Rice productivity faces critical sustainability challenges from stagnating yields and inefficient fertilizer use,particularly in intensive agricultural regions like the Yangtze River Delta(YRD)of China.Controlled-rele...Rice productivity faces critical sustainability challenges from stagnating yields and inefficient fertilizer use,particularly in intensive agricultural regions like the Yangtze River Delta(YRD)of China.Controlled-release blended fertilizers(CRBF),which synchronize nutrient release with crop demand,represent a promising strategy to enhance rice productivity.Here,we conducted an eight-year(2017–2024)field study across 25 representative sites in the YRD to evaluate CRBF’s effects,complemented by a regional extrapolation analysis.Our findings showed that,relative to conventional fertilization,CRBF increased rice yield by 4.9%,primarily by increasing the number of effective panicles(5%)and plant biomass(5.2%–11.3%).Notably,this yield benefit rose to 5.3%when CRBF was applied via deep placement,which was attributed to greater root biomass(13.1%–29.2%)and higher soil NH_(4)^(+)-N availability(24.3%–43.6%),thereby enhancing N uptake.Furthermore,initial soil organic matter was identified as the predominant modulator of CRBF effectiveness.Regional extrapolation projected that applying CRBF could enhance rice yield by 4.0%across the YRD,with deep placement providing an additional 2.1%gain.In conclusion,our study demonstrates that adopting CRBF,particularly with deep placement,is a robust and effective strategy to sustainably boost rice productivity in intensive rice cultivation systems.展开更多
Improving the quality of agricultural products depends largely on production process. In the absence of data on farmers’ practices and the average quality of cashew nuts in C<span style="white-space:nowrap;&q...Improving the quality of agricultural products depends largely on production process. In the absence of data on farmers’ practices and the average quality of cashew nuts in C<span style="white-space:nowrap;">ô</span>te d’Ivoire, the present study aimed to provide a detailed description of the cashew nut production process. Thus, a survey was carried out in the zones of Mankono, Dabakala and Bondoukou among 386 cashew producers selected at random and interviewed using the face-to-face technique. The results revealed that intercropping was practiced in cashew cultivation (42% - 62% of the producers), modern cultivation technique (72% - 98% of the producers) but with rare use of selected seeds (8% - 20% of the producers), labour/ha during nut harvesting (2.6 - 12 workers/ha). Concerning the harvesting process, the time taken to pick the nuts varies from 1 to 14 days;the use of pesticides during harvesting (14% to 97% of the producers) and the absence of sorting of the nuts in 42% of the Mankono producers justify the probable conservation of defective and immature nuts in their production. For drying, the main dryers were the slatted table, the cemented surface and the tarpaulin, but other dryers were found such as the mosquito net, the propylene rice bag, the fertiliser bag and the black bag. Generally, the drying time of cashew nuts was very short: 2 days (43% - 77% of the producers interviewed) but surprisingly 1 day (7% - 27% of the producers interviewed). For Mankono, the use of chemicals was permanent during all stages of the cashew production process. Overall, the results suggest the need to assess the real impact of farmers’ practices on the quality of cashew nuts from C<span style="white-space:nowrap;">ô</span>te d’Ivoire.展开更多
In order to determine various traits which need to be improved for improving the productive life span and longevity, purebred Sahiwal cows available at bull mother experimental farm and cattle breeding farm located at...In order to determine various traits which need to be improved for improving the productive life span and longevity, purebred Sahiwal cows available at bull mother experimental farm and cattle breeding farm located at Veterinary College, Durg, Chhattisgarh, India were used. For present investigation, 17 linear type traits were measured, scaled and scored as per the guidelines of International Committee for Animal Recording （2001）. The average score point （ASP） under 1-9 point scale score system along with respective observed group for different linear type traits were stature （6.88; taller）, chest width （5.30; intermediate）, body depth （4.11; intermediate）, rump angle （4.27; intermediate）, rump width （5.09; intermediate）, rear leg set-side view （4.55; intermediate）, rear leg set-rear view （5.95; intermediate）, foot angle （5.66; intermediate）, udder depth （5.71; intermediate）, rear udder height （4.90; intermediate）, udder balance （5.27; intermediate）, udder cleft （3.75; intermediate）, fore udder attachment （5.55; intermediate）, teat length （3.54; intermediate）, fore teat placement （5.33; intermediate）, rear teat placement （6.37; intermediate） and teat thickness （2.76; narrow）. For most of the traits, ASP which lies near midpoint （i.e. near five） is known to be ideal for dairy type cattle. Moreover, some traits also showed the presence of undesirable ASP. Hence, the traits such as body depth, rump angle, foot angle, udder depth, rear udder height, udder cleft, fore udder attachment, teat length, and teat thickness needs to be improved for improving the production sustainability and herd life of Sahiwal cattle. Thus, present investigation gives explicit clue to incorporate these conformation traits in selection program of this valuable germplasm commonly found in Southern part of Asia （India, Pakistan, Srilanka, etc.）.展开更多
Twist drill flute profile design is necessary in order to determine the required grinding wheel profile for a flute production. An accurate drill flute profile design is generated for two-flute conical twist drills us...Twist drill flute profile design is necessary in order to determine the required grinding wheel profile for a flute production. An accurate drill flute profile design is generated for two-flute conical twist drills using analytical equations to generate a drill flute profile design needed for the production of twist drills with straight lips. The required grinding wheel profile for a flute production was expressed in digitized form as well as in terms of two curve-fitted circular arcs. The drill flute profile geometry can never be precisely generated when required grinding wheel profile is represented by two circular arcs and the generated flute profile is just a very good approximation of the design flute profile. A CAD （computer aided design） software has been developed using MATLAB to determine the required grinding wheel profile for generating a given drill flute profile design.展开更多
The aim of our study was to evaluate physical properties of cashew nuts from the three main production areas in C<span style="white-space:nowrap;">ô</span>te d’Ivoire namely Bondoukou, ...The aim of our study was to evaluate physical properties of cashew nuts from the three main production areas in C<span style="white-space:nowrap;">ô</span>te d’Ivoire namely Bondoukou, Dabakala and Mankono after 6 months of storage in identical conditions. Sample cashew nuts have been collected from farmers randomly selected in 20 localities far enough apart and also veritable purveyors of nuts. The physical traits of the raw cashew nuts and their different parts were evaluated by standard methods. As results, our data showed that despite the similar mass (in mean 6.23 g) of cashew nuts independently of the origin, the mass of the kernels nuts from Bondoukou (2.17 g) were significantly higher than those from Dabakala (1.90 g) and Mankono (1.81 g) respectively in contrast to the shell mass indicating the best kernels yield at Bondoukou. Nuts water content diminished slowly from nuts at Bondoukou (3.86%) but rapidly at Mankono (5.68%) after 6 months of storage. For the morphometric characteristics, our results revealed that the nuts from Bondoukou were statistically shorter but the kernels were thicker (15.1 ± 0.50 mm) versus and for Dabakala (11.4 ± 0.16 mm) and Mankono (11.2 ± 0.19 mm) respectively. There is a clear correlation between the arithmetic diameter of the kernels and their sphericity (r = 0.99). Concerning the technological properties, out-turn was average ranged from 44.09 to 46.69 with defective up to 18% at Dabakala. Taken together, our results suggested that the cashew nuts presented different physical properties according to each region of production in C<span style="white-space:nowrap;">ô</span>te d’Ivoire requiring appropriated agricultural practices.展开更多
