INTEGRATIVE IMPACTS OF SOIL TILLAGE ON CROP YIELD, N USE EFFICIENCY AND GREENHOUSE GAS EMISSION IN WHEAT-CORN CROPPING SYSTEM

Abstract

Wheat-corn cropping system is one of the most important grain production systems in the world. However, the integrative impacts of soil tillage on crop yield, N use efficiency (NUE) and greenhouse gases (GHGS) emissions are not well documented in this system. Thus, a twoyear field experiment was carried out in a typical wheat-corn cropping system with four tillage regimes during the wheat season, including no-tillage (NT), rotary tillage (RT), sub-soiling tillage (ST) and sub-soiling with rotary tillage (SRT) in a randomized block design with three replicates. No-tillage was conducted for all treatments during corn season. Over the two years, the highest yields of wheat, corn and annual were found in the SRT treatment, while the lowest annual yield was found in the NT treatment averagely. Two-year average annual yield in the SRT was 19643.9 kg ha -1 , which was 4.8, 5.9 and 7.7% higher than that in the ST, RT and NT treatments, respectively (P<0.05). SRT also stimulated plant N uptake with a higher N harvest index and higher partial factor productivity (PFP) than those under the other tillage practices (P<0.05). Although SRT stimulated N2O emission in wheat season, it significantly reduced the emission in corn season compared with the NT (P<0.05). Thus, no significant differences in total GHGS emissions, area-scaled and yield-scaled global warming potential (GWP) were found among the tillage practices. Our results indicate that sub-soiling with rotary tillage might benefit crop production for high yield and N use efficiency with less GHGS emissions for wheat-corn cropping system in North China Plain.