豆科作物轮作与有机肥+功能微生物肥减投配施对设施菜田硝态氮累积、固氮基因和净收益的影响

Effects of leguminous crop rotation and combined application of organic fertilizer and functional microbial fertilizer on nitrate accumulation,nitrogen fixing functional gene and net income under reducing the amount of using fertilizer in vegetable fields

为降低河北省设施蔬菜种植区土壤硝态氮盈余累积量,降低地下水硝酸盐污染风险,2018—2022年连续5年,在华北典型褐土区设施菜田中,采用田间小区试验和实验室分析试验相结合的方法,以分析豆科作物轮作与有机肥+功能微生物肥减投配施对设施菜田产量和土壤硝态氮累积的影响,试验设置对照(CK)、常规施肥(T1)、减量施肥+功能微生物(T2)、减量施肥+功能微生物+豆科作物(T3)共4个处理。结果表明:相比T1处理,T2和T3处理可使番茄产量增加5.3%和25.8%;T2处理下油菜产量增加3.0%;农户年净收益提高4.4%和34.4%。5年间T2、T3处理的氮肥表观利用率较T1处理,番茄季增幅为13.5%~17.0%、11.3%~18.1%;T2处理油菜季增幅9.3%~36.6%。实时荧光定量(qPCR)结果显示,T2和T3处理土壤根际土固氮功能基因nifH拷贝数相比T1处理显著提高了16.1%和58.9%;nifH基因拷贝数与作物产量呈显著正相关关系,二者之间的回归方程为y=0.000 2x+30 355(R=0.741 2)。T2和T3处理0~100 cm土体硝态氮周年平均累积量,相比T1处理降低了51.6%和58.3%;5个轮作周期后,与T1处理相比,T2和T3处理有效降低了0~100 cm土体中55.3%和71.0%的硝态氮累积。综上,在减量施肥的背景下,选择引入豆科作物进行合理优化轮作,与有机肥+功能微生物肥配施,可从源头上减少设施蔬菜的氮肥投入,降低设施菜田土壤硝态氮淋失风险,提高作物产量和肥料利用率。

In order to decrease nitrate accumulation in vegetable planting areas in Hebei Province and reduce the risk of groundwater nitrate pollution,field plot experiments and laboratory analysis experiments were carried out in vegetable fields in typical brown soil areas in North China for five consecutive years from^(2)018 to 2022.There were four treatments:CK control,T1 conventional fertilization,T2 reduced fertilization+functional microorganisms,T3 reduced fertilization+functional microorganisms+leguminous crops.They were set up to analyze the effects of leguminous crop rotation and organic fertilizer+functional microbial fertilizer on the net income,soil nitrate accumulation and nitrogen fixing functional gene under reducing the amount of using fertilizer in vegetable greenhouse field.The results showed that compared with treatment T1,T2 and T3 could increased tomato yield 5.3%and 25.8%;the yield of T2 treatment was increased by 3.0%.The annual net income of rural households increased by 4.4%and 34.4%.The nitrogen apparent recovery fraction of tomato season under treatment T2 and treatment T3 increased by 13.5%~17.0%and 11.3%~18.1%compared with treatment T1 in five years.The rape season ranges from 9.3%to 36.6%.The qPCR results indicated that the copies number of nifH gene in rhizosphere soil was significantly increased by 16.1%and 58.9%in T2 and T3 treatment compared with T1 treatment.There was a significant positive correlation between nifH gene copies number and crop yield,and the regression equation between them was y=0.0002x+30355(R=0.7412).Compared with treatment T1,the annual average accumulation of nitrate nitrogen in 0~100 cm soil was reduced by 51.6%and 58.3%under treatment T2 and treatment T3.After five rotation cycles,compared with treatment T1,T2 and T3 effectively reduced the accumulation of nitrate nitrogen in 0~100 cm soil mass by 55.3%and 71.0%.To summary,in the background of reduced fertilization,selecting of legume crops for rational optimization of crop rotation,combined with organic fertilizer+functional microbial fertilizer reduction,can reduce nitrogen fertilizer input of facility vegetables from the source,reduce the risk of soil nitrate nitrogen leaching in facility vegetable fields,and improve crop yield and fertilizer utilization rate.