Impact on Soil Organic C and Total Soil N from Cool- and Warm-Season Legumes Used in a Green Manure-Forage Cropping System

Annual forage legumes are important components of livestock production systems in East Texas and the southeastern US. Forage legumes contribute nitrogen (N) to cropping systems through biological N fixation, and their seasonal biomass production can be managed to complement forage grasses. Our research objectives were to evaluate both warm- and cool-season annual forage legumes as green manure for biomass, N content, ability to enhance soil organic carbon (SOC) and soil N, and impact on post season forage grass crops. Nine warm-season forage legumes (WSL) were spring planted and incorporated as green manure in the fall. Forage rye (Secale cereale L.) was planted following the incorporation of WSL treatments. Eight cool-season forage legumes (CSL) were fall planted in previously fallow plots and incorporated as green manure in late spring. Sorghum-sudangrass (Sorghum bicolor x Sorghum bicolor var. sudanense) was planted over all treatments in early summer after forage rye harvest and incorporation of CSL treatments. Sorghum-sudangrass was harvested in June, August and September, and treatments were evaluated for dry matter and N concentration. Soil cores were taken from each plot, split into depths of 0 to 15, 15 to 30 and 30 to 60 cm, and soil C and N were measured using combustion analysis. Nylon mesh bags containing plant samples were buried at 15 cm and used to evaluate decomposition rate of above ground legume biomass, including change in C and N concentrations. Mungbean (Vigna radiata L. [Wilczek]) had the highest shoot biomass yield (6.24 t DM ha-1) and contributed the most total N (167 kg∙ha-1) and total C (3043 kg∙ha-1) of the WSL tested. Decomposition rate of WSL biomass was rapid in the first 10 weeks and very slow afterward. Winter pea (Pisum sativum L. spp. sativum), arrow leaf clover (Trifolium vesiculosum Savi.), and crimson clover (Trifolium incarnatum L.) were the most productive CSL in this trial. Austrian winter pea produced 8.41 t DM ha-1 with a total N yield of 319 kg N ha-1 and total C production of 3835 kg C ha-1. The WSL treatments had only small effects on rye forage yield and N concentration, possibly due to mineralization of N from a large SOC pool already in place. The CSL treatments also had only minimal effects on sorghum-sudangrass forage production. Winter pea, arrow leaf and crimson clover were productive cool season legumes and could be useful as green manure crops. Mungbean and cowpea (Vigna unguiculata [L.] Walp.) were highly productive warm season legumes but may include more production risk in green manure systems due to soil moisture competition.

Soil carbon sequestration under long-term rice-based cropping systems of purple soil in Southwest China

Carbon sequestration in agricultural soils is a complex process controlled by farming practices, climate and some other environment factors. Since purple soils are unique in China and used as the main cropland in Sichuan Basin of China, it is of great importance to study and understand the impacts of different fertilizer amendments on soil organic carbon（SOC） changes with time. A research was carried out to investigate the relationship between soil carbon sequestration and organic carbon input as affected by different fertilizer treatments at two long-term rice-based cropping system experiments set up in early 1980 s. Each experiment consisted of six identical treatments, including（1） no fertilizer（CK）,（2） nitrogen and phosphorus fertilizers（NP）,（3） nitrogen, phosphorus and potassium fertilizers（NPK）,（4） fresh pig manure（M）,（5） nitrogen and phosphorus fertilizers plus manure（MNP）, and（6） nitrogen, phosphorus and potassium fertilizers plus manure（MNPK）. The results showed that annual harvestable carbon biomass was the highest in the treatment of MNPK, followed by MNP and NPK, then M and NP, and the lowest in CK. Most of fertilizer treatments resulted in a significant gain in SOC ranging from 6.48 to 2 9.13% compared with the CK, and raised soil carbon sequestration rate to 0.10–0.53 t ha–1 yr-1. Especially, addition of manure on the basis of mineral fertilizers was very conducive to SOC maintenance in this soil. SOC content and soil carbon sequestration rate under balanced fertilizer treatments（NPK and MNPK） in the calcareous purple soil（Suining） were higher than that in the acid purple soil（Leshan）. But carbon conversion rate at Leshan was 11.00%, almost 1.5 times of that（7.80%） at Suining. Significant linear correlations between soil carbon sequestration and carbon input were observed at both sites, signifying that the purple soil was not carbon-saturated and still had considerable potential to se questrate more carbon.

