摘要： 为了研究不同的施氮模式和种植密度对西南夏玉米产量形成及茎腐病和穗粒腐病的影响。在大田试验条件下，设置2个施氮模式（CNP：传统施氮模式；RDNP：氮肥减量间隔穴深施模式）和3个密度（D1：习惯稀植5.25万株/hm²；D2：密植6.75万株/hm²；D3：密植8.25万株/hm²），分析不同施氮模式和密度对玉米产量及构成、干物质积累、光合生理特性的影响，以及探明影响玉米机收质量的茎腐病和穗粒腐病发病规律。结果表明，施氮模式对玉米产量影响不显著，但是RDNP下的氮肥偏生产力比CNP提高了33.7%；RDNP通过缓解花后净光合速率（Pn）、叶片SPAD值及叶面积指数的衰减幅度，弥补花前形成穗粒数不足，从而使其干物质总量和产量稳定不变；RDNP下的玉米茎腐病发病率和病情指数分别较CNP下降了4.8百分点和26.8%，而对穗粒腐病的发病率影响不显著。密植D2和D3较稀植D1均可显著增产，但D3持续增产幅度下降明显，同时D3下的玉米茎腐病和穗粒腐病发病严重，而D2和D1下的发病轻且二者间无显著差异。施氮模式RDNP与适度密植D2处理在氮肥减量的同时可提高玉米单产和氮肥偏生产力，有效控制玉米茎腐病和穗粒腐病，降低植株倒折风险，为西南夏玉米实现绿色增产和利于机械化收获提供理论依据。

关键词: 玉米, 氮肥减量深施, 种植密度, 玉米茎腐病, 穗粒腐病

Abstract: The objective of the study was to investigate the effects of nitrogen fertilizer management pattern and planting density on the yield formation, stalk rot and ear and kernel rot of summer corn in field condition of Southwest China. Two levels of nitrogen fertilizer management pattern were arranged, i.e. conventional nitrogen fertilization(CNP) and nitrogen fertilizer reduction plus deep application in holes between plants and rows(RDNP). And three levels of planting density were designed:commonly used rare-planting(D1, 52 500 plants/ha), densification Ⅰ(D2, 67 500 plants/ha) and densification Ⅱ(D3, 82 500 plants/ha). The yield and its composition, dry matter accumulation, photosynthetic performance and other factors that affected the mechanical harvest quality such as the incidence and severity of maize stalk rot, ear and kernel rot were analyzed. The results revealed that nitrogen fertilizer management pattern had no significant effect on the yield, but the nitrogen partial productivity was 33.7% higher in RDNP than in CNP. RDNP restrained the declining extent of net photosynthetic rate(Pn), leaf SPAD value and leaf area index during the grain-filling stage, which made up for the insufficience of grain numbers per ear formed before flowering, and stabilized the dry-matter accumulation and yield. The RDNP significantly reduced the incidence and severity of maize stalk rot by 4.8 percentage points and 26.8%, respectively, but had little effect on the incidence of ear and kernel rots compared to CNP. The grain yields of D2 and D3 were greater than that of D1, but the sustaining yield increase rate of D3 was significantly lower than that of D2. The incidence and severity of stalk rot and ear and kernel rot were relatively high in D3 than in D2 and D1, while there was no significant difference between D2 and D1. The combination of RDNP and D2 was able to increase the maize yield, improve nitrogen partial productivity, and control the occurrence of maize stalk rot and ear and kernel rot effectively, so as to reduce the risk of lodging and stem breaking. The results could provide the theoretical basis for increasing the production and facilitating the mechanized harvest of summer corn in Southwest China.

Key words: Maize, Reduced and deep placement of nitrogen fertilizer, Planting density, Maize stalk rot, Ear and kernel rot

中图分类号: 

• S513