Search

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cultivated land resource is the material base that mankind depend on for existence. Understanding how the cultivated land changes in quantity and quality has an important significance for country's food security and social stability. Based on the satellite images from Landsat TM/ETM in 2000 and OLI in 2013, this paper mapped the spatial distribution of cultivated land in the midwest Jilin province both in 2000 and 2013 and analyzed its temporal and spatial changes. Furthermore, soil data from 2351 field sampling points in study area were used to evaluate the quality of cultivated land and a comprehensive evaluation was made. Results revealed that cultivated land area in the midwest Jilin province increased from 5.61×104 km2 in 2000 to 5.64×104 km2 in 2013, among which dry farmland increased by 645 km2 and paddy field decreased by 350 km2.The transformation between dry land and paddy land was evident.Distribution of cultivated land changed differently from the east to the west:increasing in west part of study area and decreasing in east part, which resulted in the gravity center of cultivated land moved toward the west obviously. The increased cultivated lands were mainly converted from wetland and grassland, accounting for 66.04% and 21.12% of the total change area, respectively. The lost cultivated lands were mainly turned to artificial area, woodland and wetland with an area percent of 45.08%, 28.85% and 22.61%, respectively (mainly distributed around Changchun city). In terms of cultivated land quality, most cultivated lands were in uppermiddle grade in the midwest Jilin province in 2013, and the quality in the east part was better than that of the west.Although the total area of cultivated land increased, the quality of increased cultivated land mainly distributing in Baicheng and Songyuan city corresponded to lower grades including the third, fourth and fifth class with an area of 235,8 and 218 km2 respectively. Besides, the area of cultivated land in first class decreased by 305 km2, which mostly happened in the surrounding regions of Changchun city. The factors influencing the change of cultivated land were analyzed and we found that urbanization and policy were the most important driving forces to affect cultivated land quality and quantity. Accompanied by the rapid urbanization process, more and more highquality cultivated lands were occupied. Newly increased cultivated lands were mostly reclaimed from salinized land, alkalized land and wasteland, which led to an increase of cultivated land area and a decrease in quality. Overall, the cultivated land in the midwest Jilin province degraded severely during the past 15 years. This paper can provide an important reference for regional sustainable development of cultivated land resource. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Super Absorbent Polymer (SAP) is one kind of polymer with function of strong water absorbent and conservation. It has been paid attention to application in agricultural production, soil & water conservation and the pollution management in recent years. SAP is synthesized by natural hydrophilic monocase with cosslinking agent and initiator; there are three kinds of reaction type, such as graft copolymerization, carboxymethyl reaction and crosslinking reaction. Based on the raw material and synthetics techniques, the type of SAP can be divided into organic monocase polymer (such as Sodium Polyacrylate), starch polymer (such as starch graft acrylic acid sodium), organic-inorganic compound polymer (such as Bump/sodium polyacrylate) and organic monocase and functional component polymer (such as humic acid polymer). In order to summarize the new achievement of SAP research and analysis the development direction, based on authors' research accumulation and the literature's review, the paper reviews SAP development history, and summarizes the acting principle system of SAP, including five aspects. First is the principle of water absorbing, retaining and releasing of SAP itself. SAP can absorb deionized water 400~600 times or tap water 100 time of itself weight by method of water absorption and the swelling, and more than 85% water can be used by plants. Second is the principle of SAP improving soil and water conservation. SAP can improve the soil aggregate structure, increase the soil porosity and water infiltration, and reduce the evaporation of soil surface. Third is the principle of effect on SAP raising the use ratio of fertilizer, pesticide and other chemical materials. On fertilizer conservation and the use efficiency, SAP has the function on controlling nitrogen release and increasing the phosphorus release in soil. The key rule of SAP is major on reducing the rate of nitrogen release owing to nitrogen ions exchanged with functional groups of SAP and soil, the effect is stronger with increasing of SAP amount in soil. Meanwhile, SAP can increase the release rate of phosphorus fertilizer owing to the activating of soil phosphates. Fourth is the principle of effect on SAP raising water use efficiency by adjusting the plant physiological function to raise water use efficiency. This is related with SAP use way, in normal SAP is used in pot or furrow, this way can supply water directly for part root of plants, and other part root is in drought that can make plant root produce hormone ABA, and which can be moved to leaf to adjust stomata optimally for water use efficiency. Fifth is the principle of SAP effect on soil heavy metal immobilization. Heavy metal pollution in soil is a very serious problem in farmland environmental protection in China, especially Cd and Pb compound pollution. The experimental certificated that SAP and the compound materials can decrease over 50% heavy metal Pb and 80% Cd absorbent by maize in soil, and also immobilized over 69% Pb and 33% Cd absorbent by soybean in soil. On the other hands, the paper also analyzes the research development in agricultural production, vegetation construction, soil & water conservation and the pollution management, especially on water and fertilizer conservation and the high efficiency use, heavy metal pollution management of soil, etc. According to the exiting problems and practice production requirement, the development direction of SAP is to enhance the develop new type of SAP, strengthen the application basic research and the extensive technology transfer in future. [ABSTRACT FROM AUTHOR]