Economic Analysis of Diversified Rotational Cropping Systems in the Lateritic Belt of Lower Gangetic Plain of Eastern India

Economic analysis of different diversified rotational cropping systems under Farmers＇ package/practices and improved package/practices was conducted in Birbhum district, West Bengal, located in the red and lateritic belt of lower Gangetic plain of eastern lndia. Diversified triple cropping systems （peanut-brinjal＋brinjal, rice-potato-pumpkin, and cucumber-cabbage-basella） required higher cost for cultivation, but also produced higher rice equivalent yield, higher net return and higher return rupee1 invested in both management practices. Considering the resource-ability and risk-bearing capacity, and net return and return rupee^-1 （RPR） invested, these cropping systems can be recommended for resource-rich farmers. Rice-rapeseed-cowpea, rice-wheat-green gram and radish-tomato-amaranthus systems profitable. These cropping systems can be required less inputs for cultivation, were less risky, and economically viable and recommended for resource-poor farmers. Peanut-brinjal ＋ brinjal-okra-chilli ＋ chilli-cucumber-cabbage-basella system was the best among all the 3-year rotational systems in respect to RPR in both management practices. This rotational system will be suitable for resource-rich farmers. Vegetable-based rotational systems （ridge gourd-marigold-okra-black gram-pointed gourd ＋ pointed gourd-radish-tomato-amaranthus） or rice-based rotational system （rice-wheat-green gram-rice-rapeseed-cowpea-rice-potato-pumpkin） also found to be suitable to increase the profitability and system sustainability. These cropping systems can be recommended for all groups of farmers.

Increasing soil microbial biomass nitrogen in crop rotation systems by improving nitrogen resources under nitrogen application

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.

Technical efficiency and its determinants of the various cropping systems in the purple-soiled,hilly region of southwestern China

This study examines the technical efficiency(TE) differences among typical cropping systems of smallholder farmers in the purple-soiled hilly region of southwestern China.Household-,plot-,and crop-level data and community surveys were conducted to explore TE levels and determinants of typical cropping systems by using a translog stochastic frontier production function.Results indicate significant difference in TE and its determinants among cropping systems.The mean TEs of the rice cropping system(R),the rice-rape cropping system(RR),the rice-rape-potato cropping system(RRP),and the oil cropping system(O) are0.86,0.90,0.84,and 0.85,respectively,which are over 1.17 times higher than those of the maize-sweet potato-other crop cropping system(MSO) and the maize-sweet potato-wheat cropping system(MSW) at0.78 and 0.69,respectively.Moreover,Technical inefficiency(TIE) of different cropping systems is significantly affected by characteristics of the household as well as plot.However,the impact of land quality,mechanical cultivation conditions,crop structure,farming system,farm radius,household type,cultivated land area per capita,and annual household income per capitalon TIE vary by cropping system.Additionally,output elasticity of land,labor,and capital,as a group,is greater than the one of agricultural machinery and irrigation.Finally,when household-owned effective agricultural labor is at full farming capacity,optimal plot sizes for the R,RR,RRP,MSO,MSW,and 0 cropping systems are 1.12hm^2,0.35 hm^2,0.25 hm^2,2.82 hm^2,1.87 hm^2,and 1.17hm^2,respectively.

