我国甘蔗种植中存在过量施用氮肥现象.研究不同施氮量对甘蔗生物量和土壤无机氮含量的影响,对于制定合理的施氮量从而降低因氮素淋失而引起的环境污染风险具有重要意义.本研究采用田间试验,设置4个施氮处理为0(N0)、300(N300)、400(N400)和500 kg N·hm-2(N500,为当地常规施氮量),分别于2021年5月9日、5月19日、6月19日、7月20日、8月19日、9月21日、10月20日和11月19日采集土壤(0～10、10～20、20～40 cm)及测定甘蔗生物量,目的是研究不同施氮量对甘蔗苗期、分蘖期和伸长期生物量和土壤无机氮含量的影响.结果表明:6-11月,N400和N500处理中的甘蔗株高、茎生物量和根生物量显著高于N0处理;9月、10月和11月,N400和N500处理之间甘蔗株高和茎生物量没有显著性差异.甘蔗生长月份显著影响甘蔗株高及生物量,而氮肥施用量仅显著影响株高和根生物量.各施氮处理下的土壤硝态氮和铵态氮含量随土层深度增加而降低.0～10 cm 土层的硝态氮和铵态氮累积量普遍较低,20～40 cm土层的硝态氮和铵态氮累积量普遍较高.生长月份和氮肥施用量显著影响土壤铵态氮和硝态氮含量及累积量.在不同生长月份,N500处理中硝态氮和铵态氮累积量普遍高于其他施氮处理.因此,施肥量越高,无机氮淋溶损失风险越大.与常规施氮相比,适当减少氮肥用量不会显著影响甘蔗产量,但有利于降低土壤无机氮淋失风险.
Effects of nitrogen reduction fertilization on sugarcane biomass and the concentrations of soil nitrate and ammonium nitrogen
Excessive nitrogen fertilizer application is widespread in sugarcane planting in China.It is important to investigate the effects of nitrogen application rates on sugarcane biomass and concentrations of soil inorganic nitrogen for formulating reasonable nitrogen application rates to reduce the risk of environment pollution caused by nitrogen leaching.In this study,a field experiment was carried out to explore the effects of four nitrogen application rates[0(N0),300(N300),400(N400),and 500 kg N·hm-2(N500,the conventional nitrogen application rate)]on sugarcane biomass and soil inorganic nitrogen concentration in different soil depths(0-10,10-20,20-40 cm)on May 9,May 19,June 19,July 20,August 19,September 21,October 20 and November 19,2021.The results showed that sugarcane height,stem biomass,and root biomass were significantly higher under the treatments of N400 and N500 than that under N0 from June to November.There were no significant differences in sugarcane height and stem biomass between the treatments of N400 and N500 in September,October,and November.Sugar-cane height and biomass of leaf,stem and root varied across different months,while nitrogen application rates sig-nificantly affected sugarcane height and root biomass.The concentrations of soil nitrate and ammonium nitrogen de-creased with soil depth.However,the accumulated amount of soil nitrate and ammonium nitrogen at 0-10 cm soil depth was generally lower and that at 20-40 cm soil depth was generally higher.Growth month and nitrogen appli-cation rates significantly affected the concentration and accumulation of soil ammonium and nitrate nitrogen.Across different growth months,the accumulation of soil ammonium and nitrate nitrogen in the N500 treatment was general-ly higher than that in other fertilizer treatments.Therefore,the risk of inorganic nitrogen leaching may increase with increasing nitrogen application rates.Compared with conventional nitrogen application rate,reduced nitrogen appli-cation did not affect sugarcane biomass but could reduce the risk of soil inorganic nitrogen leaching.
万方数据
维普