Developing a new subsoling method is one of the important ways to improve the subsoiling efficiency and overcome the traditional subsoling weakness, i. e. limited range and inhomogeneity. The present paper proposed a noval subsoiling method based on pneumatic split technology, namely, air pressure subsoiling. During the air pressure subsoiling, air was injected into cultivated soil to result in plenty of cracks inside the soil. In order to investigate the effect of air pressure subsoiling, a simulation experiment was carried out to observe the inner and external changes of soil before and after air pressure subsoiling with 3 indices including soil porosity, soil porosity increasing rate and soil surface uplift. Experiment was carried out from December 10, 2014 to February 10, 2015 in the Agricultural Machinery Laboratory of the Engineering Research Center of Northeast Agricultural University. Test and research methods were as follows: 1) Firstly, the Miller Soil Box test equipment was used to test soil resistivity of different moisture content, porosity and saturation of black cultivated soil in the Northeast of China. The various parameters of Archie soil resistivity model were formed based on the regression analysis of our test result. Then a regression formula was acquired to calculate soil porosity by soil resistivity and soil moisture content acquired.2) According to the actual cultivated land status of subsoiling in the Northeast of China, the plough layer and plow pan were made. The procedure was that 0.2 m plow pan was set on the groove bottom at first, and then 0.2 m plough layer was covered, which had 1.17 g/cm3 bulk density and 18% moisture. Two factors and 3 levels (plow pan bulk density of 1.4, 1.6 and 1.8 g/cm3, and subsoiling air pressure of 1.4, 1.6 and 2.2 MPa) were set in the experiment. Our experiment used the self-made air pressure subsoiling equipment to inject air into the plow pan with different bulk density (0.35 m deep), before and after air pressure subsoiling, used the regression formula to calculate the soil porosity and its increasing rate before and after air pressure subsoiling, and at the same time measured the vertical rise of soil surface when measuring the soil resistivity.3) Draw contour map of soil resistivity, soil resistivity increasing rate and vertical rise by the Origin software in order to analyze the distributions and changes of soil resistivity, soil resistivity increasing rate and vertical rise before and after subsoiling. Further more, we compared air pressure subsoiling with 3 traditional subsoilers (triangle shovel, arrow shovel and chisel shovel) on the effect of subsoiling by analyzing the scope of subsoiling, uneven extent and soil porosity increasing rate. Main results obtained were as follows: 1) The regression formula of subsoiling soil porosity, soil resistivity and moisture content was obtained, which was suitable for the black soil in the Northeast of China.2) For the plow pan with bulk density of 1.4, 1.6 and 1.8 g/cm3, when subsoiling air pressure was 1.4, 1.6 and 2.2 MPa, air pressure mainly formed horizontal cracks which resulted in an obvious increase of soil porosity. These cracks could effectively break the plow pan, increase the air content in the soil after subsoiling, make the soil volume expand and the surface uplift. Excellent subsoiling could be obtained with fewer changes or effects for plough layer.3) Compared with traditional subsoiling, air pressure subsoiling had the merits of larger scope, more uniformity and higher efficiency. For the effectively influenced radius on land surface, air pressure subsoiling was about 2~2.5 times of traditional subsoiling, and it was at least 3 times of traditional subsoiling on plow pan. The results and the data obtained in this paper can provide a reference for the further study and the design of air pressure subsoiling equipment. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Micro-lysimeter, as a simple and effective method, has been widely used to measure soil evaporation. However, there are still some controversies in its manufacture and application. The objective of this paper is to explore the applicability of micro-lysimeter in measuring soil evaporation under the conditions of bare soil and film mulching in the arid region of Northwest China, and to further analyze the main influencing factors of soil evaporation. The evaporations of bare soil and with plastic film mulch were measured by several micro-lysimeter methods, and sap flow combined with soil water balance method (E(F-B)) was conducted to compare and verify the results. Partial Least Squares (PLS) method was used to evaluate the main factors affecting soil evaporation, and the contribution rates of different factors to soil evaporation were obtained. Results showed it is feasible to measure evaporation of bare soil by micro-lysimeter. The measured results of micro-lysimeters with back cover (sealed) and with gauze cover (unsealed) were similar. The linear relationship between them was E(unsealed)=1.008E(sealed) (R2=0.876 1, P<0.05), The linear relationship between measured results of micro-lysimeters with and without soil replacement was E(no soil replacement) = 0.919E(soil replacement) (R2=0.890 1, P<0.05). Those are suggested that micro-lysimeter with gauze cover (unsealed) and without soil replacement should be adopted in arid areas of Northwest China, since its simplicity, economy and little damage to farmland compared with other micro-lysimeter methods. Evaporation measured by traditional method of ‘evaporation determined by bare soil micro-lysimeter multiplied by hole rate’ (E (LB×HR) was significantly lower than that in the field with plastic film mulch, and the daily evaporation approached 0. There were no significant difference in evaporations measured by micro-lysimeter between with plastic film hole (E(LM)) and bared soil (E(LB)) method, and their average values were 0.96 and 1.24 mm/d, respectively, during the maize whole growth period. It was found that there was a big deviation between E (F-B) and E (LM) method, indicating that the soil evaporation is still large although the farmland is covered with plastic film, which further proves that it is wrong in traditional concepts that the evaporation can be neglected under the condition of plastic film mulching. Although measured evaporation in bare soil using micro-lysimeters was feasible, there would be some deviation using the method in the field with plastic film mulch. Thus evaporation through little mulch hole (0.5%-5.0%) was relative high (1.02 mm/d) and it should not be ignored. Partial Least Squares (PLS) method has been applied in many disciplines and is an effective method to solve the collinearity of independent variables. In this study, contribution rates of different influencing factors to soil evaporation were obtained using PLS method. The contribution values of main influencing factors with Variable Importance in the Projection (VIP) values above 0.8 from high to low in order were: soil water content, solar radiation, leaf area index, hole rate, temperature, and the contribution rates were 23.9%, 18.3%, 17.0%, 14.5% and 13.9%, respectively. [ABSTRACT FROM AUTHOR]

