Effects of Different Cropping Patterns of Soybean and Maize Seedlings on Soil Enzyme Activities and MBC and MBN

Through the pot experiment, the effects of different cropping patterns of soybean and maize seedlings on rhizosphere soil urease, catalase, polyphenol oxidase and invertase activities and microbial biomass carbon （MBC） and nitrogen （MBN） were studied. Six treatments of soybean-soybean, soybean-maize, soybean-mixed, maize-soybean, maize-maize and maize-mixed were conducted in pots. Results showed that catalase activity and invertase activity of maize-maize were the highest and significantly different from those of the other treatments except maize-soybean; soil polyphenol oxidase activity of soybean-maize was the highest, and reached significant level among the other treatments, but there was no significant difference of urease activity among treatment soils; MBC of maize-maize soil and MBN of maize-mixed soil reached the highest and significant levels compared with other treatments; MBC and C/N ratio had positive and very significant correlations with soil catalase activity and invertase activity, respectively. Therefore, different cropping patterns could affect rhizosphere soil enzyme activities and soil MBC and MBN, which influenced soil carbon and nitrogen mineralization.

The Quantitative Evaluation of Output Efficiency in Different Cropping Patterns

Quantitative indexes such as land equivalent ratio, yield equivalent and value of output equivalent were used to evaluate output efficiencies of different cropping patterns, i.e., sequential cropping, intercrops and crop rotation. Compared to single cropping, land use efficiencies under sequential cropping, intercrops and crop rotation were raised by 62, 38 and 21%, respectively. The unit area yield under sequential cropping, intercrops and crop rotation were raised by 63, 29 and 16%, respectively. The unit area value was also enhanced under sequential cropping and intercrops, 76 and 35% higher than that under single cropping. The paper provides a useful tool for comparing farm output efficiency and build up a theoretical basis for further research on output efficiency of various cropping patterns in the future.

Carbon Sequestration in Soil Aggregates under Different Cropping Patterns of Bangladesh

Land use change and cropping patterns are important factors for controlling carbon sequestration in soils and they may also change the relative importance of different mechanisms of soil organic matter stabilization. The study was conducted to investigate the state of carbon sequestration in soil aggregates under different cropping patterns of Khulna, Jessore and Chapainawabganj districts in Bangladesh. Thirty-six soil samples were collected from (0 - 100 cm depth) above mentioned regions of three physiographic regions: Ganges Meander Floodplain, Ganges Tidal Floodplain and High Barind Tract. The texture of the samples varied within three soil texture groups, Silt Loam, Silty Clay Loam and Silty Clay. The highest NSI value (0.89) was found under Wheat-Fallow-T. Aman cropping pattern in Silty Clay soils (sample No 15) and lowest value (0.59) was found Vegetables/Mustard-Fallow-T. Aman cropping pattern in Silt Loam soils (sample No 17). The highest value (735.20 mg•kg−1) of active C was observed under Chickpea/mustard-T. Aman (Sample No 31) and the lowest value (619.23 mg•kg−1) was found in case of Wheat-Fallow-T. Aman cropping pattern (Sample No 30). The highest SOC stock (1.62 Kg C m−2) was found in Silty Clay Loam soil under Mungbean/Ash gourd-T. Aman cropping pattern (Sample no 4) and the lowest SOC stock (0.35 Kg C m−2) was found in Silt Loam soil under Cauliflower/Pumkin/Spinach-T. Aman Cropping pattern (Sample No 2). Soil organic carbon associated with different size aggregates was the highest (3.14%) under Mungbean/Ash gourd-T. Aman (Sample No 20) and was the lowest (0.36%) under Cauliflower/Pumkin/Spinach-T. Aman cropping pattern (Sample No 2). Organic carbon content in aggregate size ranges > 2000 μm (SOC1), 2000 - 250 μm (SOC2), 250-53 μm (SOC3), and <53 μm (SOC4) varied from 0.36% - 1.90%, 0.52% - 2.10%, 0.50% - 2.60% and 0.50% - 1.62%, respectively. The percentages of SOC associated with <53 μm aggregates were higher than those of >2000 μm, 2000 - 250 μm and 250 - 53 μm, aggregates. Significant positive correlations were found between SOC stock and SOC1, SOC stock and SOC2, SOC stock and SOC3, SOC stock and SOC4.

