紫云英与尿素或控释尿素配施对双季稻产量及氮钾利用率的影响

Effect of different incorporation of Chinese milk vetch coupled with urea or controlled release urea on yield and nitrogen and potassium nutrient use efficiency in double-cropping rice system

【目的】了解化肥氮钾用量减少条件下不同比例紫云英与普通化肥尿素或控释尿素配施对双季稻产量及氮钾利用效率的影响,旨在为南方双季稻种植区制定科学减肥增效策略提供依据。【方法】通过连续6年定位田间小区试验,除对照不施肥外,试验的其他5个处理早稻施肥量均为N 150 kg/hm^2、P_2O_5 75 kg/hm^2、K_2O 120 kg/hm^2,氮素以尿素、控释尿素、紫云英按处理比例配合和施用。分析了双季稻产量,植株氮、钾养分吸收积累、利用效率及土壤氮、钾养分含量。【结果】与(CF100)处理相比,早稻翻压紫云英鲜草17145 kg/hm^2时,早、晚稻均减施氮40%、减施钾21%条件下,氮肥采用尿素处理(CF60+A40)或控释尿素处理(CRU60+A40)以及早稻翻压紫云英鲜草25715 kg/hm^2,早、晚稻均减施60%氮、32%钾条件下,氮肥采用控释尿素处理(CRU40+A60)有利于早晚稻及全年产量的提高,其中以CRU60+A40处理增产效果最佳。CF60+A40和CRU60+A40处理早晚稻的稻谷、稻草和植株氮素及钾素积累量均较CF100提高,其中CRU60+A40处理提高效果最明显。紫云英与尿素或控释尿素配施提高了早晚稻氮、钾养分利用效率,CF60+A40、CF40+A60、CRU60+A40和CRU40+A60处理的氮肥和钾肥回收利用率、氮肥和钾肥农学效率以及氮肥和钾肥偏生产力均高于CF100处理。在紫云英替代和肥料等量施用条件下,施用控释尿素处理比施用尿素处理有利于提高养分利用效率。6年12季水稻种植后,紫云英与尿素或控释尿素配施处理的土壤全氮、碱解氮和速效钾含量均较CF100处理有所提高。【结论】综合考虑作物产量效应、养分高效利用及土壤肥力维持,在该区域双季稻种植体系中早稻可用紫云英替代40%氮肥、20%钾肥,晚稻减施40%氮肥、20%钾肥,氮肥品种采用控释尿素或尿素均可,采用控释尿素有进一步提高早稻紫云英的替代比例和晚稻氮钾肥减施比例潜力。

【Objective】In order to develop scientific strategy to improve the efficiency of chemical fertilizer usage, a study of different proportion of Astragalussincus and urea or controlled release urea（CRU） under the condition of reduced nitrogen and potassium fertilizer application rate on rice yield in south China during double rice season was conducted. 【Method】The 6-year field trial was conducted to study the effects of combined applying of Astragalussincus with urea or controlled release urea（CRU） on double rice yield, content of nitrogen and potassium in rice plant, accumulation of nitrogen and potassium in rice plant, nitrogen and potassium use efficiency and status of soil nitrogen and potassium fertility. 【Results】Results showed that CF60 ＋ A40,CRU60 ＋ A40 and CRU40 ＋ A60 treatments could increase both early rice yield and late rice yield compared with CF100 treatment and the yield increasing effect was the most obvious in CRU60 ＋ A40 treatment. Both CF60 ＋A40 and CRU60 ＋ A40 treatments increased nitrogen and potassium nutrients accumulation in rice grain, rice straw in early and late rice compared with CF100 treatment. The increasing effect in CRU60 ＋ A40 was more significant than CF60 ＋ A40. Combined applying of Astragalussincus with urea or CRU could increase nitrogen and potassium nutrient use efficiency. The nitrogen recovery efficiency, potassium recovery efficiency, nitrogen agronomic efficiency, potassium agronomic efficiency, nitrogen partial factor efficiency and potassium partial factor efficiency were all higher in CF60 ＋ A40, CF40 ＋ 60 A, CRU60 ＋ A40 and CRU40 ＋ A60 treatments than in CF100 treatment. The increasing effect of nutrient use efficiency was higher with combined Astragalussincus with CRU than with urea under the same substitution proportion of Astragalussincus and the same fertilizer rate.After six years（twelve rice seasons）, contents of total N, alkalytic N and available K all increased in all the treatments combined Astragalussincus with urea or CRU compared with CF100 treatment. 【Conclusions】Considering the crop yield response, efficient use of nutrient and soil fertility cultivation, recommended fertilization practice was that in early rice season, nitrogen chemical fertilizer can be cut down by 40% and substituted by Astragalussincus, potassium chemical fertilizer can be cut down by 20% and substituted by Astragalussincus, and in late rice season, nitrogen chemical fertilizer can be cut down by 40% and potassium fertilizer can be cut down by 20% associated with the usage of urea or CRU. When CRU was adopted, the substitute proportion of Astragalussincus in early rice and the fertilizer reduction ratio in late rice can be properly raised.