控释尿素对旱作马铃薯产量及水分利用效率的影响

【目的】探究控释尿素对覆膜马铃薯氮素诊断指标、产量、经济效益及水分利用效率的影响。【方法】通过田间试验,研究了不施肥(CK)、普通尿素(CF,N施量200 kg/hm²)和控释尿素(CRU1(N施量180 kg/hm²)、CRU2(N施量160 kg/hm²)和CRU3(N施量140 kg/hm²))对马铃薯叶片叶绿素(Chl)、氮平衡指数(NBI)、类黄酮(Flav)值、产量、经济效益、水分利用效率及氮肥偏生产力的影响。【结果】马铃薯叶片Chl和NBI值均随施氮量的降低而降低,Flav值随施氮量的降低而增加。不同施肥量和生育期均显著影响叶片Chl、NBI和Flav值(P<0.01),但施肥量和生育期的互作差异不显著(P>0.05)。随着施氮量降低,马铃薯产量和经济效益均降低,表现为:CF处理>CRU1处理>CRU2处理>CRU3处理>CK。控释尿素降低了马铃薯产量和经济效益,CRU1处理减产幅度最小。与CRU1处理相比,CF处理马铃薯产量和经济效益分别提高了5.18%和24.26%,但商品薯率和氮肥偏生产力分别降低6.50%和5.33%。相似的耗水量和水分利用效率也随施氮量的降低呈减小趋势,CF处理耗水量和水分利用效率均能保持较高水平,且水分利用效率与CK、CRU2处理和CRU3处理达到显著性差异(P<0.05);与施用控释尿素CRU1、CRU2和CRU3处理相比,CF处理耗水量提高幅度为2.79%~5.02%,对应水分利用效率提高幅度为2.33%~11.58%。【结论】CF能保证旱作全覆膜马铃薯产量和水分利用效率,提高经济效益,可作为黄土丘陵沟壑区一个可行的施肥策略。

The Effects of Controlled-release of Urea on Yield and Water Use Efficiency of Rain-fed Potato

【Background】Drought and low nitrogen use efficiency are double whammy of developing sustainable agriculture in many countries in semi-arid areas that face increased land degradation and climate change.【Objective】This paper is to investigate the effects of controlled-release of urea onnitrogen form in soil,as well as yield,economic benefit,nitrogen partial productivity and water use efficiency of rain-fed potato,in attempts to provide guidance for improving fertilization management in loess hilly-gully region.【Method】The experiment was conducted in a field,and it compared the impact of common urea application(CF)and the controlled-release of urea(CRU)on yield,chlorophyll(Chl),flavonols(Flav),nitrogen balance index(NBI),nitrogen partial productivity and water use efficiency of the potato.The amount of urea used in the conventional application was 200 kg N/hm²(CF),and those used in the controlled-release were 10%(CRU1),20%(CRU2)30%(CRU3)of that used in CF,respectively.The control was non-fertilization(CK).【Result】With nitrogen application increasing,the Chl and NBI content in the leaves increased whereas the Flav decreased.Growth stage and the amount of nitrogen application both affected the Chl,NBI and Flav at significant level(P<0.01).However,the interactive effects of fertilization and growth stage were not significant(P>0.05).Both NBI and Flav were highly correlated with the yield during the tuber expansion stage.Reducing nitrogen application led to a decrease in tuber yield and economic benefit,and the reduction in economic benefit was ranked in the order of CF>CRU1>CRU2>CRU3>CK.The yields of potato in CRU2 and CRU3 were 88.90%and 85.33%of that in CF,respectively.Compared to CRU1,CF increased the tuber yield and economic benefit by 5.18%and 24.26%respectively,but it reduced the marketable potato rate and nitrogen partial productivity by 6.50%and 5.33%respectively.Reducing nitrogen application resulted in a decrease in water consumption and water use efficiency.CF increased water consumption and improved water use efficiency significantly(P<0.05)compared to CRU2 and CRU3,but insignificantly compared to CRU1(P>0.05).【Conclusion】Our results showed that compared to CRU1,CRU2,CRU3 and CF increased water consumption by 2.79%~5.02%,and water use efficiency by 2.33%~11.58%respectively.They are thus optimal urea applications to improve both potato yield and water use efficiency,while in the meantime increased the economic benefit in the loess hilly-gully region we studied.