Cowpea (<i><span style="font-family:Verdana;">Vigna</span></i><span style="font-family:Verdana;"> <i>unguiculata</i></span><span style="font-...Cowpea (<i><span style="font-family:Verdana;">Vigna</span></i><span style="font-family:Verdana;"> <i>unguiculata</i></span><span style="font-family:Verdana;">) is an important legume crop in the tropics and subtropical regions of the world. It is mainly grown for its leaves and grains, and to a lesser extent as a fodder crop. Cowpea is considered as the most important food grain legume in the dry savannas of tropical Africa. This study compared the yield of local (</span><i><span style="font-family:Verdana;">Agondire</span></i><span style="font-family:Verdana;">) and improved (SECOW 2W) cowpea varieties grown on an Oxisol. Inorganic P at levels of 0, 10, 20, and 40 kg·ha</span><sup><span style="font-family:Verdana;">-1</span></sup> <span style="font-family:Verdana;">was</span><span style="font-family:Verdana;"> tested on each variety with or without rhizobia inoculation. The experiments were set up in a randomized complete block design and replicated thrice during the short and long rains of the 2015/2016 seasons on fifteen fields in Arua district, northern Uganda. </span><i><span style="font-family:Verdana;">Agondire</span></i><span style="font-family:Verdana;"> responded significantly (P < 0.05) better than SECOW 2W when high rates of inorganic phosphorus (40 kg P ha</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">) were applied. A significant increase of 26.4% and 28.4% in grain yield of </span><i><span style="font-family:Verdana;">Agondire</span></i><span style="font-family:Verdana;"> and SECOW 2W, respectively </span><span style="font-family:Verdana;">was</span><span style="font-family:Verdana;"> obtained after inoculation with rhizobia. We concluded that inoculation and P fertilizer application increased the yield of both varieties, but with inoculation, SECOW 2W performs much better at lower P fertilizer rates than </span><i><span style="font-family:Verdana;">Agondire</span></i><span style="font-family:Verdana;">. Therefore, we recommend growing of SECOW 2W under inoculation with 20 kg P ha</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> and an application of 40 kg P ha</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> for </span><i><span style="font-family:Verdana;">Agondire</span></i><span style="font-family:Verdana;"> local cowpea variety in northern Uganda</span><span style="font-family:Verdana;">.</span>展开更多
Post-evaluation of oilfield productivity construction project is an important part of the whole process management of construction project. According to the principles of objectivity, fairness and science, the project...Post-evaluation of oilfield productivity construction project is an important part of the whole process management of construction project. According to the principles of objectivity, fairness and science, the project overview, working procedures, engineering indicators, output and cost, construction implementation, production and operation, economic benefits, impact and sustainability are comprehensively and systematically analyzed and evaluated, and the experience and lessons are summarized, which can provide reference for investment decision, project management and production construction of similar projects in the future.展开更多
To assess the level of producers’ exposure and the health risk in relation to phytosanitary practices in cashew crops in C<span style="white-space:nowrap;"><span style="white-space:nowrap;&quo...To assess the level of producers’ exposure and the health risk in relation to phytosanitary practices in cashew crops in C<span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span>te d’Ivoire, a descriptive longitudinal toxicological study was conducted in 2018-2019 with 76 cashew producers in the areas of Mankono, Dabakala and Bondoukou. The data collected permitted the assessment of phytosanitary risks on the health of producers according to the Quebec-IRPeQ pesticide risk indicators. Field observations translated into scenarios were used to determine the exposure levels of producers via the UK-POEM predictive model. The main active substances used were glyphosate, 2,4-D, cypermethrin, acetamiprid, lambdacyhalothrin, profenofos, imidacloprid, deltamethrin, mancozeb and metalaxyl. The risk indicators showed that 2,4-D (TRI = 1332.25;SRI = 432.98), profenofos (TRI = 2550.25;SRI = 637.56) and mancozeb (TRI = 841;SRI = 147.18) among herbicides, insecticides and fungicides respectively could have more adverse health effects after exposure. These findings translated into scenarios specifically showed high exposure of producers to herbicides, with exposure levels ranging from 1.31 mg/kg bw/day to 1.67 mg/kg bw/day, well above the acceptable operator’s exposure levels (AOEL). These health risks could be significantly reduced if the required personal protective equipment is worn. But, recommended doses of pesticides should be reconsidered, because in some cases, applicators exposure remained high despite the protective equipment.展开更多
Soil naturally contains various heavy metals,however,their concentrations have reached toxic levels due to excessive agrochemical use and industrial activities.Heavy metals are persistent and non-biodegradable,causing...Soil naturally contains various heavy metals,however,their concentrations have reached toxic levels due to excessive agrochemical use and industrial activities.Heavy metals are persistent and non-biodegradable,causing environmental disruption and posing significant health hazards.Microbial-mediated remediation is a promising strategy to prevent heavy metal leaching and mobilization,facilitating their extraction and detoxification.Nickel(Ni),being a prevalent heavy metal pollutant,requires specific attention in remediation efforts.Plants have evolved defense mechanisms to cope with environmental stresses,including heavy metal toxicity,but such stress significantly reduces crop productivity.Beneficial microorganisms play a crucial role in enhancing plant yield and mitigating abiotic stress.The impact of heavy metal abiotic stress on plants’growth and productivity requires thorough investigation.Bioremediation using Nickel nanoparticles(Ni NPs)offers an effective approach to mitigating environmental pollution.Microorganisms contribute to nanoparticle bioremediation by immobilizing metals or inducing the synthesis of remediating microbial enzymes.Understanding the interactions between microorganisms,contaminants,and nanoparticles(NPs)is essential for advancing bioremediation strategies.This review focuses on the role of Bacillus subtilis in the bioremediation of nickel nanoparticles to mitigate environmental pollution and associated health risks.Furthermore,sustainable approaches are necessary to minimize metal contamination in seeds.The current review discusses bacterial inoculation in enhancing heavy metal tolerance,plant signal transduction pathways,and the transition from molecular to genomic research in metal stress adaptation.Moreover,the inoculation of advantageous bacteria is crucial for preserving plants under severe mental stress.Different researchers develop a complex,vibrant relationship with plants through a series of events known as plant-microbe interactions.It increases metal stress resistance through the creation of phytohormones.In general,the defensive responses of plants to heavy metal stress,mediated by microbial inoculation require further in-depth research.Further studies should explore the detoxification mechanism of nickel through bioremediation to develop more effective and sustainable remediation strategies.展开更多
