPs increase 1.17 million,1.13 million and 1.11 million t,respectively,and the mean potential yields increase 3873.21,3766.71 and 3672.38 kg/ha,respectively for the three periods.The largest increases in mean rice potential production and mean potential yield are 1.21 million t and 4008.00 kg/ha,1.16 million t and 3846.65 kg/ha,as well as 1.13 million t and 3732.75 kg/ha,respectively under SSP 3-7.0,indicating that SSP3-7.0 is the most suitable scenario for rice growth.This study could provide scientific basis for crop planting planning and agricultural policy adjustment.
文摘North-East Trinidad is a low income, underutilized, agro-ecological significant and agricultural community with great potential for producing non-traditional crops for domestic usage and export. Diversification is critical to agro-ecological transitions to ensure food security and nutrition while conserving, protecting and enhancing natural resources. The growing demand for agro-ecological and food security solutions suggest that efforts be made to utilize sustainable agriculture, and agro-ecological methods by utilizing available rural landscapes and communities in an effort to fulfill these demands. Surveys of sustainable agriculture, organic farmers and agro-ecological interests were conducted in the impoverished region of North-East Trinidad. Survey results reported over 180 farmers with >1 - 10 acres of available farmland supported a high agricultural production capacity. The highest average per capita for vegetables was tomato (2.3 acres), for tubers was yam (1.03 acres), and for tree crops was green fig (900 plants). Livestock production was limited with duck production being highest (165). There is an increasing earning potential for small farmers and leaseholders, from utilization of non-traditional export crops and expanding agro-ecological land usage, increasing sustainable agriculture production in the area.
基金ChineseAcademyofScience (No .KZ95 1 B1 2 0 8) TheNationalNaturalScienceFoundationofChina (No .498310 2 0 )
文摘Sustainable development, as a “hot topic”, concerns not only economic development but also environmental protection. Agriculture, the base of other economic activities, has faced many difficulties that include over growth population, land decrease, and land degradation and so on. Therefore, how to increase the food supply, to meet the over\|growth population demands, is the main task all over the world at present, especially in the developing countries, such as China, but we also must protect agricultural environment for medium\| and long\|term development simultaneously. Hence, sustainable development in agriculture is the most important estate that we must concern. Its sustainable development determines the sustainability of other economic development to a great extent. Despite Chinese government has paid much attention to develop agricultural production and obtained great successions, there are also many shortcomings in Chinese agriculture. Therefore, China must seek new approaches for its development and environmental protection that suit local conditions and are based on local resources. Agro ecological engineering, the application of ecological engineering in agriculture, is very thriving in China in recent decades. In this paper, the ecological, economic and social benefits of agro\|ecological engineering are analyzed. The principles are discussed. The results indicated that agro\|ecological engineering can meet the farmer′s short\|, medium\| and long\|term benefits. In the meanwhile, it also concerns not only economic benefits but ecological and social benefits. Therefore, agro\|ecological engineering is a way that leads to sustainable agriculture in the future in China.
基金Supported by Supported by the Fundamental Research Funds for the Central Universities
文摘Using the method of emergy analysis, we analyze the input and output of agroecological economic system, and select five indicators (net emergy yield ratio, emergy investment ratio, environmental loading ratio, emergy sustainability index, and dominance of emergy yield system) for assessment. The results show that the emergy input-output in Wu'an City is in general on the rise; the emergy investment ratio rises constantly, but the net emergy yield ratio decreases, and the comparative advantage in the prices of agricultural products is gradually lost. At the same time, with increase in the non-renewable industrial support emergy, the environmental pressures are also mounting. In the future agricultural development, it is necessary to pay more attention to the coordination between agricultural development and ecological environment, achieving sustainable development of agriculture.
