基于秸秆还田下豫北地区夏玉米—冬小麦两熟农田周年氮素循环平衡研究

发布时间：2018-11-14 20:07

【摘要】：在秸秆全量还田条件下,针对氮肥用量过大而引发的肥料损失严重、资源利用率低、环境污染、农业生态环境不可持续发展等现存问题,本研究通过夏玉米-冬小麦轮作周年的田间试验,在秸秆全量还田条件下,玉米季施加氮肥433.80kg·hm~(-2),小麦季分别施加氮肥0、160、220和280kg·hm~(-2),研究秸秆还田条件下不同施氮水平对冬小麦氮养分利用和产量的影响,评估玉-麦两熟农田周年氮素循环平衡。结果表明:1.在越冬期、返青期、拔节期,小麦植株群体数、植株干物质积累量均表现为施氮处理显著高于不施氮处理。在开花期和成熟期,小麦植株群体数、植株干物质积累量随追氮量的增加而增加,220kg·hm~(-2)施氮量下最高,继续增加追氮量,小麦植株群体数、植株干物质积累量不增加,有下降趋势。可见施加氮肥能够提高小麦植株分蘖能力,对植株干物质积累有促进作用,但过量追加氮肥,小麦植株群体数、植株干物质积累量并不随之增加。2.小麦生育期植株氮含量呈现单峰曲线变化,在返青期出现高峰。植株氮含量、植株氮积累量均随施氮量的增加而增加,在280kg·hm~(-2)施氮量下最高,但氮素养分利用率和氮肥偏生产力均显著降低。不同施氮处理对氮肥农学利用率、氮素利用效率和氮素收获指数的影响未达显著水平。施加氮肥,小麦成穗数、穗粒数和结实小穗数能够有效提高,从而提高产量。施加氮肥280、220 kg·hm~(-2)时小麦籽粒产量较高,分别比不施加氮肥处理提高24.44%、19.38%。3.冬小麦土壤氮含量、氮积累量、硝态氮含量、硝态氮积累量均随着施氮量的增加而增加,在280kg·hm~(-2)施氮量下最高。玉米成熟期、小麦成熟期0~200cm土层土壤硝态氮含量和积累量以表层土最高。4.玉米季基肥、第1次追肥前发生降雨,显著减少氨挥发积累量;第2次追肥氨挥发积累量分别是基肥和第1次追肥的4.32、1.37倍。小麦季拔节期追施氮肥后进行灌溉导致氨挥发速率迅速降低,氨挥发积累量显著低于基肥;拔节期160、220、280kg·hm~(-2)施氮量下氨挥发积累量分别为不施肥的1.59、3.14、6.16倍。玉米季氨挥发速率、氨挥发积累量显著高于小麦季。5.玉麦周年共施氮433.8kg·hm~(-2)时,氮盈余-58.35kg·hm~(-2),耗竭土壤氮素资源;施氮593.8kg·hm~(-2)时,氮盈余35.01kg·hm~(-2),但籽粒产量较低,有耗竭土壤资源的风险;施氮653.8kg·hm~(-2)时,氮盈余63.39kg·hm~(-2),氮素投入与氮素输出保持平衡;施氮713.8kg·hm~(-2)时,氮盈余69.25kg·hm~(-2),投入成本高且损失高,浪费资源且污染环境。综合来看,在豫北玉麦轮作地区秸秆全量还田条件下,为有效控制氮素淋溶损失、氨挥发损失同时节约生产成本、维持农田系统氮素可持续发展,推荐周年施氮量为653.8kg·hm~(-2)。
[Abstract]:Under the condition of full straw returning to the field, the fertilizer loss caused by the excessive application of nitrogen fertilizer is serious, the utilization ratio of resources is low, the environment is polluted, the agricultural ecological environment is not sustainable development and so on. In this paper, the field experiment of summer corn-winter wheat rotation was carried out. Under the condition of full straw returning to the field, nitrogen fertilizer 433.80kg hm~ (-2) was applied in maize season, nitrogen fertilizer 0160220 and 280kg hm~ (-2) were applied in wheat season, respectively. The effects of different nitrogen application levels on the nitrogen use and yield of winter wheat were studied under the condition of straw returning to the field, and the annual nitrogen cycling balance was evaluated. The results show that: 1. In the wintering stage, the green stage, jointing stage, wheat plant population number, plant dry matter accumulation were significantly higher than that of no nitrogen application treatment. At flowering and maturation stage, the number of wheat plant population and dry matter accumulation increased with the increase of nitrogen topdressing. The highest amount of 220kg hm~ (-2) nitrogen application was observed, and the number of wheat plant population continued to increase. Dry matter accumulation did not increase, but decreased. It can be seen that the application of nitrogen fertilizer can improve the tillering ability of wheat plants and promote the accumulation of dry matter of wheat plants, but the number of population and the accumulation of dry matter of wheat plants do not increase with the excessive addition of nitrogen fertilizer. The nitrogen content of wheat plants showed a single peak curve at growth stage, and the peak appeared in the green stage. Plant nitrogen content and plant nitrogen accumulation increased with the increase of nitrogen application rate, which was the highest at 280kg hm~ (-2) nitrogen application rate, but nitrogen nutrient use efficiency and nitrogen fertilizer partial productivity decreased significantly. The effects of different nitrogen application treatments on the agronomic utilization efficiency, nitrogen use efficiency and nitrogen harvest index were not significant. The number of spikelets, grains per spike and spikelet number per spike could be increased effectively by applying nitrogen fertilizer, thus increasing the yield of wheat. The grain yield of wheat was higher when 280220 kg hm~ (-2) nitrogen fertilizer was applied than that without nitrogen fertilizer treatment, and the grain yield was increased by 24.44% 19.38.3. Soil nitrogen content, nitrogen accumulation, nitrate nitrogen content and nitrate nitrogen accumulation in winter wheat soil all increased with the increase of nitrogen application rate, which was the highest under 280kg hm~ (-2) nitrogen application rate. The content and accumulation of nitrate in 0~200cm soil layer were the highest in the surface soil layer. 4. 4. The amount of ammonia volatilization was significantly reduced before the first topdressing, and the amount of ammonia volatilization in the second topdressing was 4.32 ~ 1.37 times of that of the base fertilizer and the first topdressing, respectively. The rate of ammonia volatilization decreased rapidly and the amount of ammonia volatilization was significantly lower than that of base fertilizer after applying nitrogen fertilizer at jointing stage, and the amount of ammonia volatilization at jointing stage by 160220280kg hm~ (-2) was 6.16 times as much as that without fertilization. The rate of ammonia volatilization in maize season and the amount of ammonia volatilization accumulation in maize season were significantly higher than those in wheat season. When 433.8kg hm~ (-2) was applied to Yumai annually, nitrogen surplus-58.35kg hm~ (-2) exhausted soil nitrogen resources. When 593.8kg hm~ (-2) was applied, nitrogen was surplus 35.01kg hm~ (-2), but grain yield was lower, which was at risk of depletion of soil resources. When 653.8kg hm~ (-2) was applied, nitrogen surplus 63.39kg hm~ (-2), nitrogen input and nitrogen output kept balance; When nitrogen was applied 713.8kg hm~ (-2), nitrogen surplus 69.25kg hm~ (-2), high input cost and high loss, waste resources and pollute the environment. In general, in order to effectively control nitrogen leaching loss, ammonia volatilization loss can save production cost and maintain the sustainable development of nitrogen in farmland system under the condition of full straw returning to the field in Yu-mai rotation area of northern Henan Province. The recommended annual nitrogen application rate is 653.8kg hm~ (-2).
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S513;S512.11

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