Diamond coatings possess numerous excellent properties,making them desirable materials for high-performance surface applications.However,without a revolutionary surface modification method,the surface roughness and fr...Diamond coatings possess numerous excellent properties,making them desirable materials for high-performance surface applications.However,without a revolutionary surface modification method,the surface roughness and friction behavior of diamond coatings can impede their ability to meet the demanding requirements of advanced engineering surfaces.This study proposed the thermal stress control at coating interfaces and demonstrated a novel process of precise graphenization on conventional diamond coatings surface through laser induction and mechanical cleavage,without causing damage to the metal substrate.Through experiments and simulations,the influence mechanism of surface graphitization and interfacial thermal stress was elucidated,ultimately enabling rapid conversion of the diamond coating surface to graphene while controlling the coating’s thickness and roughness.Compared to the original diamond coatings,the obtained surfaces exhibited a 63%-72%reduction in friction coefficients,all of which were below 0.1,with a minimum of 0.06,and a 59%-67%decrease in specific wear rates.Moreover,adhesive wear in the friction counterpart was significantly inhibited,resulting in a reduction in wear by 49%-83%.This demonstrated a significant improvement in lubrication and inhibition of mechanochemical wear properties.This study provides an effective and cost-efficient avenue to overcome the application bottleneck of engineered diamond surfaces,with the potential to significantly enhance the performance and expand the application range of diamond-coated components.展开更多
Late sowing is a critical factor that hinders achieving high-yield,good-quality wheat under rice-wheat rotation.Understanding the physiological basis and regulatory pathways that lead to high yield and sound quality l...Late sowing is a critical factor that hinders achieving high-yield,good-quality wheat under rice-wheat rotation.Understanding the physiological basis and regulatory pathways that lead to high yield and sound quality late-sown wheat is crucial for developing effective cultivation strategies.A 2-year field experiment was conducted to investigate the effects of sowing date,nitrogen(N)application rate,and planting density on wheat yield,grain quality,population characteristics,and the underlying physiological factors.The results revealed significant interactions among the sowing date,planting density,and N application in regulating both yield and quality.Late sowing reduced grain yield primarily by reducing the number of spikes and kernels.However,the latter was improved by increasing N application and the planting density,thus mitigating the yield losses caused by late sowing.Moreover,the grain protein content(GPC)and wet gluten content(WGC)increased with delayed sowing dates and higher N rates but decreased with increased planting densities.For wheat yields over 9,000 or 7,500 kg ha^(-1),the latest sowing date should not be later than Nov.4 or 15,respectively.In addition,specific criteria should be met,including a maximum of 1.5 and 1.0 million stems and tillers ha^(-1),a maximum leaf area index of 6.7 and 5.5,and a dry matter accumulation(DMA)at anthesis of 14,000 and 12,000 kg ha^(-1),respectively.For high-yield,good-quality late-sown wheat,the optimal combination is a 25%increase in the N rate(300 kg N ha^(-1))and a planting density of 2.25 million(N300D225)or 3.75 million(N300D375)plants ha^(-1)for 10-or 20-day delays in sowing,respectively.These combinations result in a higher leaf net photosynthetic rate,higher activities of leaf nitrate reductase,glutamine synthetase,grain glutamic pyruvic transaminase,and a lower sugar-N ratio during post-anthesis.展开更多
Synchronizing the nitrogen(N)supply of slow-and controlled-release N fertilizers(SCRNFs)with rice N demand is essential in replacing multiple urea applications with a single basal application of SCRNFs.Traditional ass...Synchronizing the nitrogen(N)supply of slow-and controlled-release N fertilizers(SCRNFs)with rice N demand is essential in replacing multiple urea applications with a single basal application of SCRNFs.Traditional assessment of N supply characteristics primarily examines N release patterns,which are limited to coated SCRNFs and disregard N transformation mechanisms,necessitating a more universal and reliable index.Based on the capacity of crop N status to detect N deficiency or excess,we hypothesized that utilizing leaf N balance index(NBI)as a measure of N status could offer novel insights into assessing N supply characteristics of SCRNFs.Field experiments were conducted with four individual SCRNFs-humic acid urea(HAU),sulfur-coated urea(SCU),urease inhibitor urea(UIU),and polymer-coated urea(PCU)and their four combined forms,alongside high-yield urea split application as control(CK).The results revealed that NBI dynamics relative to CK reflected the N supply potential of different SCRNFs while categorizing them as short-,medium-,and long-acting fertilizers.Combinations incorporating the long-acting SCRNF(PCU)consistently demonstrated superior performance in yield(by 5.5%)and N use efficiency(by 42.8%)through providing more consistent and efficient N supply throughout the rice growth cycle.Grain yield exhibited negative correlation with the difference in NBI dynamics between SCRNFs and CK,suggesting that synchronizing N supply between one-time application of SCRNFs and conventional high-yield fertilization is crucial for high yield.These findings demonstrate the potential of N status diagnosed by leaf NBI to evaluate N supply characteristics of SCRNFs and highlight the importance of synchronized N supply for a one-time SCRNF application.展开更多
One-time application of controlled-release blended fertilizer(CRBF,a mixture of five nitrogen(N)fertilizers in a certain ratio)can achieve high yield and N use efficiency(NUE)in rice(Oryza sativa L.).However,the effec...One-time application of controlled-release blended fertilizer(CRBF,a mixture of five nitrogen(N)fertilizers in a certain ratio)can achieve high yield and N use efficiency(NUE)in rice(Oryza sativa L.).However,the effects of CRBF with one-time application on root spatial distribution and physiological characteristics remain unclear.We measured the effects of CRBF with one-time application on rice yield,NUE,root morphology and growth,and N uptake capacity in field and root box experiments.Six N treatments were set up:no nitrogen(N0),high-yield three-split application of urea as a control(CK),urea(U)with broadcast,U with side-deep fertilization,CRBF with broadcast,and CRBF with side-deep fertilization.Our findings showed that root characters were positively correlated with yield and NUE.Compared to CK and U treatments,CRBF with one-time applications increased root characters(including root biomass,root N uptake,root activity,and the expression level of ammonium transporters)at tillering and heading stages.The root length,surface area and volume in the 0-10 cm soil layer enhanced under CRBF with one-time applications at tillering stage,and in the 0-20 cm soil layer at the heading stage.This contributed a5.96%-39.40% and 3.69%-16.87% increase in plant dry matter accumulation and N uptake,and a2.08%-18.28% and 14.60%-149.57% increase in yield and NUE,in 2022 and 2023,respectively.Taken together,our findings showed that one-time application of CRBF could increase rice yield and NUE by optimizing the root morphology distribution and N uptake.展开更多
Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N ...Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates(240 kg N ha–1(N240), 180 kg N ha–1(N180), 150 kg N ha–1(N150), and 0 kg N ha–1(N0)) and three basal N application stages(seeding(L0), fourleaf stage(L4), and six-leaf stage(L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180 L4 and N240 L0(control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180 L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180 L4 did not differ significantly from those under N240 L0. Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.展开更多
