苹果园春季土施尿素的利用及其在土壤中的累积

 以7年生嘎拉苹果/平邑甜茶为试材, 利用¹⁵N示踪技术, 研究了苹果生产体系中氮素年周期的利用、残留、损失及在土壤中的迁移动态。结果表明, 对春季土施尿素的利用率盛花期较低, 为11.38% , 至采收后达到最高。土壤氮素残留率盛花期最高, 为57.10% , 果实采后残留率最低。年周期中各土层氮素残留量不同, 盛花期20～40 cm土层残留量最高, 采收后最低, 0～20 cm土层在新梢旺长期残留量最高, 果实成熟期最低, 而40～60 cm土层在果实膨大期残留量达到最高, 在采收后0～20 cm土层残留有所增加, 其余各土层残留量均达到最低值。氮素损失与土壤残留呈相反的变化趋势, 氮素损失率在盛花期最低为31.53% , 随物候期的推迟逐渐升高, 在果实采后高达58.40%

Studies on Utilization and Accumulation Dynamics of Spring Soil ~(15)N-urea Application in Apple Orchard

The utilization,residue,loss and transport dynamics of nitrogen on orchard Via soil m early technicqu of ~(15)N.The resuIts showed that the utilization ratio of N fertilizer was low.At full-bloom stage,the utilization ratio of N fertilizer was lower(11.38%).After fruit harvest,the utilization ratio of N fertilizer was the highest.At full-bloom stage,the residue rate of N fertilizer was the highest(57.10%).After fruit harvest,the residue rate of N fertilizer was the lowest.The residue rates of different phenophase are different.At full-bloom stage,the residue rate of N fertilizer of 20-40 cm layer was the highest and,after fruit harvest,it was the lowest.At the new shoot growth stage,the residue rate of N fertilizer(0-20 cm layer)was the highest and,at fruit maturity stage,it was the lowest.However,the residue rate of N fertilizer(40-60 cm laver)was up to the highest at fruit rapid-swelling stage.After fruit harvest,the residue rate of N fertilizer(0-20 cm layer)was higher than that at fruit maturity stage and the residue rate of N fertilizer(other layers)was the lowest. On the contrary,the loss rate of N fertilizer was improved gradually with the Process ol Pnenophase.At full-bloom stage,it was the lowest to 31.53%,and after harvest,the tiptop was 58.40%.