| Dry land accounts for about 70% of China’s land area, there are about 500 million hectares dry farmland which account for about 50% of the total arable land area. So,it is important to ensure agricultural sustainable development in arid areas for food security in our country. The paper focus on the crop growth and efficiently use the limited water and fertilization resources. Through the wild field and indoor experiment, as well as theoretical analysis and numerical simulation methods, the article mainly researches winter wheat growth function model under supplementary irrigation and the greenhouse gas emissions of spring corn. The main research results are as follows:1. In order to quantitatively analyze the winter wheat leaf area index under different water treatments and the accumulation of aboveground biomass change process, we respectively set the universal model for leaf area index and the ground biomass based on the effective accumulated temperature and plant height.2. The AquaCrop model is a very effective tool which can be used in the region for deficit irrigation strategies. But the ability of simulating the over-wintering stage is limited. When simulating the yield, model is more accurate in wet years than drought years. The outputs of the model show that small amount irrigation can still keep high grain yield. As AquaCrop model is a very effective tool for evaluating deficit irrigation, the user can get the best irrigation scheme. At the same time, because AquaCrop model parameters input is less than others it is a powerful tool ensure food security.3. AquaCrop model can be used for the simulation the winter wheat yield under different nitrogen levels on the loess plateau. Experimental data show that N3 treatment has the highest food production in the region. Although there are relatively higher yield in wet years, the grain yield of different fertilizer treatments had a similar trend in different years. The simulation of N4 and N5 is not very accurate.4. Plastic mulching improved soil temperature and moisture conditions at early growth stage of maize, and it significantly promoted the maize growth and increased water use efficiency. At the same time plastic mulching increase the harvest ear number per unit area and the yield. The gravel mulching did not significantly increase production in 2011, 2012 and 2013. This might be related to cover amount and cover method. Straw mulching(SM) treatment significantly improved soil moisture storage of 0-200 cm profile.5. The gravel mulching has a promoting effect on CO2 emissions, at the same time, has inhibitory effect on N2 O. Straw mulching promotes soil CO2 and N2 O emissions. The effects on CH4 emission has a lot of uncertainty, which is closely related to cover means and covering properties. Compared with uncovered treatment, plastic film mulching increased the N2 O emission peak. And the emission of CO2 and N2 O are not higher for plastic mulching.6. With the increase of soil depth, the CO2 concentration in 5cm-20 cm increased. CO2 concentration of 20 cm is significantly higher than 10 cm and 5 cm. The concentrations of N2 O are higher in 10 cm and 20 cm than that in 5 cm. The difference of N2 O concentration among 5 cm, 10 cm and 20 cm is not significant. The spatial variation of CH4 concentration is not obvious. N2 O emission only has a significant positive correlation with 20 cm water. The CO2 emission has significantly positive correlation with temperature. CH4 emissions only have significant positive correlations with the temperature and water of 20 cm. And among the three kinds of greenhouse gas, only the N2 O and CO2 emissions have significant positive correlation. |
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