Soil erosion on cropland is a major source of environmental problems in China ranging from the losses of a non-renewable resource and of nutrients at the source to contamination of downstream areas. Regional soil loss...Soil erosion on cropland is a major source of environmental problems in China ranging from the losses of a non-renewable resource and of nutrients at the source to contamination of downstream areas. Regional soil loss assessments using the Universal Soil Loss Equation (USLE) would supply a scientiifc basis for soil conservation planning. However, a lack of in-formation on the cover and management (C) factor for cropland, one of the most important factors in the USLE, has limited accurate regional assessments in China due to the large number of crops grown and their complicated rotation systems. In this study, single crop soil loss ratios (SLRs) were col ected and quantiifed for 10 primary crops from past studies or re-ports. The mean annual C values for 88 crop rotation systems in 12 cropping system regions were estimated based on the combined effects of single crop SLRs and the percentage of annual rainfal erosivity (R) during the corresponding periods for each system. The C values in different cropping system regions were compared and discussed. The results indicated that the SLRs of the 10 primary crops ranged from 0.15 to 0.74. The mean annual C value for al 88 crop rotation systems was 0.34, with a standard deviation of 0.12. The mean C values in the single, double and triple cropping zones were 0.37, 0.36 and 0.28, respectively, and the C value in the triple zone was signiifcantly different from those in single and double zones. The C values of dryland crop systems exhibited signiifcant differences in the single and triple cropping system regions but the differences in the double regions were not signiifcant. This study is the ifrst report of the C values of crop rotation systems in China at the national scale. It wil provide necessary and practical parameters for accurately assessing regional soil losses from cropland to guide soil conservation plans and to optimize crop rotation systems.展开更多
Soil microbial biomass nitrogen(MBN)contains the largest proportion of biologically active nitrogen(N)in soil,and is considered as a crucial participant in soil N cycling.Agronomic management practices such as crop ro...Soil microbial biomass nitrogen(MBN)contains the largest proportion of biologically active nitrogen(N)in soil,and is considered as a crucial participant in soil N cycling.Agronomic management practices such as crop rotation and monocropping systems,dramatically affect MBN in agroecosystems.However,the influence of crop rotation and monocropping in agroecosystems on MBN remains unclear.A meta-analysis based on 203 published studies was conducted to quantify the effect of crop rotation and mono-cropping systems on MBN under synthetic N fertilizer application.The analysis showed that crop rotation significantly stimulated the response ratio(RR)of MBN to N fertilization and this parameter reached the highest levels in upland-fallow rotations.Upland mono-cropping did not change the RR of MBN to N application,however,the RR of MBN to N application in paddy mono-cropping increased.The difference between crop rotation and mono-cropping systems appeared to be due to the various cropping management scenarios,and the pattern,rate and duration of N addition.Crop rotation systems led to a more positive effect on soil total N(TN)and a smaller reduction in soil pH than mono-cropping systems.The RR of MBN to N application was positively correlated with the RR of mineral N only in crop rotation systems and with the RR of soil pH only in mono-cropping systems.Combining the results of Random Forest(RF)model and structural equation model showed that the predominant driving factors of MBN changes in crop rotation systems were soil mineral N and TN,while in mono-cropping systems the main driving factor was soil pH.Overall,our study indicates that crop rotation can be an effective way to enhance MBN by improving soil N resources,which promote the resistance of MBN to low pH induced by intensive synthetic N fertilizer application.展开更多
The lower Ili River Basin is located in semi-arid area, and the annual rainfall is 177mm. Therefore, the irrigation is inevitable for agriculture. Large-scale irrigated agriculture had been developed since 1960's in ...The lower Ili River Basin is located in semi-arid area, and the annual rainfall is 177mm. Therefore, the irrigation is inevitable for agriculture. Large-scale irrigated agriculture had been developed since 1960's in the lower parts of the river and the total irrigated area is about 32 000 hm2. In the project area, the paddy rice-upland crop rotation has been practiced. Due to the domestic water use for hydropower and agriculture as well as water use among riparian countries, the deficit of water for agriculture in the lower part has been concerned. The authors, therefore, conducted the field survey and water balance analysis of the Akdara irrigation project in the lower Ill River Basin in order to assess the land and water uses. Moreover, the impact of the water use on water environment to the basin was analyzed. The following results were obtained as following (1) the groundwater level in the irrigated district varied from 1.5 m to 3.5 m through year. (2) 1970's groundwater level was drastically raised from 8 m to 3 m and the groundwater had been recharged in this period. (3) Water use efficiency of agriculture, which is the ratio of total evapotranspiration to the total water withdrawal was as low as 0.23.展开更多
To estimate the impact of crop rotation on the pathotype and genetic structure of Phythophthora sojae in fields, 372 isolates of P. sojae were obtained from long-term localisation experimental fields in Heilongjiang P...To estimate the impact of crop rotation on the pathotype and genetic structure of Phythophthora sojae in fields, 372 isolates of P. sojae were obtained from long-term localisation experimental fields in Heilongjiang Province of China. The hypocotyl inoculation method was used to characterize the virulence of P. sojae on 13 differential cultivars, and the amplified fragment length polymorphism(AFLP) technique was used to analyze difference in the genetic structure of P. sojae. The results indicated that an abundant diversity of genetic structures and pathotypes of P. sojae, a more uniform distribution of pathotypes and less dominance of pathotypes occurred in corn-soybean and wheat-soybean rotation fields than in a continuous soybean mono-cropping field. These findings suggested that P. sojae did not easily become the dominant race in rotation fields, which maintain disease resistance in soybean varieties. Therefore, the results of this study suggested that Phytophthora stem and root rot of soybeans could be effectively controlled by rotating soybeans with non-host crops of corn and wheat.展开更多
Based on the"Web of Science Core Collection"(SCIE database),this article used the visualization software CiteSpace to visualize and analyze the crop rotation fallow patterns in the past five years.It analyze...Based on the"Web of Science Core Collection"(SCIE database),this article used the visualization software CiteSpace to visualize and analyze the crop rotation fallow patterns in the past five years.It analyzed the countries,institutions,keywords and hot topics of related literature to explore their research characteristics and development,and to provide reference for crop rotation fallow research and practice.The research shows that:1)developed countries are the main research force in the field of crop rotation and fallowing,and the connection between the research of each country and each institution is not close;2)research hotspots can be mainly summarized as:crop growth and yield,greenhouse gas emissions and soil health analysis,and the research in this field is constantly refined,combining macro and micro;3)In recent years,there is a big gap between China and foreign countries in the field of crop rotation and fallow research.It is necessary to strengthen the cooperation with research institutions in developed countries in Europe and the United States,and to carry out cross-regional and interdisciplinary research cooperation to improve the quality of papers and scientific research level.展开更多