Study on changes in microscopic structure of saline-alkali soil induced by different land usage in the Yellow River Delta is important to understand their consequence for soil mechanical and hydrological processes and improve soil management and remediation. This paper presents the results of an experimental study on microscopic structure of soils taken from farmland, grassland and beach at different soil depths in this region. The particle size and mineral composition of each soil sample were measured using the particle size distribution analysis and X-ray diffraction analysis, respectively. The poresize distribution was analyzed using mercury intrusion porosimetry, and soil particle arrangement and pore characteristics were measured using scanning electron microscopy (SEM). The results showed that the main particles of the three soils were silt, accounting for more than 60% of the total particle composition. The clay content in the three soils increased in the order of farmland > beach > grassland. Primary minerals such as quartz, calcite and albite were dominant in the three soils, accounting for more than 85% of their total mineral composition. The clay minerals in the three soils were dominate by illite, and the proportion of the clay minerals was less than 15% of the total mineral composition. The clay mineral content was higher in the farmland soil than in the grassland and beach soils and, as such, the mineral composition alone cannot explain the low permeability of the soils. The porosity of the farmland, beach and grassland soils was 25%, 32.58%-39.94% and 40.84%46.16% respectively. With increasing depth, the porosity of the grassland and beach soil increased, whereas the change in farmland soil porosity did not show an identifiable trend. The pore characteristics of the grassland and beach soils were similar, while the farmland soil was dominated by micropores and ultra-micropores with pore diameter less than 2 µm. The specific pore surface area of the farmland soil was considerably larger than that of grassland and beach soils, with the adsorption capacity of the former much higher than that of the latter. Farmland soil was densely structured; it was dominated by micro-fissures, with disordered structures formed between the skeleton particles; its basic structural units were flat and flaky particles; the skeleton particles ware dominantly surface contact while the particles were cemented by clay minerals. The microstructure of the grassland soil was closely inlaid particles with a "brick-wall" arrangement, and the particle connection was mainly surface contact; it was composed of closely inlaid massive particles and overhead pores; there was no cementation between its skeleton particles. The beach soil was composed of closely accumulated granular particles and intergranular pores; there was no cementation between skeleton particles. These results improved our understanding of the changes in microscopic structure of saline-alkali soils in response to land usage in the Yellow River Delta. They provide guidance for remediation, utilization and development of coastal saline-alkali soil in the Yellow River Delta. [ABSTRACT FROM AUTHOR]

The change process of cultivated layer quality for slope farmland at plot scale is influenced by the interactive effects between erosive rainfall and artificial farming activities at different temporal and spatial scales. For a slope surface, there exists a successive erosion process of rainfall-runoff-infiltration and the consequence is first reflected in the quality of cultivated layer. Among the factors induced the erosion process at plot scale, terrain is an important factor because it could redistribute the ratio of rainfall--infiltration, which directly cause a different erosion process for an erosive rainfall and the different degradation degree during a rainy season and a growth season. Taking purple soil slope farmland as an example, the paper firstly analyzed the varying characteristics of cultivated layer quality of slope farmland, then quantitatively evaluated the effects of four terrain factors, altitude, slope angle, effective soil thickness and slope position on cultivated layer quality and their sensitivity of impact, adopted principal component analysis and evaluation model. The results indicated: 1) Such soil properties as cultivated layer thickness, soil organic matter and soil bulk density of cultivated layer were all within the suitable scope and soil nutrient properties were generally at middle & low levels. The variation coefficients of soil bulk density and soil total porosity showed weak variability (CV<10%), presenting 7.97% and 8.36% respectively and the other soil properties showed moderate variability. 2)Minimum data set for cultivated layer quality evaluation of purple soil slope farmland consisted of eight soil parameters, bulk density, penetration resistance, soil organic matter, clay content, cultivated layer thickness, soil shear strength, saturated water conductivity and bioavailable phosphorus. Soil physical properties are more important than chemical properties except soil organic matter for erosion control and crop growth of slope farmland. Evaluation based on the MDS revealed that the cultivated layer quality varied spatially over the slope, being 0.458 in the low part of the slope, 0.443 in the middle part of the slope and 0.417 in the upper part of the slope and the quality value of the lower slope was 3.39% and 9.83% higher than that of the middle slope and upper slope positions, respectively. 3) The factors affecting cultivated layer quality divided into four types: slope-angle impacted type, slope location impacted type, effective soil layer thickness impacted type and altitude impacted type and they accounted for 38.89%, 22.22%, 14.81% and 24.08% of the total samples taken from slope farmland respectively. The slope angle was the main determinant of cultivated layer quality because it could induce directly many ecological processes at plot scale. The slope angle and effective soil layer thickness could be modified by such soil and water conservation measures as terrace, biological ridge and soil improvement methods. But the slope location and altitude could not be modified easily only by selecting suitable crop system. 4) The quality of cultivated layer had positive correlation with its thickness and location in the slope, and negative correlation with altitude and slope angle. Sensitivity analysis revealed that the determinants were ranked in the order of altitude (-0.399) > location in the slope (0.192) > slope angle (-0.112) > effective soil layer thickness (0.110) based on their impact on cultivated lay quality. These results could provide some useful evaluation parameters and its regulating direction for cultivated layer quality, which contributed to the sustainable utilization of purple soil slope farmland. Furthermore, other samples of slope farmland should be studied in order to find out the critical values of MDS according to 2 functions of cultivated layer, erosion control and soil productivity. [ABSTRACT FROM AUTHOR]

In order to quantitatively analyze the relationship between the phreatic evaporation and water surface evaporation of different soil textures in bare soil area, soils with different texture and sand samples were taken from the test site in Hefei University of Technology. After pretreatment such as drying and particles sieving, 4 types of homogeneous test materials were selected including coarse sand, fine sand, loam and sand soil. Then, a self-made phreatic evaporation measurement device was made with diameters of 60 and 25 mm and a height of 42 mm. It can easily solve the problem of automatic water replenishment during the evaporation process, so that the groundwater depth can always be 0. Based on the self-designed device, a total of 5 groups of comparative test schemes were constructed, including coarse sand, fine sand, loam, sandy soil and water in bare soil area. Under the same environmental conditions, daily phreatic evaporation of the 4 different soil textures and water surface evaporation were observed for a total of 127 days from December 24, 2018 to April 29, 2019. By analyzing the relationship between phreatic evaporation and water surface evaporation for soils with different textures, linear mathematical equations were established. The