聚丙烯酰胺用量对盆栽平邑甜茶幼苗生长及15N-尿素吸收、利用和损失的影响

Effects of Different Polyacrylamide Amount on the Growth and ^(15)N-Urea Absorption,Utilization and Loss of Potted Malus hupehensis Seedlings

以一年生平邑甜茶(Malus hupehensis)盆栽幼苗为试材,采用15 N同位素示踪技术,研究不同聚丙烯酰胺(PAM)用量与尿素混施对平邑甜茶幼苗生长及15 N-尿素吸收、利用和损失的影响。结果表明,在生长后期,随着PAM用量的增加,植株株高、总鲜样质量和氮肥吸收、利用率均呈现出先增大后减小的趋势,且均以PAM用量180mg/kg的处理最高,分别为29.93cm,31.29g,20.30mg和7.35%,显著高于对照(18.93cm,23.33g,8.13mg和3.59%);植株地上部从肥料中吸收分配到的15 N量对该部分全氮量的贡献率(Ndff)高于地下部,施用PAM后各处理显著高于对照,且均以PAM 180mg/kg处理最高;施用PAM后各处理的15 N残留率均显著高于对照,并随着PAM用量的增加而逐渐升高,分别为300>240>180>120>60>0(CK)mg/kg,而土壤氮素的损失率则随PAM用量的增加而减少,分别为0(CK)>60>120>180>240>300mg/kg。合理施用PAM显著促进植株的生长及对15 N的吸收利用,降低土壤氮素的损失,且以PAM用量180mg/kg的处理效果最佳。

One-year-old potted Malus hupehensis seedlings and 15 N trace technique were used to explore the effects of polyacrylamide（PAM）mixed with nitrogen fertilizer on plant growth and the absorption,utilization and loss of 15 N-urea.The main results were as follows：The growth of plant,15 N-Urea absorption and nitrogen utilization ratio showed increased at first and then decreased with the increase of PAM amount,and with PAM 180mg/kg treatment was the highest,they were 29.93 cm,31.29 g,20.30 mg and 7.35%respectively,which were obviously higher than CK（18.93 cm,23.33 g,8.13 mg and 3.59%）at the late stage.Ndff values of shoots were higher than roots for all treatments at the late stage,and applications of PAM in various processing were obviously higher than CK,and with PAM 180mg/kg treatment was the highest.Amount of reside rate in soil by using PAM applications were obviously higher than CK,which increased with the increase of amount of PAM（300〉240〉180〉120〉60〉0mg/kg）,but the 15 N loss rate decreased with the increase of amount of PAM（0〉60〉120〉180〉240〉300mg/kg）.As a whole,with the reasonable application of PAM,the growth of plant and the utilization of 15 N significantly increased and the loss of nitrogen decreased,and with PAM 180mg/kg soil treatment showing the best.