Agriculture has increased the release of reactive nitrogen to the environment due to crops’low nitrogen-use efficiency(NUE)after the application of nitrogen-fertilisers.Practices like the use of stabilized-fertiliser...Agriculture has increased the release of reactive nitrogen to the environment due to crops’low nitrogen-use efficiency(NUE)after the application of nitrogen-fertilisers.Practices like the use of stabilized-fertilisers with nitrification inhibitors such as DMPP(3,4-dimethylpyrazole phosphate)have been adopted to reduce nitrogen losses.Otherwise,cover crops can be used in crop-rotation-strategies to reduce soil nitrogen pollution and benefit the following culture.Sorghum(Sorghum bicolor)could be a good candidate as it is drought tolerant and its culture can reduce nitrogen losses derived from nitrification because it exudates biological nitrification inhibitors(BNIs).This work aimed to evaluate the effect of fallow-wheat and sorghum cover crop-wheat rotations on N_(2)O emissions and the grain yield of winter wheat crop.In addition,the suitability of DMPP addition was also analyzed.The use of sorghum as a cover crop might not be a suitable option to mitigate nitrogen losses in the subsequent crop.Although sorghum–wheat rotation was able to reduce 22%the abundance of amoA,it presented an increment of 77%in cumulative N_(2)O emissions compared to fallow–wheat rotation,which was probably related to a greater abundance of heterotrophic-denitrification genes.On the other hand,the application of DMPP avoided the growth of ammonia-oxidizing bacteria and maintained the N_(2)O emissions at the levels of unfertilized-soils in both rotations.As a conclusion,the use of DMPP would be recommendable regardless of the rotation since it maintains NH_(4)^(+)in the soil for longer and mitigates the impact of the crop residues on nitrogen soil dynamics.展开更多
Nitrogen(N)is a key factor in the positive response of cereal crops that follow leguminous crops when compared to gramineous crops in rotations,with the nonrecyclable rhizosphere-derived N playing an important role.Ho...Nitrogen(N)is a key factor in the positive response of cereal crops that follow leguminous crops when compared to gramineous crops in rotations,with the nonrecyclable rhizosphere-derived N playing an important role.However,quantitative assessments of differences in the N derived from rhizodeposition(NdfR)between legumes and gramineous crops are lacking,and comparative studies on their contributions to the subsequent cereals are scarce.In this study,we conducted a meta-analysis of NdfR from leguminous and gramineous crops based on 34 observations published worldwide.In addition,pot experiments were conducted to study the differences in the NdfR amounts,distributions and subsequent effects of two major wheat(Triticum aestivum L.)-preceding crops,corn(Zea mays L.)and soybean(Glycine max L.),by the cotton wick-labelling method in the main wheat-producing areas of China.The meta-analysis results showed that the NdfR of legumes was significantly greater by 138.93%compared to gramineous crops.In our pot experiment,the NdfR values from corn and soybean were 502.32 and 944.12 mg/pot,respectively,and soybean was also significantly higher than corn,accounting for 76.91 and 84.15%of the total belowground nitrogen of the plants,respectively.Moreover,in different soil particle sizes,NdfR was mainly enriched in the large macro-aggregates(>2 mm),followed by the small macro-aggregates(2–0.25 mm).The amount and proportion of NdfR in the macro-aggregates(>0.25 mm)of soybean were 3.48 and 1.66 times higher than those of corn,respectively,indicating the high utilization potential of soybean NdfR.Regarding the N accumulation of subsequent wheat,the contribution of soybean NdfR to wheat was approximately 3 times that of corn,accounting for 8.37 and 4.04%of the total N uptake of wheat,respectively.In conclusion,soybean NdfR is superior to corn in terms of the quantity and distribution ratio of soil macro-aggregates.In future field production,legume NdfR should be included in the nitrogen pool that can be absorbed and utilized by subsequent crops,and the role and potential of leguminous plants as nitrogen source providers in crop rotation systems should be fully utilized.展开更多
Conservation Agriculture(CA)covers more than 205 million hectares in the world.This made it possible to face and mitigate the challenges of climate change,reducing soil erosion and providing multiple ecosystem service...Conservation Agriculture(CA)covers more than 205 million hectares in the world.This made it possible to face and mitigate the challenges of climate change,reducing soil erosion and providing multiple ecosystem services.The first elementary factor influenced is the yield evaluation.It has a direct effect on farmers’choices for sustainable production.The present article records a review focused on wheat yield average positive change compared between conventional tillage(CT)and no tillage(NT)systems.The international database collected showed that NT is adaptable everywhere.The results of wheat yield differentiation showed the influence of crop rotation depending on stations located in different climatic zones.In more than 40 years of research,specialists have succeeded in demonstrating the importance of crop productivity like wheat.The whole integrates also experimentations where the initiation starts more than ten years.展开更多
Certain agricultural management practices are known to affect the soil microbial community structure;however,knowledge of the response of the fungal community structure to the long-term continuous cropping and rotatio...Certain agricultural management practices are known to affect the soil microbial community structure;however,knowledge of the response of the fungal community structure to the long-term continuous cropping and rotation of soybean,maize and wheat in the same agroecosystem is limited.We assessed the fungal abundance,composition and diversity among soybean rotation,maize rotation and wheat rotation systems and among long-term continuous cropping systems of soybean,maize and wheat as the effect of crop types on fungal community structure.We compared these fungal parameters of same crop between long-term crop rotation and continuous cropping systems as the effect of cropping systems on fungal community structure.The fungal abundance and composition were measured by quantitative real-time PCR and Illumina MiSeq sequencing.The results revealed that long-term continuous soybean cropping increased the soil fungal abundance compared with soybean rotation,and the fungal abundance was decreased in long-term continuous maize cropping compared with maize rotation.The long-term continuous soybean cropping also exhibited increased soil fungal diversity.The variation in the fungal community structure among the three crops was greater than that between long-term continuous cropping and rotation cropping.Mortierella,Guehomyces and Alternaria were the most important contributors to the dissimilarity of the fungal communities between the continuous cropping and rotation cropping of soybean,maize and wheat.There were 11 potential pathogen and 11 potential biocontrol fungi identified,and the relative abundance of most of the potential pathogenic fungi increased during the long-term continuous cropping of all three crops.The relative abundance of most biocontrol fungi increased in long-term continuous soybean cropping but decreased in long-term continuous maize and wheat cropping.Our results indicate that the response of the soil fungal community structure to long-term continuous cropping varies based upon crop types.展开更多
This study was designed to find out an optimised planting system of reducing non-point (source) pollution by analyzing the reasons and the factors of influence non-point pollution in farmland of Erhai Lake basin. Th...This study was designed to find out an optimised planting system of reducing non-point (source) pollution by analyzing the reasons and the factors of influence non-point pollution in farmland of Erhai Lake basin. The results showed that incomes, residual nitrogen in soil, and the loss of nitrogen in surface water in rice-garlic system were higher than those in rice-fava bean system. There were positive correlations between the nitrogen loss of farmland, nitrogen inputs, residual nitrogen in soil, and incomes of farmland. Economic benefits and environment benefits are both appropriate, if the area of rice-garlic system would be reduced to 53% and the area of rice-fava bean system increased to 36% of total cropping area in the investigated watershed. Adjustment of planting structure and introduction of reasonable rotation systems is considered an effective measure of controlling agricultural non-point pollution in watersheds of Erhai Lake.展开更多
Reduced tillage provides ecological and economic benefits to arable land on the Loess Plateau of China, where soil erosion has long been a serious problem and soil water availability is largely restricted. However, hi...Reduced tillage provides ecological and economic benefits to arable land on the Loess Plateau of China, where soil erosion has long been a serious problem and soil water availability is largely restricted. However, high abundances of weeds in reduced tillage systems cause significant yield losses. In this study, we explored the effects of no-tillage and stubble retention on the number and density of weeds and weed seeds in a 12-year maize-winter wheat-common vetch rotation on the Loess Plateau. Four treatments including conventional tillage, no-tillage, conventional tillage+stubble retention and no-tillage+stubble retention were designed and applied. We found that no-tillage increased the number of weed species and weed density in most of the crops, while stubble retention decreased weed density in maize and tended to suppress weeds in both no-tillage treatments(no-tillage and no-tillage+stubble retention). No-tillage led to an increase in the number of weed species in the weed seedbank and tended to increase seed density during the spring growth of winter wheat, but it decreased seed density during post-vetch fallow. Stubble retention tended to reduce seed density during the spring growth of winter wheat and post-vetch fallow. We concluded that no-tillage can promote weeds in the experimental crop rotation, while stubble retention suppresses weeds in untilled fields. The combined effects of stubble retention and no-tillage on weed suppression varied among the three crops. Based on these results, we recommend stubble retention in untilled legume-crop rotations on the Loess Plateau to improve the control of weeds.展开更多
