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

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Journal of Mountain Science 2016年第12期13卷 2205-2223页

作者： ZHANG Shi-chao wei chao-fu SHAO Jing-an WU Zhao-juan Key Laboratory of Surface Process and Environment Remote Sensing in the Three Gorges Reservoir Area College of Geography and Tourism Chongqing Normal University Chongqing 401331 China Key Laboratory of Arable Land Conservation (Southwest China) Ministry of Agriculture College of Resources and Environment Southwest University Chongqing 400715 China Academy of Agricultural Sciences Chongqing 401329 China

This study examines the technical efficiency(TE) differences among typical cropping systems of smallholder farmers in the purple-soiled hilly region of southwestern ***-,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 *** indicate significant difference in TE and its determinants among cropping *** 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,***,Technical inefficiency(TIE) of different cropping systems is significantly affected by characteristics of the household as well as ***,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 ***,output elasticity of land,labor,and capital,as a group,is greater than the one of agricultural machinery and ***,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.

关键词： Cropping systems Technical efficiency Land management Plot Purple-soil Stochastic Frontier Production function

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AN INSIGHT ON DRIVERS OF LAND USE CHANGE AT REGIONAL SCALE

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Chinese Geographical Science 2006年第2期16卷 176-182页

作者： SHAO Jing-an wei chao-fu XIE De-ti College of Resource and Environment Southwest University Chongqing 400716 P. R. China Chongqing Key Laboratory of Digital Agriculture Chongqing 400716 P. R. China

The studies of driving forces of regional land use change (LUC) are to reveal the real motivation behind the LUC and its interacting mechanism, so as to simulate and predict the process of LUC. Presently, studies rooting from different natural and socio-economic backgrounds and from different scales have deepened the people’s understanding and cognition to driving forces of regional LUC. Biophysical driving forces are relatively stable, and have the cumulating effects. Human driving forces are relatively active, and are main driving forces of short-term regional LUC. Existing regional LUC models can answer the three main problems: which contribution (why), which location (where) and what rate (when). But, regional land use system is defined as the self-organized system, usually affected by the cri- tical value area and sudden change, and controlled by different stages. To reduce the impact of critical threshold and break on land use system, the studies of LUC driving forces will aim at following priority areas: data linkage between remote sensing and no-remote sensing data; underlying driving force identification; driving factor quantification; driving factor scale dependence; and driving process integration simulation.

关键词： land use change driving forces driving mechanism process simulation regional scale

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Soil Geochemistry Changes Induced by a Foreign Soil Reconstruction Project in Three Gorges Reservoir Region of China

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Journal of Mountain Science 2015年第6期12卷 1511-1520页

作者： LIU Juan wei chao-fu LUO You-Jin DU Jing College of Resources and Environment Southwest University Chongqing Academy of Agricultural Sciences

Fertile topsoil was added onto the surface of barren slope land in Three Gorges Reservoir region of China in an anthropogenic process known as the foreign soil reconstruction project. The main goal of this paper was to reveal the influence of anthropogenic activities on pedogenic processes and soil classifications. Chemical weathering indices and comparative analysis were applied to discuss changes in geochemical compositions and weathering features of purplish soils(Cambisols) before and after the project. Results showed that:(1) The foreign soil reconstruction project slightly altered the major element composition of topsoil and improved the soil structure. Although the distributions of major elements in the original topsoil, original subsoil, foreign topsoil and newly constructed topsoil were all similar to that in upper continental crust, newly constructed topsoil was the most similar soil.(2) The chemical index of alteration was more sensitive than the weathering index of Parker at indicating chemical weathering status of purplish soil. The chemical weathering status of newly constructed topsoil was higher than that of the original topsoil and lower than that of foreign topsoil.(3) Anthropogenic activities may provide a promising new thought for the anthropogenic soil classification system. The scope and subgroups of Anthrosols should be extended and strengthened. Or there may be a need to combine Anthrosols and Technosols orders to create a new soil order. The results may be used for optimizing soil mellowing engineering activities and enriching the soil classification system.

