Effect Of Deep Tillage And Nitrogen Apllication On Photosynthetic Performance And Nitrogen Use In High-Yeild Spring Maize

The deep tillage can loose soil. It is the reliable measures of high yield cultivation. The senescence situation of spring maize, yield and nitrogen fertilizer utilization rate is distinguishing. Under different N application rate Integrated these two measures.We take two hybrids (ND314and XD20) as test material which are implemented for the high yield more than15t/hm2for many years in the plain irrigation area of Inner Mongolia. Set deep tillage and different N application rate (pure N0,300,450,600kg/hm2) as the treat.According to the cordination of the soil physical properties, and leaf senescence, and nitrogen absorption and utilization, and grain filling, we discussed how to raise the utilization ratio of nitrogen fertilizer. The results are as follows:1.The deep tillage can reduce soil bulk density and the compactness, and increase the proportion of the gas rate and liquid rate, so that improve soil physical properties. The the vertical distribution of root system was optimized,and the root dry weight in30-60cm increased, the root length and root surface area and root volume of ND314in70-80cm are increased, these indicators of XD20in30-70cm are increased.2. The deep tillage can slow the aging speed of blades, and maintain higher leaf area index and net photosynthetic rate. We can build suitable plants ageing process and achieve the purpose of increasing efficiency by the deep tillage and appropriate N application.3. The yield of300kg/hm2and450kg/hm2are closed, and they are all more than600kg/hm2. Nitrogen fertilizer efficiency of300kg/hm2are more than450kg/hm2å'Œ600kg/hm2. The yield of300kg/hm2in deep tillage can catch the450kg/hm2without deep tillage, and the partial factor productivity of300kg/hm2in deep tillage increase40%than450kg/hm2without it.4. The deep tillage can improve the active growth phase and increase thousand seed weight. The root vertical distribution was optimized and leaf senescence become slow after the deep tillage, is the fundmental reason that the deep tillage treatment are better than the shallow rotary treatment. Improvement of grain weight lead to the increase of yields in different nitrogen rate under deep tillage. The grain weight more significantly correlated to the active growth phase than maximum grain filling rate. The active growth phase of300kg/hm2in deep tillage extended0.9-11.4days than450kg/hm2without it. On the whole, the deep tillage has higher yields, attributed to the process of growth with higher net photosynthetic rate, and developed deep root system, and longer active growth phase. Therefore under the deep tillage and the right amount of nitrogen(pure N300kg/hm2), we can maintain net photosynthesis rate in flower period, and enlarge the total capacity, and improve the efficiency of nitrogen absorption, in order to achieve the high-efficient and high-yield cultivation.