Through collecting rhizosphere soil sample from a 30-year long-term fixed location test site that use“rice-ricerape”crop rotation(RRR)and“rice-rice-fallow”continuous cropping systems(RRF),this paper investigated e...Through collecting rhizosphere soil sample from a 30-year long-term fixed location test site that use“rice-ricerape”crop rotation(RRR)and“rice-rice-fallow”continuous cropping systems(RRF),this paper investigated effects of long-term crop rotation on physicochemical property and bacterial community of rhizosphere soil.Results showed that total nitrogen(TN),total phosphorus(TP)and available potassium(AK)contents in rhizosphere soil under long-term RRR were decreased by 28.09%,15.69%and 6.25%respectively.Alkali-hydrolyzable nitrogen(AN)and available phosphorus(AP)contents were 10.59%and 13.25%higher than those of soil in RRF respectively.Three soil samples collected during different periods also showed that RRR resulted in a lower rhizosphere soil pH than RRF.Clone library analysis revealed that significant difference in rhizosphere soil bacterial community was observed between RRR and RRF continuous cropping.Abundance ofα-Proteobacteria,β-Proteobacteria andγ-Proteobacteria were higher in rhizosphere soil of RRR compared to RRF.pH of rhizosphere soil was significantly correlated with Acidobacteria level,while total organic carbon(TOC)content was significantly correlated with Proteobacteria level.Long-term RRR enhanced conversion of N and P in rhizosphere soil,increased bio-availability to crop,and promoted diversity of soil bacterial community.Bacterial diversity in RRR could be ecological significance in maintaining soil fertility and functionality.展开更多
To investigate the effects of crop rotation on oilseed flax growth and yield,three season experiments were carried out in semi-arid area of Dingxi,Gansu from 2017 to 2019.The designed 6 rotational systems were FFF(fla...To investigate the effects of crop rotation on oilseed flax growth and yield,three season experiments were carried out in semi-arid area of Dingxi,Gansu from 2017 to 2019.The designed 6 rotational systems were FFF(flax-flaxflax),PFF(potato-flax-flax),WPF(wheat-potato-flax),FPF(flax-potato-flax),PWF(potato-wheat-flax)and FWF(flax-wheat-flax).Flax growth and yield investigation results showed that crop rotation increased leaf area duration,dry matter accumulation,seed nitrogen accumulation,water and nitrogen used efficiency,compared with continuous cropping of flax.Flaxseed yields in rotation systems were 22.23%–44.11%greater than those of continuous cropping system.Those in wheat and potato stubbles had higher tiller number(21.43%and 29.46%),more branches(14.24%and 6.97%),effective capsules(26.35%and 28.79%),higher water use efficiency(40.26%and 33.5%),higher nitrogen partial factor productivity(33.85%and 31.46%)and dry matter(41.98%and 25.47%)than those in oilseed flax stubble.It concluded that crop rotation system was an effective measure for oilseed flax productivity in semi-arid area by improving yield components and promoting biomass.展开更多
We used an ongoing long-term field trial established since 1960 in Burkina Faso, to study the microbial properties of a Ferric Lixisol under various crop management and fertilization regimes. Microbial respiration rat...We used an ongoing long-term field trial established since 1960 in Burkina Faso, to study the microbial properties of a Ferric Lixisol under various crop management and fertilization regimes. Microbial respiration rate, microbial biomass carbon (MBC) and soil bacteria’s number were assessed in soil samples taken at 0<span style="font-family:;" "=""> </span><span style="font-family:;" "="">-</span><span style="font-family:;" "=""> </span><span style="font-family:;" "="">20 cm depth. The crop management were continuous cropping of sorghum (<i>Sorghum bicolor L</i>.) (S/S) and rotation between sorghum and cowpea (<i>Vigna unguiculata L</i>.) (S/C), while the fertilization regimes were: 1) Control (te);2) Low rate of mineral fertilizer (fm);3) Low rate of mineral fertilizer + sorghum straw restitution (fmr);4) Low rate of mineral fertilizer + low rate of manure (fmo);5) High rate of mineral fertilizer (FM);and vii) High rate of mineral fertilizer + high rate of manure (FMO). The manure is applied every second year. The results indicate that sorghum/cowpea rotation significantly increase MBC and bacteria number as compared to continuous sorghum cropping. MBC ranged from 335.5 to 54.85 μg C g</span><span style="font-family:;" "=""><sup><span style="white-space:nowrap;">−</span><span>1</span></sup><span> soil with S/S and from 457.5 to 86.6 μg C g</span><sup><span style="white-space:nowrap;">−</span><span>1</span></sup><span> soil with S/C. Application of high level of manure and mineral fertilizer increase microbial respiration rate and MBC. The highest MBC was observed with FMO and the lowest with the control. In general, the metabolic quotient (qCO<sub>2</sub>) was negatively impacted by the fertilization and cowpea rotation. For S/S rotation, qCO<sub>2</sub> of the control was 1.5 to 2 times that of the treatments with low mineral fertilizer (fmr, fmo and fm) and 3 times that of the high rate of fertilization (FM and FMO). With S/C rotation, qCO<sub>2</sub> of the control was 2 times of that fmr, FM and FMO and 0.8 times that of fmo and fm. Soil bacteria in the fmr were 63.6 and 12.4 times the control in the S/S and S/C rotations, respectively. In sum, combined application of manure and mineral fertilizer with crop rotation is the best management practices to improve in sustainable way microbial activities in tropical soil.</span></span>展开更多
To better understand the effects of direct sowing under mulch-based cropping system (DMC) in Burkina Faso’s cotton production systems, randomized blocks of Fisher experimental design were implemented at Farako-B<s...To better understand the effects of direct sowing under mulch-based cropping system (DMC) in Burkina Faso’s cotton production systems, randomized blocks of Fisher experimental design were implemented at Farako-B<span style="white-space:nowrap;">a</span> research station from 2010 to 2019. The study was conducted on lixisoil to evaluate DMC effects on biomass production, crops yields and soil chemical properties in a maize and cotton rotation system associated with cover crop. Conventional tillage and direct seeding without cover crop were compared to DMC under <em>B</em>. <em>ruziziensis</em> (GERM. & EVRARD), DMC under <em>B</em>. <em>ruziziensis</em> + <em>M</em><em>.</em> <em>cochinchinensis</em> mulch and DMC under <em>C. juncea</em> (L.) mulch used in association with maize. Biomass production, crop yields and soil chemistry were evaluated. Results showed that over 10 years, no-till with or without a cover crop provided cotton seed and maize yields that were statistically equivalent to the tillage commonly practiced by farmers. Cover crop has allowed increasing the biomass production compared to Conventional Tillage and Direct Seeding. Maize yield has not varied significantly with the cover crop. After 10 years of maize and cotton rotation, the improvement raised from +27% to +38% for organic matter and from +15% to +29% for nitrogen with DMC including legumes such as <em>M. cochinchinensis</em> and <em>C. juncea</em> compared to Conventional Tillage on 0 - 5 cm depth. No significant differences were found on soil pH like P<sub>2</sub>O<sub>5</sub> and K<sub>2</sub>O content. Although DMC with <em>C. juncea</em> used as cover crop did not provide the best biomass production, it contributes to increase nitrogen and organic matter and presents better mineral balances in 10 years of rotation. The 5 - 10 cm and 10 - 20 cm were little influenced by DMC systems.展开更多