Sixteen cotton cultivars widely planted in China were sowed under five different drought concentrations(0,2.5,5,7.5,and 10%)using PEG6000 to screen the indices of drought resistance identification and explore the drou...Sixteen cotton cultivars widely planted in China were sowed under five different drought concentrations(0,2.5,5,7.5,and 10%)using PEG6000 to screen the indices of drought resistance identification and explore the drought resistance of different cotton cultivars.Eighteen physiological indices including root,stem,and leaf water contents(RWC,SWC,and LWC),net photosynthetic rate(Pn),the maximum photochemical quantum yield(Fv/Fm),the actual photochemical quantum yield(ΦPSII),non-photochemical quenching coefficient(NPQ),leaf water potential(LWP),osmotic potential(Ψs),leaf relative conductivity(REC),leaf proline content(Pro),leaf and root soluble protein contents(LSPC and RSPC),leaf and root malondialdehyde(MDA)contents(LMDA and RMDA),root superoxide dismutase,peroxidase,and catalase activities(RSOD,RPOD,and RCAT)were measured.Results indicated the 18 physiological indices can be converted into five or six independent comprehensive indices by principal component analysis,and nine typical indices(Fv/Fm,SWC,LWP,Pro,LMDA,RSPC,RMDA,RSOD,and RCAT)screened out by a stepwise regression method could be utilized to evaluate the drought resistance.Moreover,the 16 cotton cultivars were divided into four types:drought sensitive,drought weak sensitive,moderate drought resistant,and drought resistant types.The resistance ability of two selected cotton cultivars(drought resistant cultivar,Dexiamian 1;drought sensitive cultivar,Yuzaomian 9110)with contrasting drought sensitivities were further verified by pot experiment.Results showed that the responses of final cotton biomass,yield,and yield composition to drought were significantly different between the two cultivars.In conclusion,drought resistant cultivar Dexiamian 1 and drought sensitive cultivar Yuzaomian 9110 were screened through hydroponics experiment,which can be used as ideal experimental materials to study the mechanism of different cotton cultivars with contrasting drought sensitivities in response to drought stress.展开更多
Soil alkali-hydrolyzable nitrogen, which is sensitive to N fertilization rate, is one of the indicators of soil nitrogen supplying capacity. Two field experiments were conducted in Dongtai(120°19″ E, 32°52...Soil alkali-hydrolyzable nitrogen, which is sensitive to N fertilization rate, is one of the indicators of soil nitrogen supplying capacity. Two field experiments were conducted in Dongtai(120°19″ E, 32°52″ N), Jiangsu, China in 2009 and Dafeng(120°28″ E, 33°12″ N), Jiangsu province, China in 2010. Six nitrogen rates(0, 150, 300, 375, 450, and 600 kg ha^(-1)) were used to study the effect of N fertilization rate on soil alkali-hydrolyzable nitrogen content(SAHNC), subtending leaf nitrogen concentration(SLNC), yield, and fiber quality. In both Dongtai and Dafeng experiment station, the highest yield(1709 kg ha^(-1)), best quality(fiber length 30.6 mm, fiber strength 31.6 c N tex^(-1), micronaire 4.82), and highest N agronomic efficiency(2.03 kg kg^(-1)) were achieved at the nitrogen fertilization rate of 375 kg ha^(-1). The dynamics of SAHNC and SLNC could be simulated with a cubic and an exponential function,respectively. The changes in SAHNC were consistent with the changes in SLNC. Optimal average rate(0.276 mg day^(-1)) and duration(51.8 days) of SAHNC rapid decline were similar to the values obtained at the nitrogen rate of 375 kg ha^(-1)at which cotton showed highest fiber yield, quality, and N agronomic efficiency. Thus, the levels and strategies of nitrogen fertilization can affect SAHNC dynamics. The N fertilization rate that optimizes soil alkali-hydrolyzable nitrogen content would optimize the subtending leaf nitrogen concentration and thereby increase the yield and quality of the cotton fiber.展开更多
A three-year experiment was conducted in the middle-lower reaches of the Yangtze River in China to study the influence of continuous wheat straw return during the rice season and continuous rice straw return in wheat ...A three-year experiment was conducted in the middle-lower reaches of the Yangtze River in China to study the influence of continuous wheat straw return during the rice season and continuous rice straw return in wheat on methane （CH 4 ） emissions from rice fields in which, the rice-wheat rotation system is the most dominant planting pattern. The field experiment was initiated in October 2009 and has continued since the wheat-growing season of that year. The analyses for the present study were conducted in the second （2011） and third （2012） rice growing seasons. Four treatments, namely, the continuous return of wheat straw and rice straw in every season （WR）, of rice straw but no wheat straw return （R）, of wheat straw but no rice straw return （W） and a control with no straw return （CK）, were laid out in a randomized split-plot design. The total seasonal CH 4 emissions ranged from 107.4 to 491.7 kg/ha （2011） and 160.3 to 909.6 kg/ha （2012）. The increase in CH 4 emissions for treatments WR and W were 289% and 230% in the second year and 185% and 225% in the third year, respectively, in relation to CK. We observed less methane emissions in the treatment R than in CK by 14%-43%, but not statistically significant. Treatment R could increase rice productivity while no more CH 4 emission occurs. The difference in the total CH 4 emissions mainly related to a difference in the methane flux rate during the first 30-35 days after transplant in the rice growing season, which was caused by the amount of dissolved oxygen in paddy water and the amount of reducible soil materials.展开更多
In the coastal saline soils,moisture and salinity are the functions of groundwater depth affecting crop growth and yield.Accordingly,the objectives of this study were to:1)investigate the combined effects of moisture ...In the coastal saline soils,moisture and salinity are the functions of groundwater depth affecting crop growth and yield.Accordingly,the objectives of this study were to:1)investigate the combined effects of moisture and salinity stresses on wheat growth as affected by groundwater depth,and 2)find the optimal groundwater depth for wheat growth in coastal saline soils.The groundwater depths(0.7,1.1,1.5,1.9,2.3,and 2.7 m during 2013-2014(Y1)and 0.6,1.0,1.4,1.8,2.2,and 2.6 m during 2014-2015(Y2))of the field experiment were maintained by soil columns.There was a positive correlation between soil moisture and salinity.Water logging with high salinity(groundwater depth at 0.7 m in Y1 and 0.6 m in Y2)showed a greater decline towards wheat growth than that of slight drought with medium(2.3 m in Y1)or low salinity(2.7 m in Y1,2.2 and 2.6 m in Y2).The booting stage was the most sensitive stage of wheat crop under moisture and salinity stresses.Data showed the most optimal rate of photosynthesis,grain yield,and flour quality were obtained under the groundwater depth(ditch depth)of 1.9 m(standard soil moisture with medium salinity)and 2.3 m(slight drought with medium salinity)in Y1 and 1.8 m(standard soil moisture with medium salinity)and 2.2 m(slight drought with low salinity)in Y2.The corresponding optimal soil relative moisture content and conductivity with the 1:5 distilled water/soil dilution,in the depth of 0-20 cm and 20-40 cm in coastal saline soils,were equal to 58.67-63.07%and 65.51-72.66%in Y1,63.09-66.70%and 69.75-74.72%in Y2;0.86-1.01 dS m^-1 and 0.63-0.77 dS m^-1 in Y1,0.57-0.93 dS m^-1 and 0.40-0.63 dS m^-1 in Y2,respectively.展开更多
Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatel...Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatellite loci were polymorphic, with polymorphism information content(PIC) values ranging from 0.593 to 0.952. Totally 92 alleles were identified, and the number of alleles(Na) and effective alleles(Ne) varied between 4 and 21 and 2.7 and 14.6, respectively. Observed heterozygosity(Ho) values were lower than the expected heterozygosity(He) values(0.526–0.754), which indicated that the seven stocks possessed a rich genetic diversity. Thirty-seven tests were detected for reasonable significant deviation from Hardy-Weinberg equilibrium. Fis values were positive at five loci, suggesting that there was a relatively high degree of inbreeding within stocks. Pairwise Fst values ranged from 0.0225 to 0.151, and most of the stock pairs were moderately differentiated. Genetic distance and cluster analysis using UPGMA revealed a close genetic relationship of L. vannamei between Pop2 and Pop3. AMOVA indicated that the genetic variation among stocks(11.3%) was much lower than that within stocks(88.7%). Although the seven stocks had a certain degree of genetic differentiation and a rich genetic diversity, there is an increasing risk of decreased performance due to inbreeding in subsequent generations.展开更多
基金supported by the National Key Research and Development Program of China(2023YFD2301300)the National Natural Science Foundation of China(U24A20402,32301354).
