[Objective] The aim was to explore release characteristics of vinyl chlo- ride-vinyl acetate copolymer controlled-release N fertilizer and the effects on minerat nitrogen in soils. [Method] Vinyl chloride-vinyl acetat...[Objective] The aim was to explore release characteristics of vinyl chlo- ride-vinyl acetate copolymer controlled-release N fertilizer and the effects on minerat nitrogen in soils. [Method] Vinyl chloride-vinyl acetate copolymer and hydroxyl-modi- fied VCNAc were taken as coating materials to prepare slow release fertilizer. Nutri- ent release characteristics of VC/VAc slow release fertilizer was evaluated by water immersion method and the effects of VC/VAc slow release fertilizer on mineral ni- trogen were researched by pot experiment. [Result] The release periods of VC-VAc controlled-release urea and hydroxyl-modified VC/VAc coated urea were 60 and 50 d, respectively. Furthermore, the content of ammonium nitrogen reached the peak on the 30th d and the content of nitrate nitrogen reached the peak on the 60th d in soils in treatments with VCNAc and hydroxyl-modified VC/VAc; the content of nitrate nitrogen rose again on the 120th d in the treatment with VC/VAc. In terms of wheat yield, different treatments showed insignificant differences and rice yield in the treatment with VCNAc was significantly higher than that in the treatment with hy- droxyl-modified VCNAc （P〈0.05）. [Conclusion] The release days of slow controlled- release fertilizer vary upon pot experiment method and water immersion method. Slow controlled-release fertilizer is not suitable for monoculture, due to long fertilizer efficiency, but multiple cropping would be optimal for its role to be fully exploited.展开更多
以洛川、礼泉县作为黄土高原新、老苹果产区的代表,调查了两县400余个果园化肥养分投入情况,测定了两县各15个成龄果园0~40 cm土壤养分状况,旨在比较新、老果区的养分管理现状和土壤养分状况,为苹果园的合理施肥提供科学指导。结果表明...以洛川、礼泉县作为黄土高原新、老苹果产区的代表,调查了两县400余个果园化肥养分投入情况,测定了两县各15个成龄果园0~40 cm土壤养分状况,旨在比较新、老果区的养分管理现状和土壤养分状况,为苹果园的合理施肥提供科学指导。结果表明:黄土高原苹果产区果园氮、磷、钾肥过量投入现象较为普遍,礼泉果园氮(N)、磷(P_2O_5)、钾(K_2O)化肥平均施用量依次为1115 kg hm^(-2)、656 kg hm^(-2)、968 kg hm^(-2),其中,氮、磷、钾肥投入过量比例依次高达95.3%、91.3%和100%;洛川果园氮、磷、钾化肥平均施用量依次为1208 kg hm^(-2)、828 kg hm^(-2)和1114 kg hm^(-2),其中,氮、磷、钾肥投入过量比例依次高达99.3%、98.7%和100%。两县果园土壤有效磷、钾养分过量问题较为普遍,其中,老果区礼泉县更为突出。因此,应适当控制氮、磷、钾投入,优化果园养分管理,减少不合理施肥可能带来的问题。展开更多
基金Supported by National Department Public Benefit Research Foundation(201203013)Modern Agricultural Industry Technology System(CARS-11-B-15)+2 种基金IPNI Project(JIANGSU-10)Special Fund for Agro-scientific Research in the Public Interest(201003014-1-2)Jiangsu Agriculture S&T Self-Innovation Project[CX(12)3037]~~
文摘[Objective] The aim was to explore release characteristics of vinyl chlo- ride-vinyl acetate copolymer controlled-release N fertilizer and the effects on minerat nitrogen in soils. [Method] Vinyl chloride-vinyl acetate copolymer and hydroxyl-modi- fied VCNAc were taken as coating materials to prepare slow release fertilizer. Nutri- ent release characteristics of VC/VAc slow release fertilizer was evaluated by water immersion method and the effects of VC/VAc slow release fertilizer on mineral ni- trogen were researched by pot experiment. [Result] The release periods of VC-VAc controlled-release urea and hydroxyl-modified VC/VAc coated urea were 60 and 50 d, respectively. Furthermore, the content of ammonium nitrogen reached the peak on the 30th d and the content of nitrate nitrogen reached the peak on the 60th d in soils in treatments with VCNAc and hydroxyl-modified VC/VAc; the content of nitrate nitrogen rose again on the 120th d in the treatment with VC/VAc. In terms of wheat yield, different treatments showed insignificant differences and rice yield in the treatment with VCNAc was significantly higher than that in the treatment with hy- droxyl-modified VCNAc （P〈0.05）. [Conclusion] The release days of slow controlled- release fertilizer vary upon pot experiment method and water immersion method. Slow controlled-release fertilizer is not suitable for monoculture, due to long fertilizer efficiency, but multiple cropping would be optimal for its role to be fully exploited.
文摘以洛川、礼泉县作为黄土高原新、老苹果产区的代表,调查了两县400余个果园化肥养分投入情况,测定了两县各15个成龄果园0~40 cm土壤养分状况,旨在比较新、老果区的养分管理现状和土壤养分状况,为苹果园的合理施肥提供科学指导。结果表明:黄土高原苹果产区果园氮、磷、钾肥过量投入现象较为普遍,礼泉果园氮(N)、磷(P_2O_5)、钾(K_2O)化肥平均施用量依次为1115 kg hm^(-2)、656 kg hm^(-2)、968 kg hm^(-2),其中,氮、磷、钾肥投入过量比例依次高达95.3%、91.3%和100%;洛川果园氮、磷、钾化肥平均施用量依次为1208 kg hm^(-2)、828 kg hm^(-2)和1114 kg hm^(-2),其中,氮、磷、钾肥投入过量比例依次高达99.3%、98.7%和100%。两县果园土壤有效磷、钾养分过量问题较为普遍,其中,老果区礼泉县更为突出。因此,应适当控制氮、磷、钾投入,优化果园养分管理,减少不合理施肥可能带来的问题。