Variation of Physical and Chemical Properties of Soils under Different Cropping Systems in the Watershed of Kpocomey, Southern Benin

Soils degradation is one of the constraints in food security achievement in Benin. This study aimed at assessing the effect of cropping systems and slope on soil physical and chemical properties in the watershed of Kpacomey located in the Aplahoué district. Soil samples were collected from three parallel transects along the slope. Sampling was carried out under different treatments combining cropping systems (Maize-Cassava, pure Palm grove, Palm grove-Maize-Cassava and Teak Plantation) along with slope levels (low slope, medium slope and high slope degree). The impact of cropping systems and slope on soil properties was assessed by determining the physical and chemical parameters. The cropping systems significantly (p < 0.05) influenced soil bulk density, root biomass, soil acidity and soil organic matter. The lowest soil bulk density (1.38 g/cm3) was recorded under the Palm grove-Maize-Cassava cropping system while the highest (1.47 g/cm3) was obtained with pure Palm grove cropping system. Root biomass was more abundant (0.28%) with the pure Palm grove cropping system. However, root biomass was significantly (p < 0.05) influenced by slope. Soil crusting resulted in no significant influence (p > 0.05) on the effect of cropping systems and slope. Moreover, cropping systems resulted in significant effects (p < 0.05). Soil organic matter and soil-assimilated phosphorus content were significantly influenced by the effect of the slope. These findings indicated that cropping systems and slope are significant drivers in soil degradation in the Kpacomey watershed and bringing out cropping systems that best aim at soil conservation.

Weed Incidences and Their Effect on Crop Productivity under Diversified Rotational Cropping Systems in the Lateritic Belt of Lower Gangetic Plain of Eastern India

A field experiment was conducted from 2002-2005 on a sandy clay loam red and lateritic soil under irrigation in a farmer＇s field at Senkapur （Lat. 23°36.79′ N, Long. 87°38.14′E, Elev. 46 m AMSL）, Birbhum, West Bengal, India. The objective was to provide the temporal changes of weed diversity and density, ecology, and impact of rotational cropping systems on different crops under double and triple cropping systems with improved （IP） and farmer＇s packages （FP）. There was significantly higher weed density in FP than in IP on all years. Grasses and sedges were more in vegetable-based rotational systems; but grasses and broad leaf weeds （BLWs） were more in rice-based rotational systems. The lowest weed population was in vegetable-based systems. Grasses increased in rice-based systems but gradually decreased in vegetable-based systems in subsequent years. Sedge density was higher in vegetable- than in rice-based rotational systems. Density of BLWs was higher but that of sedges was lower in rice-based rotational systems as compared to vegetable-based systems. Density of BLWs gradually decreased in all rotational systems over the years in both packages. Density of weeds decreased gradually in subsequent years indicating the positive effect of rotational systems on suppression of weeds. Results indicate that the weed density can be reduced through judicious diversified rotational cropping systems. Peanut-brinjal＋brinjal, okra-chilli＋chilli and cucumber-cabbage-basella systems greatly reduced the weed density in both packages, and hence can be recommended for the lateritic belt of lower Gangetic plain of eastern India.

Assessment of Heavy Metals Control from Soil and Vegetable Plants in Different Growing Systems

Heavy metals contents of soils and vegetable edible parts were studied at three crop systems （conventional, in conversion and organic） from seven traditional sites for vegetable growing in North-eastern Romania, during 2010. The main goal of the research was to find a correlation between the heavy metals contents and the crop systems. Determination of heavy metals was performed by atomic absorption spectrometry （AAS）, using a Shimadzu spectrophotometer, 6300 version, equipped with graphite furnace and autosampler. Heavy metals contents in the soils varied with the metals and locations, according to the crop system. The following experimental average contents were determined： Mn-262.03 mg kg1, Zn-45.60 mg kgq, Cu-28.53 mg kgl, Pb-5.20 mg kg1 and Cd-1.84 mg kg1. In vegetable edible parts, heavy metal varied with metals, sites and plant species, without a significant correlation with crop system. The trend of heavy metals in conventional and organic crops was Zn 〉 Cu 〉 Mn = Pb 〉 Cd, but in conversion crops it was Zn 〉 Mn = Pb 〉 Cu 〉 Cd. The highest content was of Zn （4.85 mg kg＇t）, at a cabbage crop in conversion. Cd was not detected in vegetable products and Pb was detected only in some vegetable samples. Research emphasized that heavy metals contents from soil and vegetable edible parts did not exceed the admitted maximum limits, according to Romanian and European Regulations. Final conclusion of research is that no correlations exist between crop systems and heavy metals contents from soil and plant.

