Strategic tillage effects on soil properties and agricultural productivity in the paddies of Southern China

Strategic tillage (ST) has been proposed to maintain the benefits and alleviate the negative effects of long-term no-till (NT) management. In this study, the effects of ST on soil properties and yield loss were evaluated for a double-cropped rice (Oryza sativa L.) paddy from 2006 to 2017 in Southern China. Three tillage systems were investigated: long-term NT, continuous rotary tillage (RT), and ST. The results showed that ST effectively solved the problem of long-term NT management: low and unstable bulk density in the soil surface layer. Compared with NT, ST significantly increased the available P (AP) concentration, available K (AK) concentration, the AP storage by 16.55% and the AK storage by 21.37% in the upper 20cm soil. Moreover, the soil pH for NT and ST was lower than RT. ST increased the acidification risk in the 0-5 cm soil layer (pH was 4.84 in 2017) but significantly reduced the risk of yield loss compared to continuous NT. The average yield gap between ST and NT ranged from 408.21kgha(-1) (during 2006-2009) to 1,144.85kgha(-1) (during 2014-2017). ST reduced soil organic carbon (SOC) and total nitrogen (TN) concentration compared to NT in the 0-5 cm soil layer. However, it did not affect SOC and TN storage, although light fraction organic carbon (LOC) storage for ST was 36.59% lower than that for NT. ST is a promising option for promoting and maintaining the sustainability of rice production in Southern China.