The effect of corn straw return on corn production in Northeast China: An integrated regional evaluation with meta-analysis and system dynamics

Northeast China (NEC) is the corn granary of China, with average 38% of corn sowing area, 41% of corn production and over 80% corn commodity rate, which makes a great contribution to China's food security. Straw return is the primary way for disposal after harvesting. However, it is controversial in the effect of corn straw return on corn yield, the optimal amount of corn straw return is still unclear. Furthermore, NEC farmers are unwilling to adopt, so these issues require comprehensive regional evaluation. To begin with, this paper studied effects of corn straw return on corn yield increase with meta-analysis. The results illustrated that corn straw return has positive effect on corn yield increase. Secondly, in order to find optimal proportions, n-fold cross-validation method was implemented, and an inventory of corn straw return on corn yield in NEC was compiled. The optimal scheme of corn straw return is 48% of corn straw could bring 5.83% corn yield increase. Finally, results from system dynamics with Monte Carlo (MC) simulation revealed that such production increase potential (around 6.1 million tons of corn) was being blocked by the unaffordable cost for farmers under ordinary scenario. Interestingly, this paper contrived an extreme scenario that corn straw return could be profitable. The flexible adjustment of subsidy could become the motivation for measurement adaptation. This paper concludes that, corn straw return is a sustainable safeguard that can promote corn production in NEC, thus to China's food security in the long run.