关键词： Anthropogenic activities Weathering status Foreign soil reconstruction project Pedogenic processes Three Gorges Reservoir region China

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Shear strength features of soils developed from purple clay rock and containing less than two-millimeter rock fragments

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Journal of Mountain Science 2016年第8期13卷 1464-1480页

作者： ZHONG Shou-qin ZHONG Mang wei chao-fu ZHANG wei-hua HU Fei-nan College of Resources and Environment Southwest University Chongqing 400715 China Key Laboratory of Arable Land Conservation (Southwest China) Ministry of Agriculture Chongqing 400715 China

Soil shear strength is an important indicator of engineering design and an essential parameter of soil precision tillage and agricultural machinery and equipment design. Although numerous studies have investigated the characteristics of different soil shear strengths, only a few of these works have paid attention to soils containing considerable quantities of rock fragments. To date, most studies on the effects of rock fragments on the shear strength have paid attention to the role of rock fragments with sizes 〉2 mm. The effects of rock fragments 〈2 mm in soil are generally ignored. Similar to rock fragments 〉2 ram, the presence of rock fragments 〈2 mm could also change the mechanical properties of soils. Thus, in the present study we evaluated the potential influence of 〈2 mm rock fragments on soil shear strength via an unconsolidated undrained （UU） triaxial compression test. Our results were as follows：（1） A certain quantity of 〈2 mm rock fragments presented in purple soils developed from clay rocks; and an appropriate quantity of 〈2 mm rock fragments could improve the shear strength of soils. （2） The different PSDs of soils containin 〈2 mm rock fragment mainly caused variations in the internal friction angle of soils. （3） The shear strengths of the two mudstone-developed red-brown and gray-brown purple soils was more sensitive to water than that of the shale-developed coarse-dark purple soil. As the soil water content increased from 9% to 23%, the changes in the cohesion, internal friction angle, shear strength, and the maximum principal stress difference were smaller in the coarse dark purple soil than in the two other soils. We therefore concluded that 〈2 mm rock fragments in purple soils exerted important effects on soil shear strength. A better understanding of the differences among the shear strength features of purple soils could help improve the design of agricultural machinery and equipment.

关键词： Shear strength Purple soils Rockfragments Particle size distribution (PSD) Soil watercontent Triaxial test

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Effects of Land Management Practices on Soil Water in Southwestern Mountainous Area, China

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Agricultural Sciences in China 2008年第7期7卷 871-886页

作者： SHAO Jing-an wei chao-fu XIE De-ti College of Resources and Environment Southwest University Chongqing 400716 P.R. China Geography Science Institute of Chongqing Normal University Chongqing 400047 P.R. China

The effects of selected land management practices （cross-sloping tillage, ridge culture, organic manure, and straw mulch） on soil water conservation in a southwestern mountainous area, China, were studied during November 2002 to November 2004. The experimental field is divided into three parts based on soil layer depths, 0-60 cm （part Ⅰ）, 0-40 cm （part Ⅱ）, and 0- 20 cm （part Ⅲ）, and they all had the same slope azimuth （SE）, slope （10°）, and slope type （linear）. The experimental plots were subjected to the following treatments： cross-sloping tillage （CST）; cross-sloping tillage with organic manure （CST/ OM）; cross-sloping tillage with straw mulch （CST/SM）; contour ridge culture （CRC）; contour ridge culture with organic manure （CRC/OM）; and contour ridge culture with straw mulch （CRC/SM）, to identify the effects of management practices on soil water. Water contents were determined for soil samples collected, using a 2.2 cm diameter manual probe. Soil water was monitored once every five days from Nov. 20, 2002 to Nov. 20, 2004. The results indicated that, in the study stages, an integration of rainfall, evaporative losses, and crop transcription controlled the basic tendencies of profile （mean） soil water, while land management practices, to a certain extent, only modified its amount, distribution, and routing. Moreover, these modifications also mainly focused on the first 20 cm depth of topsoil layer. When each management practice was compared with control treatment, season changes of profile （mean） soil water were pronounced, while interannual changes among them were not significant. More comparisons indicated that, in the study stages, contour ridge culture had better effects than cross-sloping tillage. And under the same tillage, the combination of organic manure could achieve more than straw mulch. These management practices should be recommended considering the effectiveness of soil and water management techniques in the southwestern mountainous area, China.

