Effect of tillage practices on net carbon flux and economic parameters from farmland on the Loess Plateau in China

It is important to evaluate the effect of tillage practices on carbon flow and economic parameters in order to better understand soil carbon sequestration and mitigation of carbon release into the atmosphere, and to increase income for farmers. A 2-year field experiment was conducted in a winter wheat-summer corn rotation system on dryland farmland on the Loess Plateau in Northwest China with four treatments; zero tillage with straw mulching (zero tillage), rotary tillage with straw incorporation (rotary tillage), chisel plow tillage with straw incorporation (chisel plow), and conventional mouldboard plow tillage without crop straw (conventional tillage). Results showed that zero tillage reduced carbon emissions, mainly through reduction of emissions from tillage practices, and served as a net carbon sink, as did rotary tillage and chisel plow, while conventional tillage served as a net carbon source. Specifically, zero tillage reduced carbon emissions from farm inputs by 168.8 and 75.0 kg C ha(-1) yr(-1) compared with conventional tillage and rotary tillage (or chisel plow), respectively. The difference in annual rate of carbon sequestration between 2013 and 2015 was 1.21-fold higher with zero tillage than with conventional tillage, suggesting zero tillage released less CO2 and was therefore better able to mitigate against global warming. Chisel plow significantly (P < 0.05) improved net return values by 10.7%-63.2% in the 2013-14 cropping year and by 12.8%-93.7% in the 2014-15 cropping year, respectively when compared to other tillage treatments. Zero tillage was the most effective method for reducing carbon inputs and increasing carbon sequestration, and chisel plow was the best option for provision of economic parameters on dryland farmland in this region. Therefore, the application of conservation (zero, rotary and chisel plow) tillage could be a C-smart and effective economic agricultural practice for winter wheat-summer corn ecosystems under rain fed condition. (C) 2016 Elsevier Ltd. All rights reserved.