文摘Rice productivity faces critical sustainability challenges from stagnating yields and inefficient fertilizer use,particularly in intensive agricultural regions like the Yangtze River Delta(YRD)of China.Controlled-release blended fertilizers(CRBF),which synchronize nutrient release with crop demand,represent a promising strategy to enhance rice productivity.Here,we conducted an eight-year(2017–2024)field study across 25 representative sites in the YRD to evaluate CRBF’s effects,complemented by a regional extrapolation analysis.Our findings showed that,relative to conventional fertilization,CRBF increased rice yield by 4.9%,primarily by increasing the number of effective panicles(5%)and plant biomass(5.2%–11.3%).Notably,this yield benefit rose to 5.3%when CRBF was applied via deep placement,which was attributed to greater root biomass(13.1%–29.2%)and higher soil NH_(4)^(+)-N availability(24.3%–43.6%),thereby enhancing N uptake.Furthermore,initial soil organic matter was identified as the predominant modulator of CRBF effectiveness.Regional extrapolation projected that applying CRBF could enhance rice yield by 4.0%across the YRD,with deep placement providing an additional 2.1%gain.In conclusion,our study demonstrates that adopting CRBF,particularly with deep placement,is a robust and effective strategy to sustainably boost rice productivity in intensive rice cultivation systems.
文摘Improving the quality of agricultural products depends largely on production process. In the absence of data on farmers’ practices and the average quality of cashew nuts in C<span style="white-space:nowrap;">ô</span>te d’Ivoire, the present study aimed to provide a detailed description of the cashew nut production process. Thus, a survey was carried out in the zones of Mankono, Dabakala and Bondoukou among 386 cashew producers selected at random and interviewed using the face-to-face technique. The results revealed that intercropping was practiced in cashew cultivation (42% - 62% of the producers), modern cultivation technique (72% - 98% of the producers) but with rare use of selected seeds (8% - 20% of the producers), labour/ha during nut harvesting (2.6 - 12 workers/ha). Concerning the harvesting process, the time taken to pick the nuts varies from 1 to 14 days;the use of pesticides during harvesting (14% to 97% of the producers) and the absence of sorting of the nuts in 42% of the Mankono producers justify the probable conservation of defective and immature nuts in their production. For drying, the main dryers were the slatted table, the cemented surface and the tarpaulin, but other dryers were found such as the mosquito net, the propylene rice bag, the fertiliser bag and the black bag. Generally, the drying time of cashew nuts was very short: 2 days (43% - 77% of the producers interviewed) but surprisingly 1 day (7% - 27% of the producers interviewed). For Mankono, the use of chemicals was permanent during all stages of the cashew production process. Overall, the results suggest the need to assess the real impact of farmers’ practices on the quality of cashew nuts from C<span style="white-space:nowrap;">ô</span>te d’Ivoire.
文摘In order to determine various traits which need to be improved for improving the productive life span and longevity, purebred Sahiwal cows available at bull mother experimental farm and cattle breeding farm located at Veterinary College, Durg, Chhattisgarh, India were used. For present investigation, 17 linear type traits were measured, scaled and scored as per the guidelines of International Committee for Animal Recording （2001）. The average score point （ASP） under 1-9 point scale score system along with respective observed group for different linear type traits were stature （6.88; taller）, chest width （5.30; intermediate）, body depth （4.11; intermediate）, rump angle （4.27; intermediate）, rump width （5.09; intermediate）, rear leg set-side view （4.55; intermediate）, rear leg set-rear view （5.95; intermediate）, foot angle （5.66; intermediate）, udder depth （5.71; intermediate）, rear udder height （4.90; intermediate）, udder balance （5.27; intermediate）, udder cleft （3.75; intermediate）, fore udder attachment （5.55; intermediate）, teat length （3.54; intermediate）, fore teat placement （5.33; intermediate）, rear teat placement （6.37; intermediate） and teat thickness （2.76; narrow）. For most of the traits, ASP which lies near midpoint （i.e. near five） is known to be ideal for dairy type cattle. Moreover, some traits also showed the presence of undesirable ASP. Hence, the traits such as body depth, rump angle, foot angle, udder depth, rear udder height, udder cleft, fore udder attachment, teat length, and teat thickness needs to be improved for improving the production sustainability and herd life of Sahiwal cattle. Thus, present investigation gives explicit clue to incorporate these conformation traits in selection program of this valuable germplasm commonly found in Southern part of Asia （India, Pakistan, Srilanka, etc.）.
文摘Twist drill flute profile design is necessary in order to determine the required grinding wheel profile for a flute production. An accurate drill flute profile design is generated for two-flute conical twist drills using analytical equations to generate a drill flute profile design needed for the production of twist drills with straight lips. The required grinding wheel profile for a flute production was expressed in digitized form as well as in terms of two curve-fitted circular arcs. The drill flute profile geometry can never be precisely generated when required grinding wheel profile is represented by two circular arcs and the generated flute profile is just a very good approximation of the design flute profile. A CAD （computer aided design） software has been developed using MATLAB to determine the required grinding wheel profile for generating a given drill flute profile design.
文摘The aim of our study was to evaluate physical properties of cashew nuts from the three main production areas in C<span style="white-space:nowrap;">ô</span>te d’Ivoire namely Bondoukou, Dabakala and Mankono after 6 months of storage in identical conditions. Sample cashew nuts have been collected from farmers randomly selected in 20 localities far enough apart and also veritable purveyors of nuts. The physical traits of the raw cashew nuts and their different parts were evaluated by standard methods. As results, our data showed that despite the similar mass (in mean 6.23 g) of cashew nuts independently of the origin, the mass of the kernels nuts from Bondoukou (2.17 g) were significantly higher than those from Dabakala (1.90 g) and Mankono (1.81 g) respectively in contrast to the shell mass indicating the best kernels yield at Bondoukou. Nuts water content diminished slowly from nuts at Bondoukou (3.86%) but rapidly at Mankono (5.68%) after 6 months of storage. For the morphometric characteristics, our results revealed that the nuts from Bondoukou were statistically shorter but the kernels were thicker (15.1 ± 0.50 mm) versus and for Dabakala (11.4 ± 0.16 mm) and Mankono (11.2 ± 0.19 mm) respectively. There is a clear correlation between the arithmetic diameter of the kernels and their sphericity (r = 0.99). Concerning the technological properties, out-turn was average ranged from 44.09 to 46.69 with defective up to 18% at Dabakala. Taken together, our results suggested that the cashew nuts presented different physical properties according to each region of production in C<span style="white-space:nowrap;">ô</span>te d’Ivoire requiring appropriated agricultural practices.
