Effects of earthworm activity on farmland nitrogen transformation under nitrogen fertilizer application:a Meta-analysis
Earthworms can promote plant N utilization,increase soil N retention,and cause soil N loss through gas escape and leaching in natural soil.However,it is unclear how continuous N fertilizer application affects earthworms on farmland soil.Therefore,202 data records from 52 pieces of literature were collected and analyzed using a Meta-analysis of N fertilizer type,fertilizer rate,and fertilization method,and the effects of earthworm activity on farmland soil N transformation under N fertilizer application were comprehensively evaluated.The overall results showed that earthworm activity significantly increased crop biomass(aboveground and belowground by 12.00%and 19.30%,respectively),crop total nitrogen(TN)content(aboveground and belowground by 20.35%and 21.06%,respectively),soil available N content(9.16%),microbial biomass N(MBN)content(23.19%),urease activity(23.73%),N2O emission(16.41%),and N leaching(16.15%).The effects of earthworm activity on soil N transformation differed under different fertilizer types,rates,and methods.Earthworm activity had a significant positive effect on crop biomass(aboveground and belowground biomass increased by 17.90%and 18.03%,respectively)and TN content(aboveground and belowground increased by 37.62%and 25.76%,respectively)when organic-inorganic mixed fertilizer was applied.Earthworm activity significantly increased crop aboveground biomass and aboveground TN content regardless of N fertilizer application rate;however,no such results were found for other parameters.When N fertilizer was applied deeply,earthworm activity significantly increased crop biomass(aboveground and belowground biomass by 16.75%and 22.75%,respectively),TN content(aboveground and belowground by 33.24%and 27.62%,respectively),and microbial activity(MBN and urease by 27.87%and 28.21%,respectively).However,when N fertilizer was applied on the soil surface,earthworm activity only significantly increased available N content(17.56%)and urease activity(9.03%).Furthermore,earthworm activity significantly increased the ecosystem multifunctionality index by 5.93%.Compared with N fertilizer applied on the soil surface,deep application of N fertilizer was more conducive to promoting the positive role of earthworms in farmland soil N transformation.There was no significant difference in the comprehensive effects of N fertilizer types and application rates on the earthworm-induced N transformation.
万方数据
维普