基金Supported by Agricultural Sci-tech Autonomous Innovation Fund Project of Jiangsu Province(CX(13)4054)
文摘Establishing agro-ecological compensation mechanism is the objective requirement for protecting agricultural ecological environment on the prerequisite of stabilizing and benefiting farmers,to realize protection in the process of development and promote development through protection.This study analyzed existing problems in the practice of establishing agro-ecological compensation mechanism in Jiangsu Province,including failure to form systematic compensation system due to limited technological reserve,failure to bring into play expected compensation effect due to scant attention,and failure to set up perfect input mechanism due to insufficient financing channel.In line with these problems,it came up with feasible policy recommendations,including strictly implementing top frame design for agro-ecological compensation and giving impetus to standardized and institutionalized work,building pilot demonstration area for agro-ecological compensation,setting up diversified agro-ecological compensation approaches,establishing long-term security mechanism for agro-ecological compensation,and strengthening propaganda and education of agro-ecological compensation.It is expected to provide reference for establishing agro-ecological compensation mechanism in Jiangsu Province,and also provide system guarantee for promoting ecological progress and agricultural modernization in Jiangsu Province.
文摘Rainfall variability plays an important role in many socio-economic activities such as food security, livelihood and farming in Ghana. Rainfall impact studies are thus very crucial for proper management of these key sectors of the country. This paper examines the seasonal and annual rainfall variability in the four agro-ecological zones of Ghana from the CHIRPS V2 rainfall time series spanning a period of 1981-2015. The rainfall indices were computed with the aid of the FClimDex package whereas the trends of these indices were further tested using the Mann Kendall trend test. The results show good agreement (r ≥ 0.7) between CHIRPS V2 and gauge in almost all portions of country although high biases were observed especially in DJF season over parts of the Northeastern (NE) portions of the country. The mean seasonal rainfall climatology over the country is observed to be in the range of 20 - 80 mm, 60 - 200 mm, 100 - 220 mm and 40 - 180 mm in DJF, MAM, JJA and SON seasons respectively with high intensities of rainfall dominating Southwestern portions of the country. The trend analysis revealed positive trends of consecutive dry days in the Transition, Forest and Coastal zones and negative trends in the Savannah zone of the country. Decreasing trends of consecutive wet days are observed over the Savannah, Transition and Coastal zones whereas increasing trends dominate the Forest zone. Savannah, Forest and Transition zones show weak increasing trends of the number of heavy rainfall days whilst weak decreasing trends are observed over the Coastal zone of the country. Similarly, weak increasing trends of the number of very heavy rainfall days are observed over all the agro-ecological zones except in the Transition zone. It is observed that the annual wet day rainfall total has increasing trend in the Savannah and Forest zones of the country whereas decreasing trends cover the remainder of the zones. The trends of these indices in the agro-ecological zones were all significant at a significant value of 0.05. This paper assessed the performance of the CHIRPS V2 rainfall data over the region and reports on the biases in seasonal rainfall amounts which are limited in previous studies. These findings have adverse impacts on rain-fed agricultural practices, water resource management and food security over the country.