Characterization of Farming Systems Using Land as a Driver of Production and Sustainability in the Vhembe District, Limpopo, South Africa

South African agricultural farming systems are characterised by a duality in which there exists large-scale commercial farmers and small-scale farmers. Large-scale commercial farmers, historically identified as capital intensive and characterized by the size of the landholdings, are considered as the main drivers of national food security. Small-scale farmers on the other hand are viewed as important drivers of food security at the household level. These two main farming systems can be found within the Vhembe district municipality of the Limpopo Province and are characterised differently according to land descriptors. The study used an analysis of primary data obtained from in-depth interviews and secondary data obtained from an agricultural database to identify and characterize large- and small-scale farming systems within the Vhembe district. The study examined the land resource namely farm size and land ownership, topography and soil description, rainfall and its variability and threats and hazards used under three different high value crop (HVC) commodities, macadamia nuts, mangos and avocado pears. The study further examined yield and income from farming as drivers of production that would ensure the sustainability of long-term food security at both national and household level. The study revealed that gender of farmers within the farming systems was predominantly (79%) male across all commodities. Age distribution results showed an aging population of farmers mostly (90%) above the age of 51. Communal land ownership was the dominant (74%) land ownership amongst participants. Yield is not solely dependent on farm size and requires consideration of a broader array of land management aspects. There was a strong, significant correlation between income and farm size. These factors have implications for sustainability of the two farming systems and illustrate how certain aspects of land as a driver of production such as land ownership, rainfall variability, yield and income from farming can impact sustainability.

Characterizing Spatial Patterns of Phenology in Cropland of China Based on Remotely Sensed Data

This study used time-series of global inventory modeling and mapping studies （GIMMS） normalized difference vegetation index （NDVI） datasets at a spatial resolution of 8 km and 15-d interval to investigate the spatial patterns of cropland phenology in China. A smoothing algorithm based on an asymmetric Gaussian function was first performed on NDVI dataset to minimize the effects of anomalous values caused by atmospheric haze and cloud contamination. Subsequent processing for identifying cropping systems and extracting phenological parameters, the starting date of growing season （SGS） and the ending date of growing season （EGS） was based on the smoothed NVDI time-series data. The results showed that the cropping systems in China became complex as moving from north to south of China. Under these cropping systems, the SGS and EGS for the first growing season varied largely over space, and those regions with multiple cropping systems generally presented a significant advanced SGS and EGS than the regions with single cropping patterns. On the contrary, the phenological events of the second growing season including both the SGS and EGS showed little difference between regions. The spatial patterns of cropping systems and phenology in Chinese cropland were highly related to the geophysical environmental factors. Several anthropogenic factors, such as crop variety, cultivation levels, irrigation, and fertilizers, could profoundly influence crop phenological status. How to discriminate the impacts of biophysical forces and anthropogenic drivers on phenological events of cultivation remains a great challenge for further studies.

Impact of soil texture and sweetpotato cropping system on soil erosion and nutrient loss in the Three Gorges Reservoir Area of the Changjiang River

This study investigated the impact of soil texture and sweetpotato cropping system on soil erosion and nutrient loss in the drought infield of the Three Gorges Reservoir Area of Changjiang River under field conditions. A factorial experiment was conducted in the study using five soil textures and two cropping systems. The lost soil during the crop season was recovered by a soil-blocking device and the dry weights for the total lost soil and its nutrient components, such as ammonium nitrogen, effective phosphorus, K^＋ and organic matter were analyzed. We found that soil texture significantly affected the dry weights of the total lost soil, effective phosphorus, K^＋, and organic matter, while sweetpotato cropping systems and interaction between soil texture and sweetpotato cropping system affected the dry weights of the total lost soil, the effective phosphorus and organic matter. Among the five soil textures tested, Da and Huang caused significantly less soil erosion and nutrient loss compared with the other three soil textures; intercropping sweetpotato with corn significantly reduced soil erosion and nutrient loss.