Rice is often grown as multiple seasons in one year,alternating between flooded and upland systems.A major constraint,introduced from the flooded system,is a plough pan that may decrease rooting depth and productivity...Rice is often grown as multiple seasons in one year,alternating between flooded and upland systems.A major constraint,introduced from the flooded system,is a plough pan that may decrease rooting depth and productivity of follow-on upland rice.Roots penetrating the plough pan under flooded rice system can leave a legacy of weaker root growth pathways.Deeper rooting rice cultivars could have a bigger impact,but no direct evidence is available.To explore whether a deep rather than a shallow rooting rice cultivar grown in a flooded cropping cycle benefited deeper root growth of follow-on rice in an upland,reduced tillage cropping cycle,a simulated flooded paddy in greenhouse was planted with deep(Black Gora) and shallow(IR64) rooting cultivars and a plant-free control.Artificial plough pans were made in between the topsoil and subsoil to form different treatments with no plough pan(0.35 MPa),soft plough pan(1.03 MPa) and hard plough pan(1.70 MPa).After harvest of this ‘first season’ rice,the soil was drained and undisturbed to simulate zero-tillage upland and planted rice cultivar BRRI Dhan 28.The overall root length density(RLD),root surface area,the numbers of root tips and branching of BRRI Dhan 28 did not vary between plough pan and no plough pan treatments.Compared with the shallow rooting rice genotype,the deep rooting rice genotype as ‘first season’ crop produced 19% greater RLD,34% greater surface area and 29% more branching of BRRI Dhan 28 in the subsoil.In the topsoil,however,BRRI Dhan 28 had 28% greater RLD,35% greater surface area and 43% more branching for the shallow rather than deep rooting genotype planted in the ‘first season’.The results suggested that rice cultivar selection for a paddy cycle affects root growth of a follow-on rice crop grown under no-till,with benefits to subsoil access from deep rooting cultivars and topsoil proliferation for shallow rooting cultivars.展开更多
Pot experiments were conducted under greenhouse condition to investigate whether Cd and Pb uptake by rice could be reduced when it was rotated with oilseed rape and compost application.The results showed that the rice...Pot experiments were conducted under greenhouse condition to investigate whether Cd and Pb uptake by rice could be reduced when it was rotated with oilseed rape and compost application.The results showed that the rice grown after oilseed rape had significantly lower Cd and Pb concentrations in both straw and grains.Cd and Pb concentrations in the grains of the rice rotated with oilseed rape decreased by approximately 46-80% and 17-86%,respectively,although the Cd and Pb removal by oilseed rape ranged only from 2.39-3.67 and 0.032-0.13% of the total content in soil.Compost amendment also decreased the bioavailability of Cd and Pb in the soil and reduced Cd and Pb uptake by oilseed rapes and rice.The concentrations of Cd and Pb significantly decreased in the exchangeable and carbonate fractions and Pb concentration decreased in the organic matter and sulfide fractions in the contaminated soil after planting oilseed rapes.展开更多
Mono-cropping systems consisting of general low-yielding cereals are crucial productivity constraints in dry areas of the Mediterranean region.A crop rotation consisting of quinoa(Chenopodium quinoa Willd.)-wheat(Trit...Mono-cropping systems consisting of general low-yielding cereals are crucial productivity constraints in dry areas of the Mediterranean region.A crop rotation consisting of quinoa(Chenopodium quinoa Willd.)-wheat(Triticum aestivum L)-chickpea(Cicer arietinum)was compared with monocropping in the Mediterranean region of Turkey.A four year crop rotation trial was set up in Adana,Turkey.A total of nine crop rotation systems of Quinoa(Q),chickpea(L)and wheat(W)were considered in this study.The four year results revealed that there was significant difference in grain and biomass yields,but no significant difference in plant height,harvest index,and 1000 grain weight of wheat among the treatments in crop rotation except number of grains per spike and soil organic matter.Continuous wheat and chickpea-wheat-chickpea-wheat(LWLW)produced significantly greater grain yield in 2010/2011 and 2011/2012.QWLW and QWQW rotation produced significantly lower biomass yield in 2008/2009.The maximum biomass yield of LWLW rotation resulted in 2011/2012 growing season.Therefore,the effect of previous crop on wheat grain and biomass yield in the four years of the rotation study was significantly different.In the long run,the favorable effects of legume-based rotations on crop yields and water productivity are apparent.展开更多
The results of the long-term investigations in dynamics for study of the conditions of taxonomic groups of microorganisms of irrigated gleyey-yellow soils of the subtropical zone under vegetable crops in rotation with...The results of the long-term investigations in dynamics for study of the conditions of taxonomic groups of microorganisms of irrigated gleyey-yellow soils of the subtropical zone under vegetable crops in rotation with the continuous growing of these cultures have been presented. The results of the researches study demonstrated an important vibration of the microorganisms quantity under growing cultures happens. The most quantity of microorganisms, consuming organic nitrogen is observed in irrigative gleyey-yellow soils of the humid subtropical zone. Intensity of mineralization of organic matters was lower in irrigative gleyey-yellow soils. A quantity of microorganisms was lower, but a coefficient of mineralization was higher under continuous cultures as compared the analogous soils under crop rotation. These data show that a type of the soil influence on the rhizosphere microflora insignificantly, while plant shows a significant effect on its quantity and compositions.展开更多
Many of the important questions facing farming systems in the world today require long-term studies to provide meaningful information and answers. A long-term agronomic experiment (LTAE) should (1) have long-term obje...Many of the important questions facing farming systems in the world today require long-term studies to provide meaningful information and answers. A long-term agronomic experiment (LTAE) should (1) have long-term objectives; (2) study important soil processes or ecological processes; and (3) be related to the productivity and sustainability of systems. A well established LTAE can provide both insights into how the system operates and foresight into where the system goes. The prerequisites for setting up a LTAE are the secured land, continuous funding and dedicated scientists. A number of principles must be considered carefully when establishing a LTAE, (1) the site must be representative of large areas; (2) the treatments should be simple, but focusing on the big questions; (3) the plots should be large enough to allow subsequent modification of the experiment if this becomes necessary; (4) crop rotations should minimise, wherever possible, the risk of build-up of pests and diseases, and rotational phase should be considered in a rotational experiment; (5) a clearly defined experimental protocol should be developed to ensure data collected is scientifically valid and statistically analysable, but with flexibility to allow essential changes; (6) soil samples, possibly plant samples, should be achieved to provide better answer to the original questions when new, perhaps more accurate analytical techniques are developed, or answer new research questions that were not considered in the original design. The MASTER experiment in Australia was used as a case study to demonstrate how these principles are implemented in practice.展开更多
基金financially supported by the Fund for Creative Research Groups of National Natural Science Foundation of China (41321001)
文摘Soil erosion on cropland is a major source of environmental problems in China ranging from the losses of a non-renewable resource and of nutrients at the source to contamination of downstream areas. Regional soil loss assessments using the Universal Soil Loss Equation (USLE) would supply a scientiifc basis for soil conservation planning. However, a lack of in-formation on the cover and management (C) factor for cropland, one of the most important factors in the USLE, has limited accurate regional assessments in China due to the large number of crops grown and their complicated rotation systems. In this study, single crop soil loss ratios (SLRs) were col ected and quantiifed for 10 primary crops from past studies or re-ports. The mean annual C values for 88 crop rotation systems in 12 cropping system regions were estimated based on the combined effects of single crop SLRs and the percentage of annual rainfal erosivity (R) during the corresponding periods for each system. The C values in different cropping system regions were compared and discussed. The results indicated that the SLRs of the 10 primary crops ranged from 0.15 to 0.74. The mean annual C value for al 88 crop rotation systems was 0.34, with a standard deviation of 0.12. The mean C values in the single, double and triple cropping zones were 0.37, 0.36 and 0.28, respectively, and the C value in the triple zone was signiifcantly different from those in single and double zones. The C values of dryland crop systems exhibited signiifcant differences in the single and triple cropping system regions but the differences in the double regions were not signiifcant. This study is the ifrst report of the C values of crop rotation systems in China at the national scale. It wil provide necessary and practical parameters for accurately assessing regional soil losses from cropland to guide soil conservation plans and to optimize crop rotation systems.