results revealed that the change trend of phreatic evaporation and water surface evaporation was basically the same during the experiment. The high air temperature would lead to larger soil evaporation. However, the phreatic evaporation of the 4 different soil textures was not equal to the water surface evaporation, and the difference between them was more significant as the air temperature was increased. The determination coefficients between phreatic evaporation value of different soil textures and the water surface evaporation were all greater than 0.97. Especially for fine sand, the correlation coefficient reached 0.99, which indicated that there was a significant correlation between phreatic evaporation and water surface evaporation (P<0.05). And the conversion coefficients were achieved between them according to the linear mathematical equations. Generally, in soil bare areas with similar climatic conditions in Hefei, the conversion coefficient of coarse sand was 0.94, and the coefficients of fine sand, loam and sand are 1.04, 1.14 and 1.19, respectively. The phreatic evaporation value of coarse sand was less than the evaporation of water surface. The phreatic evaporation values of fine sand, loam and sand were greater than water evaporation. Under bare soil conditions, this conversion coefficient was only related to soil texture. In addition, the loam and sandy soil evaporation in the Wudaogou test site of Anhui Province, China was selected to verify the rationality of the conversion coefficient obtained above. The results showed that when the groundwater depth was 0.4 m, the relative error of the loam evaporation calculated by the substitution method and the phreatic evaporation coefficient method were -10.30% and 2.25%, respectively. Moreover, the sand evaporation calculated by the substitution method was 5.11 mm smaller than the measured value with a relative error of -17.79%, while the sand evaporation calculated using the phreatic evaporation coefficient method was only less than the measured value of 0.56 mm, and the relative error was reduced to -1.94%. Therefore, when calculating the phreatic evaporation at different groundwater depths, directly replacing phreatic evaporation with water surface evaporation would inevitably cause larger relative errors. However, the relative error of the calculation result obtained from the phreatic evaporation coefficient method was smaller, and the calculated value was much closer to the measured value. The coefficient method proposed in this paper would significantly improve the reliability and accuracy of the calculation results of phreatic evaporation. [ABSTRACT FROM AUTHOR]

Soil respiration is mediated by microbial activities, temperature, humidity and other environmental factors in soil. The increase in use of microbial organic fertilizer and drip irrigation in greenhouse production could alter soil micro-environment, particularly the rhizosphere, thereby leading to a change in soil respiration. This paper investigated the response of soil respiration to different combinations of drip irrigation amounts and microbial organic fertilizer applications. We experimentally compared three irrigation amounts 15, 18 and 21 mm – associated with three microbial organic fertilizer applications 2800, 3600 and 4400 kg/hm². The treatment with inorganic fertilizer application served as the control. In each treatment, we measured soil respiration rate and accumulated carbon emission, as well as other determinants. The soil temperature and humidity were measured following the soil respiration measurement using the delta-T sensor (delta-T company, UK); soil organic matter was measured using the potassium dichromate sulfuric acid oxidation external heating method; the activity of dehydrogenase was determined using the TTC colorimetry method; the activity of urease was determined by the phenol sodium colorimetry method; the activity of catalase was determined by the KMnO4 volumetric method. We analyzed the responsive change in soil respiration to these determinants and root biomass. The results showed that, compared to the CK, drip irrigation and microbial organic fertilization improved soil organic matter and increased the activities of dehydrogenase, urease and catalase by 11.6%-27.6%, 8.0%-27.7% and 1.8%-11.2%, respectively; the increase in urease activities was at significant level (p<0.05). The soil respiration rate was positively correlated to the root biomass, temperature and organic matter content at significant level of p<0.01, and to the enzymatic activities at significant level of p<0.05. Among all treatments, irrigating 18 mm of water and applying 4400 kg/hm² of microbial organic fertilizer produced the highest root biomass, reaching 394 g/m² 120 days after the transplanting. Overall, combining drip irrigation and microbial organic fertilization increased root biomass by 25.9%-43.4%, compared to the CK. When irrigation amount was 15 and 18 mm, the carbon emission increased significantly (p<0.05) when the fertilizer application increased from 3600 kg/hm² to 4400 kg/hm². The cumulative carbon emission peaked at 415.2 g/m² when the irrigation amount was 18 mm and the microbial fertilization was 4400 kg/hm², significantly higher than that under other treatments (p<0.05). The lowest cumulative carbon emission was from the CK, being 255.3 g/m² only. In summary, this study showed that drip irrigation and microbial organic fertilization combined to impact soil carbon emission by changing organic matter content and root biomass in the soil. Our results have important implications for improving ecological cultivation in greenhouse production. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to solve the problems of high resistance and high power consumption of rotary tillage and land preparation, the rotary blade is studied based on theoretical analysis, simulation and field experiment in this paper. First, a wedge drag reduction rotary blade is designed based on the theoretical force model of cutting tools in mechanical soil dynamics. Second , the three-dimensional model of the national rotary blade and the wedge drag reduction rotary blade is established by using the Inventor software and the simulation experiment is carried on. The cutting soil model of 2 kinds of rotary blades is established by using HyperMesh software, and the material parameters, boundary constraints and working parameters are defined. On this basis, the soil cutting process, stress and cutting resistance are analyzed. It is proved that the wedge drag reduction rotary blade design is reasonable. In order to verify whether the wedge drag reduction rotary blade meets the strength requirement, the stress of the rotary blades is analyzed, and the cutting resistance of the national rotary blade and the wedge drag reduction rotary blade are compared. Third, field comparative experiments are carried out on national rotary blade and wedge drag reducing rotating blade with the evaluation indexes of torque, power consumption and soil breakage. The results show that the cutting resistance of the wedge drag reduction rotary blade is smaller than that of the national rotary blade; the maximum stress of the national rotary blade is 35.68 MPa and the maximum stress of the wedge drag reduction rotary blade is 29.49 MPa, which is less than that of the