Low N apparent surplus with higher rice yield under long-term fertilizer postponing in the rice-wheat cropping system

Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplus and increases rice yields,but the effects of long-term FP on N surplus and rice yields remain unknown.Our study was the first to investigate the impacts of long-term FP(11 years)on N apparent surplus and rice yields.FP effects in the short term(≤6 years)did not affect rice yields,whereas FP effects in the long term(>6 years)increased rice yields by 13.9%compared with conventional fertilization(CF).FP did not affect panicles per unit area,1000-kernel weight,and filled-kernel rate,but spikelets per panicle increased over time due to spikelet formation stimulation.FP also reduced the N apparent surplus over time more strongly than CF owing to higher N accumulation and N utilization efficiency.FP effects in the long term also significantly increased soil organic matter,total N,and NH4_(+)^(-)N content.Our results were supported by a pot experiment,showing that rice yields in soils with a history of FP were significantly higher than those for soils without a history of FP,indicating that FP increased rice yields more strongly in later years mainly because of soil quality improvement.Our findings suggest that longterm FP can reduce N loss while increasing rice yields by improving soil quality.

N-Credits from Different Maturing Cowpea Varieties to Carrot in Rotation

Legumes constitute a major component of sustainable cropping systems due to their biological nitrogen fixing potential. A field study was conducted in 2020 and 2021 at Ashanti-Mampong in the forest transition zone of Ghana to quantify nitrogen credits to carrot from early (70 - 75 days) and medium maturing (80 - 85 days) cowpea varieties (Asetenapa and Soronko) respectively, and Obatanpa maize variety as a reference crop. The experimental design was a split plot with five Nitrogen levels (0, 30, 45, 60 and 90 N kg/ha) applied to carrot as sub-plots following the legumes and the maize variety as main plots. NPK (15:15:15) was applied at the rate of 250 kg/ha to provide the nitrogen. The sub-plot treatments (0, 30, 45, 60 and 90 N kg/ha) were planted following the two cowpea varieties and the maize variety as a reference crop. Soronko had the highest number of nodules (176) while Asetenapa had the lowest nodules (55). Nitrogen credit to carrot from the early-maturing cowpea (Asetenapa) was 32 N kg/ha in the first year of incorporation and 18 N kg/ha in the second year after incorporation. N-credit from the medium-maturing cowpea (Soronko) was 18 N kg/ha and 29 N kg/ha in the first and second year after incorporation respectively. Obatanpa maize variety with 0 kg N/ha fertilizer level produced the lowest carrot yield, indicating that the soil amendment increased yields. The species and maturity of legumes are important determinants of their N credit contribution to crops in rotation.

Changes in rice cropping systems in the Poyang Lake Region, China during 2004-2010

Rice cropping systems not only characterize comprehensive utilization intensity of agricultural resources but also serve as the basis to enhance the provision services of agro-ecosystems. Yet, it is always affected by external factors, like agricultural policies. Since 2004, seven consecutive No.1 Central Documents issued by the Central Government have focused on agricultural development in China. So far, few studies have investigated the effects of these policies on the rice cropping systems. In this study, based upon the long-term field survey information on paddy rice fields, we proposed a method to discriminate the rice cropping systems with Landsat data and quantified the spatial variations of rice cropping systems in the Poyang Lake Region （PLR）, China. The results revealed that： （1） from 2004 to 2010, the decrement of paddy rice field was 46.76 km2 due to the land use change. （2） The temporal dynamics of NDVI derived from Landsat historical images could well characterize the temporal development of paddy rice fields. NDVI curves of single cropping rice fields showed one peak, while NDVI curves of double cropping rice fields displayed two peaks annually. NDVI of fallow field fluctuated between 0.15 and 0.40. NDVI of the flooded field during the transplanting period was relatively low, about 0.20±0.05, while NDVI during the period of panicle initiation to heading reached the highest level （above 0.80）. Then, several temporal windows were determined based upon the NDVI variations of different rice cropping systems. （3） With the spatial pattern of paddy rice field and the NDVI threshold within optimum temporal windows, the spatial variation of rice cropping systems was very obvious, with an increased multiple cropping index of rice about 20.2% from 2004 to 2010. The result indicates that agricultural policies have greatly enhanced the food provision services in the PLR, China.

