关键词: 土壤微生物碳、氮生物量, 土壤微生物碳、氮生物量

Abstract: The objective of experiment was to quantify effects of controlled-release fertilizer application rates on summer maize nitrogen nutrition, the temporal and spatial distribution of leaf nitrogen content of summer maize, cultivar ‘Zhengdan958’, was examined. Four application levels of controlled release fertilizer were designed as 0, 682, 1023, 1364 kg/hm2 respectively. The results showed that: all three main effects on leaf nitrogen content of application rates, leaf-position and sampling period was significant, the same was the interaction between application and sampling period, but the interaction between application rates and leaf-position was not. After emergence, maize leaf nitrogen content was the highest at big trump stage, and the least at maturity stage. Leaf nitrogen contents of middle layer leaves were the largest, compared to the upper and lower layer leaves, of which leaf nitrogen contents appeared to be of fluctuation. Thought leaf nitrogen contents of different layer leaves changed due to fertilizer application rates, the temporal and spatial distribution pattern didn’t changed. There was significant positive correlation between middle layer leaf nitrogen content and crop yield, which reached the maximum value when fertilizer application rate was 1023 kg/hm2. The middle layer leaf could be used as the indicative leaf position of monitoring maize’s nitrogen nutritional status.