基金Financial supports were received from the Agro-scientific Research in the Public Interest of China(201503122)。
文摘Soil microbial biomass nitrogen(MBN)contains the largest proportion of biologically active nitrogen(N)in soil,and is considered as a crucial participant in soil N cycling.Agronomic management practices such as crop rotation and monocropping systems,dramatically affect MBN in agroecosystems.However,the influence of crop rotation and monocropping in agroecosystems on MBN remains unclear.A meta-analysis based on 203 published studies was conducted to quantify the effect of crop rotation and mono-cropping systems on MBN under synthetic N fertilizer application.The analysis showed that crop rotation significantly stimulated the response ratio(RR)of MBN to N fertilization and this parameter reached the highest levels in upland-fallow rotations.Upland mono-cropping did not change the RR of MBN to N application,however,the RR of MBN to N application in paddy mono-cropping increased.The difference between crop rotation and mono-cropping systems appeared to be due to the various cropping management scenarios,and the pattern,rate and duration of N addition.Crop rotation systems led to a more positive effect on soil total N(TN)and a smaller reduction in soil pH than mono-cropping systems.The RR of MBN to N application was positively correlated with the RR of mineral N only in crop rotation systems and with the RR of soil pH only in mono-cropping systems.Combining the results of Random Forest(RF)model and structural equation model showed that the predominant driving factors of MBN changes in crop rotation systems were soil mineral N and TN,while in mono-cropping systems the main driving factor was soil pH.Overall,our study indicates that crop rotation can be an effective way to enhance MBN by improving soil N resources,which promote the resistance of MBN to low pH induced by intensive synthetic N fertilizer application.
基金Supported by Global COE Program (Global Center of Excellence for Dryland Science) Funded by MEXT"Historical Interactions between the Multi-Cultural Societies and the Natural Environment in a Semi-Arid Region in Central Eurasia" Project Funded by Research Institute for Humanity and Nature, Japan
文摘The lower Ili River Basin is located in semi-arid area, and the annual rainfall is 177mm. Therefore, the irrigation is inevitable for agriculture. Large-scale irrigated agriculture had been developed since 1960's in the lower parts of the river and the total irrigated area is about 32 000 hm2. In the project area, the paddy rice-upland crop rotation has been practiced. Due to the domestic water use for hydropower and agriculture as well as water use among riparian countries, the deficit of water for agriculture in the lower part has been concerned. The authors, therefore, conducted the field survey and water balance analysis of the Akdara irrigation project in the lower Ill River Basin in order to assess the land and water uses. Moreover, the impact of the water use on water environment to the basin was analyzed. The following results were obtained as following (1) the groundwater level in the irrigated district varied from 1.5 m to 3.5 m through year. (2) 1970's groundwater level was drastically raised from 8 m to 3 m and the groundwater had been recharged in this period. (3) Water use efficiency of agriculture, which is the ratio of total evapotranspiration to the total water withdrawal was as low as 0.23.
基金Supported by the Special Fund for Agro-scientific Research in the Public Interest(201303018)the National Natural Science Foundation of China(31370449)
文摘To estimate the impact of crop rotation on the pathotype and genetic structure of Phythophthora sojae in fields, 372 isolates of P. sojae were obtained from long-term localisation experimental fields in Heilongjiang Province of China. The hypocotyl inoculation method was used to characterize the virulence of P. sojae on 13 differential cultivars, and the amplified fragment length polymorphism(AFLP) technique was used to analyze difference in the genetic structure of P. sojae. The results indicated that an abundant diversity of genetic structures and pathotypes of P. sojae, a more uniform distribution of pathotypes and less dominance of pathotypes occurred in corn-soybean and wheat-soybean rotation fields than in a continuous soybean mono-cropping field. These findings suggested that P. sojae did not easily become the dominant race in rotation fields, which maintain disease resistance in soybean varieties. Therefore, the results of this study suggested that Phytophthora stem and root rot of soybeans could be effectively controlled by rotating soybeans with non-host crops of corn and wheat.
基金funded by the National Research Foundation of China(32160310)National Key Research and Development Program of China(2016YFD0300208)+1 种基金Scientific Project of Department of Jiangxi Education of China(GJJ200444)Key disciplines(construction)of ecology in the 13th Five-Y ear Plan of Jiangxi Agricultural University.
文摘Based on the"Web of Science Core Collection"(SCIE database),this article used the visualization software CiteSpace to visualize and analyze the crop rotation fallow patterns in the past five years.It analyzed the countries,institutions,keywords and hot topics of related literature to explore their research characteristics and development,and to provide reference for crop rotation fallow research and practice.The research shows that:1)developed countries are the main research force in the field of crop rotation and fallowing,and the connection between the research of each country and each institution is not close;2)research hotspots can be mainly summarized as:crop growth and yield,greenhouse gas emissions and soil health analysis,and the research in this field is constantly refined,combining macro and micro;3)In recent years,there is a big gap between China and foreign countries in the field of crop rotation and fallow research.It is necessary to strengthen the cooperation with research institutions in developed countries in Europe and the United States,and to carry out cross-regional and interdisciplinary research cooperation to improve the quality of papers and scientific research level.
基金supported by the Spanish Government(RTI2018-094623-B-C21 and C22 MCIU/AEI/FEDER,UE)the Basque Government(IT-932-16).Dr.Adrian Bozal-Leorri held a grant from the Basque Government(PRE-2020-2-0142)Dr.Mario Corrochano-Monsalve held a grant from the Ministry of Economy and Business of the Spanish Government(BES-2016-076725).
