26 / 2021-06-26 12:59:44

Annual low-rate biochar application tends to surpass high single model in rice yield promotion after 5 years

Biochar; Rice yield; Carbon; recycle; application strategy

Biochar has been widely reported to increasing rice yield effectively. Whereas, the popular high single biochar model was doubtful in increasing rice yield for a long term. Hence, this study explored rice production promotion effect of annual low-rate biochar application strategy (AL, 8 ✕ 35% = 2.8 t ha^-1) in a 6 years field experiment. A comparation was made by the same amount material of rice straw (8 t ha^-1) and high single biochar application model (HS, 22.5 t ha^-1). Results showed that RS showed the best rice production promotion effect, considering the material cost. AL also increased rice yield significantly (p < 0.05) during experimental years. HS significantly increased rice yield in the first and the last 2 years and with higher promotion in the last year significantly (p < 0.05) compared with HS. The relatively higher rice yield in AL compared with HS resulted from higher soil total carbon, pH and Ca in AL. The higher total carbon content in AL mainly resulted from the higher recalcitrant carbon compared with that in HS. For the consideration of carbon sequestration and methane mitigation, annual low-rate biochar amendment was proposed to be an optimal strategy for rice production promotion prolonged effectively, stably and sustainably.