地膜覆盖对半干旱区玉米地土壤氮素循环和肥料氮去向的影响

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	地膜覆盖对半干旱区玉米地土壤氮素循环和肥料氮去向的影响
Alternative Title	Effect of plastic mulch on nitrogen cycling and fate of fertilizer nitrogen in field-grown maize at a semiarid site
	刘小娥
Subtype	博士
Thesis Advisor	李小刚
	2014-12-09
Degree Grantor	兰州大学
Place of Conferral	兰州
Degree Name	博士
Keyword	地膜覆盖土壤温度土壤水分氨挥发土壤氮素矿化土壤无机氮肥料氮利用效率肥料氮的去向
Abstract	全膜双垄集雨沟播技术由于其显著地增产作用在干旱半干旱地区被广泛的推广应用。我们于2011−2012年在甘肃省榆中县进行了两年的大田试验。通过对土壤温度、水分、玉米产量、水分利用效率、土壤氨挥发、土壤氮素矿化、土壤无机氮含量和肥料氮去向的研究，主要得出以下研究结果： 1. 地膜覆盖对土壤温度和水分的影响与玉米的生长发育有关。在没有玉米种植的条件下，覆膜处理增加了整个实验期的0−20cm土壤温度和0−100cm的土壤储水量，而在有玉米种植的条件下，覆膜处理对土壤温度和储水量的增加只表现在玉米生长发育的前两个月。 2．地膜覆盖较地膜不覆膜减少了土壤氨挥发的损失量，增加了土壤氮素净矿化速率，是地膜覆盖下土壤无机氮含量增加的主要原因。地膜覆盖增加了土壤氮素的有效性。地膜覆盖改变了农田中的氮循环。 3. 地膜覆盖较地膜不覆膜增加了玉米对氮素的吸收量，但降低了玉米当季肥料氮的利用率，说明地膜覆盖下玉米增加的氮素主要来自于土壤中的氮素。地膜覆盖减少了以氨挥发形式损失的肥料氮，增加了当季肥料氮在土壤中的残留量，从而增加了肥料氮淋洗的风险。玉米收获时，大量肥料氮和土壤氮在土壤剖面残留，因此有必要对肥料氮的施用量进行调整。
Other Abstract	Four treatments were evaluated in 2011 and 2012. Main results as follows: 1. Compared with no mulch, the presence of mulch in both the 2011 and 2012 cropping seasons consistently increased soil temperature in the 0−20 cm soil layer and soil water storage in the 0−100 cm depth over the course of the whole experiment under no maize planting, whereas it increased in the first two months of the season only under maize planting. 2. The reduced ammonia volatilization and stimulated N mineralization were responsible for the increased soil N content and uptake by maize under mulch compared with no mulch. Our results demonstrate that plastic mulch prominently changes N cycling in croplands. 3. 15N isotope traced results in field experiment showed that the increased in-season maize N uptake under mulch relative to no mulch came from soil and did not from the applied urea. Plastic mulch blocked ammonia volatilization and decreased microbial immobilization whereas increased urea N leaching from soil. A more precise use rate and allocation strategy of fertilization over the growing season is needed to be designed in mulched maize production.
URL	查看原文
Language	中文
Document Type	学位论文
Identifier	https://ir.lzu.edu.cn/handle/262010/221549
Collection	生命科学学院
Recommended Citation GB/T 7714	刘小娥. 地膜覆盖对半干旱区玉米地土壤氮素循环和肥料氮去向的影响[D]. 兰州. 兰州大学,2014.

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