文摘Cowpea (<i><span style="font-family:Verdana;">Vigna</span></i><span style="font-family:Verdana;"> <i>unguiculata</i></span><span style="font-family:Verdana;">) is an important legume crop in the tropics and subtropical regions of the world. It is mainly grown for its leaves and grains, and to a lesser extent as a fodder crop. Cowpea is considered as the most important food grain legume in the dry savannas of tropical Africa. This study compared the yield of local (</span><i><span style="font-family:Verdana;">Agondire</span></i><span style="font-family:Verdana;">) and improved (SECOW 2W) cowpea varieties grown on an Oxisol. Inorganic P at levels of 0, 10, 20, and 40 kg·ha</span><sup><span style="font-family:Verdana;">-1</span></sup> <span style="font-family:Verdana;">was</span><span style="font-family:Verdana;"> tested on each variety with or without rhizobia inoculation. The experiments were set up in a randomized complete block design and replicated thrice during the short and long rains of the 2015/2016 seasons on fifteen fields in Arua district, northern Uganda. </span><i><span style="font-family:Verdana;">Agondire</span></i><span style="font-family:Verdana;"> responded significantly (P < 0.05) better than SECOW 2W when high rates of inorganic phosphorus (40 kg P ha</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">) were applied. A significant increase of 26.4% and 28.4% in grain yield of </span><i><span style="font-family:Verdana;">Agondire</span></i><span style="font-family:Verdana;"> and SECOW 2W, respectively </span><span style="font-family:Verdana;">was</span><span style="font-family:Verdana;"> obtained after inoculation with rhizobia. We concluded that inoculation and P fertilizer application increased the yield of both varieties, but with inoculation, SECOW 2W performs much better at lower P fertilizer rates than </span><i><span style="font-family:Verdana;">Agondire</span></i><span style="font-family:Verdana;">. Therefore, we recommend growing of SECOW 2W under inoculation with 20 kg P ha</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> and an application of 40 kg P ha</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> for </span><i><span style="font-family:Verdana;">Agondire</span></i><span style="font-family:Verdana;"> local cowpea variety in northern Uganda</span><span style="font-family:Verdana;">.</span>
文摘Post-evaluation of oilfield productivity construction project is an important part of the whole process management of construction project. According to the principles of objectivity, fairness and science, the project overview, working procedures, engineering indicators, output and cost, construction implementation, production and operation, economic benefits, impact and sustainability are comprehensively and systematically analyzed and evaluated, and the experience and lessons are summarized, which can provide reference for investment decision, project management and production construction of similar projects in the future.
文摘To assess the level of producers’ exposure and the health risk in relation to phytosanitary practices in cashew crops in C<span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span>te d’Ivoire, a descriptive longitudinal toxicological study was conducted in 2018-2019 with 76 cashew producers in the areas of Mankono, Dabakala and Bondoukou. The data collected permitted the assessment of phytosanitary risks on the health of producers according to the Quebec-IRPeQ pesticide risk indicators. Field observations translated into scenarios were used to determine the exposure levels of producers via the UK-POEM predictive model. The main active substances used were glyphosate, 2,4-D, cypermethrin, acetamiprid, lambdacyhalothrin, profenofos, imidacloprid, deltamethrin, mancozeb and metalaxyl. The risk indicators showed that 2,4-D (TRI = 1332.25;SRI = 432.98), profenofos (TRI = 2550.25;SRI = 637.56) and mancozeb (TRI = 841;SRI = 147.18) among herbicides, insecticides and fungicides respectively could have more adverse health effects after exposure. These findings translated into scenarios specifically showed high exposure of producers to herbicides, with exposure levels ranging from 1.31 mg/kg bw/day to 1.67 mg/kg bw/day, well above the acceptable operator’s exposure levels (AOEL). These health risks could be significantly reduced if the required personal protective equipment is worn. But, recommended doses of pesticides should be reconsidered, because in some cases, applicators exposure remained high despite the protective equipment.
基金supported by the project of Sanya Yazhou Bay Science and Technology City,Grant No.SKJC-2023-02-004Education Department of Hainan Province,Grant No.Hnky2024ZD-27Key R&D Project of Hainan Province(Science and Technology Commissioner):405314040001.
文摘Soil naturally contains various heavy metals,however,their concentrations have reached toxic levels due to excessive agrochemical use and industrial activities.Heavy metals are persistent and non-biodegradable,causing environmental disruption and posing significant health hazards.Microbial-mediated remediation is a promising strategy to prevent heavy metal leaching and mobilization,facilitating their extraction and detoxification.Nickel(Ni),being a prevalent heavy metal pollutant,requires specific attention in remediation efforts.Plants have evolved defense mechanisms to cope with environmental stresses,including heavy metal toxicity,but such stress significantly reduces crop productivity.Beneficial microorganisms play a crucial role in enhancing plant yield and mitigating abiotic stress.The impact of heavy metal abiotic stress on plants’growth and productivity requires thorough investigation.Bioremediation using Nickel nanoparticles(Ni NPs)offers an effective approach to mitigating environmental pollution.Microorganisms contribute to nanoparticle bioremediation by immobilizing metals or inducing the synthesis of remediating microbial enzymes.Understanding the interactions between microorganisms,contaminants,and nanoparticles(NPs)is essential for advancing bioremediation strategies.This review focuses on the role of Bacillus subtilis in the bioremediation of nickel nanoparticles to mitigate environmental pollution and associated health risks.Furthermore,sustainable approaches are necessary to minimize metal contamination in seeds.The current review discusses bacterial inoculation in enhancing heavy metal tolerance,plant signal transduction pathways,and the transition from molecular to genomic research in metal stress adaptation.Moreover,the inoculation of advantageous bacteria is crucial for preserving plants under severe mental stress.Different researchers develop a complex,vibrant relationship with plants through a series of events known as plant-microbe interactions.It increases metal stress resistance through the creation of phytohormones.In general,the defensive responses of plants to heavy metal stress,mediated by microbial inoculation require further in-depth research.Further studies should explore the detoxification mechanism of nickel through bioremediation to develop more effective and sustainable remediation strategies.
基金support from the National Natural Science Foundation of China(NSFC)[No.52475464,52475463]National Natural Science Foundation of Jiangsu Province(No.BK20231442)+4 种基金the Fundamental Research Funds for the Central Universities(No.NS2024032)the International Joint Laboratory of Sustainable Manufacturing,Ministry of Education and the Fundamental Research Funds for the Central Universities(No.NG2024007)China Scholarship Council(No.202206830048)the Foundation of the Graduate Innovation Center,Nanjing University of Aeronautics and Astronautics(No.kfjj20200510)Funding for Outstanding Doctoral Dissertation in NUAA(No.BCXJ23-09)。
文摘Diamond coatings possess numerous excellent properties,making them desirable materials for high-performance surface applications.However,without a revolutionary surface modification method,the surface roughness and friction behavior of diamond coatings can impede their ability to meet the demanding requirements of advanced engineering surfaces.This study proposed the thermal stress control at coating interfaces and demonstrated a novel process of precise graphenization on conventional diamond coatings surface through laser induction and mechanical cleavage,without causing damage to the metal substrate.Through experiments and simulations,the influence mechanism of surface graphitization and interfacial thermal stress was elucidated,ultimately enabling rapid conversion of the diamond coating surface to graphene while controlling the coating’s thickness and roughness.Compared to the original diamond coatings,the obtained surfaces exhibited a 63%-72%reduction in friction coefficients,all of which were below 0.1,with a minimum of 0.06,and a 59%-67%decrease in specific wear rates.Moreover,adhesive wear in the friction counterpart was significantly inhibited,resulting in a reduction in wear by 49%-83%.This demonstrated a significant improvement in lubrication and inhibition of mechanochemical wear properties.This study provides an effective and cost-efficient avenue to overcome the application bottleneck of engineered diamond surfaces,with the potential to significantly enhance the performance and expand the application range of diamond-coated components.
