摘要
【目的】水肥是作物产量的两大限制因子。当前在作物生产中对水氮资源利用不够合理,不仅浪费水资源,而且严重威胁环境。为了探讨华北山前平原冬小麦-夏玉米轮作体系合理的水氮配合措施,在5年水氮定位试验基础上对周年轮作体系产量、氮吸收与利用状况进行了分析。【方法】试验为冬小麦夏玉米周年轮作种植,设置水、氮两因子,裂区试验设计,水分为主区,施氮量为副区。水分设置限水和适水两个处理,根据华北山前平原冬小麦夏玉米灌溉制度,冬小麦限水和适水下灌水次数分别为1水(拔节期)和2水(拔节+开花水),夏玉米限水和适水下灌水次数根据不同年型降水量而定(1水为播前水,2水为播前水+12展叶水,3水为播前水+12展叶水+开花水)。周年设置6个施氮水平,小麦+玉米氮肥用量分别为(0+0)、(60+60)、(120+120)、(180+180)、(240+240)、(300+300)kg·hm-2。【结果】在供水量较高和较适宜的条件下(年供水量大于609.5 mm),水分不是氮肥肥效发挥的限制因素,氮肥对产量的贡献较大;而供水量较低的条件下,肥效受较大抑制,供水对产量贡献较大。供水量和施氮量有明显的耦合效应,限水和适水下得到最高产量的施氮量冬小麦分别为134.8和126.4kg·hm-2、夏玉米分别为176.8和127.2 kg·hm-2。限水和适水下单季施氮量分别为300和240 kg·hm-2时,地上部总氮量达较高值,但限水和适水下夏玉米和限水下冬小麦氮量超过60 kg·hm-2、适水下冬小麦施氮量超过120 kg·hm-2时,秸秆残留氮素明显增加,对籽粒氮的贡献变小。氮肥偏生产力随施氮量增加而降低,且随年度推移氮肥偏生产力明显降低,尤其是小麦季施氮量60 kg·hm-2处理随年份增加降低尤为迅速。在本试验条件下周年施氮量限水240 kg·hm-2、适水120 kg·hm-2就能保持土壤有机质和全氮含量不降低。【结论】限水条件下水是限制氮肥肥效发挥的主要因素,通过改善水分条件可更有效的提高氮肥肥效,因此在干旱年型应降低施氮量。中高产田冬小麦-夏玉米轮作体系限水和适水下得到最高产量的施氮量分别为311.6和253.6 kg·hm-2,此时最佳产量可分别达16 127.5和17 272.9 kg·hm-2。
【Objective】Water and fertilizer are the major limiting factors in crop production. At present, the utilization of water and nitrogen is not reasonable, not only giving rise to a waste of water resources, but also making a threat to the environment. In order to discuss a reasonable collocation of water and nitrogen in winter wheat and summer maize rotation system, grain yield and nitrogen uptake and utilization were analyzed based on a 5-year experiment carried out in North China Plain（NCP）.【Method】In the winter wheat and summer maize rotation system, the split plot design was employed with main plot of water（limiting water and suitable water）, sub-plot of nitrogen fertilizer（（0＋0）,（60＋60）,（120＋120）,（180＋180）,（240＋240） and（300＋300） kgN·hm-2, respectively, for wheat and maize rotation system）, and three replicates in each sup-plot. Limiting and suitable water was employed according to winter wheat and summer maize irrigation system in the piedmont plain of North China, and the irrigation treatments included two, limiting water treatment irrigated 1 water at jointing stage and suitable water treatment irrigated 2 water at jointing and blossom stages for winter wheat, while for summer maize which irrigation time was confirmed according to the different years precipitation, and 1 water before sowing, 2 water before sowing and 12 leaf, and 3 water before sowing, 12 leaf and blossom stages.【Result】When water supply was more than 609.5 mm for wheat and maize, limiting factors of effect of N fertilizer was not water, and the contribution of N fertilizer to yield was larger; while water supply was lower, the effect of N fertilizer was restrained, and the contribution of water to yield was larger. Water and N had an obvious coupling effect, the N application rate for getting a high yield were 134.8 kg·hm-2 and 126.4 kg·hm-2 for wheat, and 176.8 kg·hm-2 and 127.2 kg·hm-2 for maize under limiting and suitable water conditions, respectively. When N fertilizer rate was 300 kg·hm-2 and 240 kg·hm-2, respectively, under limiting and suitable water for the two seasons crop, shoot N was amounted to a higher value, but N fertilizer rate was more than 60 kg·hm-2 for maize under two water conditions and for wheat under limiting water, and 120 kg·hm-2 for wheat under suitable water conditions, straw residual N significantly increased. Partial productivity of N fertilizer（PPNF） decreased with the increase of nitrogen application rate, and with the years passing, PPNF decreased significantly, especially the treatments of nitrogen application rate at 60 kg·hm-2 for wheat season, which PPNF decreased rapidly. The soil organic matter and total nitrogen content did not decrease when nitrogen application rate reached 240 kg·hm-2 of limiting water and 120 kg·hm-2 of suitable water treatments for winter wheat and summer maize rotation system.【Conclusion】The major factor for limiting fertilizer efficiency was water under the condition of limiting water, therefore the amount of nitrogen application should be reduced in dry years. For winter wheat and summer maize rotation system, the N application rates for getting maximum yields were 311.6 kg·hm-2 and 253.6 kg·hm-2 respectively, and which grain yields were 16 127.5 kg·hm-2 and 17 272.9 kg·hm-2, respectively, under limiting and suitable water conditions.
出处
《中国农业科学》
CAS
CSCD
北大核心
2014年第19期3839-3849,共11页
Scientia Agricultura Sinica
基金
国家科技支撑计划(2013BAD07B05
2011BAD16B08)
国家公益性行业(农业)科研专项(201203100)
河北省自然科学基金(C2014301007)
关键词
冬小麦
夏玉米
水氮
产量
氮素吸收利用
winter wheat summer maize water and nitrogen yield nitrogen uptake and utilization