关键词： land management practices soil water precision water management southwestern mountainous area China

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LAND USE CHANGE AND ITS SOCIO-ECONOMIC DRIVING FORCES UNDER STRESS OF PROJECT IN OLD RESERVOIR AREA——Case Study of Linshui Reservoir Area of Dahonghe Reservoir in Sichuan Province

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Chinese Geographical Science 2005年第4期15卷 315-324页

作者： SHAO Jing-an HUANG Xue-qin QU Ming wei chao-fu XIE De-ti College of Resource and Environment Southwest University Chongqing 400716 P. R. China Chongqing Key Laboratory of Digital Agriculture Chongqing 400716 P. R. China

The old reservoir areas built in 1950s- 1970s left behind many socio-economic problems, because of the administrative backward migration and little migration fund, and all these problems would be tied to land. Based on interviewing with peasant households, combining land use survey and socio-economic statistical index, this paper analyzed land use change and its corresponding driving forces in Linshui reservoir area of Dahonghe Reservoir. Results showed that land use change in the reservoir area was mainly embodied on low-lying land submergence and migration requisition land. The former changed the land use patterns, and the latter mainly reconstructed original land property and made land over-fragmented. Cultivated land per capita was 0.041ha in this area, below the cordon of cultivated land per capita enacted by FAO. Currently, there were still 30.25% of peasant households being short of grain in trimester of one year, and there were 35.27% of people living under the poverty line. The conditions of eco-environmerit in Linshui Reservoir Area were worse, and healthy and sub-healthy eco-environment accounted for less proportion, composed of green belt around the reservoir area and paddy field ecosystem, and economic forest and orchard ecosystem, respectively. The stress of the reservoir project was macroscopic background to analyze the driving factors of land use change, and real underlying diving factor of the land use change in the area was the change of cultural landscape under the stress of reservoir project. The rapid increase of population was the key factor to induce the change of man-land relationship in the reservoir area, the low level of rural economy was the crucial factor to decide how migrants input for production, and the belief of migrants, influencing the land use patterns in a certain extent, was the inducing factor to keep land use stable. The low-lying submergence and infrastructure construction accompanied the reservoir project were leading facto

关键词： land use change socio-economic driving factor project stress old reservoir area

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Driving forces and their interactions of soil erosion in soil and water conservation regionalization at the county scale with a high cultivation rate

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Journal of Mountain Science 2023年第9期20卷 2502-2518页

作者： LUO Bang-lin LI Jiang-wen GONG Chun-ming ZHONG Shou-qin wei chao-fu College of Resources and Environment Southwest UniversityChongqing 400716China Key Laboratory of Eco-environment in Three Gorges Region(Ministry of Education) Southwest UniversityChongqing 400716China Chongqing Water Conservancy&Electric Power Construction Survey&Design Research Institute Co. LTDChongqing 401120China Key Laboratory of Arable Land Conservation(Southwestern China) Ministry of AgricultureChongqing 400715China State Cultivation Base of Eco-agriculture for Southwest Mountainous Land Southwest UniversityChongqing 400715China

Soil erosion control based on county scale Soil and Water Conservation Regionalization(SWCR)is an essential component of China's ecological civilization *** SWCR,the quantitative analysis of the spatial heterogeneity and driving factors of soil erosion among different regions is still *** is of great significance for soil erosion control to deeply examine the factors contributing to soil erosion(natural,land use,and socioeconomic factors)and their interaction at the county and regional *** study focused on a highly cultivated area,Hechuan District of Chongqing in the Sichuan *** district(with 30 townships)was divided into four soil and water conservation regions(Ⅰ-Ⅳ)using principal component and hierarchical cluster *** driving factors of soil erosion were identified using the geographical detector *** results showed thatⅰ)the high cultivation rate was a prominent factor of soil erosion,and the sloping farmland accounted for 78.4%of the soil erosion in the study area;ⅱ)land use factors demonstrated the highest explanatory power in soil erosion,and the average interaction of land use factors explained 60.1%of soil erosion in the study area;ⅲ)the interaction between natural factors,socioeconomic factors,and land use factors greatly contributes to regional soil erosion through nonlinear-enhancement of double-factor *** study highlights the importance of giving special attention to the effects of land use factors on soil erosion at the county scale,particularly in mountainous and hilly areas with extensive sloping farmland and a high cultivation rate.

关键词： Soil and Water Conservation Regionalization Driving factors Soil erosion Geographical detector model Spatial heterogeneity

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Effect of Tillage System on Distribution of Aggregates and Organic Carbon in a Hydragric Anthrosol

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Pedosphere 2008年第5期18卷 574-581页

作者： GAO Ming LUO You-Jin WANG Zi-Fang TANG Xiao-Hong wei chao-fu College of Resources and Environment Southwest University Chongqing 400716 （China）.