基金supported by the National Natural Science Foundation of China(32272215)the Key R&D Program of Jiangsu Province,China(BE2021361-1)the Collaborative Innovation Center for Modern Crop Production by Province and Ministry(CIC-MCP),Nanjing Agricultural University,China。
文摘Late sowing is a critical factor that hinders achieving high-yield,good-quality wheat under rice-wheat rotation.Understanding the physiological basis and regulatory pathways that lead to high yield and sound quality late-sown wheat is crucial for developing effective cultivation strategies.A 2-year field experiment was conducted to investigate the effects of sowing date,nitrogen(N)application rate,and planting density on wheat yield,grain quality,population characteristics,and the underlying physiological factors.The results revealed significant interactions among the sowing date,planting density,and N application in regulating both yield and quality.Late sowing reduced grain yield primarily by reducing the number of spikes and kernels.However,the latter was improved by increasing N application and the planting density,thus mitigating the yield losses caused by late sowing.Moreover,the grain protein content(GPC)and wet gluten content(WGC)increased with delayed sowing dates and higher N rates but decreased with increased planting densities.For wheat yields over 9,000 or 7,500 kg ha^(-1),the latest sowing date should not be later than Nov.4 or 15,respectively.In addition,specific criteria should be met,including a maximum of 1.5 and 1.0 million stems and tillers ha^(-1),a maximum leaf area index of 6.7 and 5.5,and a dry matter accumulation(DMA)at anthesis of 14,000 and 12,000 kg ha^(-1),respectively.For high-yield,good-quality late-sown wheat,the optimal combination is a 25%increase in the N rate(300 kg N ha^(-1))and a planting density of 2.25 million(N300D225)or 3.75 million(N300D375)plants ha^(-1)for 10-or 20-day delays in sowing,respectively.These combinations result in a higher leaf net photosynthetic rate,higher activities of leaf nitrate reductase,glutamine synthetase,grain glutamic pyruvic transaminase,and a lower sugar-N ratio during post-anthesis.
基金the Natural Science Foundation of Jiangsu Province,China(BK20200539)the Jiangsu Provincial Key Research and Development Program,China(BE2019377 and BE2019343)the Science and Technology Planning Program of Suzhou,China(ST202228).
文摘Synchronizing the nitrogen(N)supply of slow-and controlled-release N fertilizers(SCRNFs)with rice N demand is essential in replacing multiple urea applications with a single basal application of SCRNFs.Traditional assessment of N supply characteristics primarily examines N release patterns,which are limited to coated SCRNFs and disregard N transformation mechanisms,necessitating a more universal and reliable index.Based on the capacity of crop N status to detect N deficiency or excess,we hypothesized that utilizing leaf N balance index(NBI)as a measure of N status could offer novel insights into assessing N supply characteristics of SCRNFs.Field experiments were conducted with four individual SCRNFs-humic acid urea(HAU),sulfur-coated urea(SCU),urease inhibitor urea(UIU),and polymer-coated urea(PCU)and their four combined forms,alongside high-yield urea split application as control(CK).The results revealed that NBI dynamics relative to CK reflected the N supply potential of different SCRNFs while categorizing them as short-,medium-,and long-acting fertilizers.Combinations incorporating the long-acting SCRNF(PCU)consistently demonstrated superior performance in yield(by 5.5%)and N use efficiency(by 42.8%)through providing more consistent and efficient N supply throughout the rice growth cycle.Grain yield exhibited negative correlation with the difference in NBI dynamics between SCRNFs and CK,suggesting that synchronizing N supply between one-time application of SCRNFs and conventional high-yield fertilization is crucial for high yield.These findings demonstrate the potential of N status diagnosed by leaf NBI to evaluate N supply characteristics of SCRNFs and highlight the importance of synchronized N supply for a one-time SCRNF application.
基金supported by the National Key Research and Development Program of China(2023YFD2301304,2022YFD2301404-4,2023YFD2302600,and 2022YFE0116200)Open Subjects of the Key Laboratory of Agro-Environment in the Middle and Lower Yangtze River Plain,Ministry of Agriculture and Rural Affairs of China(2023F12)+1 种基金National Natural Science Foundation of China(32301964)Sanya Yazhou Bay Science and Technology City Project(SKJC-2023-02-004)。
文摘One-time application of controlled-release blended fertilizer(CRBF,a mixture of five nitrogen(N)fertilizers in a certain ratio)can achieve high yield and N use efficiency(NUE)in rice(Oryza sativa L.).However,the effects of CRBF with one-time application on root spatial distribution and physiological characteristics remain unclear.We measured the effects of CRBF with one-time application on rice yield,NUE,root morphology and growth,and N uptake capacity in field and root box experiments.Six N treatments were set up:no nitrogen(N0),high-yield three-split application of urea as a control(CK),urea(U)with broadcast,U with side-deep fertilization,CRBF with broadcast,and CRBF with side-deep fertilization.Our findings showed that root characters were positively correlated with yield and NUE.Compared to CK and U treatments,CRBF with one-time applications increased root characters(including root biomass,root N uptake,root activity,and the expression level of ammonium transporters)at tillering and heading stages.The root length,surface area and volume in the 0-10 cm soil layer enhanced under CRBF with one-time applications at tillering stage,and in the 0-20 cm soil layer at the heading stage.This contributed a5.96%-39.40% and 3.69%-16.87% increase in plant dry matter accumulation and N uptake,and a2.08%-18.28% and 14.60%-149.57% increase in yield and NUE,in 2022 and 2023,respectively.Taken together,our findings showed that one-time application of CRBF could increase rice yield and NUE by optimizing the root morphology distribution and N uptake.
基金financial support from theNational Natural Science Foundation of China (31471443, 31501262)the Fundamental Research Funds for the Central Universities, China (KJQN201632)the Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University
文摘Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates(240 kg N ha–1(N240), 180 kg N ha–1(N180), 150 kg N ha–1(N150), and 0 kg N ha–1(N0)) and three basal N application stages(seeding(L0), fourleaf stage(L4), and six-leaf stage(L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180 L4 and N240 L0(control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180 L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180 L4 did not differ significantly from those under N240 L0. Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.
基金supported by the National Natural Science Foundation of China (31630051 and 31571606)the Jiangsu Collaborative Innovation Center for Modern Crop Production, China (JCIC-MCP)the earmarked fund for China Agriculture Research System (CARS-18-14)
文摘Sixteen cotton cultivars widely planted in China were sowed under five different drought concentrations(0,2.5,5,7.5,and 10%)using PEG6000 to screen the indices of drought resistance identification and explore the drought resistance of different cotton cultivars.Eighteen physiological indices including root,stem,and leaf water contents(RWC,SWC,and LWC),net photosynthetic rate(Pn),the maximum photochemical quantum yield(Fv/Fm),the actual photochemical quantum yield(ΦPSII),non-photochemical quenching coefficient(NPQ),leaf water potential(LWP),osmotic potential(Ψs),leaf relative conductivity(REC),leaf proline content(Pro),leaf and root soluble protein contents(LSPC and RSPC),leaf and root malondialdehyde(MDA)contents(LMDA and RMDA),root superoxide dismutase,peroxidase,and catalase activities(RSOD,RPOD,and RCAT)were measured.Results indicated the 18 physiological indices can be converted into five or six independent comprehensive indices by principal component analysis,and nine typical indices(Fv/Fm,SWC,LWP,Pro,LMDA,RSPC,RMDA,RSOD,and RCAT)screened out by a stepwise regression method could be utilized to evaluate the drought resistance.Moreover,the 16 cotton cultivars were divided into four types:drought sensitive,drought weak sensitive,moderate drought resistant,and drought resistant types.The resistance ability of two selected cotton cultivars(drought resistant cultivar,Dexiamian 1;drought sensitive cultivar,Yuzaomian 9110)with contrasting drought sensitivities were further verified by pot experiment.Results showed that the responses of final cotton biomass,yield,and yield composition to drought were significantly different between the two cultivars.In conclusion,drought resistant cultivar Dexiamian 1 and drought sensitive cultivar Yuzaomian 9110 were screened through hydroponics experiment,which can be used as ideal experimental materials to study the mechanism of different cotton cultivars with contrasting drought sensitivities in response to drought stress.
