接触施用包膜控释肥对玉米产量、根系分布和土壤残留无机氮的影响

Effects of co-situs application of polymer-coated fertilizers on grain yield,root distribution and soil residual N_(min) in summer maize

采用田间小区试验,研究了习惯施肥与接触施用包膜控释肥料对夏玉米生长、产量、根系分布和土壤无机氮残留的影响。结果表明,接触施用包膜控释肥料没有抑制玉米的出苗和幼苗生长;减氮1/3的控释肥处理（N 120kg/hm2）与习惯施肥处理（N180 kg/hm2）的玉米产量没有差异。在0—30 cm土层,与对照和习惯施肥处理相比,接触施用控释肥增加了距茎基部0—10 cm区域内玉米根长密度的分布,占总根长的59%~64%;玉米收获后,减量控释肥处理土壤剖面各个土层Nmin含量与对照相比无显著增加,习惯施肥和全量控释肥处理（N 180 kg/hm2）在60—90、90—120 cm土层的Nmin累积显著高于对照。综合考虑玉米生长、产量以及根系分布和氮素淋失风险,本试验条件下,接触施用控释肥N120 kg/hm2是夏玉米季较为理想的选择。

A field experiment was conducted to study effects of co-situs application of polymer-coated fertilizers（PCF）on the summer maize grain yield,root distribution,and the Nmin residual in soil profile.Before the maize sowing,the polymer-coated fertilizers were applied in the top-soil with a 4-8 cm depth,which just under the seed point.The amount of applied coated-fertilizers was N 180 kg/ha for the treatment PCFN1,and N 120 kg/ha for the treatment PCFN2.A conventional fertilizer treatment that received N 180 kg/ha and a CK treatment that received no N were included.The main results were as follows： 1）No negative impacts on seed generation and seedling growth occurred from the treatments with single co-situs application of coated-fertilizers;2）The maize grain yields from N fertilized treatments were significantly increased,which were 9.61 to 10.4 t/ha higher than the CK treatment（8.71 t/ha）.The yield from the PCFN2 treatment was same to that from conventional fertilizer treatment;3）In the plough layers（0-30 cm）,root length density in the area of 0 to 10 cm near the stem from PCFN1 or PCFN2 treatments accounted for 59%-64% of the total root,which were higher than those from conventional fertilizer or CK treatments;4）There was no significant increase of accumulation of residual Nmin in the PCFN2 treatment compared to CK treatment;Nmin in the 60-90 and 90-120 cm layers from the conventional fertilizer or PCFN1 treatments were significantly higher than that of CK treatment after maize harvest.Taking maize yield,root distribution and N leach risk into consideration,the co-situs application of polymer-coated fertilizers with N 120 kg/ha was the best for summer maize in this experimental area.