文摘Agriculture has increased the release of reactive nitrogen to the environment due to crops’low nitrogen-use efficiency(NUE)after the application of nitrogen-fertilisers.Practices like the use of stabilized-fertilisers with nitrification inhibitors such as DMPP(3,4-dimethylpyrazole phosphate)have been adopted to reduce nitrogen losses.Otherwise,cover crops can be used in crop-rotation-strategies to reduce soil nitrogen pollution and benefit the following culture.Sorghum(Sorghum bicolor)could be a good candidate as it is drought tolerant and its culture can reduce nitrogen losses derived from nitrification because it exudates biological nitrification inhibitors(BNIs).This work aimed to evaluate the effect of fallow-wheat and sorghum cover crop-wheat rotations on N_(2)O emissions and the grain yield of winter wheat crop.In addition,the suitability of DMPP addition was also analyzed.The use of sorghum as a cover crop might not be a suitable option to mitigate nitrogen losses in the subsequent crop.Although sorghum–wheat rotation was able to reduce 22%the abundance of amoA,it presented an increment of 77%in cumulative N_(2)O emissions compared to fallow–wheat rotation,which was probably related to a greater abundance of heterotrophic-denitrification genes.On the other hand,the application of DMPP avoided the growth of ammonia-oxidizing bacteria and maintained the N_(2)O emissions at the levels of unfertilized-soils in both rotations.As a conclusion,the use of DMPP would be recommendable regardless of the rotation since it maintains NH_(4)^(+)in the soil for longer and mitigates the impact of the crop residues on nitrogen soil dynamics.
基金financially supported by the National Key Technology Research and Development Program of China(2021YFD1901001-08)the Key Scientific and Technological Project of Henan Provincial Education Department,China(232102111119)。
文摘Nitrogen(N)is a key factor in the positive response of cereal crops that follow leguminous crops when compared to gramineous crops in rotations,with the nonrecyclable rhizosphere-derived N playing an important role.However,quantitative assessments of differences in the N derived from rhizodeposition(NdfR)between legumes and gramineous crops are lacking,and comparative studies on their contributions to the subsequent cereals are scarce.In this study,we conducted a meta-analysis of NdfR from leguminous and gramineous crops based on 34 observations published worldwide.In addition,pot experiments were conducted to study the differences in the NdfR amounts,distributions and subsequent effects of two major wheat(Triticum aestivum L.)-preceding crops,corn(Zea mays L.)and soybean(Glycine max L.),by the cotton wick-labelling method in the main wheat-producing areas of China.The meta-analysis results showed that the NdfR of legumes was significantly greater by 138.93%compared to gramineous crops.In our pot experiment,the NdfR values from corn and soybean were 502.32 and 944.12 mg/pot,respectively,and soybean was also significantly higher than corn,accounting for 76.91 and 84.15%of the total belowground nitrogen of the plants,respectively.Moreover,in different soil particle sizes,NdfR was mainly enriched in the large macro-aggregates(>2 mm),followed by the small macro-aggregates(2–0.25 mm).The amount and proportion of NdfR in the macro-aggregates(>0.25 mm)of soybean were 3.48 and 1.66 times higher than those of corn,respectively,indicating the high utilization potential of soybean NdfR.Regarding the N accumulation of subsequent wheat,the contribution of soybean NdfR to wheat was approximately 3 times that of corn,accounting for 8.37 and 4.04%of the total N uptake of wheat,respectively.In conclusion,soybean NdfR is superior to corn in terms of the quantity and distribution ratio of soil macro-aggregates.In future field production,legume NdfR should be included in the nitrogen pool that can be absorbed and utilized by subsequent crops,and the role and potential of leguminous plants as nitrogen source providers in crop rotation systems should be fully utilized.
文摘Conservation Agriculture(CA)covers more than 205 million hectares in the world.This made it possible to face and mitigate the challenges of climate change,reducing soil erosion and providing multiple ecosystem services.The first elementary factor influenced is the yield evaluation.It has a direct effect on farmers’choices for sustainable production.The present article records a review focused on wheat yield average positive change compared between conventional tillage(CT)and no tillage(NT)systems.The international database collected showed that NT is adaptable everywhere.The results of wheat yield differentiation showed the influence of crop rotation depending on stations located in different climatic zones.In more than 40 years of research,specialists have succeeded in demonstrating the importance of crop productivity like wheat.The whole integrates also experimentations where the initiation starts more than ten years.
基金funded by the National Key Research and Development Program of China(2016YFD02003009-6 and 2016YFD0300806)the National Natural Science Foundation of China(41771327 and 41571219)the earmarked fund for China Agriculture Research System(CARS04)
文摘Certain agricultural management practices are known to affect the soil microbial community structure;however,knowledge of the response of the fungal community structure to the long-term continuous cropping and rotation of soybean,maize and wheat in the same agroecosystem is limited.We assessed the fungal abundance,composition and diversity among soybean rotation,maize rotation and wheat rotation systems and among long-term continuous cropping systems of soybean,maize and wheat as the effect of crop types on fungal community structure.We compared these fungal parameters of same crop between long-term crop rotation and continuous cropping systems as the effect of cropping systems on fungal community structure.The fungal abundance and composition were measured by quantitative real-time PCR and Illumina MiSeq sequencing.The results revealed that long-term continuous soybean cropping increased the soil fungal abundance compared with soybean rotation,and the fungal abundance was decreased in long-term continuous maize cropping compared with maize rotation.The long-term continuous soybean cropping also exhibited increased soil fungal diversity.The variation in the fungal community structure among the three crops was greater than that between long-term continuous cropping and rotation cropping.Mortierella,Guehomyces and Alternaria were the most important contributors to the dissimilarity of the fungal communities between the continuous cropping and rotation cropping of soybean,maize and wheat.There were 11 potential pathogen and 11 potential biocontrol fungi identified,and the relative abundance of most of the potential pathogenic fungi increased during the long-term continuous cropping of all three crops.The relative abundance of most biocontrol fungi increased in long-term continuous soybean cropping but decreased in long-term continuous maize and wheat cropping.Our results indicate that the response of the soil fungal community structure to long-term continuous cropping varies based upon crop types.
基金funded by the National Water Special Program of China during 11th Five-Year Plan period(2008ZX07105-002)
文摘This study was designed to find out an optimised planting system of reducing non-point (source) pollution by analyzing the reasons and the factors of influence non-point pollution in farmland of Erhai Lake basin. The results showed that incomes, residual nitrogen in soil, and the loss of nitrogen in surface water in rice-garlic system were higher than those in rice-fava bean system. There were positive correlations between the nitrogen loss of farmland, nitrogen inputs, residual nitrogen in soil, and incomes of farmland. Economic benefits and environment benefits are both appropriate, if the area of rice-garlic system would be reduced to 53% and the area of rice-fava bean system increased to 36% of total cropping area in the investigated watershed. Adjustment of planting structure and introduction of reasonable rotation systems is considered an effective measure of controlling agricultural non-point pollution in watersheds of Erhai Lake.
