Search

[Objective] Winter wheat in Northern China is often rotated with other crops which are expected to have a legacy effect. This paper aims to study the effect of different tillage and preceding crops on soil nutrients, yield and water use efficiency of the winter wheat. [Method] The field experiment consisted of a rotary tillage (RT) and a no-tillage (NT). The preceding crops for each tillage were corn (MW) or soybean (SW). During the experiment, we measured the changes in soil nutrients, soil water content, water and fertilizer use efficiency, and yield of the wheat. [Result] For the same preceding crop, non-tillage increased soil water content compared to rotary tillage; under the same tillage, soil water content with maize as the preceding crop was higher than that with soybean as the preceding crop. In all treatments, soil nutrients decreased with soil depth. In the 0-50 cm soil layer, NTSW increased soil organic carbon, soil total nitrogen and nitrate nitrogen by 4.14%-13.54%, 35.51%-54.44% and 55.75%-112%, respectively, compared to the RTMW. RTMW had the highest available phosphorus and potassium in the 10-50 cm soil layer. The RTSW had the highest ammonium nitrogen in the 0-50 cm soil layer, 13.39%-20.64% more than that in the RTMW. The winter wheat in NTSW had the highest spike numbers, spikelet numbers, thousand-grain weight; and its grain yield was 16.62% higher than that of RTMW. The NTSW had the highest water use efficiency, 8.67% more than that of RTMW. The NTSW had the highest nitrogen, phosphorus and potassium use efficiency. [Conclusion] The NTSW facilitated nutrient accumulation in the winter wheat field. It had the highest water and fertilizer use efficiency and increased grain yields the most as a result. [ABSTRACT FROM AUTHOR]

Rapeseed is an essential oil crop in China. Hubei, Hunan and Jiangxi provinces in the middle reaches of the Yangtze River are the main planting areas, which account for more than 42% of the total planted area of rapeseed in China. The area has more than 3467 ha of winter fallow field, with massive potential for utilization. The total mechanization rate of rapeseed tillage, seeding and harvesting in the 3 provinces is higher than national average. Still, the uneven development, insufficient utilization of idle fields in winter, low levels of mechanization and intelligence, are technical bottlenecks for improving whole mechanization. This paper analyzes the basic situation and existing problems of the rapeseed industry in the middle reaches of the Yangtze River, combing tillage, seeding, harvesting key aspects of mechanization and intelligent technology, and gives the technical routes of the whole process of rapeseed production that could be promoted. Meanwhile, a comparative analysis of the technical characteristics and difficulties in promoting the application of the "tillage, seeding and harvesting" aspects of rapeseed production was carried out. Development trend of rapeseed production technology mode is semi-mechanized, mechanized to intelligent in the winter fallow fields. The technical development paths of each link are discribed as "anti-blocking, anti-sticky, anti-tangle, and high-speed, efficient, low consumption" mechanized tillage. Integrated tillage and seeding technology to complete multiple working procedures simultaneously. High efficiency, low consumption and low loss of rapeseed mechanized harvesting technology should be combined with harvesting and two-stage harvesting synergistic development. The mechanization technology of feeding, vegetable and fertilizer and the critical technology of intelligent rapeseed production should also be developed and applied simultaneously. To achieve high yield, several suggestions for promoting full mechanization technology model for rapeseed in the mid-winter fields of the Yangtze River are proposed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage 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 Food & Machinery is the property of Food & Machinery 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 Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation 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.)

(Objective) Soil aggregate is a functional unit used to describe the effect of management practices on soil physical properties and soil functions. It is dynamic and varies with various factors. In this paper, we studied its variation in response to different managements during the freezing-thawing fallow season. (Method) The experiment was conducted in a wheat-corn field at an irrigation area at Hongyashan in Minqin County in Shiyang River Basin. The treatments we compared were winter irrigation (for water storage) and pro-harvest tillage in autumn. In each treatment, we measured the size distribution of mechanically stable aggregates and water stable aggregates at different soil depths before and after the freezing-thawing season, respectively. (Result) The freezing-thawing did not show noticeable influence on macro-aggregate content and mean weight-diameter of the mechanically stable aggregates, but significantly reduced the content of water stable macro-aggregates and their mean weight diameter. The autumn tillage temporally increased large mechanically stable aggregate content and water stable aggregate content, as well as their average weight diameter, but the effect waned before the soil was frozen. The winter irrigation did not show an identifiable impact on mechanically stable large aggregates, but increased the large water-stable aggregate content and their average weight diameter. (Conclusion) Freezing-thawing crushed large soil large aggregates, significantly reducing the content of water-stable aggregates as a result. Winter irrigation aggravated this effect. Autumn plough increased the content of large aggregates and aggregates diameter temporally, and the effect waned and completely vanished before the soil was frozen. [ABSTRACT FROM AUTHOR]

