地膜覆盖对土壤氮素矿化的影响

发布时间：2018-05-16 16:08

本文选题：地膜覆盖 + 土壤水分　；参考：《兰州大学》2017年硕士论文

【摘要】：全膜双垄沟播技术在干旱半干旱地区的应用十分广泛,这种技术明显的提高了玉米(Zea Mays L.)的产量,但一些具体的机理我们并不是很清楚,前人对于地膜覆盖对于土壤中的氮素变化有所研究,但是对于地膜覆盖与氮肥梯度对土壤氮素的研究和地膜覆盖和秸秆还田对土壤氮素的研究还很少,我这次设计的试验主要目的在于:地膜覆盖与氮肥梯度的相互作用以及地膜覆盖和秸秆还田对土壤氮素变化和玉米生长的影响。试验地点选取在甘肃省小康营乡的两块地。主要试验结果如下:1.未培养的结果显示:在玉米种植一年内,土壤表层的无机氮变化情况,可得出覆膜处理的氮素含量要远高于不覆膜的氮素含量,氮素变化并不呈现一定的统一规律,覆膜处理促进氮素的矿化,可是其植物生长比较好,对于氮素的消耗也是比较多的,加上氮素的反硝化作用,以及淋溶等作用的各不相同,最后导致每个处理的结果并没有出现一定的规律。2.从整个生长季节来看,氮素的矿化速率在播种到130天的过程中在下降,但是都是正速率,到了八月份以后两块地的矿化速率呈现负值,并且均呈现覆膜要比裸地矿化速率高并影响极其显著(P0.001),对于(样地1)覆膜可以很明显的增加矿化速率,然而氮肥梯度的不同对矿化速率的增加不显著(P0.05),地膜覆盖和氮肥梯度没有交互作用,覆膜处理较不覆膜处理氮的总矿化量也有明显增加,在播种130天的时候氮素累积量达到最大值。对于秸秆还田样地(样地2),覆膜增加了氮素的矿化速率并影响极其显著(P0.001),秸秆还田对氮素矿化速率的作用不显著(P0.05),两者之间没有交互作用。地膜覆盖增加了累积矿化量,在播种后130天的时候累积矿化量达到了最大值,在播种地膜覆盖和氮素矿化均改变了农田中的氮循环,但是覆膜的作用很明显较大。3.在收获期间我们进行了地下部分氮素的测定,由表层(0-20cm)到底层(180-200cm)氮素在6个处理下均呈现降低趋势,但是覆膜的施氮处理在(130-160cm)又出现了升高的趋势,这也说明了覆膜促进了淋溶的进行,使得在这个深度出现了波动,我们对收获时期的产量做了总结,覆膜和施肥的增产作用很明显。
[Abstract]:The full film double ridge seeding technique is widely used in arid and semi-arid areas, and this technique has obviously improved Zea Mays L. However, some specific mechanisms are not well understood. Previous studies on the change of nitrogen in soil by plastic film mulching have been carried out. However, there are few studies on the effects of film mulching and nitrogen gradient on soil nitrogen and mulching and returning straw to soil nitrogen. The main purpose of this experiment is to study the interaction between mulching and nitrogen gradients and the effects of mulching and straw returning on soil nitrogen and maize growth. The site of the experiment was two plots in Xiaokangying Township, Gansu Province. The main results are as follows: 1. The results showed that the inorganic nitrogen content in the surface layer of maize was much higher than that in the non-mulching treatment during the first year of maize planting, and the change of nitrogen did not show a uniform rule. Film mulching can promote the mineralization of nitrogen, but its plants grow better and consume more nitrogen. The denitrification and leaching of nitrogen are different from each other. Finally, the result of each processing did not appear a certain rule. 2. During the whole growing season, the mineralization rate of nitrogen decreased from seeding to 130 days, but it was both positive. After August, the mineralization rate of the two plots showed a negative value. Moreover, the rate of mineralization was higher than that of bare land, and the effect of film mulching was extremely significant (P 0.001), and the rate of mineralization could be increased obviously for (sample land 1). However, the difference of nitrogen fertilizer gradient had no significant effect on the increase of mineralization rate, but there was no interaction between film mulching and nitrogen fertilizer gradient, and the total mineralization amount of nitrogen in film mulching treatment was significantly higher than that in non-film mulching treatment. Nitrogen accumulation reached a maximum at 130 days after sowing. For the field with straw returning to the sample land (sample land 2), the film mulching increased the nitrogen mineralization rate and significantly affected the nitrogen mineralization rate (P0.001), but the effect of straw returning to the field on the nitrogen mineralization rate was not significant (P 0.05), and there was no interaction between the two. Film mulching increased the accumulation of mineralization, and reached the maximum at 130 days after sowing. Both mulching and nitrogen mineralization changed the nitrogen cycle in farmland, but the effect of film mulching was obvious. 3. During the harvest period, we measured the nitrogen content in the underground part, from the surface layer (0-20 cm) to the bottom layer (180-200 cm). The nitrogen content decreased under 6 treatments, but the nitrogen application of film mulching increased in the range of 130-160 cm). This also shows that the film mulching promotes the leaching process and makes it fluctuate at this depth. We sum up the yield of the harvest period and the effect of film mulching and fertilization on increasing yield is obvious.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S316;S153

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