缓释肥施用量对超高产夏玉米氮素积累分配的影响

明确缓释肥施用量对超高产夏玉米氮素积累和分配的影响及其对产量形成的作用。以‘苏玉29’‘、苏玉30’为材料，采用裂区设计，设置7个缓释肥水平（N0、270、315、360、405、450、495kg/hm²），研究夏玉米氮素积累和分配在不同处理下的变化趋势。结果表明：随着缓释肥施用量增加，两品种（‘苏玉29’、‘苏玉30’）氮素积累量与氮素利用效率均呈单峰变化趋势，在N405kg/hm²水平下达最大值，且‘苏玉29’氮素利用率显著高于‘苏玉30’。百千克籽粒需氮量随缓释肥施用量增加先升后降，在N405kg/hm²水平下达最大值，而每千克氮生产籽粒量的变化规律相反。随着施氮水平提升，玉米偏生产力降低。最高产处理下，茎、叶、鞘氮素转移率和对籽粒产量的贡献率显著高于其他处理。回归分析表明，成熟期叶片中氮素分配比例较高有利于‘苏玉29’高产，苞叶和穗轴中氮素分配比例较高有利于‘苏玉30’高产。在本实验条件下，两品种在N405kg/hm²时产量最高，氮素积累量、氮肥利用率和百千克籽粒需氮量最高，茎、叶、鞘的氮素转移率及其对产量的贡献率较高。

Effects of Slow-release Fertilizer Treatments on Nitrogen Accumulation and Distribution of Super-high Yield Summer Maize

The effects of different slow-release fertilizer amounts (N 0, 270, 315, 360, 405, 450, and 495 kg/ha, respectively) on N accumulation and distribution of summer maize under super-high yield conditions were studied. A field trial was conducted with split plot design in 2013 using two maize hybrids (Suyu29 and Suyu30) as materials. The results showed that with the increase of slow-release amounts, the N accumulation amount and N use efficiency raise first and fall late and peaked at N 405 kg/ha, and those two parameters were higher for Suyu29 than Suyu30. The N-requirement for 100 kg grain raise first and fall later and peaked at N 405 kg/ha for both varieties, and the change tend for grains per kg nitrogen production was on the contrary. The partial fertilizer productivity gradually decrease with the increase of N amount. Under the treatment with highest yield, the N translocation rate and contribution to yield of leaf, stem and sheath was higher than the other treatments. The results of regression analysis showed high distribution percentage in leaf was in favor of high yield for Suyu29, and high distribution percentage in bract and cob were in favor of high yield for Suyu30. Under the condition similar to present paper, the plants with N 405 kg/ha have higher grain yield, N accumulation amount, N use efficiency, N-requirement for 100 kg grain, and the N translocation and contribution rate of leaf, stem and sheath.