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Copyright of Journal of Soil & Water Conservation (1009-2242) is the property of Institute of Soil & Water Conservation 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 Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office 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 Journal of Changzhou University (Natural Science Edition) / Changzhou Daxue Xuebao (Ziran Kexue Ban) is the property of Editorial Department of Journal of Changzhou University 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.)

Rice is one of the most significant cash crops, with a yield of over 200 million tons each year in China. After harvesting, the rice grain can be dried in time to prevent mold, sprouting, and other defects, particularly for the high yield and quality. Hot-air drying has been the primary approach for drying rice. However, the uniform drying cannot be fully met using one-way ventilation with vertical box-type hot-air dryers. The uniform distribution of airflow can depend mainly on the structure and arrangement of the angle tubes in the drying section. In this study, four-way ventilation was proposed for the mixed-flow drying section, in order to improve the uniformity of airflow distribution in the grain layer for high rice quality. The double-side inlet variable diameter air ducts were also designed in this case. A mathematical model was then established to couple the heat and moisture transfer within the rice layer using the CFD platform, according to the porous media heat and mass transfer theory. FLUENT software was also used to simulate the static flow field, temperature, and humidity distribution in the drying section. The simulation results showed that the best reducer angle of the double-side inlet air duct was 0.85°, fully meeting the industrial requirement of uniform air distribution in the drying section. The wind velocity non-uniformity coefficient of the section below the inlet air duct was reduced by 6.11 percentage points after optimization. The uneven distribution of flow field, temperature, and moisture were obtained along the longitudinal direction of the inlet air duct using double-side inlet variable diameter air ducts in the drying section. An experimental bench was also utilized to verify the simulation. The three-factor five-level quadratic orthogonal rotation combination and parameters optimization were carried out with the temperature of hot air, the air velocity, and the initial moisture content as the experimental factors, while the drying rate, the crackle-added ratio, and the taste value as the experimental index. Design Expert 8.0.6 was utilized to analyze the experimental data for the regression equations and response surface plots. The optimal combination of operating parameters was obtained as follows. The optimal hot-air temperature, the inlet air velocity of the air duct, and the initial moisture content were calculated as 43℃, 4.1m/s, and 18.2%, respectively, where the drying rate, crackle-added ratio, and taste value were 1.116 %/h, 1.7%, and 80.33 points, respectively. Anyway, the experimental parameters were better consistent with the mathematical modelling. The drying experiments showed that the moisture non-uniformity of the rice was less than 0.7%, indicating the better drying performance of four-way ventilation mixed flow drying section for rice. The drying section with optimal parameters can be expected to apply for the double inlet variable diameter air ducts during rice drying. This finding can provide an effective reference to optimize the drying process after rice harvesting. [ABSTRACT FROM AUTHOR]

A slope farmland has been one of the most serious land-use types of soil and water loss, as well as the non-point source pollution. Natural conditions and unreasonable farming have also posed great damage to the ecological environment, particularly on the quality degradation of slope farmland. Therefore, it is very necessary to construct the quality control system of slope farmland in recent years. Taking sloping farmland in Yunnan province of China as a research object, a factor analysis model was first established to diagnose the quality obstacle factors of slope farmland. The types of quality obstacles were then ranked to define in each region, thereby identifying the controllable factors, the regulation priority, and objectives of slope farmland quality. The quality regulation potential of slope farmland was calculated to determine the zoning regulation mode in different regions. The results showed that: 1) The main types of quality obstacles were erosion degradation, drought, and water shortage, as well as the nutrient poverty type in the sloping farmland. There was some difference in the combination and performance of obstacle factors in different regions. 2) The adjustable factors of slope farmland quality included the thickness of arable layer, soil bulk density, pH value, organic matter, the total nitrogen, available phosphorus, available potassium, irrigation assurance rate, and field slope, among which the field slope, soil organic matter, irrigation assurance rate, available phosphorus, available potassium and pH value were the priority adjustment and control factors. The goal of quality control in the sloping farmland was to make the controllable factors in the appropriate range under various control measures. An optimal range of factors were achieved, where the thickness of plough layer ≥17.35 cm, soil organic matter ≥28.89 g/kg, soil available phosphorus ≥32.44 mg/kg, soil available potassium ≥137.81 mg/kg, irrigation assurance rate ≥73.33%, soil bulk density ≤1.31 g/cm3, field slope ≤12.87°, and pH value 6.06-8.06. 3) The objectives of quality control in the sloping farmland included the ideal and actual state. In an ideal state, the potential of quality control in the sloping farmland was 0.347, indicating an upgrade from the "medium" to the "higher" level. In the actual state, the potential of quality control in the sloping farmland was 0.198, indicating that the quality level was improved from the current "medium" to "high". The potential of actual state control was used as the standard quality control of slope farmland. 4) According to the general idea of "erosion control, water regulation, and fertility enhancement", the integrated mode of quality control in the sloping farmland was constructed as follows. The tillage modes were utilized to promote soil and water conservation, such as ridge, contour, and reverse slope tillage, as well as the conservation tillage (rotary, subsoiling, and no tillage + deep tillage) in farming measures. The water engineering slope to ladder project and high-efficiency water-saving measures can be implemented to actively promote the straw returning, green and organic fertilizer application. The soil testing and formula fertilization among soil fertility measures can be used to increase the content of soil organic matter and nutrients in the slope cultivated land. This finding can provide a scientific guide for the quality cultivation and management of regional slope farmland at a provincial scale. [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.)