national rotary blade and far less than the yield strength of the material 430 MPa. On the premise of ensuring the strength of the blade body, the weight of the wedge drag reduction rotary blade is reduced by about 50 g, which is about 8.3% lower than that of the national rotary blade. The maximum cutting resistance of the national rotary blade is 530 N, the average cutting resistance is 375.5 N, and the maximum cutting resistance of the wedge drag reduction rotary blade is 510 N, the average cutting resistance is 335.5 N, the average cutting resistance of the wedge drag reduction rotary blade is 10.65% lower than that of the national rotary blade, which proves the feasibility of the wedge drag reduction rotary blade designed; The average torque of the wedge drag reduction rotary blade is 11.35% lower than that of the national rotary blade. In the working process of rotary blades, the average power consumption of the national rotary blade is 74.2 kW, the average power consumption of the wedge drag reduction rotary blade is 67.3 kW, and the average power consumption of the wedge drag reduction rotary blade is 9.29% lower than that of the national rotary blade. The average breaking rate of soil of the national rotary blade is 75%, and the average breaking rate of wedge drag reduction rotary blade is 79%, which is 4% higher than that of the national rotary blade; After continuous 33 hm2 tillage, rotary blades did not break, and the average wear of the national rotary blade is 98.5 g, the average wear of the wedge shaped drag reduction rotary blade is 97.3 g, the wear difference is 1.3%, and the wear degree is the same. The wedge drag reduction rotary blade can effectively solve the problems of high resistance and high power consumption of rotary blade, which is helpful to accelerate the development of arable land machinery, improve the mechanization level of cultivated land, and reduce the production cost of crops. [ABSTRACT FROM AUTHOR]

Sloping farmland is an important part of cultivated land resources in Yunnan district. The evaluation of cultivated-layer soil quality and the appropriate range of parameters for sloping farmland are the basis for the development of reasonable plough layer. Based on the Soil Management Assessment Framework (SMAF), taking the cultivated-layer soil quality of sloping farmland in Yunnan province as the research object, this paper constructed a soil quality index evaluation model (CLSQI) for sloping farmland, and used the minimum data set (MDS) method to screen the evaluation indicators to evaluate the soil quality of sloping farmland in Yunnan, proposed the range of soil parameters for rational tillage in sloping farmland. The results showed that the minimum data set (MDS) of soil quality evaluation of sloping farmland in Yunnan region consisted of five indicators: pH value, total nitrogen, total porosity, soil shear strength and slope. The comparative analysis of AL-CLSQI (the cultivated-layer soil quality index calculated by all indicators) and AL-CLSQI (the cultivated-layer soil quality index calculated by the minimum data set index) showed that the evaluation accuracy of cultivated-layer soil quality based on MDS index was higher. In the primary selection index system, the weights of soil bulk density, total porosity, capillary porosity, shear strength, and slope grade were larger, while in the MDS index system, the weight of the slope and total nitrogen content was larger. The cultivated-layer soil quality index (CLSQI) of sloping cultivated land was between 0.39 and 0.84, the mean value was 0.59±0.11, and the coefficient of variation was 0.19. The cultivated-layer soil quality of sloping farmland was generally “medium”, and it was generally low. The CLSQI of the sloping farmland in different sampling areas was significantly different (P<0.05), and the size relationship was: Chuxiong＞Shuangbai＞Xuanwei＞Ninger＞Malong＞ Shilin. The 0～20 cm sampling depth sloping farmland CLSQI (mean value 0.59) was greater than >20 cm (mean value 0.56), and the CLSQI (mean value 0.61) of purple soil sloping farmland was larger than the red soil (mean value 0.54) (P<0.05), while the ridge and contour farming cultivation mode sloping farmland CLSQI was larger than that of the straight-plowing. The order of the CLSQI of the sloping farmland in different agricultural divisions was: Northeastern Yunnan＞Central Yunnan ＞Southwest Yunnan. According to the corresponding relationship between the soil quality of the cultivated-layer and the crop productivity and membership function, the cultivated-layer was in a relatively reasonable state when the soil quality grade of the sloping farmland was at a “higher” and above level (CLSQI≥0.6). The appropriate range of MDS indicators for cultivated-layer of sloping land in Yunnan were indicated as follows: the pH value of 5.58～7.82, the total nitrogen content of ≥1.37 g/kg, the total porosity content of ≥52.28%, the soil shear strength value of ≥5.19 kPa, and slope value of ≤11.79°. The suitable range of the above-mentioned cultivated-layer soil parameters can be used as the standard for the rational cultivated-layer diagnosis of sloping farmland in Yunnan. The research can provide theoretical basis and parameter support for the quality evaluation of ploughed plough layer and the construction of reasonable plough layer. [ABSTRACT FROM AUTHOR]

Cracks are common in nature and affect a number of soil properties. They increase the permeability, reduce the soil strength and stability, and thus affect the growth of plant roots. This paper presented a model for crack formation which was introducing the correlation length to constructing the soil critical strain random field to optimize the cracking model. The model was based on a lattice of Hookean springs with finite strength and the critical strain. The concept of correlation length was introduced to constructs the critical strain random field, the correlation length was used for reflects the spatial continuity of the soil. The critical strain random fields were generated using program written by Fortran language. The model reproduced the dynamics characteristic of the development of crack network in nature, and some of the parameters of the model represented the physical properties of the soil. We processed the digital images to quantitatively analyze the geometric characteristics of cracks. The typical procedure of digital image processing included: the color image of the crack patterns was converted into a gray one, the gray image was further changed into a binary one with the threshold division method. After the process, the cracks and aggregates were simply distinguished in a black-white image, in which the black lines and the white areas represent the crack networks and the aggregates, respectively. We optimized the threshold to make the binary images as clear as possible, and processed the images through binarization, noise removal and edge extraction of crack for extraction of morphological properties. Finally, the influence on model simulation cracking of spatial correlation length, heterogeneity in random field was analyzed. Comparison of crack area, crack length, Euler number density by calculating experiment and simulation images, it could be drawn that crack morphology could be described by Minkowski area, length, Euler number density effectively. By