苜蓿轮作玉米后玉米植株养分吸收与转运特性

Nutrient Absorption and Utilization of Maize of Alfalfa-maize Rotation

为探讨苜蓿轮作玉米后玉米植株养分吸收与转运特性,以7龄紫花苜蓿地为前茬,连续3年采用当地同一高产栽培方案种植玉米,测定植株N、P、K养分的吸收、积累及转运。结果表明:苜蓿轮作玉米后,植株氮、磷含量吐丝后随着玉米种植年限的增加而显著下降,植株钾含量在吐丝前随着玉米种植年限的增加而降低。植株氮、磷、钾积累量随着玉米种植年限的增加而下降,不同年份植株氮吸收量和吸收比例在乳熟-成熟期差异最大,植株磷吸收量和吸收比例差异不显著,植株钾吸收量和吸收比例在出苗-大喇叭口期差异最大。植株氮转运量、转运率及对籽粒的贡献均随玉米种植年限增加而增加;植株磷转运量、转运率及对籽粒的贡献随玉米种植年限增加差异甚微;植株钾转运量、转运率及对籽粒的贡献均随玉米种植年限增加而降低。苜蓿轮作玉米后,随玉米种植年限增加,植株N、P、K吸收养分能力下降,氮养分转运率增加。

In order to investigate the N, P and K absorption, accumulation, transport of maize of alfalfa-maize rotation, contents of N and P of maize, absorption and transfer amounts were studied under three-year high- yielding cultivation maize for preceding seven-growth-year alfalfa. The results showed： The contents of N and P of maize significantly decreased with tillage years prolonged after silking, content of K of maize decreased before silking. Accumulations of N, P and K in plant decreased with tillage years prolonged. Absorption amount and absorption percentage of N in plant were significant difference from milking to maturity, that of P were not significant, that of K in plant were significant difference from seeding to trumpeting. Transfer amounts, transfer rate and contribution rate for seed of N increased with tillage years prolonged. There were not significant differences transfer amounts, transfer rate and contribution rate for seed of P with tillage years prolonged, that of K decreased with tillage years prolonged. The capacity of N, P and K nutrient absorption decreased with tillage years prolonged, and N transfer increased.