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Copyright of Journal of Central China Normal University is the property of Huazhong Normal 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.)

(Objective) Bioavailable water and nutrients to crops depend not only on root architecture but also on how water and nitrogen fertilizer are applied. In this paper, we investigated the effects of irrigation and fertilization on water and nitrogen dynamics in soil of a winter wheat field under border irrigation.(Method) The experiment was conducted in a wheat field in Henan province, where changes in water and nitrogen in soil under border irrigation were measured. These data were used to validate the HYDRUS-1D model, and the validated model was then used to elucidate how a change in irrigation and fertilization modulates water and nitrogen dynamics in the root zone of wheat under border irrigation. (Result) The HYDRUS-1D model simulated water and nitrogen dynamics in the root zone well. The coefficient of determination (R2) between the simulated and measured data was greater than 0.84, with its associated RMSE and MAE less than 0.807 and 0.695, respectively. Increasing the low critical soil water content for resuming irrigation moved nitrate in the top 0~20 cm soil layer to 20~100 cm soil layer 1~2 days after the irrigation, but it did not show significant effects on ammonium dynamics in the soil. Increasing nitrogen fertilization increased nitrate and ammonium nitrogen in the 0~60 cm soil layer significantly, especially in the 0~40 cm soil, but reduced water content in the 0~40 cm soil layer. (Conclusion) The HYDRUS-1D model is able to simulate water and nitrogen movement in soil under border irrigation, and the simulated results can help to improve irrigation and fertilization management for wheat production in the studied and similar areas. [ABSTRACT FROM AUTHOR]

Huang-Huai-Hai region is the major superiority area of planting industry and breeding industry in China. With the increasing attention to the rural environment problems caused by crop straw and livestock manures, it is important to analyze “raising by planting” in Huang-Huai-Hai region, realize agricultural waste comprehensive utilization, and implement green development. “Raising by planting” was the core idea of this paper. The “raising by planting” calculation methods were as follow. First, technical regulations for production of wheat-corn and field research results in Hebei, Henan and Shandong provinces were used to summarize production model of wheat-corn in Huang-Huai-Hai region. So the conventional fertilization could be defined. According to test results of researches, this paper determined the amount of partial replacement of chemical fertilizer by organic manures. At the same time, thermophilic aerobic composting was chosen as techniques of livestock manure comprehensive utilization. The untreated amount of livestock manures was calculated. Then, the quantities of different species of livestock and poultry were calculated. According to the technical regulations, the amount of nitrogenous fertilizer were 532.5, 562.5 and 575 kg/hm2 in Hebei, Henan and Shandong provinces. The ratio of partial replacement of chemical fertilizer by organic manures was 30%. So the amount of replacement were 159.75, 168.75 and 172.5 kg/hm2. At the same time, there were no influence on grain security after the replacement of chemical fertilizer by organic manures. Due to the additional application of organic manures promoted soil nitrogen leaching risk, the environmental risk assessment of nitrogen in arable farmland was used. Nitrogen input mainly consisted of nitrogenous fertilizer, organic manure converted from livestock manures, seed, straw returning, atmospheric dry and wet deposition and irrigation water. Nitrogen output mainly consisted of grain and straw. Grade of environment risk in farmland in Hebei, Henan and Shandong provinces were all medium risk. Nitrogen loss rate of thermophilic aerobic composting fromlivestock and poultry manures was 42.26%. Other calculation parameters of livestock and poultry production, such as feeding period, population structure, were defined by many research papers. So in production model of wheat-corn in Huang-Huai-Hai Region, 6 dairy cows, or 18 beef cattle, or 47 to 51 swine, 731 to 789 laying hens or 8062 to 8705 broilers per hectare were land carrying capacity. Besides, at the field scale, various factors, such as soil fertility and soil microbial, might affect the ratio of partial replacement of chemical fertilizer by organic manures. So more researches were needed in the amount of replacement. On account of medium environment risk in farmland, lowering the risks was necessary. Nitrogen input structure: 46.3% chemical fertilizer, 27.5% straw returning, 19.8% organic manure, 4.0% atmospheric dry and wet deposition, 2.0% irrigation water and 0.4% seed. So reducing straw returning was one of risk solutions. In simulation results, reducing corn stalk or wheat straw both lowered environment risk effectively. The results provide a reference for planting and raising combination in Huang-Huai-Hai region. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology 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 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.)