设施蔬菜有机肥/秸秆替代化肥模式对土壤线虫群落的影响

Effects of partial substitution of chemical fertilizer with manure and/or straw on soil nematode community in greenhouse vegetable production

【目的】利用天津市西青区基地日光温室蔬菜不同施肥模式定位试验,研究有机肥/秸秆替代化肥模式对设施蔬菜土壤线虫总数、群落结构和生态指数的影响,为构建健康的土壤动物区系提供科学依据。【方法】定位试验共设6个处理,分别为:1)全部施用化肥氮(4/4CN);2)3/4化肥氮+1/4猪粪氮(3/4CN+1/4MN);3)2/4化肥氮+2/4猪粪氮(2/4CN+2/4MN);4)1/4化肥氮+3/4猪粪氮(1/4CN+3/4MN);5)2/4化肥氮+1/4猪粪氮+1/4秸秆氮(2/4CN+1/4MN+1/4SN);6)2/4化肥氮+2/4秸秆氮(2/4CN+2/4SN),各处理为等氮磷钾设计。第16茬(土壤消毒后)和第18茬(土壤消毒1年后)蔬菜(春茬番茄)拉秧后,分别采集0—5、5—10和10—20 cm土层土壤样品,测定土壤线虫相关指标。【结果】1)有机肥/秸秆替代化肥模式0—5、5—10和10—20 cm土层土壤线虫总数均高于单施化肥模式,平均分别增加16.8%、31.8%和11.2%;配施高量有机肥模式(1/4CN+3/4MN)和配施秸秆模式(2/4CN+1/4MN+1/4SN、2/4CN+2/4SN)各土层线虫总数相对较高,较单施化肥模式分别提高12.1%~26.4%、34.3%~42.8%、13.2%~18.3%。2)与单施化肥模式相比,有机肥/秸秆替代化肥模式,尤其是配施高量有机肥模式和配施秸秆模式可提高0—5和5—10 cm土层土壤有益线虫(食细菌、食真菌和捕食/杂食性线虫)营养类群个体数量,其中0—5 cm土层上述线虫营养类群个体数量平均分别增加13.0%、7.4%和26.7%,5—10 cm土层平均分别增加35.5%、20.2%和56.5%。有机肥/秸秆替代化肥模式0—5和5—10 cm土层土壤有害植食性线虫数量虽均高于单施化肥模式,但其相对丰度均低于单施化肥模式,平均分别降低6.3%和13.1%。3)有机肥/秸秆替代化肥模式,尤其是配施高量有机肥模式和配施秸秆模式,MI值、WI值、EI值和SI值均高于单施化肥模式,0—5 cm土层平均分别增加3.9%、11.5%、6.2%和130.4%,5—10 cm土层平均分别增加1.8%、19.1%、2.4%和138.7%。【结论】在N、P2O5和K2O投入量不变的情况下,有机肥/秸秆替代化肥模式可促进土壤有益线虫(食细菌线虫、食真菌线虫和捕食/杂食性线虫)生长繁殖,还可降低土壤有害植食性线虫相对丰度,对土壤有害植食性线虫起到一定的抑制作用。综合来看,有机肥/秸秆替代化肥模式,尤其是配施高量有机肥模式和配施秸秆模式,可优化土壤线虫群落结构,降低土壤环境的受干扰程度,改善土壤的质量,使设施蔬菜土壤生态系统向稳定健康的方向发展。结合本试验9年产量数据(2/4CN+1/4MN+1/4SN模式产量最高)、土壤线虫群落相关研究结果以及实际可操作性,化肥与有机肥、秸秆配施模式(2/4CN+1/4MN+1/4SN)可实现设施蔬菜持续高产。

【Objectives】A fixed-site greenhouse vegetable field fertilization experiment was carried out in Xiqing District,Tianjin to investigate the effects of partial substitution of chemical fertilizer with manure and/or straw on the total number of soil nematode,nematode community structure and nematode ecological indices for providing a scientific basis for the construction of healthy soil fauna.【Methods】Six treatments were included based on substitution of chemical fertilizer nitrogen(N)with different exogenous organic resources:1)complete chemical N(4/4 CN);2)3/4 chemical N plus 1/4 manure N(3/4 CN+1/4 MN);3)2/4 chemical N plus 2/4 manure N(2/4 CN+2/4 MN);4)1/4 chemical N plus 3/4 manure N(1/4 CN+3/4 MN);5)2/4 chemical N plus 1/4 manure N plus 1/4 straw N(2/4 CN+1/4 MN+1/4 SN),and 6)2/4 chemical N plus 2/4 straw N(2/4 CN+2/4 SN).All treatments had the same amounts of N,P2 O5,and K2 O inputs.After the uprooting stage of the 16th-season vegetable(after soil disinfection)and the 18th-season vegetable(one year after soil disinfection),surface soil(0-5,5-10,and 10-20 cm depth)samples were collected for the determination of the nematode-associated indices.【Results】1)The total number of nematode were increased in organic-amended soils by 16.8%,31.8%,and11.2%,respectively,compared with those in 4/4 CN-treated soils in the 0-5,5-10,and 10-20 cm soil layers.Moreover,the total number of nematode in the 1/4 CN+3/4 MN,2/4 CN+1/4 MN+1/4 SN,and 2/4 CN+2/4 SN treatments were relatively higher than other organic-amended treatments,which were increased by12.1%-26.4%,34.3%-42.8%,and 13.2%-18.3%,respectively,compared with those in the 4/4 CN treatment in different layers.2)The number of beneficial nematodes,i.e.,bacterivore,fungivore,and omnivore-predator,were higher in organic-amended soils than those in 4/4 CN-treated soil by respective average of 13.0%,7.4%,and 26.7%in the 0-5 cm soil layer,and 35.5%,20.2%,and 56.5%in the 5-10 cm soil layer.In comparison with the 4/4 CN treatment,organic amendments increased the number of harmful herbivore,but decreased the relative abundances of harmful herbivore by average of 6.3%and 13.1%,respectively,in the 0-5 cm and 5-10 cm layers.3)The organic amendments,especially the 1/4 CN+3/4 MN,2/4 CN+1/4 MN+1/4 SN and 2/4 CN+2/4 SN treatments had higher MI,WI,EI and SI values than the 4/4 CN treatment,which were increased by3.9%,11.5%,6.2%,and 130.4%,respectively,in the 0-5 cm soil layer,and by 1.8%,19.1%,2.4%,and138.7%,respectively,in the 5-10 cm soil layer.【Conclusions】Under the same N,P2 O5,and K2 O rates,organic amendments could promote the growth of nematodes and relative abundances of beneficial nematodes(i.e.,bacterivore,fungivore,and omnivore-predator).Conversely,organic amendments could decrease the relative abundances of harmful herbivores,and thus inhibite harmful herbivores growth.Overall,organic amendments could optimize soil nematode community structure,decrease soil environmental interference,and improve soil quality conditions,which is beneficial for soil ecosystems healthy development in the greenhouse vegetable production.Combined with the 9-year yield of this experiment(the yield is highest in the 2/4 CN+1/4 MN+1/4 SN treatment),soil nematode data and practical operability,chemical fertilizer plus organic manure plus corn straw(2/4 CN+1/4 MN+1/4 SN)is a continuous high-yield fertilization treatment for greenhouse vegetables.