The Quantification of the Ecosystem Services of Forming Ridges in No-Tillage Farming in the Purple Soil Region of China: A Meta-Analysis

Forming ridges in no-tillage farming (FRNF) is an important conservation tillage practice in the purple soil region of China. Whether FRNF will enhance ecosystem services remains unclear. There is a lack of a systematic quantitative research about the effect of FRNF on ecosystem services. We collected 611 data entries from 21 previous publications to quantitatively evaluate the effects of FRNF on runoff and sediment loss, soil physicochemical properties and biomass. The results showed that compared with conventional tillage, (1) FRNF reduced runoff and sediment loss by 49% and 73%, respectively, due to the blocking effect of the ridge-ditch structure; (2) FRNF increased the concentrations of soil organic carbon, total nitrogen, available nitrogen, available phosphorus and available potassium by 15%, 14%, 30%, 58% and 17%, respectively; (3) FRNF decreased soil bulk density on the ridges by 11% and increased soil moisture content in the furrows by 28%, while it had insignificant effects on soil bulk density in the furrows and soil moisture content on the ridges; and (4) FRNF increased aboveground and belowground biomass (maize, oilseed rape, potato, sweet potato and wheat) by 23% and 63%, respectively. Overall, these results highlighted the importance of FRNF in regulating soil erosion, physicochemical properties and biomasses in the purple soil region of China. The implementation of FRNF in this region could significantly improve the ecosystem services in agro-ecosystems.