基金supported by the National Natural Science Foundation of China(31572460)the Fundamental Research Funds for the Central Universities(lzujbky-2017-ot01)the National Key Research and Development Program of China(2016YFC0400302)
文摘Reduced tillage provides ecological and economic benefits to arable land on the Loess Plateau of China, where soil erosion has long been a serious problem and soil water availability is largely restricted. However, high abundances of weeds in reduced tillage systems cause significant yield losses. In this study, we explored the effects of no-tillage and stubble retention on the number and density of weeds and weed seeds in a 12-year maize-winter wheat-common vetch rotation on the Loess Plateau. Four treatments including conventional tillage, no-tillage, conventional tillage+stubble retention and no-tillage+stubble retention were designed and applied. We found that no-tillage increased the number of weed species and weed density in most of the crops, while stubble retention decreased weed density in maize and tended to suppress weeds in both no-tillage treatments(no-tillage and no-tillage+stubble retention). No-tillage led to an increase in the number of weed species in the weed seedbank and tended to increase seed density during the spring growth of winter wheat, but it decreased seed density during post-vetch fallow. Stubble retention tended to reduce seed density during the spring growth of winter wheat and post-vetch fallow. We concluded that no-tillage can promote weeds in the experimental crop rotation, while stubble retention suppresses weeds in untilled fields. The combined effects of stubble retention and no-tillage on weed suppression varied among the three crops. Based on these results, we recommend stubble retention in untilled legume-crop rotations on the Loess Plateau to improve the control of weeds.
基金supported by the National Natural Science Foundation of China(No.31572203).
文摘Through collecting rhizosphere soil sample from a 30-year long-term fixed location test site that use“rice-ricerape”crop rotation(RRR)and“rice-rice-fallow”continuous cropping systems(RRF),this paper investigated effects of long-term crop rotation on physicochemical property and bacterial community of rhizosphere soil.Results showed that total nitrogen(TN),total phosphorus(TP)and available potassium(AK)contents in rhizosphere soil under long-term RRR were decreased by 28.09%,15.69%and 6.25%respectively.Alkali-hydrolyzable nitrogen(AN)and available phosphorus(AP)contents were 10.59%and 13.25%higher than those of soil in RRF respectively.Three soil samples collected during different periods also showed that RRR resulted in a lower rhizosphere soil pH than RRF.Clone library analysis revealed that significant difference in rhizosphere soil bacterial community was observed between RRR and RRF continuous cropping.Abundance ofα-Proteobacteria,β-Proteobacteria andγ-Proteobacteria were higher in rhizosphere soil of RRR compared to RRF.pH of rhizosphere soil was significantly correlated with Acidobacteria level,while total organic carbon(TOC)content was significantly correlated with Proteobacteria level.Long-term RRR enhanced conversion of N and P in rhizosphere soil,increased bio-availability to crop,and promoted diversity of soil bacterial community.Bacterial diversity in RRR could be ecological significance in maintaining soil fertility and functionality.
基金This study was supported by Gansu Provincial Key Laboratory of Aridland Crop Science of Gansu Agricultural University(GSCS-2020-Z6)the China Agriculture Research System of Construct Special(CARS-14-1-16)+1 种基金the National Natural Science Programs of China(31660368,32060437)the Fuxi Outstanding Talent Cultivation Plan of Gansu Agriculture University(Gaufx-02J05).I am very grateful to all my working partners.
文摘To investigate the effects of crop rotation on oilseed flax growth and yield,three season experiments were carried out in semi-arid area of Dingxi,Gansu from 2017 to 2019.The designed 6 rotational systems were FFF(flax-flaxflax),PFF(potato-flax-flax),WPF(wheat-potato-flax),FPF(flax-potato-flax),PWF(potato-wheat-flax)and FWF(flax-wheat-flax).Flax growth and yield investigation results showed that crop rotation increased leaf area duration,dry matter accumulation,seed nitrogen accumulation,water and nitrogen used efficiency,compared with continuous cropping of flax.Flaxseed yields in rotation systems were 22.23%–44.11%greater than those of continuous cropping system.Those in wheat and potato stubbles had higher tiller number(21.43%and 29.46%),more branches(14.24%and 6.97%),effective capsules(26.35%and 28.79%),higher water use efficiency(40.26%and 33.5%),higher nitrogen partial factor productivity(33.85%and 31.46%)and dry matter(41.98%and 25.47%)than those in oilseed flax stubble.It concluded that crop rotation system was an effective measure for oilseed flax productivity in semi-arid area by improving yield components and promoting biomass.
文摘We used an ongoing long-term field trial established since 1960 in Burkina Faso, to study the microbial properties of a Ferric Lixisol under various crop management and fertilization regimes. Microbial respiration rate, microbial biomass carbon (MBC) and soil bacteria’s number were assessed in soil samples taken at 0<span style="font-family:;" "=""> </span><span style="font-family:;" "="">-</span><span style="font-family:;" "=""> </span><span style="font-family:;" "="">20 cm depth. The crop management were continuous cropping of sorghum (<i>Sorghum bicolor L</i>.) (S/S) and rotation between sorghum and cowpea (<i>Vigna unguiculata L</i>.) (S/C), while the fertilization regimes were: 1) Control (te);2) Low rate of mineral fertilizer (fm);3) Low rate of mineral fertilizer + sorghum straw restitution (fmr);4) Low rate of mineral fertilizer + low rate of manure (fmo);5) High rate of mineral fertilizer (FM);and vii) High rate of mineral fertilizer + high rate of manure (FMO). The manure is applied every second year. The results indicate that sorghum/cowpea rotation significantly increase MBC and bacteria number as compared to continuous sorghum cropping. MBC ranged from 335.5 to 54.85 μg C g</span><span style="font-family:;" "=""><sup><span style="white-space:nowrap;">−</span><span>1</span></sup><span> soil with S/S and from 457.5 to 86.6 μg C g</span><sup><span style="white-space:nowrap;">−</span><span>1</span></sup><span> soil with S/C. Application of high level of manure and mineral fertilizer increase microbial respiration rate and MBC. The highest MBC was observed with FMO and the lowest with the control. In general, the metabolic quotient (qCO<sub>2</sub>) was negatively impacted by the fertilization and cowpea rotation. For S/S rotation, qCO<sub>2</sub> of the control was 1.5 to 2 times that of the treatments with low mineral fertilizer (fmr, fmo and fm) and 3 times that of the high rate of fertilization (FM and FMO). With S/C rotation, qCO<sub>2</sub> of the control was 2 times of that fmr, FM and FMO and 0.8 times that of fmo and fm. Soil bacteria in the fmr were 63.6 and 12.4 times the control in the S/S and S/C rotations, respectively. In sum, combined application of manure and mineral fertilizer with crop rotation is the best management practices to improve in sustainable way microbial activities in tropical soil.</span></span>
文摘To better understand the effects of direct sowing under mulch-based cropping system (DMC) in Burkina Faso’s cotton production systems, randomized blocks of Fisher experimental design were implemented at Farako-B<span style="white-space:nowrap;">a</span> research station from 2010 to 2019. The study was conducted on lixisoil to evaluate DMC effects on biomass production, crops yields and soil chemical properties in a maize and cotton rotation system associated with cover crop. Conventional tillage and direct seeding without cover crop were compared to DMC under <em>B</em>. <em>ruziziensis</em> (GERM. & EVRARD), DMC under <em>B</em>. <em>ruziziensis</em> + <em>M</em><em>.</em> <em>cochinchinensis</em> mulch and DMC under <em>C. juncea</em> (L.) mulch used in association with maize. Biomass production, crop yields and soil chemistry were evaluated. Results showed that over 10 years, no-till with or without a cover crop provided cotton seed and maize yields that were statistically equivalent to the tillage commonly practiced by farmers. Cover crop has allowed increasing the biomass production compared to Conventional Tillage and Direct Seeding. Maize yield has not varied significantly with the cover crop. After 10 years of maize and cotton rotation, the improvement raised from +27% to +38% for organic matter and from +15% to +29% for nitrogen with DMC including legumes such as <em>M. cochinchinensis</em> and <em>C. juncea</em> compared to Conventional Tillage on 0 - 5 cm depth. No significant differences were found on soil pH like P<sub>2</sub>O<sub>5</sub> and K<sub>2</sub>O content. Although DMC with <em>C. juncea</em> used as cover crop did not provide the best biomass production, it contributes to increase nitrogen and organic matter and presents better mineral balances in 10 years of rotation. The 5 - 10 cm and 10 - 20 cm were little influenced by DMC systems.
