氮肥调控对夏玉米根区土壤氮素吸收及其生产效率影响

Effects of nitrogen fertilizer regulation on soil nitrogen uptake and production efficiency in root zone of summer maize

为研究不同氮肥调控模式对于夏玉米生产效率的差异性影响,以松嫩平原黑土耕作区为研究对象,设置3种施肥水平(N1:280 kg/hm2,N2:320 kg/hm2,N3:360 kg/hm2),3种施肥比例(F1:20%-30%-50%,F2:33%-33%-33%,F3:50%-30%-20%),组合成9种处理.比较分析了不同处理下植株根系特征、植株氮素累积、作物产量及植株生产效率的差异,采用相关分析揭示植株根表面积对氮素累积量贡献效果,构建植株吸氮量与作物收获指数间的关联函数及其互作效应关系,最终筛选最优的氮素调控模式.结果表明,植株根系受氮素调控驱动影响较为显著,其中N1F2,N1F3处理条件下的植株根系总长较N1F1分别增加了306.4 cm和436.1 cm,且其根表面积和根质量也呈现不同程度的增加;在N2,N3施肥水平下,3种施肥比例分别呈现出相同的规律;植株根表面积与氮素累积量间关系密切,随着氮素的补给量增加,在N2施肥水平下,根表面积的增加对于氮素累积的促进最明显;N2F3处理条件下氮肥偏生产力达33.89 kg/kg,氮肥利用效率达到最优.另外,植株吸氮量与作物产量及收获指数具有显著的二次函数关系,表明在氮素供给与植株生产力之间存在最佳阈值.综合植株根系长势、氮素累积及生产效率状况等因素,最终决策N2F3的调控模式最适宜该区域.

In order to study the effects of different nitrogen regulation models on summer maize productivity, and seek a reasonable and efficient management mode of nitrogen fertilizer, three fertilization levels（N1：280 kg/hm^2,N2：320 kg/hm^2,N3：360 kg/hm^2）were set up in the black soil cultivation area of the Songnen Plain, and three fertilization ratios（F1：20%-30%-50%,F2：33%-33%-33%,F3：50%-30%-20%）were used for each treatment, with total 9 treatments. The characteristics of root system, plant nitrogen accumulation, crop yield and plant production efficiency were compared and analyzed under different treatments. At the same time, the correlation effect of plant root surface area on nitrogen accumulation was revealed by correlation analysis, and the correlation function between plant nitrogen uptake and crop harvest index was constructed. Finally, the optimal nitrogen control mode was selected. The results show that the root system of plants is affected by nitrogen regulation, the total root length of plants under N1F2 and N1F3 treatments increases by 306.4 cm and 436.1 cm, respectively, compared with N1F1, and its root surface area and root mass also show increasing in different degrees. At the same time, at the N2 and N3 fertilization levels, the three kinds of fertilization treatments show the same rule, but the N3 level is weakened compared with N2. There is a close relationship between plant root surface area and nitrogen accumulation, with the increase of nitrogen supply, the increase of root surface area has the most obvious effect on nitrogen accumulation at N2 fertilization level. The partial productivity of nitrogen fertilizer reaches 33.89 kg/kg1 under N2F3 treatment, and the utilization efficiency of nitrogen fertilizer reaches the optimum level. In addition, there is a significant quadratic function relationship between plant nitrogen uptake, crop yield and harvest index, indicating that there is the best threshold between nitrogen supply and plant productivity. Based on the factors such as root growth, nitrogen accumulation, and production efficiency, the N2F3 regulatory mode is finally determined to be the most suitable for this region.