The effect of different tillage systems on the size distribution of aggregates and organic carbon distribution and storage in different size aggregates in a Hydragric Anthrosol were studied in a long-term experiment in Chongqing,China. The experiment included three tillage treatments:conventional tillage with rotation of rice and winter fallow(CT-r) system,no-till and ridge culture with rotation of rice and rape(RT-rr) system,and conventional tillage with rotation of rice and rape(CT-rr) system. The results showed that the aggregates 0.02-0.25 mm in diameter accounted for the largest portion in each soil layer under all treatments. Compared with the CT-r system,in the 0-10 cm layer,the amount of aggregates > 0.02 mm was larger under the RT-rr system,but smaller under the CT-rr system. In the 0-20 cm layer,the organic carbon content of all fractions of aggregates was the highest under the RT-rr system and lowest under the CT-rr system. The total organic carbon content showed a positive linear relationship with the amount of aggregates with diameter ranging from 0.25 to 2 mm. The storage of organic carbon in all fractions of aggregates under the RT-rr system was higher than that under the CT-r system in the 0-20 cm layer,but in the 0-60 cm soil layer,there was no distinct difference. Under the CT-rr system,the storage of organic carbon in all fractions of aggregates was lower than that under the CT-r system;most of the newly lost organic carbon was from the aggregates 0.002-0.02 and 0.02-0.25 mm in diameter.

关键词： aggregates Hydragric Anthrosol organic carbon tillage system

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Soil heavy metal(loid)s and risk assessment in vicinity of a coal mining area from southwest Guizhou, China

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Journal of Central South University 2016年第9期23卷 2205-2213页

作者： QIN Fan-xin wei chao-fu ZHONG Shou-qin HUANG Xian-fei PANG Wen-pin JIANG Xin College of Resources and Environment Southwest University Chongqing 400716 China Key Laboratory for Information System of Mountainous Areas and Protection of Ecological Environment of Guizhou Province Guizhou Normal University Guiyang 550001 China

Total concentrations of arsenic, lead, cadmium, mercury, nickel, chromium, and copper in the soils from near a coal mine area in southwest Guizhou, China, were measured to evaluate the level of contamination, and the potential ecological risks posed by the heavy metals were quantitatively estimated. Results reveal that all heavy metals/metalloid exceeded the background values for soil environmental quality of heavy metals in Guizhou area. Geo-accumulation index(I_(geo)) showed that arsenic had the highest contamination level(I_(geo)=4) among the seven heavy metals/metalloid, and the contamination levels of mercury and lead were also relatively high(I_(geo)=3). Pearson correlation and cluster analysis identified that mercury, copper and arsenic had a relationship, and their presence might be mainly related to mining activity, coal and oil combustion, and vehicle emissions. Improved Nemerow index indicated that the overall level of heavy metal contamination in the studied area ranged from moderately–heavily contaminated to heavily contaminated level. Potential ecological risk index(R_I) analysis manifested that the whole ecological risk level ranged from high degree to very high degree(325.30≤R_I≤801.02) in the studied soil samples, and the potential ecological risk factors (E_r^i) of heavy metals/metalloid were as follows: Hg > As > Cd > Pb > Cu > Ni > Cr, and the E_r^i of Hg and As reached very high risk grade.

关键词： heavy metals soil contamination ecological risk coal mining area Xingren county

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Tillage Effect on Organic Carbon in a Purple Paddy Soil

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Pedosphere 2006年第5期16卷 660-667页

作者： HUANG Xue-Xia GAO Ming wei chao-fu XIE De-Ti PAN Gen-Xing College of Resources and Environment Southwest Agricultural University Chongqing 400716 （China） College of Environmental Science and Technology Guangzhou University Guangzhou 510006 （China） College of Resources and Environment Nanjing Agricultural University Nanjing 210095 （China）

The distribution and storage of soil organic carbon (SOC) based on a long-term experiment with various tillage systems were studied in a paddy soil derived from purple soil in Chongqing, China. Organic carbon storage in the 0-20 and 0-40 cm soil layers under different tillage systems were in an order: ridge tillage with rice-rape rotation (RT-rr) > conventional tillage with rice only (CT-r) > ridge tillage with rice only (RT-r) > conventional tillage with rice-rape rotation (CT-rr). The RT-rr system had significantly higher levels of soil organic carbon in the 0-40 cm topsoil, while the proportion of the total remaining organic carbon in the total soil organic carbon in the 0-10 cm layer was greatest in the RT-rr system. This was the reason why the RT-rr system enhanced soil organic carbon storage. These showed that tillage system type was crucial for carbon storage. Carbon levels in soil humus and crop-yield results showed that the RT-rr system enhanced soil fertility and crop productivity. Adoption of this tillage system would be beneficial both for environmental protection and economic development.

关键词： carbon sequestration organic carbon storage purple paddy soil tillage system

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