辽河三角洲稻区缓释肥施用下氮肥减施潜力研究

Reduction potential of nitrogen fertilizer under slow-release fertilizer application in Liaohe Delta rice area

为明确辽河三角洲典型单季稻区氮肥减施潜力,采用区域施肥调查和田间试验相结合的方法,以了解区域施肥现状以及不同缓释肥减量替代化肥对产量、氮素供给和流失风险的影响。结果表明,目前辽河三角洲单季稻氮肥施用量主要分布在200~350 kg·hm^(-2)之间,区域平均施氮量为294.5 kg·hm^(-2),区域平均经济产量为10479.9 kg·hm^(-2),依据水稻需氮量计算得出适宜的施氮量为182~202 kg·hm^(-2)。经研究表明,根据目前区域内可选择的肥料类型选择适宜的缓释肥料,减氮潜力在19.2%~30.8%之间,在保证作物产量的条件下,可以提高1.39%~15.79%的氮肥利用率,维持土壤养分含量,有效降低田面水中68.4%~79.6%的氮含量,增加541.4~5816.6元·hm^(-2)的经济效益。综上,在减氮潜力较高的地区,适当减氮条件下施用缓释肥可以在保证作物产量的同时降低氮素损失的环境风险,减少人工成本,提高经济效益。

In order to clarify the potential of nitrogen(N)fertilizer reduction of typical single-cropping rice in Liaohe Delta,on the basis of understanding the status of regional fertilization,N supply and N loss risk were studied using a method combining the investigation of current situation of regional fertilization and in-situ field experiment in this study.The results showed that the amount of N fertilizer application varied in the range of 200~350 kg·hm^(-2) in the single-cropping rice region in Liaohe Delta and the regional average fertilization amount was 294.5 kg·hm^(-2) with the regional average economic yield of 10479.9 kg·hm^(-2).According to the N fertilizer requirement during rice growing,the recommended nitrogen application rate was 182~202 kg·hm^(-2).Under the condition of ensuring crop yield,suitable slow-release fertilizer reduced the application of nitrogen fertilizer by 19.2%~30.8%,increased the utilization rate of nitrogen fertilizer by 1.39%~15.79%,and maintained soil nutrient content.The nitrogen content in the surface water decreased by 68.4%~79.6%.And the economic benefit increased by 541.4~5816.6 yuan·hm^(-2).In summary,in regions with high nitrogen reduction potential,the replacement of chemical fertilizers with slowrelease fertilizers under the condition of appropriately reducing nitrogen input can ensure crop yield and reduce the environmental risk of nitrogen loss with the reduction of labor cost and the improvement of economic benefits.