文摘Dried fish are susceptible to bacteria and fungi attack and are liable to chemical changes which cause losses in quality and reduction of shelf-life. It is important therefore to maintain the quality of fish because continuous consumption of contaminated fish and their products may predispose consumers to health hazards. Maintenance of high quality fish therefore calls for adequate and effective preservation techniques. The study examined the effectiveness of essential oils of Ocimum basilicum and Ocimum gratissimum from two Agro-ecological zones of Cameroon in limiting the microbial proliferation and preserving the quality of smoke-dried Oreochromis niloticus fish stored at 25˚C for two months. The plant materials were harvested from the Western Highlands and Monomodal Humid Forest agroecological zones of Cameroon. Extraction of the essential oil from the plants was done by hydro-distillation. The fish species (Oreochromis niloticus) used in this study was chosen based on a survey study on the most consumed species of freshwater smoke-dried fish in the Western Highlands and Monomodal Humid Forest Agro-ecological zones of Cameroon. Heterotrophic bacteria counts, fungi counts and Enterobacteriaceae counts were used to assess the level heterotrophic bacteria, fungi and Enterobacteriaceae respectively in the fish samples during storage and were done by culture techniques using total plate count agar, potato dextrose agar and violet red bile glucose agar respectively. Total volatile basic nitrogen, peroxide value, and thiobarbituric acid reactive substance assays were used as spoilage indices to assess the nutritional quality of the fish during storage. From the survey study, Oreochromis niloticus was the most consumed smoke-dried fish in the Western Highlands (35.45%) and Monomodal Humid Forest (34.55%) agroecological zones. All the EOs caused a significant reduction in the microbial loads, total volatile basic nitrogen, peroxide value, and thiobarbituric acid reactive substance of smoke-dried Oreochromis niloticus as storage progressed. However, the reduction in these values was more pronounced in samples treated with essential oils of O. gratissimum from the Western Highlands, with heterotrophic bacteria, fungi and Enterobacteriaceae counts being 5.89, 6.97 and 4.59 log<sub>10</sub> cfu/g respectively at the end of the storage period. This was followed by essential oils of O. gratissimum from the Monomodal Humid Forest with heterotrophic bacteria, fungi and Enterobacteriaceae counts being 6.11, 7.79 and 4.86 log<sub>10</sub> cfu/g respectively at the end of the storage period. Also, essential oils of O. gratissimum from the Western Highlands was more effective in preserving the fish quality as lowest total volatile basic nitrogen (12.29 mg/100g), peroxide value (2.79 mEq O<sub>2</sub>·Kg<sup>−1</sup>) and thiobabituric reactive substance (1.695 mg MDA/Kg) values were observed for fish samples treated with this extract at the end of the storage period. This was followed by essential oils of O. gratissimum from the Monomodal Humid Forest with total volatile basic nitrogen (14.95 mgN/100g), Peroxide value (3.23 mEq O<sub>2</sub>·Kg<sup>−1</sup>) and thiobabituric reactive substance (2.354 mg MDA/Kg) at the end of the storage period. From the results obtained, essential oils from O. gratissimum were more effective than that from O. basilicum in the two agroecological zones and should be considered as natural alternative to chemical preservatives for further application in food preservation.
文摘Chemical insecticides have been considered as a means to combat crop pests. Although their effectiveness is evident, their impact on the environment is increasingly being discussed. The aim of this study is to determine the agro-ecological potential of a biological insecticide (C<sub>25</sub>H<sub>32</sub>O<sub>12</sub>) based on Aloe barbadensis in a Sahelian context. For this purpose, a completely randomized block experimental design with 3 replications and 4 treatments was set up to experiment with Aloe barbadensis as a bioinsecticide against pests of Abelmoschus esculentus. However, data were collected using an observation and parameter monitoring grid. This includes the cultivation of Abelmoschus esculentus, soil preparation, seeding and watering, plot labeling, preparation of the bioinsecticide (selection and preparation of raw materials, grinding of Aloe barbadensis miller and extraction of the crude bioinsecticide, quantification of treatment doses and dilution, and obtaining the formulated bioinsecticide), plant watering, plant treatment, and finally parameter monitoring. The results obtained reveal that the level of damage is significantly high in the control treatment T0 (63%) compared to the other treatments, with 29% for treatment T1, 7% for T2, and 1% for T3, implying a strong action capability of this insecticide against pests of Abelmoschus esculentus. Therefore, it can be concluded that for a normal growing season of Abelmoschus esculentus, this biological insecticide should be sprayed 12 times. Furthermore, this biological insecticide is unique in that it does not inflict any gastric toxicity on the pests, which gives it the characteristic of being a repellent. It is a biological insecticide whose efficacy period has been tested, with a minimum duration of 21 days. In conclusion, this formulated bioinsecticide based on Aloe barbadensis demonstrates significant efficacy against pests of Abelmoschus esculentus. In the future, we will consider experimenting with its effectiveness against pests of other plants.
