河套灌区麦后复种毛叶苕子与化学氮肥减量配施对作物产量和土壤肥力的影响

Effects of multiple cropping of hairy vetch after wheat and reduced chemical nitrogen fertilizer application on crop yield and soil fertility in Hetao irrigation area

研究河套灌区春小麦后复种毛叶苕子还田条件下,小麦季不同施氮水平对小麦-绿肥轮作体系产量、土壤肥力及经济效益的影响,旨在为河套灌区绿肥还田下小麦氮肥减量提供科学依据。2018—2020年在内蒙古巴彦淖尔市农牧业科学研究所园子渠试验站进行田间定位试验,采用随机区组试验设计,以麦后夏休闲+小麦常规施氮为对照(CK),设置麦后复种毛叶苕子50%翻压还田+小麦减氮10%(GN_(90))、减氮20%(GN_(80))和减氮30%(GN_(70))。与CK相比,2019年GN_(80)处理显著提高春小麦产量12%,2020年GN_(90)、GN_(80)显著增加了春小麦产量,增幅分别为16%和13%。春小麦季减氮对复种毛叶苕子鲜草产量没有影响,2020年毛叶苕子产量仅为2019年的52%。麦后复种毛叶苕子结合氮肥减量10%~30%显著增加了春小麦穗粒数及千粒重,实现增产稳产。与CK比较,2019年不同处理对土壤全量及速效养分含量影响不显著;2020年GN_(90)处理显著提高了土壤有机质含量,增幅为37%。GN_(90)、GN_(80)、GN_(70)处理的土壤全氮含量分别显著增加了40%、23%、17%,GN_(90)、GN_(80)处理显著提高了有效磷含量,增幅分别21%、23%。2019年GN_(90)、GN_(80)、GN_(70)经济效益较CK分别增加39%、33%、29%;2020年由于毛叶苕子牧草收益大幅降低,导致GN_(80)、GN_(70)处理的纯增收益较CK分别低3%、5%。河套灌区麦后复种毛叶苕子50%翻压还田,后茬小麦季减氮10%可以提高小麦产量、培肥土壤,同时具有较高经济生态效益,是一种适宜河套地区春小麦种植的绿色高效栽培模式。

To provide scientific supports for the reduction of nitrogen fertilizer during wheat production through green manure returning,the effects of nitrogen application rates on grain yield,soil fertility and economic benefits of the spring wheatsummer hairy vetch rotation system were studied in the Hetao irrigation area.A field experiment from 2018 to 2020 was carried out at the Yuanziqu experimental station of the Institute of Agriculture and Animal Husbandry Science,Bayannaoer city,Inner Mongolia.The randomized block experiment design was adopted with summer fallow without nitrogen fertilization reduction in wheat season as the control (CK),the combination of hairy vetch returning with half aboveground biomass and nitrogen reduction in wheat season by 10%(GN_(90)),20%(GN_(80)) and 30%(GN_(70)) as treatments.Compared with CK,GN_(80) significantly increased the grain yield of spring wheat by 12%in 2019,and GN_(90) and GN_(80) increased by 16%and 13%in 2020,respectively.Nitrogen reduction in spring wheat season had no effects on the fresh grass yield of summer hairy vetch,and the yield of hairy vetch in 2020 was only 52%of that in 2019.Combined with the 10%-30%reduction of nitrogen fertilizer in wheat season,the multiple cropping of summer hairy vetch significantly increased the number of spikelets and1000-grain weight of spring wheat,thus achieving higher grain yield.Compared with CK,the multiple cropping of summer hairy vetch had no effect on soil total and available nutrient contents in 2019,while remarkable increases were found in 2020.GN_(90) increased soil organic matter by 37%.GN_(90),GN_(80) and GN_(70) increased soil total nitrogen by 40%,23%and 17%,respectively.GN_(90),GN_(80) treatments increased available phosphorus by 21%,23%,respectively.In 2019,the economic benefits of GN_(90),GN_(80) and GN_(70) were increased by 39%,33%and 29%,respectively,compared with CK.In 2020,the net income of GN_(80) and GN_(70) were 3%and 5%lower than CK,respectively,due to the sharp decrease in the production of hairy vetch forage.Overall,the multiple cropping of summer hairy vetch and half returning,combined with nitrogen reduction by 10%in the subsequent wheat could increase wheat grain yield,improve soil fertility,and increase economic and ecological benefits.It could be a green and efficient farming system for spring wheat planting in the Hetao irrigation area.