生命科学学院知识库

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（P < 0.001），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（P > 0.05），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（P < 0.001），秸秆还田对氮素矿化速率的作用不显著（P > 0.05），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。

Film fully-mulched ridge-furrow cropping technology was widely used in arid and semi-arid region, that technique significantly improves the corn production, but some we are not very clear, the mechanism of predecessors for plastic film mulching on soil nitrogen change to research, but plastic film mulching and nitrogen fertilizer， of soil nitrogen in soil coating and straw incorporation is very few on soil nitrogen research. My purpose of the design of experiment is that plastic film mulching and the interaction of nitrogen fertilizer change，of soil nitrogen in soil coating and straw incorporation the effects of maize growth and soil nitrogen. The experiment site selectied in Yuzhong-Xiaokangying village in Gansu province. The main results were as follows:

1. No training results show that: within a year to the corn, the change of the soil inorganic nitrogen can be concluded that the nitrogen content of laminating process is much higher than no effect of the content of nitrogen, nitrogen change does not present a certain law of the unity, laminating process greatly promote n mineralization, but the plants grow better, for the consumption of nitrogen is more, plus nitrogen denitrification, and leaching effect of each are not identical, finally lead to the result of each processing does not appear a certain rule.

2.  From the point of the whole growing season, nitrogen mineralization rate in the process of planting to 130 days in the fall, but they are all positive rate, then two mineralization rate of negative in August, and coated than bare land mineralization rate are high and extremely significant (P < 0.001), the sample (1) coated can obviously increase the mineralization rate, however, different nitrogen fertilizer on the mineralization rate of increase was not significant (P > 0.05), plastic film mulching and no interaction of nitrogen fertilizer, coated with less total coated with nitrogen mineralization amount has increased significantly, at the time of planting 130 days n accumulation amount reaches maximum value. For straw returned sample (sample 2), the effect of increased nitrogen mineralization rate and influence is extremely significant (P < 0.001), straw returned to the role of nitrogen mineralization rate was not significant (P > 0.05), no interaction between the two. Plastic mulching increased the cumulative amount of mineralization, 130 days after sowing cumulative mineralization amount has reached the maximum value when the sowing and nitrogen mineralization of plastic film mulching were changed in the farmland nitrogen cycle, but the effect of coated obviously larger.

3. During the harvest of the underground part of nitrogen determination by the surface（0-20cm） to the bottom （180-200cm） under six processing, all showed a trend of decrease, but the effect of nitrogen treatment rise and reduce the trend in 130-160 cm, it also illustrates the effect of promoting the leaching, and appears in the depth of the fluctuations. our production made a summary of the harvest period, laminating and fertilizer production effects are obvious.