calculating the average μ, standard deviation δ of cracks area, length, Euler number density, the images of average density value μ and μ±δ are basically the same in the change trend between experimental and simulated process. After calculation, the coefficients of determination R2 for the area, length and Euler number density are all larger than 0.5, and the root mean square error and deviation are small enough. The consistency index IA quite approach to 1, which indicating that the calibration results are satisfactory. The two models are compared, among them the determination coefficient R2 is between 0.889-0.968, the consistency index IA is between 0.964-0.993, which reflecting the dynamic cracking process of cracks well. The greater the correlation length and the smaller the variance, the lower the discretization degree of the random field, that the more uniform the soil cracking. On the contrary, there are mainly isolated cracks. And the mean value is too small, the whole strain of the random field is low, the simulated crack does not consistent with the development of the natural crack. [ABSTRACT FROM AUTHOR]

The minimum data set (MDS) is the least indicators collection that can reflect the information of total soil quality well, which can effectively improve the real-time characteristic and application of soil quality assessment. In order to characterize the soil quality of cultivated layer for slope farmland in southern red soil hilly area, the paper established the MDS for quality diagnosis of cultivated layer for slope farmland by cluster analysis (CA) and principal component analysis (PCA) respectively, and furthermore analyzed soil quality characteristics of cultivated layer adopting 3 different soil quality indices (SQI), including SQI-T (data from total soil indicators), SQI-CA (data from CA indicators) and SQI-PCA (data from PCA indicators). The results showed: 1) Soil quality of cultivated layer for slope farmland varied significantly among different red soil sites. The average cultivated layer thickness of 19.93±4.9 cm was in suitable level for crop growth, and the soil organic matter content of 17.43±8.71 g/kg and the soil total nitrogen content of 0.97±0.42 g/kg were in moderately barren level, but the soil nutrients of effective phosphorus of 26.1±22.22 mg/kg and available potassium of 155.46±88.35 mg/kg were rich for crop growth. The soil pH value of 5.34±0.77 was faintly acidic. 2) The MDS on soil quality diagnosis of cultivated layer for red soil slope farmland included such indicators as cultivated layer thickness, soil bulk density, soil penetration resistance, soil organic substance, pH value and soil available phosphorus. The assessment results of soil quality of cultivated layer based on 3 different data sets are distinct greatly, the variation range and the mean of soil quality index were showed as SQI-T > SQI-CA > SQI-PCA and the variation coefficients presented as SQI-T < SQI-CA < SQI-PCA. Furthermore, the relevance and Nash efficiency coefficient between SQI-CA and SQI-T were higher than that between SQI-PCA and SQI-T, and the relative deviation coefficient and the average relative error between SQI-CA and SQI-T were lower than that between SQI-PCA and SQI-T, which illustrated that MDS-CA (MDS based on CA) was more appropriate than MDS-PCA (MDS based on PCA) to reflect the information of the total data set (TDS) for soil quality assessment of cultivated layer for red soil slope farmland. 3) From the perspective of soil and water conservation, fertilizer conservation and yield-increasing potential, the suitability thresholds of those diagnostic parameters for cultivated layer of red soil slope farmland were indicated as follows: the cultivated layer thickness of ≥20.39 cm, the soil bulk density of 0.92-1.21 g/cm3, the soil penetration resistance of ≤1.21 kg/cm3, the soil organic matter content of ≥18.82 g/kg, the pH value of 5.04-5.38 and the effective phosphorus content of ≥28.83 mg/kg. Rational deep-loosening is one of the effective measures for reasonable cultivated layer construction. These results can provide some useful parameters not only for the soil quality recovery of the cultivated layer but also for the suitability regulation of the crop growth and the control of soil and water loss of slope farmland, which are also conducive to the sustainable utilization of the slope farmland resources in red soil hilly area. [ABSTRACT FROM AUTHOR]

In order to discuss the effect of rainfall and vegetion on soil erosion of sloping farmland in cimiamon soil region in western Liaoning, the experiment was earned out under natiual rainfall on artificial slope nmoff plots from 2006 to 2010. The nmoff plots with an intei-val of 1 m were designed according to the 20-year standard and each area was 60 m2 Slope factor was set as 5° and 10° respectively. Among 3 nmofi'plots built under the same slope, 2 plots were practiced by millet-sweet potato rotation, and another nmoff plot was set as the control, which was the natmal hillside field in 2006-2007 and bare slope (coverage <5%) in 2008-2010. Millet and sweet potato were planted as test crops by contour tillage and row spacing was 50 cm. The result showed that soil erosion in the sloping familand mainly occmred between Jiuie and August, paiticularly in July. The siuface nmoff and erosion amoimt increased in accordance with the increasing of giadient and the effect of slope on erosion amount was greater than nmoff with the slope increasing. When rainfall reached a ceitain intensity, soil erosion would occm*. The experiment also showed that the siuface nmoff and erosion amount on sweet potato field had significantly positive relations with the rainfall (P<0.01 for nmoff. P<0.05 for erosion amount), the maximum 30-niinute rainfall intensity (P<0.01), the rainfall erosivity (which was the product of the former 2 factors) (P<0.01), and the product of rainfall and average rainfall intensity (P<0.01); the nmoff on bare soil field had significantly positive relations with the rainfall (P<0.01 and P<0.05 on 5° and 10° bare soil field, respectively), and the rainfall erosivity (P<0.01): the erosion amount had significantly positive relations with the maximum 30-niinute rainfall intensity (P<0.05 andP<0.01 on 5° and 10° bare soil field, respectively), and the rainfall erosivity (P<0.01), but had not positively significant relation with rainfall. The siuface nmoff and erosion amount were mostly affected by the precipitation and the maximum 30-minute rainfall intensity respectively tluougli regiession analysis and the both had not positively significant relation with average rainfall intensity on sweet potato and bare soil field. Erosion amoimt had a relation of power fiinction and a significantly positive conelation with siuface nmofi' under medium and higlier rainfall intensity (P<0.01). The siuface nmoff and erosion amount on sweet potato field had a significantly negative exponential fimetion relation (P<0.05). The amoimt of soil erosion on sweet potato field was the largest, the following was millet field and that of wild glass giound was the least. Multi variance regiession analysis revealed that the factors impacting the amoimt of soil erosion from high to low were siuface nmoff. rainfall erosivity, and vegetation coverage, and the effects of rainfall erosivity and vegetation coverage on soil erosion increased with the slope increasing. Vegetation cover was especially impoitant to protect against soil erosion on sloping farmland in western Liaoning, and crop management would be paid more attention with the increasing of gradient. The effects of different factors such as rainfall and crop varieties on soil erosion on sloping familand were preliminarily known after the 5-year experiment in tliis paper. The research provides theoretical basis and teclmical support for the effective prevention and treatment of soil erosion in the region. [ABSTRACT FROM AUTHOR]