基金funded by the Commonwealth Scholarship Commission in the UK。
文摘Rice is often grown as multiple seasons in one year,alternating between flooded and upland systems.A major constraint,introduced from the flooded system,is a plough pan that may decrease rooting depth and productivity of follow-on upland rice.Roots penetrating the plough pan under flooded rice system can leave a legacy of weaker root growth pathways.Deeper rooting rice cultivars could have a bigger impact,but no direct evidence is available.To explore whether a deep rather than a shallow rooting rice cultivar grown in a flooded cropping cycle benefited deeper root growth of follow-on rice in an upland,reduced tillage cropping cycle,a simulated flooded paddy in greenhouse was planted with deep(Black Gora) and shallow(IR64) rooting cultivars and a plant-free control.Artificial plough pans were made in between the topsoil and subsoil to form different treatments with no plough pan(0.35 MPa),soft plough pan(1.03 MPa) and hard plough pan(1.70 MPa).After harvest of this ‘first season’ rice,the soil was drained and undisturbed to simulate zero-tillage upland and planted rice cultivar BRRI Dhan 28.The overall root length density(RLD),root surface area,the numbers of root tips and branching of BRRI Dhan 28 did not vary between plough pan and no plough pan treatments.Compared with the shallow rooting rice genotype,the deep rooting rice genotype as ‘first season’ crop produced 19% greater RLD,34% greater surface area and 29% more branching of BRRI Dhan 28 in the subsoil.In the topsoil,however,BRRI Dhan 28 had 28% greater RLD,35% greater surface area and 43% more branching for the shallow rather than deep rooting genotype planted in the ‘first season’.The results suggested that rice cultivar selection for a paddy cycle affects root growth of a follow-on rice crop grown under no-till,with benefits to subsoil access from deep rooting cultivars and topsoil proliferation for shallow rooting cultivars.
基金supported by the National Natural Science Foundation of China (40971261)the Special Fund for Argo-Scientific Reserch in the Public Interest,China (200903015).
文摘Pot experiments were conducted under greenhouse condition to investigate whether Cd and Pb uptake by rice could be reduced when it was rotated with oilseed rape and compost application.The results showed that the rice grown after oilseed rape had significantly lower Cd and Pb concentrations in both straw and grains.Cd and Pb concentrations in the grains of the rice rotated with oilseed rape decreased by approximately 46-80% and 17-86%,respectively,although the Cd and Pb removal by oilseed rape ranged only from 2.39-3.67 and 0.032-0.13% of the total content in soil.Compost amendment also decreased the bioavailability of Cd and Pb in the soil and reduced Cd and Pb uptake by oilseed rapes and rice.The concentrations of Cd and Pb significantly decreased in the exchangeable and carbonate fractions and Pb concentration decreased in the organic matter and sulfide fractions in the contaminated soil after planting oilseed rapes.
基金support of the EU project ref.KBBE-2008-212337(SWUP-MED)Sustainable water use securing food production in dry areas of the Mediterranean region,which allowed carrying out these experiments.
文摘Mono-cropping systems consisting of general low-yielding cereals are crucial productivity constraints in dry areas of the Mediterranean region.A crop rotation consisting of quinoa(Chenopodium quinoa Willd.)-wheat(Triticum aestivum L)-chickpea(Cicer arietinum)was compared with monocropping in the Mediterranean region of Turkey.A four year crop rotation trial was set up in Adana,Turkey.A total of nine crop rotation systems of Quinoa(Q),chickpea(L)and wheat(W)were considered in this study.The four year results revealed that there was significant difference in grain and biomass yields,but no significant difference in plant height,harvest index,and 1000 grain weight of wheat among the treatments in crop rotation except number of grains per spike and soil organic matter.Continuous wheat and chickpea-wheat-chickpea-wheat(LWLW)produced significantly greater grain yield in 2010/2011 and 2011/2012.QWLW and QWQW rotation produced significantly lower biomass yield in 2008/2009.The maximum biomass yield of LWLW rotation resulted in 2011/2012 growing season.Therefore,the effect of previous crop on wheat grain and biomass yield in the four years of the rotation study was significantly different.In the long run,the favorable effects of legume-based rotations on crop yields and water productivity are apparent.
文摘The results of the long-term investigations in dynamics for study of the conditions of taxonomic groups of microorganisms of irrigated gleyey-yellow soils of the subtropical zone under vegetable crops in rotation with the continuous growing of these cultures have been presented. The results of the researches study demonstrated an important vibration of the microorganisms quantity under growing cultures happens. The most quantity of microorganisms, consuming organic nitrogen is observed in irrigative gleyey-yellow soils of the humid subtropical zone. Intensity of mineralization of organic matters was lower in irrigative gleyey-yellow soils. A quantity of microorganisms was lower, but a coefficient of mineralization was higher under continuous cultures as compared the analogous soils under crop rotation. These data show that a type of the soil influence on the rhizosphere microflora insignificantly, while plant shows a significant effect on its quantity and compositions.
基金supported by the CAS/SAFEA International Partnership Program for Creative Research Teams (CXTD-Z2005-2-4)
文摘Many of the important questions facing farming systems in the world today require long-term studies to provide meaningful information and answers. A long-term agronomic experiment (LTAE) should (1) have long-term objectives; (2) study important soil processes or ecological processes; and (3) be related to the productivity and sustainability of systems. A well established LTAE can provide both insights into how the system operates and foresight into where the system goes. The prerequisites for setting up a LTAE are the secured land, continuous funding and dedicated scientists. A number of principles must be considered carefully when establishing a LTAE, (1) the site must be representative of large areas; (2) the treatments should be simple, but focusing on the big questions; (3) the plots should be large enough to allow subsequent modification of the experiment if this becomes necessary; (4) crop rotations should minimise, wherever possible, the risk of build-up of pests and diseases, and rotational phase should be considered in a rotational experiment; (5) a clearly defined experimental protocol should be developed to ensure data collected is scientifically valid and statistically analysable, but with flexibility to allow essential changes; (6) soil samples, possibly plant samples, should be achieved to provide better answer to the original questions when new, perhaps more accurate analytical techniques are developed, or answer new research questions that were not considered in the original design. The MASTER experiment in Australia was used as a case study to demonstrate how these principles are implemented in practice.