连作秸秆还田下玉米氮素积累与氮肥替代效应研究

Nitrogen accumulation and nitrogen substitution effect of maize under straw returning with continuous cropping

针对东北地区农作物秸秆资源丰富,然而焚烧弃置严重,养分利用率较低等问题,探讨常年玉米连作下还田秸秆的氮肥替代效应在松嫩平原玉米种植生产上的可行性。试验于2017—2019年在东北农业大学校内试验场进行,采用框栽、连作方式,采用再裂区试验设计,主处理为秸秆不还田(S0)和秸秆还田(S1),副处理为3个施尿素梯度0(N0)、175(N1)、350(N2)kg hm^(-2),再副处理为一次性施肥(基追比1:0)和2次均匀施肥(基追比1:1)。结果表明,每公顷还12 t玉米秸秆可替代单质氮36.80 kg,2017—2019年黑龙江省产生的玉米秸秆量平均为4650.05万吨,秸秆还田可替代单质氮14.27万吨。在2次均匀施氮肥处理下,秸秆氮肥替代量比一次性施氮肥处理高26.88%。秸秆还田与玉米氮肥利用率负相关,在当地农业常用施尿素量350 kg hm^(-2)(纯氮161 kg hm^(-2))下,玉米氮肥利用率3年平均S0较S1高6.09%,产量S1较S0高4.66%,且在秸秆还田、2次等量施氮肥处理玉米产量最高为268.22 g框^(-1)。综上所述,东北地区玉米秸秆还田的氮肥替代效果显著,将秸秆中残留养分有效转化为玉米生长所需氮素,有利于秸秆资源的肥料化利用,且作物秸秆与氮肥的长期配施能够显著提高玉米生物产量、产量和氮素累积,是东北地区玉米增产增效的栽培模式。

Crop straw resources in Northeast China are rich,but burning and discarding are serious,and nutrient utilization rate is very low.We explored the feasibility of the substitution of straw returning to nitrogen fertilizer and its effects on nitrogen accumulation under continuous cropping in cold region.A frame culture and continuous positioning experiment was carried out in the experimental site of Northeast Agricultural University from 2017 to 2019,with ^(15)N labeled urea.A three-factor split-plot design was adopted in this experiment,the main plot was straw returning method with no straw returning(S0)and straw returning(S1),and the sub-plot was nitrogen application levels with 0(N0),175(N1),and 350(N2)kg hm^(-2).Two application methods were set for each fertilizer application amount,one ratio of base fertilizer and top dressing applied was 1:1,and the other ratio of base fertilizer and top dressing applied was 1:0.The results were as follows:When the straw returning amount was 12 t hm^(-2),the returning straw could replace 36.8 kg hm^(-2) pure nitrogen.The average amount of maize straw was 46.50 million tons in Heilongjiang Province from 2017 to 2019,and straw returning could replace 142,700 tons pure nitrogen.The replace amount of pure nitrogen in the ratio of base fertilizer and top dressing(1:1)was 26.88% higher than that in 1:0.Straw returning was negatively correlated with nitrogen use efficiency in maize.The average nitrogen use efficiency of maize in S0 treatment was 6.09% higher than S1 treatment,and the yield of S1 treatment was 4.66% higher than S0 treatment when the urea application amount was 350 kg hm^(-2)(161 kg hm^(-2) pure nitrogen).The highest yield of maize was 268.22 g frame^(-1) in the treatment of straw returning and topdressing with commonly fertilizer applied in local agriculture.In conclusion,the nitrogen substitution effect was remarkable under maize straw returning in Northeast China.Long-term combined application of crop straw and nitrogen fertilizer significantly improved the biomass,yield,and nitrogen accumulation of maize,which was a cultivation mode for increasing yield and efficiency of maize in Northeast China.