Food legume production in China

Food legumes comprise all legumes grown for human food in China as either dry grains or vegetables,except for soybean and groundnut.China has a vast territory with complex ecological conditions.Rotation,intercropping,and mixed cropping involving pulses are normal cropping systems in China.Whether indigenous or introduced crops,pulses have played an important role in Chinese cropping systems and made an important contribution to food resources for humans since ancient times.The six major food legume species(pea,faba bean,common bean,mung bean,adzuki bean,and cowpea) are the most well-known pulses in China,as well as those with more local distributions;runner bean,lima bean,chickpea,lentil,grass pea,lupine,rice bean,black gram,hyacinth bean,pigeon pea,velvet bean,winged bean,guar bean,sword bean,and jack bean.China has remained the world's leading producer of peas,faba beans,mung beans,and adzuki beans in recent decades,as documented by FAO statistics and China Agriculture Statistical Reports.The demand for food legumes as a healthy food will markedly increase with the improvement of living standards in China.Since China officially joined the World Trade Organization(WTO) in2001,imports of pea from Canada and Australia have rapidly increased,resulting in reduced prices for dry pea and other food legumes.With reduced profits for food legume crops,their sowing area and total production has decreased within China.At the same time,the rising consumer demand for vegetable food legumes as a healthy food has led to attractive market prices and sharp production increases in China.Vegetable food legumes have reduced growing duration and enable flexibility in cropping systems.In the future,production of dry food legumes will range from stable to slowly decreasing,while production of vegetable food legumes will continue to increase.

Tillage and residue management effect on soil properties,crop performance and energy relations in greengram(Vigna radiata L.)under maize-based cropping systems

Effect of tillage and crop residue management on soil properties,crop performance,energy relations and economics in greengram(Vigna radiata L.)was evaluated under four maize-based cropping systems in an Inceptisol of Delhi,India.Soil bulk density,hydraulic conductivity and aggregation at 0-15 cm layer were significantly affected both by tillage and cropping systems,while zero tillage significantly increased the soil organic carbon content.Yields of greengram were significantly higher in maize-chickpea and maize-mustard systems,more so with residue addition.When no residue was added,conventional tillage required 20%higher energy inputs than the zero tillage,while the residue addition increased the energy output in both tillage practices.Maize-wheat-greengram cropping system involved the maximum energy requirement and the cost of production.However,the largest net return was obtained from the maize-chickpea-greengram system under the conventional tillage with residue incorporation.Although zero tillage resulted in better aggregation,C content and N availability in soil,and reduced the energy inputs,cultivation of summer greengram appeared to be profitable under conventional tillage system with residue incorporation.

Farmer-based Rice Cropping Systems in the Poyang Lake Region, China: Analysis of Characteristics and Policy Implications

This paper examines the spatial characteristics of farmer/household behaviors in regional rice cropping systems(RCS), and the results provide necessary information for developing strategies that will maintain regional food security. Through field study and statistical analysis based on 402 households questionnaires finished in 2014-2015 in the Poyang Lake Region(PLR) of China, we arrived at two main conclusions. First, single-and double cropping rice were found across the study area, but showed a general distribution trend, with double cropping rice in the southeast part(especially in Jinxian county) and single cropping rice in the northwest(particularly in De’an county). Second, the household decisions concerning RCS varied in different parts of the PLR, but double cropping was the dominant type, with about 63.57% of the respondent households in the PLR cultivating double cropping rice. However, the multiple-cropping index of paddy rice was only 1.55. About 3% of interviewed households had altered their RCS during this period. Based on these findings, the local governments should guide farmers’ paddy field cultivation behaviors by increasing the comparative efficiency of rice production, promoting appropriate scale operations and land conversion, as well as optimizing rice growing conditions to improve the multiple cropping index and enhance food provision. Finally, land-use efficiency and more sustainable use of land resources should be improved.

