Assessing the Meteorological Risks and Environmental Effects of Policy Stimulated Soybean Cultivation in Northeast China

In the past decade, China imported massive quantities of soybean from the international market to meet its increasing domestic demand for protein. However, China's soybean imports from US decreased from 32.86 Mt (Million tons, 34% of the total 95.54 Mt) in 2017 to 16.64 Mt (19% of the total 88.03 Mt) in 2018 due to the China-US trade war. To reduce China's reliance on imports, the Chinese government has been making policy incentive, e.g. higher subsidies, to encourage farmers for soybean cultivation. Traditionally Northeast China is the key production area for soybean.

Soybean cultivation is tightly linked to the regional climate and environment. On the one hand, the local soybean growth is vulnerable to the frequent meteorological hazards (e.g. droughts, floods) in the Northeast China. The meteorological risks for soybean production in this area still remain unknown. On the other hand, albeit with relatively high production cost and low water use efficiency, the local soybean cultivation is expected to effectively improve the nitrogen use efficiency and therefore alleviate the growing environment pollutions in this region. Yet so far there are few quantitative research being reported on this environmental issue.

Our research aims to explore both the meteorological risks and environmental costs of the policy-driven soybean expansion. We have developed a new version of the soybean growth algorithms within the DNDC (DeNitrification-DeComposition) model including nitrogen biogeochemical processes and performed regional simulations for soybean-related cropping systems in Northeast China. We will present the following results by combining model outputs and observations: (i) potential yield and the meteorological risks of soybean cultivation; (ii) fertilizer reduction in different crop rotation systems and the corresponding benefits to water ecosystem; and (iii) consequences of different policy scenarios (e.g. change in subsidy, GMO permission) to soybean production and environment.