氮肥减施对玉米机收品种产量和生物量分配的影响

氮肥的过量施用会造成资源浪费和环境污染，不利于农业生产发展。为探索黄淮海地区夏玉米生产上氮肥的投入量，以该地区20个玉米机收品种为研究对象，通过在两个试验点设置0 kg N·hm-2(不施氮，N0)、120 kg N·hm-2(较正常施氮量减少1/2，N1)、160 kg N·hm-2(减氮1/3，N2)、200 kg N·hm-2(减氮1/6，N3)和240 kg N·hm-2(正常施氮量，N4)共5个施氮处理，研究了各品种在不同施氮水平下产量和生物量分配的差异以及产量和生物量之间的关系。结果表明，与N4相比，N3和N2下产量未有显著下降，品种WY178和WK518表现为高产。河南郸城点，N2、N3和N4处理间的产量差异不明显，平均较N0产量提高18.0%，WY178在N0、N2和N4处理下均表现为高产。陕西户县点，N3和N4处理间产量差异不明显，平均较N0增加13.3%，品种DH528和WK518在N0、N2和N4处理下均表现为高产。随施氮量增加，河南郸城点玉米地上部总生物量呈先增后降趋势，在N2下达最高，为19.12 t·hm-2；而陕西户县点的生物量无显著变化，平均为19.64 t·hm-2。各机收品种的总生物量在河南郸城点以WY178和WK518最高，二者无显著差异，陕西户县点以WK518最高，为22.18 t·hm-2；各机收品种间的生物量差异主要来源于籽粒和茎等器官，相对于其他品种，WK518籽粒和XD724茎重较高，平均分别为10.61和5.48 t·hm-2。施氮量与产量、总生物量呈显著正相关，总生物量和产量间的回归方程达显著水平。因此，黄淮海地区使用WK518和WY178等高产品种，采取减施氮肥1/6~1/3（施氮量在160~200 kg N·hm-2）等措施能够保证玉米达到高产高效的目的。

Effects of Reducing Nitrogen Applications on Yield and Biomass Distribution of Mechanized Harvesting Maize Varieties

Excessive nitrogen fertilizer application would lead to resource waste and environment pollution, and hinder agriculture production. To optimize the input of nitrogen fertilizer, a field experiment used 20 mechanized harvesting maize varieties in Huang-Huai-Hai Region was conducted, 5 treatments including N fertilization with 0 kg N·hm-2 (no nitrogen, N0)、120 kg N·hm-2 (reducing 1/2 N fertilization, N1)、160 kg N·hm-2 (reducing 1/3 N, N2)、200 kg N·hm-2 (reducing 1/6 N, N3) and 240 kg N·hm-2 (normal N fertilization, N4). Effects of reducing nitrogen applications on the yield, biomass distribution and the relationship between yield and biomass were researched. The result indicated that no significant difference on the yield was found among N2, N3 and N4. Varieties of WY178 and WK518 had high yield. Compared to N0, grain yield of N2, N3 and N4 increased significantly averagely by 18.0% in Dancheng, Henan. WY178 had high yield under N0, N2 and N4 treatments. In Huxian, Shaanxi, there was no significant difference between N3 and N4 for grain yield, which averagely increased by 13.3% than that of N0. N0, N2 and N4 treatments of WK518 and DH528 had high yield. With the increasing of nitrogen application, shoot biomass increased first then decreased in Dancheng, highest biomass was in treatment of N2 by 19.12 t·hm-2, while no significant difference was obtained in Huxian. WY178 and WK518 had the highest shoot biomass content in Dancheng, while WK518’s in Huxian was 22.18 t·hm-2. The difference of biomass resulted from the difference of grain and stem. Grain weight of WK518 and stem weight of XD724 were the highest with 10.61 and 5.48 t·hm-2, respectively. The correlations between nitrogen application, yield and shoot biomass was significant, as well as regression equation between shoot biomass and yield. In conclusion, using high yield varieties such as WK518 and WY178, as well as reducing 1/3~1/6 nitrogen applications (160~200 kg N·hm-2) in the field could achieve high yield and high efficiency in maize production in Huang-Huai-Hai Region.