基金Supported by China Agricultural Industry Research System(CARS-12)
文摘The evolvement of IPM has experienced several significant stages. IPM is an ecosystem as a governance unit. It allows the presence of low numbers of pests because a direct or indirect relationship between biological species and their associated environmental living conditions could keep a long-term ecological balance. IPM also emphasizes overall benefits; it is necessary to integrate all kinds of safe, effective, economic, and simple managements as far as possible. When synthesizing and coordinating various managements, effective control object, effective time limit, effective scope, and effective degree of the individual method should be analysed first. The ultimate goal of IPM is for the sustainable development of agriculture. In the future IPM system engineering, crop resistance, the role of natural enemies, agricultural control, and the application of biological control technologies will be greatly strengthened, and the role of chemical pesticides will be significantly reduced. Safe, effective, and long-lasting control of pest populations will be below the level of harm caused, which could protect the ecological environment and the health of people and livestock, and promote the development of production.
基金supported by the Natural Sci-ence Foundation of Jiangsu Province (Grant No. BK2005040)the MOHURD Program of China (Grant No. 06-R5-10).
文摘Regional agriculture is the basis of regional sustainable development, so sustainable regional agricultural development is essential to the sustainable development of the whole society and becomes the focus of global research. The classification of regional agricultural structure is the basic work of regional agriculture study. This paper constructs index system （27 indices） of regional agricultural structure types with the three big indices： natural resources, developmental level of the agro-economy, and agro-ecological conditions. This paper also endows weight to every sub-classification index by means of AHP and obtains the comprehensive evaluation value of the three types of indices with arithmetic average weight approach. The regional agricultural structure can be classified into eight types in accordance with this evaluation results. The empirical study of China shows that the 31 provinces （municipalities and autonomous regions） are of different agriculture structural types. Finally, countermeasures of sustainsable agricultural development are put forward for the different agriculture structure features.
基金supported by the NOVOD Board, Ministry of Agriculture, Government of India
文摘Azadirachta indica seed samples were collected from four different agro-ecological regions（AERs） viz.,AER-2,AER-4,AER-5A and AER-5B of Gujarat state,India during 2000 to 2002 with an aim to assess variability in azadirachtin,oil and fatty acids content of the seeds and assess correlation of these parameters with morphological characters.Azadirachtin,oil and fatty acids content indicated significant（p0.01） variations between years and AERs in Gujarat.The azadirachtin ranged from 142 to 9 527 μg·g-1 seed kernel with an average of 2 426 μg·g-1 for the state.AER-5B recorded highest azadirachtin and oil content.Fatty acid composition was found to be affected by environmental factors particularly varying degree of annual rainfall and temperature during fruit ripening period.Conclusively trees growing in AER-5B performed better in term of azadirachtin,oil and stearic acid content.Tree girth at breast height showed no significant relation with these biochemicals.
基金supported by the National Natural Science Foundation of China (31101192)the Animal and Plant Breeding Project of Chongqing,China (cstc2010AB1053)+2 种基金the Application Development Key Project of Chongqing,China (cstc2013yykfb80010)the Fundamental Research Funds for the Central Universities,China (XDJK2011C004)the "111" Project (B12006) of Ministry of Education,China
文摘To determine the genetic diversity and population structure of sweet potato accessions cultivated in China, and to establish the genetic relationships among their germplasm types, a representative collection of 240 accessions was analyzed using inter-simple sequence repeat （ISSR） markers. The mean genetic similarity coefifcient, Nei’s gene diversity, and shared allele distance of tested sweet potato accessions were 0.7302, 0.3167 and 0.2698, respectively. The 240 accessions could be divided into six subgroups and ifve subpopulations based on neighbor-joining （NJ） clustering and STRUCTURE results, and obvious genetic relationships among the tested sweet potato accessions were identiifed. The marker-based NJ clustering and population structure showed no distinct assignment pattern corresponding to lfesh color or geographical ecotype of the tested sweet potato germplasm. Analysis of molecular variance （AMOVA） revealed small but signiifcant difference between white and orange-lfeshed sweet potato accessions. Small but signiifcant difference were also observed among sweet potato accessions from the Southern summer-autumn sweet potato region, the Yellow River Basin spring and summer sweet potato region and the Yangtze River Basin summer sweet potato region. This study demonstrates that genetic diversity in the tested sweet potato germplasm collection in China is lower than that in some reported sweet potato germplasm collections from other regions. Pedigree investigations suggest that more diverse Chinese sweet potato varieties should be formed by broadening the selection scope of breeding parents and incorporating the introduced varieties into future breeding programs.