Background Nutrient cycling and kinetic in soil is mediated by biogeochemical processes which in turn is modulated by soil water and temperature. The aim of this paper is to investigate the hydrothermal effects on bioavailability of phosphorus (P) in different soils. Method We studied soils with different cultivations using culture experiments: paddy field, upland, vegetable and forest in the same region. There were three moisture treatments for each soil by keeping the soil water content at 40% (W40), 70% (W70) and 100% (W100) of the saturated water content, respectively. For each soil water, there were further three temperature treatments by keeping the soil temperature at 15 (T15), 25 (T25) and 35 (T35), respectively. All soils were incubated for 15 days, after which we measured the contents of P in different forms.ResultWhen temperature and soil moisture were the same, the contents of bioavailable P and Olsen-P in different soils were ranked in the order of forest > vegetable > upland > paddy field. When the temperature was the same, soil water content up-regulated HCl-P, Citrate-P, Enzyme-P and Olsen-P, regardless of the soils. When soil moisture content was the same, the temperature positively impacted HCl-P and Olsen-P, negatively affected Citrate-P (p<0.01), and had no significant correlation with enzyme-P despite enzyme-P peaking at 35 . The content of Olsen-P in all soils was positively correlated with the content of HCl-P and Enzyme-P, and negatively correlated with the content of Citrate-P and CaCl2-P. The analysis of variance showed significant difference in interaction between phosphorus with temperature and moisturetemperature combination between the soils, and the effect was ranked in the order of temperature > moisture > temperature -moisture coupling. Conclusion Increasing soil moisture increased HCl-P, Citrate-P, Enzyme-P and Olsen-P in all soils. Increasing soil temperature increased HCl-P and Olsen-P, while reducing Citrate-P. Among all P forms we measure, only CaCl2-P and Enzyme-P were jointly affected by soil water and temperature. In a certain range, the effects of temperature and moisture on bioavailability of different P forms are integrative in all four soils we studied. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower 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.)

In order to understand the heavy metal pollution in surrounding farmland tillage soil caused by coal mine, this paper studied the area around a coal mine in southwest Shandong province. The 104 samples of surrounding farmland tillage soil were collected, and the concentration of heavy metals including Cr, Ni, Cu, Cd, Zn, Pb were tested by ICP-MS. Single factor index, nemero index and geoaccumulation index were used to analyze the spatial distribution characteristics and the appraise pollution level of six heavy metals. The results show that the six kinds of heavy metals are obviously accumulated, and have different spatial distribution characteristics in the nearby regions of coal gangue dump, industrial square, coal transfer station and transit lines. Only Cu and Ni elements have significant correlation in spatial distribution. The total pollution is in a light degree. It has no Cr element pollution, small-scale slight pollution area of Ni element, some slight pollution area and small-scale moderately pollution area of Cd element in the research area. Other elements including Cu, Zn and Pb are relatively safe. [ABSTRACT FROM AUTHOR]

The Qinghai-Tibet Plateau( QTP) is an important ecological barrier in China. In recent years, the large-scale conversion and reclamation of farmland in the QTP are bound to weaken or induce soil erosion. To explore the impact of different land-use change patterns on soil erosion in the QTP, taking the farming area of the QTP as an example, based on the CSLE model, the soil erosion status of the farming area in 2015 is analyzed, and the comprehensive index of soil erosion intensity change and the contribution of erosion reduction is proposed for the first time. The concept and calculation formula is used to quantify the impact of cultivated land changes on soil erosion and analyze the contribution of different cultivated land change patterns to soil erosion reduction. The results show that: ① The average soil erosion module in the farming areas of the QTP in 2015 is 195.6 t/(hm²·a), and the potential annual soil loss is approximately 446.51 × 106 t/a. ② The composite index of variation in soil erosion intensity in returning farmland to forest, back tillage to grass, and unused land-to-farmland are -378.24, -118.54 and -5.44 t/(hm²·a), and the effect of reducing soil erosion decreases in turn, while the composite index of variation in soil erosion intensity in grassland and forest land reclamation as cultivated land, and farmland that degrades into unused land are 16.53, 32.34 and 200.61 t/(hm²·a), the effect of increasing soil erosion increased in turn. ③ Land-use changes in 2000-2015 reduced soil erosion intensity by 245.54 t/(hm²·a) in the agricultural areas of the QTP with a decrease of 55.66% compared to the unchanging land-use scenario. Under the dual influence of soil erosion intensity change comprehensive index and area, the order of contribution of different land-use changes to soil erosion reduction is: returning farmland to grassland > returning farmland to forest > conversion of unused land to cultivated land > conversion of woodland to cultivated land > conversion of cultivated land to unused land > conversion of grassland to cultivated land. The research results provide a reference for the sustainable development and utilization of water and soil resources and ecological environmental protection in the agricultural areas of the QTP. [ABSTRACT FROM AUTHOR]