As the ecological security barrier in the north of China, Inner Mongolia is also the important agricultural and animal husbandry production base, and about one third of this region belongs to sandy land. Some sandy land is arable since plant growth requirements can be satisfied under natural conditions or when some artificial measures are used. Usually, some problems such as water shortage, water and nutrition leakage, high temperature on soil surface, and complex topography, exist for arable sandy land, but farmers cannot take effective measures to deal with these problems except make some simple management according to their experiences. The difficulties in optimizing crop planting structure and choosing irrigation methods usually lead to substantial waste of water and nutrient resources, lowing land productivity level, and even un-cultivation land. In order to provide references for local farmers to sustainably use arable sandy land by overcoming these limitation factors, seven farm crops (spring maize (Zea mays), spring wheat (Triticum aestivum), millet (Pennisetum glaucum), soybean (Glycine max), rapeseed (Brassica rapus), rice (Oryza sativa) and potato (Solanum tuberosum)), which had large planting areas and higher grain yields in the last five years in Inner Mongolia, were evaluated according to their water requirement, effective accumulated temperature, soil pH value, response to increased temperature, economic benefit, and drought resistance, respectively. Meanwhile, eight forage grasses (Agropyron, Artemisia desertorum, Caragana korshinskii Kom, Elymus dahuricus Turcz, Leymus chinensis Tzvel.cv, Medicago sativa L, Astragalus adsurgens Pall., and Bromus inermis Leyss.cv.) with large planting areas in the last 10 years and one another popular forage grass (Zea mays L.cv.) in Inner Mongolia were also evaluated according to precipitation, temperature, soil pH value, nutrient value, respectively. Based on crop planting models, the specific characteristics of various irrigation methods, as well as specific soil and climate conditions and topography characteristics for arable sandy land in Inner Mongolia, appropriate water saving irrigation method was chosen for each crop. The results indicated that the rank of comprehensive suitability for farm crops in arable sandy land was: spring maize, spring wheat, millet, soybean, rape seed, rice and potato. For forage grass, the rank of comprehensive suitability in arable sandy land was: Agropyron, Artemisia desertorum, Zea mays L.cv., Caragana korshinskii Kom, Elymus dahuricus Turcz, Leymus chinensis, Medicago sativa L., Astragalus adsurgens Pall. and Bromus inermis Leyss.cv. These loosely planted (wide seeding/row spacing) crops such as maize, rice, soybean and potato were suggested to be drip-irrigated and even under mulch film, while those closely planted (narrow seeding/row spacing) crops such as forage grass were suggested to be irrigated through sprinklers. When crop suitability was evaluated, we used data from various published papers with different experimental conditions. In addition, when evaluating indicators were chosen and their weight factors were determined, subjectivity might really exist. Therefore, the evaluating method adopted in this study can be further improved. However, the results are still reliable and valuable for application and can provide reference for utilizing arable sandy land in Inner Mongolia sustainably and efficiently. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, the experiment area is dry and prone to soil erosion, in order to stop slope runoff and promote rapid vegetation restoration, a restoration program was implemented. So it is significant for grassland ecological construction to study on the effects of ecological restoration measures on soil properties and soil quality. A study had been done to investigate the different of 0-40 cm soil depth of soil properties and assessment of soil quality under different restoration measures in typical steppe grassland in Ningxia. We selected the sites that has been subject to enclosure(FY), contour trench(SP), fish-scale pits(YL), which were implement in 2001 and grazed(FM) (as a reference, traditional grazing with some supplement) grassland. The results showed that: 1) Soil bulk density of grazing grassland was the highest (P <0.05) whereas the soil clay content, field water holding capacity and total porosity were the lowest (P<0.05), and there was no significant difference (P > 0.05) in soil physical properties between enclosure, contour trench, and fish-scale pits grassland. 2) Soil organic matter and total nitrogen were the highest (P < 0.05) in enclosure grassland, followed by grazed grassland, and the lowest in contour trench. The content of total phosphorus was higher (P = 0.05) in grazed and enclosure grassland, but was the lowest (P < 0.05) in contour trench grassland. The available K content was the highest in grazed grassland the lowest in fish-scale pits grassland (P<0.05). The content of available N was highest in enclosure grassland but lowest in contour trench grassland which were 161.75 mg/kg and 77.17 mg/kg respectively (P<0.05). 3) Soil sucrase and urease activity showed FY>SP>YL>FM; protease and phosphatase activity both showed the highest (P <0.05) in enclosure grassland and the lowest (P <0.05) in the fish-scale pits grassland; the bacteria, actinomycetes and fungi were varied in each treatment; the amount of microorganisms showed FY>FM≈SP>YL whereas microbial biomass carbon and nitrogen showed FY>YL≈SP>FM (P<0.05). 4). As a whole, soil bulk density was negatively correlated with other indexes, and negatively correlated with clay content, field water holding capacity, total porosity, sucrase activity, urease activity, microbial biomass carbon and microbial biomass nitrogen (P<0.01). There was a significant positive correlation between soil organic matter, total nitrogen and available nitrogen (P<0.01) and the correlation between soil enzyme activity and soil microbial population (P<0.05). Soil capillary porosity (except soil microbial biomass nitrogen) and available potassium were not correlated with other indexes (P>0.05). 5) The comprehensive score of soil quality evaluated by the membership function factor analysis method was: enclosure> grazed> contour trench>fish-scale pits grassland. In summary, the enclosure grassland was more conducive to the restoration of typical grassland. Based on the study of the effects of enclosure, contour trench and fish-scale pits on the soil physical and chemical properties and biological traits, the membership quality of soil under different restoration measures was evaluated by membership function and factor analysis and can provide the basis for the ecological construction of typical grassland in Ningxia. The results showed that the enclosure was the most beneficial to the restoration of soil quality in degraded grassland in the study area. [ABSTRACT FROM AUTHOR]