基金funded by the National Key Technology R&D Program of China (No. 2014BAD11B02)the Special Fund for Agro-scientific Research in the Public Interest (No. 201203096)+1 种基金the National Natural Science Foundation of China (Nos. 31401327, 30971735)the China Agriculture Research System (No. CARS-18-20)
文摘Soil alkali-hydrolyzable nitrogen, which is sensitive to N fertilization rate, is one of the indicators of soil nitrogen supplying capacity. Two field experiments were conducted in Dongtai(120°19″ E, 32°52″ N), Jiangsu, China in 2009 and Dafeng(120°28″ E, 33°12″ N), Jiangsu province, China in 2010. Six nitrogen rates(0, 150, 300, 375, 450, and 600 kg ha^(-1)) were used to study the effect of N fertilization rate on soil alkali-hydrolyzable nitrogen content(SAHNC), subtending leaf nitrogen concentration(SLNC), yield, and fiber quality. In both Dongtai and Dafeng experiment station, the highest yield(1709 kg ha^(-1)), best quality(fiber length 30.6 mm, fiber strength 31.6 c N tex^(-1), micronaire 4.82), and highest N agronomic efficiency(2.03 kg kg^(-1)) were achieved at the nitrogen fertilization rate of 375 kg ha^(-1). The dynamics of SAHNC and SLNC could be simulated with a cubic and an exponential function,respectively. The changes in SAHNC were consistent with the changes in SLNC. Optimal average rate(0.276 mg day^(-1)) and duration(51.8 days) of SAHNC rapid decline were similar to the values obtained at the nitrogen rate of 375 kg ha^(-1)at which cotton showed highest fiber yield, quality, and N agronomic efficiency. Thus, the levels and strategies of nitrogen fertilization can affect SAHNC dynamics. The N fertilization rate that optimizes soil alkali-hydrolyzable nitrogen content would optimize the subtending leaf nitrogen concentration and thereby increase the yield and quality of the cotton fiber.
基金supported by the National Science and Technology Support Plan Project in China (No. 2012BAD04B08, 2011BAD16B14)
文摘A three-year experiment was conducted in the middle-lower reaches of the Yangtze River in China to study the influence of continuous wheat straw return during the rice season and continuous rice straw return in wheat on methane （CH 4 ） emissions from rice fields in which, the rice-wheat rotation system is the most dominant planting pattern. The field experiment was initiated in October 2009 and has continued since the wheat-growing season of that year. The analyses for the present study were conducted in the second （2011） and third （2012） rice growing seasons. Four treatments, namely, the continuous return of wheat straw and rice straw in every season （WR）, of rice straw but no wheat straw return （R）, of wheat straw but no rice straw return （W） and a control with no straw return （CK）, were laid out in a randomized split-plot design. The total seasonal CH 4 emissions ranged from 107.4 to 491.7 kg/ha （2011） and 160.3 to 909.6 kg/ha （2012）. The increase in CH 4 emissions for treatments WR and W were 289% and 230% in the second year and 185% and 225% in the third year, respectively, in relation to CK. We observed less methane emissions in the treatment R than in CK by 14%-43%, but not statistically significant. Treatment R could increase rice productivity while no more CH 4 emission occurs. The difference in the total CH 4 emissions mainly related to a difference in the methane flux rate during the first 30-35 days after transplant in the rice growing season, which was caused by the amount of dissolved oxygen in paddy water and the amount of reducible soil materials.
基金funded by the National Key R&D Program of China (2017YFD0201900)the Fundamental Research Funds for the Central Universities, China (KYYJ201802)the earmarked fund for China Agriculture Research System (CARS-15-14)
文摘In the coastal saline soils,moisture and salinity are the functions of groundwater depth affecting crop growth and yield.Accordingly,the objectives of this study were to:1)investigate the combined effects of moisture and salinity stresses on wheat growth as affected by groundwater depth,and 2)find the optimal groundwater depth for wheat growth in coastal saline soils.The groundwater depths(0.7,1.1,1.5,1.9,2.3,and 2.7 m during 2013-2014(Y1)and 0.6,1.0,1.4,1.8,2.2,and 2.6 m during 2014-2015(Y2))of the field experiment were maintained by soil columns.There was a positive correlation between soil moisture and salinity.Water logging with high salinity(groundwater depth at 0.7 m in Y1 and 0.6 m in Y2)showed a greater decline towards wheat growth than that of slight drought with medium(2.3 m in Y1)or low salinity(2.7 m in Y1,2.2 and 2.6 m in Y2).The booting stage was the most sensitive stage of wheat crop under moisture and salinity stresses.Data showed the most optimal rate of photosynthesis,grain yield,and flour quality were obtained under the groundwater depth(ditch depth)of 1.9 m(standard soil moisture with medium salinity)and 2.3 m(slight drought with medium salinity)in Y1 and 1.8 m(standard soil moisture with medium salinity)and 2.2 m(slight drought with low salinity)in Y2.The corresponding optimal soil relative moisture content and conductivity with the 1:5 distilled water/soil dilution,in the depth of 0-20 cm and 20-40 cm in coastal saline soils,were equal to 58.67-63.07%and 65.51-72.66%in Y1,63.09-66.70%and 69.75-74.72%in Y2;0.86-1.01 dS m^-1 and 0.63-0.77 dS m^-1 in Y1,0.57-0.93 dS m^-1 and 0.40-0.63 dS m^-1 in Y2,respectively.
基金supported by the National High Technology Development Project of China under contract No. 2012AA10A404the Recommended International Advanced Agricultural Science and Technology Project of China under contract No. 2012-S5
文摘Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatellite loci were polymorphic, with polymorphism information content(PIC) values ranging from 0.593 to 0.952. Totally 92 alleles were identified, and the number of alleles(Na) and effective alleles(Ne) varied between 4 and 21 and 2.7 and 14.6, respectively. Observed heterozygosity(Ho) values were lower than the expected heterozygosity(He) values(0.526–0.754), which indicated that the seven stocks possessed a rich genetic diversity. Thirty-seven tests were detected for reasonable significant deviation from Hardy-Weinberg equilibrium. Fis values were positive at five loci, suggesting that there was a relatively high degree of inbreeding within stocks. Pairwise Fst values ranged from 0.0225 to 0.151, and most of the stock pairs were moderately differentiated. Genetic distance and cluster analysis using UPGMA revealed a close genetic relationship of L. vannamei between Pop2 and Pop3. AMOVA indicated that the genetic variation among stocks(11.3%) was much lower than that within stocks(88.7%). Although the seven stocks had a certain degree of genetic differentiation and a rich genetic diversity, there is an increasing risk of decreased performance due to inbreeding in subsequent generations.
