冬种紫云英和稻草还田下氮钾肥减量施用对双季水稻产量和养分吸收的影响

Yield and Nutrient Uptake of Double Rice Affected by Winter Legume Covering(Astragalus sinicus L.) and Straw Retention with Reduced Rates of Inorganic Nitrogen and Potassium Fertilizers

大量研究表明有机培肥对提高作物产量、土壤肥力以及农田生产力的可持续性具有重要作用,但对有机肥在化肥减量方面的研究相对较少。本研究利用豆科绿肥生物固氮和稻草富含钾素的特点,以明确双季稻系统冬种紫云英和稻草联合还田在减少化学氮钾肥用量上的效果。于2013—2014年开展田间试验,设置无肥对照、单施化肥(NPK)、在NPK的基础上,冬种紫云英联合双季稻草还田(GM+RS)、冬种紫云英联合稻草还田下,NK肥在NPK的基础上减少20%,P不变(G+S-20%)、冬种紫云英联合稻草还田下,NK肥在NPK的基础上减少40%,P不变(G+S-40%)等5个处理,以明确冬种紫云英和稻草还田下NK肥减量施用对双季水稻产量和养分吸收的影响。结果表明,与NPK处理相比,GM+RS处理的早晚稻产量均有增加的趋势,但仅在2014年的早稻季存在显著差异。NPK与G+S-20%处理的水稻产量无显著差异,G+S-20%处理甚至显著提高了2014年的早稻产量。与NPK处理相比,除2014年的早稻外,G+S-40%处理有降低水稻产量的趋势,但差异均不显著。有机肥处理主要是通过有效穗数影响水稻产量。NPK和G+S-20%处理的N素吸收量无显著差异。与NPK相比,G+S-40%处理降低了2013年早晚稻的N素吸收,但差异不显著。但是,2014年G+S-40%处理早晚稻的N素吸收均显著低于NPK处理。与NPK处理相比,G+S-20%和G+S-40%处理均显著提高了早稻地上部的PK吸收量,晚稻季差异不显著或者有降低趋势。因此,冬种紫云英和双季稻草还田具有显著的节肥效果,而且冬种紫云英和双季稻草还田下有进一步降低早稻化学P肥和K肥用量的潜力。

A large host of research indicates that organic amendments could increase crop yield,soil fertility,and the sustainability of cropland productivity.However,not so much information has been reported regarding the effect of organic fertilizers on reducing the rates of inorganic fertilizers.The aim of the present field study was to investigate the effect of winter legume covering（ Astragalus sinicus L.） and straw retention on reducing the rates of inorganic nitrogen（ N） and potassium（ K） fertilizers in a double rice system. A field experiment was conducted in a double rice cropping system in 2013—2014,with five treatments：（ 1） non-fertilized control（ CK）;（ 2） inorganic N,phosphorus（ P）,and K fertilization（ NPK）;（ 3） winter legume covering and straw retention plus inorganic NPK fertilizers（ GM＋RS）;（ 4） winter legume covering and straw retention with20% less inorganic NK fertilizers（ G＋S-20%）; and（ 5） winter legume covering and straw retention with 40%less inorganic NK fertilizers（ G＋S- 40%）. The results showed that compared to the NPK treatment,the GM ＋RS treatment tended to increase rice yield,but only statistically significantly in the early rice season in 2014.The G ＋S- 20% treatment did not significantly affect rice yield,even significantly increased the yield of early rice in 2014.The G＋S-40% treatment tended to reduce rice yield,but without statistical difference except the early rice in 2014.Rice yield was mainly affected by the number of effective panicles.No significant difference in N uptake was found between the NPK and G＋S-20% treatments.The G＋S-40% tended to reduce the N uptake of rice in 2013,but without significant difference,whereas significant difference was observed in 2014.Compared to the NPK treatment,both the G＋S-20% and G＋S-40% significantly increased the P and K uptake of early rice,while no significant difference or declining trend were found in late rice. These results indicate that winter legume covering and straw retention could significantly save inorganic fertilizers,and there is room for reducing the rates of inorganic P and K for early rice in the present cropping system.