RESUMO
In order to clarify the impact of no-tillage on the quality of farmland soil aggregates in China and promote the adaptive application of no-tillage practicesï¼ a Meta-analysis was conducted by collecting data from 116 published studies. The effects of no-tillage on aggregate size distributionï¼ mean weight diameter ï¼MWDï¼ï¼ and aggregate-associated C were studied. The results showed that compared with that under tillageï¼ no-tillage significantly increased the proportion of macroaggregates ï¼10.9%ï¼ and MWD ï¼12.8%ï¼ and decreased the proportion of clay and silt ï¼-15.5%ï¼ but had no significant effect on soil microaggregate and aggregate-associated C. The subgroup and Meta regression analysis showed that no-tillage significantly increased the proportion of macroaggregates in Northwest China ï¼17.6%ï¼ and MWD in North China ï¼15.4%ï¼. In upland and clay loamï¼ no-tillage increased MWD by 12.6% and 18.4%ï¼ respectively. The effect of no-tillage on increasing the proportion of macroaggregates increased with the soil pH. When straw returnedï¼ no-tillage significantly increased the proportion of macroaggregates ï¼9.6%ï¼ and MWD ï¼11.6%ï¼ï¼ but no significant effect of no-tillage on aggregates was found after straw removal. Regarding test durationï¼ short-term ï¼ < 5 aï¼ no-tillage could significantly increase the proportion of macroaggregatesï¼ whereas long-term ï¼ > 10 aï¼ no-tillage could improve the MWD. In different soil layersï¼ no-tillage could only significantly improve the aggregate size distribution and MWD in topsoil ï¼0-20 cmï¼ but had no effect in subsoil ï¼ > 20 cmï¼. In summaryï¼ no-tillage could improve aggregate size distribution and stability but had no effect on aggregate-associated C. Production regionï¼ soil propertiesï¼ field management methodsï¼ and other factors should be fully considered in production practice to effectively improve the quality of soil aggregates.