The purpose of this study was to model sediment concentration of sheet erosion on rangeland, which has a major impact on strengthening river basin management and controlling the source of soil erosion. The impact of herbaceous vegetation on sediment concentration under different slopes or rain intensities was studied by artificial rainfall experiment. The relationship of sediment concentration and slope gradient, rainfall intensity, and hydraulic parameters, such as shear stress, stream power and unit stream power, was investigated to derive an accurate experimental model. Each experiment soil pan with metal frames was 140 cm long, 120 cm wide and 2.5 cm deep. The experiment soil sample was collected from Ansai County, Shaanxi Province in China. After the soil was packed, herbaceous vegetation (Poa pratensis L.) was transplanted in a banded uniform layout. Poa pratensis L. was a gramineous plant, and the current year's Poa pratensis L. was selected. The duration of all simulated rainfall events was 40 min. The experiment was conducted at 5 herbaceous vegetation cover densities (30%, 40%, 50%, 60%, and 70%), 5 rainfall intensities (0.7, 1, 1.5, 2, and 2.5 mm/min) and 5 slopes (7°, 10°, 15°, 20°, and 25°), respectively. All combinations were tested with 2 replicates of each run, a total of 90 experimental units. All statistical analyses were carried out using Excel or spss 18.0. Results show that: 1) Herbaceous vegetation not only decreases sediment concentration, but also reduces the effect of rainfall intensity or slope on it, which would increase with cover increasing. Cover increases from 30% to 70%, herbaceous vegetation decreases sediment concentration by more than 5 kg/m3, and reduces the effect of rainfall intensity or slope on it by more than 10 kg/m3. Under different slopes or rainfall intensities, sediment concentration decreases as linear equations with cover, and the relationship between sediment concentration and cover is significant (P<0.01). Under different covers, sediment concentration totally increases as power equations or exponential equations with rainfall intensity or slope, the relationship between sediment concentration and rainfall intensity is very well (P<0.01), and the relationship between sediment concentration and slope is also good (P<0.01). 2) Unit stream power is the parameter most suitably describing sediment concentration with an exponential equation among the 3 hydraulic parameters considered in this paper. Sediment concentration increases as shear stress or stream power increases, and both can be described by a logarithmic equation, but the relationship between sediment concentration and shear stress or stream power is poor. 3) Rainfall intensity, slope and cover can be used to predict sediment concentration with an exponential function accurately, which was satisfactory for predicting sediment concentration with the R2 value of 0.937 and the NE (Nash coefficient) of 0.894. Meanwhile, unit stream power also can be used to predict sediment concentration with a power function equation, which was satisfactory for predicting sediment concentration with the R2 value of 0.940 and the NE of 0.986. Vegetation species, layout and root morphology affect the simulation effect of sediment concentration on rangeland. In the later period, the vegetation species, layout and root morphology should be studied to quantify the sediment concentration and optimize the sediment concentration model. [ABSTRACT FROM AUTHOR]

Cultivated layer soil quality is highly sensitive to both soil erosion and artificial farming tillage in Purple Hilly Area. Soil erosion is a key factor that causes soil degradation and soil productivity instability of cultivated layer for slope farmland. Taking slope farmland in purple hilly area as an example, this paper has conducted cluster analysis on soil quality, permeability and cultivated layer type of slope farmland with different land productivity grades, and further discussed the effect of soil erosion on thickness of cultivated layer and the soil body configuration with reasonable cultivated layers of slope farmland. Results indicated that: (1) The soil quality of cultivated layer for purple soil slope farmland presented a moderate variability, the variation coefficients were 12.18% and 37.26% for the effective soil layer thickness (15-80 cm) and the cultivated layer thickness (15-25 cm), respectively, and the variation coefficient was 94.51% for the soil available phosphorus, indicating that the variability of soil physical properties was weaker than that of chemical properties. The cultivated layer configuration below the third grade of land productivity was almost full virtual or full real profile structures, and meanwhile, the production of slope farmland with the fifth grade of land productivity fell by about 50%. (2) There were significant (P<0.05) differences in soil physical properties, water-retention properties and tillage performances of cultivated layer at different slope position and different vertical depth of purple soil slope farmland, in which the soil bulk density showed upper slope > lower slope > middle slope, and soil shear strength showed upper slope > middle slope > lower slope, the soil stable infiltration rate showed the contrary order, and the soil penetration resistance was middle slope > upper slope > lower slope. The soil bulk density, shear strength and penetration resistance all presented bottom soil layer > subsoil layer > cultivated layer except soil infiltration; about 70% of the rain stored in 0-40 cm soil layer of slope farmland could be used by crops. (3) The average annual thinning of cultivated layer thickness varied between 1.04 and 3.04 mm for the moderate erosion degree of slope farmland. The reasonable cultivated layer of slope farmland could be established effectively by regulating such means as the minimum data set (MDS), which included soil layer thickness, cultivated layer thickness, soil bulk density, soil shear strength, soil organic matter and soil infiltration capacity for evaluating the cultivated layer soil quality of slope farmland, and moreover, the reasonable cultivated layer configuration overall should maintain the type of upper part loose and lower part tight, the cultivated layer thickness of 20-25 cm and the effective soil layer thickness of 50-60 cm. (4) Purple soil slope farmland could be divided into 4 kinds of cultivated layer types, whose obstacle cultivated layer was mainly manifested as the effective soil layer thickness restricted type (Class II), the cultivated layer thickness restricted type (Class III) and the soil nutrients restricted type (Class IV), accounting for 30%, 10% and 3% of total cultivated layer, respectively; so the regulating of reasonable cultivated layer of purple soil slope farmland should focus on effective soil layer thickness and cultivated layer thickness. These results can not only deepen the objective understanding of relationship between soil erosion and cultivated layer degradation but provide some essential parameters and technical supports for constructing reasonable cultivated layer of slope farmland in purple hilly area. [ABSTRACT FROM AUTHOR]