基金Project supported by the Norwegian Agency for Development Cooperation (NORAD), Tanzania.
文摘Soil samples from thirty sites representing four agro-ecological zones in the Western Usambara Mountains (WUM) of the Lushoto District in northern Tanzania were collected and analyzed for different nutrients. The results suggested that the major soil fertility constraint was P deficiency. On the basis of critical levels established in other areas, 90% of the soils were ranked as P deficient. This was followed by N, which was ranked as inadequate in 73% of the sites. Magnesium, K, and Ca also appeared limiting with 67%, 53% and 50% of the soils falling below the established critical values, respectively. A few soils (10%) were also found to contain exchangeable Al. The metallic micronutrients (Cu, Fe, and Zn) were adequate in all soils. Two sites had excessive Mn that could lead to toxicity in crops, and one was Mn deficient.
基金Supported by the National Natural Science Foundation of China(71063015)the Eleventh Five-Year Plan Social Sciences Project in Jiangxi Province(10YJ61)the Science and Technology Project of the Education Department of Jiangxi Province(GJJ11271)
文摘By using emergy analysis theory and methods, we conduct quantitative analysis on the input and output of emergy, and sustainable development of agro-ecological system in Poyang Lake Area. The results show that compared with the national average, the environmental loading ratio is relatively low in this area; the net emergy yield rate is high; the sustainable development ability is strong. Finally according to the results of emergy analysis, corresponding countermeasures are put forward as follows: develop agriculture based on the existing rich natural resources; increase technological inputs; develop circular agriculture; promote sustainable agricultural development.
文摘Acid Lime (Citrus aurantifolia Swingle) is one of the important commercial fruits cultivated from terai to high hill of Nepal. It is an important source of vitamin “C” (ascorbic acid) for human nutrition. Amount of juice, TSS (Total soluble solids), TA (Titrable acid) and vitamin C are the determining factors of quality of acid lime fruits which may vary according to bearing sides of the trees. The main objective of this study is, to determine the variation of fruit quality at different sides of the tree. Total of 15 bearing trees were selected randomly (5 trees per site) from three different agro ecological domain representing terai (1200 m asl) and samples were collected from the selected trees. Randomly ten fruits (from east, west, centre, north and south sides) were collected from each tree and analyzed for amount of vitamin C, TSS, TA and juice. Highest ascorbic acid 79.6 mg and 69.9 mg was observed in south side fruits whereas lowest 62.8 mg and 55.1 mg was observed in centre fruits in the high and mid hills zone respectively, but in terai, highest ascorbic acid 58.7 mg was observed in north side and lowest 41.8 mg was observed in centre. Highest amount of juice 43.9% was observed in south side fruits and lowest 36.6% in centre fruits, but amount of TSS 8.2% and TA 7.2% was observed in south side fruits and lowest 7.3% TSS and 7.0% TA was observed in centre fruits in high hills. In terai highest TSS 8.3% and TA 7.4% was observed in north side fruits and lowest TSS 7.3% and TA 6.7% was observed in centre fruits. Variation of TSS, TA percent and ascorbic acids was observed according to the agro ecological zone.
