Factors contributing to the superior post-heading nutrient uptake by no-tillage rice

No-tillage (NT) is expected to be an alternative practice for rice production in China since it has potential benefits including labor saving and soil conservation. NT can lead to superior post-heading nutrient uptake and consequently increased post-heading biomass production in rice, but limited information is available on the factors contributing to the superior post-heading nutrient uptake. In this study, post-heading nutrient uptake and related soil and root characteristics were compared between NT and conventional tillage (CT) rice in field experiments in Changsha, Hunan Province of China in 2013 and 2014 and Nanning, Guangxi Province of China in 2014. Results showed that post-heading N, P and K uptake were 28–49% higher under NT than under CT. NT had 10–18% higher available N, P and K contents and 5–9% higher root distribution percentage at 0–5 cm soil depth and consequently 11–16% higher rhizophere soil available N, P and K contents than CT. There was no significant difference in rhizophere soil pH between NT and CT. NT had equal root biomass, length and surface but 37–49% higher root oxidation activity compared to CT. These results suggest that improvement in nutrient supply and root physiology are responsible for the superior post-heading nutrient uptake by NT rice.