Cropping Pattern Modifications Change Water Resource Demands in the Beijing Metropolitan Area

Adequate freshwater supply has become an issue of increasing local and international concern. Reducing water use in agriculture, which is the largest water using sector of the economy, is both important and urgent. The aim of this paper was to quantify how recent cropping pattern changes have influenced water resources in the great Beijing metropolitan area, an expanding megacity which also includes rural counties. Crop production affects blue water use through water consumption and water pollution, the latter assessed here using a critical dilution method. From 1990 to 2010, the total blue water used by crop production declined due to a decrease in overall cropped area, initially in response to local government policies favouring urban development. However, the average blue water use per hectare increased from 2 112 m3 ha-~ yr-~ in 1990 to 2 764 m3 ha-1 yr-1 in 2003, largely as the result of a transition from cereal to vegetable crops, and in particular an increase in intensively managed plastic and glass covered vegetable production systems. Current policies aim to conserve agricultural land, in the interests of food security, and to stimulate cereal production systems with higher ecosystem services provision. As such, in 2010 the average blue water use was 2 425 m3 ha-~ yr-l. These results demonstrate that cropping pattern changes in peri-urban regions and rural communities surrounding the Beijing metropolitan area can have a substantial impact on water resources. They also highlight the tradeoffs between food production and urban and industrial water supply and the need for integrated policy development.

Linking a farmer crop selection model(FCS) with an agronomic model(EPIC) to simulate cropping pattern in Northeast China

In this paper, authors established a farmer crop selection model（FCS） for the three provinces of Liaoning, Jilin and Heilongjiang of the Northeast China. With linking to the environmental policy integrated climate model（EPIC）, the simulated results of FCS model for maize, rice and soybean were spatialized with 1 km×1 km grids to obtain cropping pattern. The reference map of spatial distribution for the three staple crops acquired by remote sensing imageries was applied to validate the simulated cropping pattern. The results showed that（1） the total simulation accuracy for the study area was 78.62%, which proved simulation method was applicable and feasible;（2） simulation accuracy for Jilin Province was the highest among the three provinces with a rate of 82.45% since its simple cropping system and not complex topography;（3） simulation accuracy for maize was the best among the three staple crops with a ratio of 81.14% because the study area is very suitable for maize growth. We hope this study could provide the reference for cropping pattern forecasting and decision-making.

Characterizing historical(1992–2010) transitions between grassland and cropland in mainland France through mining land-cover survey data

Grassland, as one of the largest ecosystems on the earth, supports various goods and services to humanity.Historically, humans have increased agricultural output primarily by cropland expansion and agricultural intensification.The cropland area was primarily gained at the expense of grassland and forests.Apart from grassland conversion, increasing consumption of calorie- and meat-intensive diets drives the intensification of livestock systems, which is shifting steadily from grazing to feeding with crops.To cope with the environmental degradation due to agriculture, various forms of ‘green payment＇ were implemented to promote the adoption of sustainable farming practices over the last two decades in the European Union.The aim of this study is to monitor the recent transitions（1992–2010） between grassland and cropland during two Common Agricultural Policy（CAP） reforms at the French mainland scale.We proposed an innovative approach to link grassland conversion to agricultural commodities and farming systems practices.We first assessed the grassland-to-cropland conversion and further investigated the crop sequence patterns that were observed to be dominant after the conversion through mining land-cover survey data Teruti and Teruti-Lucas.We found the trends of the transitions between grassland and cropland over the two time intervals： The loss of grassland（1992–2003） and restoration or re-expansion of grassland（2006–2010） in mainland France.Our finding on the crop sequence patterns after the grassland conversion reveals two notable evolutions of agricultural production systems.These evolutions were related to the increase in the proportion of cropland in the total agricultural land use.One evolution was most likely influenced by the demand for fodder： The conversion from grazing livestock to feeding livestock.Another evolution was the conversion from livestock production to field crop production.Our results indicate that the intensification of livestock farming systems continued over the last two decades in France.We conclude that, the approach developed in this study can be considered as a generic method for monitoring the transitions between grassland and cropland and further identifying the crop sequence patterns after the grassland conversion from time-series land cover data.