Cultivated land being an essential natural resource, has been increasingly occupied in the last 60 years with the acceleration of urbanization. It is necessary to be careful in land use, in order to ensure food security and human existence. In addition, the quality degradation of cultivated land has seriously threatened to food security due to the misuse of land. Slope farmland, one type of cultivated land, is widely distributed in the plateau and mountain areas in the central and western China. Scientific quality evaluation of slope farmland is closely related to local food security and ecological environment, further to implement national protection schemes, such as the “Trinity” of quantity, quality and ecology. However, there are some features of slope farmland, such as wide distribution, large slope, soil erosion, frequent seasonal drought, low soil quality, to make accurate evaluation difficult. The evaluation index and model are also lacking. Taking the slope farmland in Yunnan as a research area, this study aims to construct a quality evaluation system of slope farmland based on the framework of “element demand regulation”. The 30 m × 30 m grid (pixel) was selected as an evaluation unit for the comprehensive weight. The quality of slope farmland was evaluated quantitatively, together with its characteristics of spatial distribution. The results showed that: 1) Index system of the Minimum Data Set (MDS) in quality evaluation of slope farmland consisted of 14 indexes, including the effective thickness of soil layer, arable layer thickness, bulk density of soil, soil texture, pH value of soil, organic matter, effective phosphorus, available potassium, accumulated temperature (≥10 ℃), field regularity, contiguity, amount of rainfall, assurance rate of irrigation, and field slope. 2) Slope farmland Integrated Fertility Index (SIFI) was distributed between 0.36 and 0.81, with an average value of 0.59. Most evaluation units of SIFI was less than 0.6, showing a significant difference (P<0.05). The SIFI size relationship between five types of soil in slope farmland were ranked in order: Lateritic red earths, Red earths, Purplish soils, Yellow earths, Yellow-brown earths. SIFI increased with the elevation in the range of 0-1 000 m, while decreased larger than 1 000 m, indicating the variation of SIFI was related to the range of elevation. 3) The quality of slope farmland can be Grade 6, 5, 7 and 4, according the national standard. Specifically, the quality of slope farmland was relatively high Grade 4 and 5 at the southern border, central, southeast, and western Yunnan, whereas, northeast and northwest Yunnan indicated low Grade 6 and 7. The Lorenz curve of quality grade showed a pattern of “S-type” distribution in different regions, indicating a low grade in Yunnan province. This finding can provide a scientific basis to improve the quality evaluation system of slope land, thereby to efficiently implement geological regulation of slope farmland. [ABSTRACT FROM AUTHOR]

Slope farmland is an important part of cultivated land resources in hilly areas of China. Identifying the spatio-temporal distribution and evolution characteristics of slope farmland resources is of great significance for rational planning and utilization of slope farmland resources and water and soil ecological environment construction. In this paper, using the land use data for 7 time points from 1980 to 2015, based on GIS spatial analysis technology, dynamic degree model, kemel density estimation and landscape pattern index model, the spatio-temporal distribution pattern and evolution law of slope farmland in Yunnan for nearly 35 years were quantitatively analyzed. The results showed that: 1) the area of slope farmland in Yunnan was 472.55×104 hm², accounting for 69.79% of the cultivated land area, and the average slope was 15.62°. The relationship between the area ratio of slope farmland in different agricultural divisions was: Southwestern Yunnan>Northeastern Yunnan>Northwestern Yunnan>Southern fringe>Western Yunnan> Southeastern Yunnan>Central Yunnan, and the average slope size relationship was: Northwestern Yunnan>Southwestern Yunnan>Northeastern Yunnan>Western Yunnan> Southern fringe >Southeastern Yunnan > Central Yunnan. 2) In the past 35 years, significant dynamic transfers had occurred in slope farmland, forest land, grassland and paddy fields, but the process of transfer in and out was generally balanced, and the area of slope farmland has a slight increase trend during the process of land use transfer. 3) The slope of most slope farmland was more than 8°, and the proportion of slope farmland with slope >15° was 78.54%. The area of slope farmland with different slopes in the past 35 years had a dynamic process. It showed an increasing trend for the slope farmland area with slope <15°, while decreasing trend for the slope farmland area with slope >15°. The area of slope farmland with different slopes has the dynamic process of “decreased→increased→decreased” or “decreased→increased→ decreased→increased”, and the fluctuation degree of >25° slope farmland was the largest. 4) With the evolution of spatio-temporal distribution of slope farmland in the past 35 years, the distribution characteristics of kemel density value in slope farmland have changed, but the change range was small. The distribution of slope farmland in most areas was in low-density value, and the area of high-density value was the smallest. Slope farmland distribution clusters were represented by four significant distribution zones: the Lincang distribution zone, the Lincang-Xishuangbanna distribution zone, the Pu’er distribution zone and the Zhaotong distribution zone. 5) Among the eight types of land use, the landscape dominance of slope farmland was in the middle position, and the fragmentation characteristics of slope farmland were the most significant among all land use types. In the past 35 years, the degree of fragmentation of slope farmland landscape has decreased, and the degree of contiguous use of slope farmland has been strengthened. The research results can provide theoretical support for the rational planning and utilization of sloping farmland and soil and water ecological environment protection in Yunnan. [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]

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.)