Agro-climatic adaptation of cropping systems under climate change in Shanghai

Climate change affects the heat and water resources required by agriculture, thus shifting cropping rotation and intensity. Shanghai is located in the Taihu Lake basin, a transition zone for various cropping systems. In the basin, moderate climate changes can cause major shifts in cropping intensity and rotation. In the present study, we integrated observational climate data, one regional climate model, land use maps, and agricultural statistics to analyze the relationship between heat resources and multi-cropping potential in Shanghai. The results of agro-climatic assessment showed that climate change over the past 50 years has significantly enhanced regional agro- climatic resources, rendering a shift from double cropping to triple cropping possible. However, a downward trend is evident in the actual multi-cropping index, caused principally by the increasing costs of farming and limitations in the supply of labor. We argue that improving the utilization rate of the enhanced agro-climatic resources is possible by introducing new combinations of cultivars, adopting more laborsaving technologies, and providing incentives to farmers.

Comprehensive evaluation of multiple cropping systems on upland red soil

According to the principles and methods of ecology and system engineering,we set up an evaluation indicator system for multi-component and multiple crop-ping systems,evaluated the comprehensive benefits of multi-component and multiple cropping systems using grey relation clustering analysis and screened out the optimized model based on research done in the upland red soil in Jiangxi Agricultural University from 1984 to 2004.The results show that the grey relation degree of"cabbage/potato/maize-sesame"was the highest among 23 multi-component and multiple cropping systems and was clustered into the optimized system.This indicates that"cabbage/potato/maize-sesame"can bring the best social,economic and ecological benefits,increase product yield and farmers’income and promote sustainable development of agricultural production.Therefore,it is suitable for promotion on upland red soil.The grey relation degree of"canola/Chinese milk vetch/maize/mung bean/maize"was second,which is suitable for imple-mentation at the city outskirts.In conclusion,these two planting patterns are expected to play important roles in the reconstruction of the planting structure and optimization of the planting patterns on upland red soil.

AGRI-ENVIRONMENTAL ASSESSMENT OF CONVENTIONAL AND ALTERNATIVE BIOENERGY CROPPING SYSTEMS PROMOTING BIOMASS PRODUCTIVITY

Bioenergy,currently the largest renewable energy source in the EU(64%of the total renewable energy consumption),has sparked great interest to meet the32%renewable resources for the 2030 bioeconomy goal.The design of innovative cropping systems informed by bioeconomy imperatives requires the evaluate of the effects of introducing crops for bioenergy into conventional crop rotations.This study aimed to assess the impacts of changes in conventional cropping systems in mixed dairy cattle farms redesigned to introduce bioenergy crops either by increasing the biomass production through an increase of cover crops,while keeping main feed/food crops,or by substituting food crops with an increase of the crop rotation length.The assessment is based on the comparison between conventional and innovative systems oriented to feed and biogas production,with and without tillage,to evaluate their agri-environmental performances(biomass production,nitrogen fertilization autonomy,greenhouse gas emissions and biogas production).The result showed higher values in the biogas cropping system than in the conventional and feed ones for all indicators,biomass productivity(27%and20%higher,respectively),nitrogen fertilization autonomy(26%and 73%higher,respectively),methanogenic potential(77%and 41%higher,respectively)and greenhouse gas emissions(15%and 3%higher,respectively).There were no negative impacts of no-till compared to the tillage practice,for all tested variables.The biogas cropping system showed a better potential in terms of agri-environmental performance,although its greenhouse gas emissions were higher.Consequently,it would be appropriate to undertake a multicriteria assessment integrating agri-environmental,economic and social performances.