From statistics to grids:A two-level model to simulate crop pattern dynamics

Crop planting patterns are an important component of agricultural land systems.These patterns have been significantly changed due to the combined impacts of climatic changes and socioeconomic developments.However,the extent of these changes and their possible impacts on the environment,terrestrial landscapes and rural livelihoods are largely unknown due to the lack of spatially explicit datasets including crop planting patterns.To fill this gap,this study proposes a new method for spatializing statistical data to generate multitemporal crop planting pattern datasets.This method features a two-level model that combines a land-use simulation and a crop pattern simulation.The output of the first level is the spatial distribution of the cropland,which is then used as the input for the second level,which allocates crop censuses to individual gridded cells according to certain rules.The method was tested using data from 2000 to 2019 from Heilongjiang Province,China,and was validated using remote sensing images.The results show that this method has high accuracy for crop area spatialization.Spatial crop pattern datasets over a given time period can be important supplementary information for remote sensing and thus support a wide range of application in agricultural land systems.

Study on the Characteristics and Efficient Cultivation Techniques of "Rice-Rice-Potato" Triple Cropping Rotation Pattern

The efficient cultivation technique of "rice-rice-potato" triple cropping rotation pattern is summarized by analyzing its characteristics and cultivation techniques in Yangjiang region of Guangdong Province,China,and machine-transplanted cultivation technique of double cropping rice and cultivation techniques of winter potato black film mulching are emphatically introduced,in order to promote the development of potato industry in Yangjiang City.The results will provide a scientific basis for the popularization and application of the "rice-rice-potato" triple cropping rotation pattern.

Crop water requirements of major crops indryland of northern China

The concept of crop water requirements is discussed, based on which the calculation modelof crop water requirements is established. In light with crop, soil and meteorological data. the cropwater requirements of major crops in sub-humid and send-arid dryland farming areas of northernChina. including wheat maize , cotton. millet, soybean, sweet potato and potato, are calculated, andthe patterns of crop water requirements of these crops are revealed and discussed in this paper.

Study on a new grain-cash cropping pattern in paddy field

We studied a new grain-cash cropping pattern composed of "barley/watermelon + waize-rice", comparing with "barley / watermelon-rice" (CKI), "watermelon-rice", (CK2). The experiment was conducted in CNRRI’s field for 3 yr, employing completely randomized design with three replications, and each plot occupied 207 m~2. The soil in the experiment field contained: N, 2.48 g. kg, quick effective P 4 mg. kg, and quick effective K 53 mg·kg. The varieties tested were Zhemai 2 (barley), Zhemi 1 (watermelon), Suyu 1 (maize), and Shanyou 63 (hybrid rice).

Impacts of climate change on water quantity, water salinity, food security, and socioeconomy in Egypt

Climate change might have direct impacts on water quantity in Egypt and lead to indirect effects on Mediterranean saltwater intrusion to groundwater,which exposes agriculture to vulnerability.This study investigated impacts of climate change on agriculture,with particular regard to food security and socioeconomy,and quantified the effectiveness of cropping pattern adaptation measures by integrating three mathematical models.The BlueM model was used for hydrological simulations of Nasser Lake under flooding scenarios to predict the water supply from the High Aswan Dam.The water and salinity balance(WB-SAL)model was adopted to estimate the water salinity in the Nile Delta.The simulated results from the BlueM and WB-SAL models were integrated with the agricultural simulation model for Egypt(ASME)to project cropping patterns,food security,and socioeconomy throughout the country.The results showed that future climate change will directly affect the total crop area;crop areas for 13 crop types;the self-sufficiency of wheat,rice,cereal,and maize supplies;and socioeconomic indicators.The proposed cropping pattern adaptation measures focus on fixing the crop areas of rice and orchards and providing half of the population with lentils,maize,onion,vegetables,milk,and meat.The adaptation measures have the potential to promote food security without causing deterioration of the socioeconomic situation.However,water availability has much more significant effects on food security and socioeconomy than cropping pattern adaptation measures do.Accordingly,the country should rationalize water use efficiency and increase water supply.©2021 Hohai University.Production and hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Agronomic cultivation measures on productivity of oilseed flax:A review

