长期定点施肥对制种玉米土壤理化性状及重金属含量的影响

Effects of Continuous Cropping System of Maize Seed Production on Soil Physical-Chemical Properties and Content of Heavy-metal in Hexi Corridor

利用制种玉米长期定点施肥试验,研究不同种植年限制种玉米田土壤物理化学性质和土壤重金属含量的变化,评价制种玉米田重金属的污染程度。结果表明,随着种植年限增加,制种玉米田容重变化值较小,孔隙度适中;土壤pH值升高;土壤有机质、全P、全K、碱解氮、速效钾均呈现先增加后下降的趋势;速效磷含量增加。土壤中铜、锌、锰、铁、铅与铬6种重金属都没有超标,而重金属镉严重超标。在河西走廊制种玉米种植区,在现有施肥模式下,制种玉米连作可使土壤物理性状改善,土壤pH值升高,土壤养分呈现先增加后下降的趋势;速效磷总体水平偏高;养分间水平不均衡;重金属镉严重超标,制种玉米对重金属的富集能力较低。应调整施肥模式以进行种子安全生产。

This paper studied the effects of continuous cropping of maize seed production on soil physical-chemical properties and contents of heavy-metal by located field experiment,the pollution degree of heavy metal was evaluated,too.Results showed that change of bulk density was small,porosity was moderate,pH value increased,soil organic matter,total P,total K,available-N and available-K increased firstly,then decreased,available-P increased.Content of Fe,Cu,Zn,Mn,Pb and Cr was not excessive,and content of Cd was seriously excessive with continuous cropping.In Hexi corridor,under long-term continuous cropping,soil physical characteristics ameliorated,pH value increased,soil nutrients increased firstly,then decreased,content of available-P was high,soil nutrients was in imbalance.Cd was seriously excessive.These caused obvious obstacles of nutrients.Accumulation ability of maize was lower.Fertilization mode should be adjusted for safety seed production.