Oilseed flax is one of the most important oil crops in China.With the improvement of people's living standards and the deepening knowledge of the nutritional value of oilseed flax,the demand and economic value of oilseed flax are increasing,and the cultivated area in China is expanding.However,the grain yield of oilseed flax is lower than other oil crops.It varies significantly from year to year,combined with a lower degree of mechanization,which has greatly limited the healthy development of the flax industry.Some of the effects of agronomic measures on productivity and water use efficiency of oilseed flax are reviewed in this paper.The major agronomic strategies for the productivity of oilseed flax were presented based on fertilization,plant density,irrigation,cropping pattern and weed control.Future research should investigate the effect of silicon and potassium fertilizers on the mechanism of lodging resistance of oilseed flax,the effects of diversified cropping systems(strip intercropping and crop rotation)on high and stable productivity and efficient utilization of resources.

Increasing Wages,Factor Substitution,and Cropping Pattern Changes in China

This article analyzed the influence of increasing wages on cropping patterns from theoretical and empirical perspectives.The results showed that the increasing labor cost provided a significant incentive to adjust the grain cropping pattern,which increased the production of the three major cereal grains but reduced the production of other grain crops.Increasing wages had a significant negative impact on cash crops.More laborintensive cash crops experienced a larger negative impact in the context of increasing wages.The increase in labor costs also had a negative impact on the proportion of vegetables produced,which was more evident in northern China.A further mechanism test indicated that factor substitution was a significant reason for cropping pattern changes;this illustrated the substitution of labor by machinery not only between grain crops and cash crops but also among different cash crops.

IMPACTS OF CLIMATE CHANGE ON CROPPING SYSTEM AND ITS IMPLICATION FOR AGRICULTURE IN CHINA

Based on the analyses on amplitudes of historical variation of temperature and precipitation in the past 500 years and latest 100 years,according to the regional climate change scenarios for China estimated by composite GCM,the potential impacts of climate change on cropping systems in China in future are simulated and assessed using the cropping system model development specially for the Chinese cropping patterns.It is shown that under the projected future climate change by 2050 the most parts of the present double cropping area would be replaced by the different triple cropping patterns while the current double cropping area would shift towards the central part of the present single cropping area.More explicitly,the northern boundary of triple cropping area would shift from its current border at the Changjing River to the Huanghe River,a shift of more than 5 degrees of latitude.And the shift of multiple cropping areas leads to a significant decrease of single cropping area. Furthermore,considering the changes mentioned above in combination with the likely negative balance of precipitation and evapotranspiration and,therefore,increase of moisture stress(i.e. less water availability),as well as the possible increase of heat stress disaster and decrease of LGS (length of growing season),the potential implication of climate change for agriculture in China are also analyzed roughly in this paper. As a result,however,it is still very difficult to reach a specific conclusion that the future climate change will he favorable or unfavorable to farm in China because of the complicated Chinese farming patterns,the complex-various social and economic environment of agricultural development and,especially,a great scientific uncertainties in the investigation/prediction of climate change.

Cropping pattern optimization considering uncertainty of water availability and water saving potential

In arid and semi-arid areas,the profitability of irrigated agriculture mainly depends on the availability of water resources and optimal cropping patterns of irrigation districts.In this study,an integrated agricultural cropping pattern optimization model was developed with considering the uncertainty of water availability and water saving potential in the future,aiming to maximize agricultural net benefit per unit of irrigation water.The available water which was based on the uncertainty of runoff was divided into five scenarios.The irrigation water-saving potential in the future was quantified by assuming an increase in the rate irrigation water-saving of 10% and 20%.The model was applied to the middle reaches of Heihe River basin,in Gansu Province,China.Results showed that if the irrigation water-saving rate was assumed to increase by 10%,then the net water-saving quantity would increase by 21.5-22.5 million m3 and the gross water-saving quantity would increase by 275.7-303.0 million m3.Similarly,if the irrigation water-saving rate increased by 20%,then the net water-saving quantity would increase by 43.0-45.1 million m3 and the gross water-saving quantity would increase by 331.7-383.2 million m3.If the agricultural cropping pattern was optimized,the optimal water and cultivated area allocation for maize would be greater than those for other crops.Under the premise that similar volume of irrigation water quantity was available in different scenarios,results showed differences in system benefit and net benefit per unit of irrigation water,for the distribution of available irrigation water was diverse in different irrigation districts.