Effects of different tillage practices on the carbon footprint of wheat and maize production in the Loess Plateau of China

Appropriate tillage practices reduce a crop's carbon footprint (CF) and mitigate climate change. However, little is known about the CF of winter wheat and spring maize production under different tillage practices in the Loess Plateau of China. To quantify the tillage differences and crop type differences in CF, a field experiment was established in 2007 in which the following six tillage practices were evaluated: plow tillage (PT), no-tillage (NT), subsoil tillage (ST), PT/NT rotation, NT/ST rotation and ST/PT rotation. The results showed PT had the positive CF value (488 kg CO2-eq ha(-1)), indicating a carbon source. However, NT, ST, ST/PT, PT/NT and NT/ST significantly decreased the CF (-628, -1382, -2328, -3038 and -3545 kg CO2-eq ha(-1)), demonstrating these tillage practices served as carbon sinks. The functional unit-scaled CFs (yield-scaled CF, cost-scaled CF, production value-scaled CF and net income-scaled CF) were similar to the trend of CF, which exhibited the following order: NT/ST > PT/NT > ST/PT > ST > NT > PT. The CF and functional unit-scaled CFs of winter wheat production were significantly higher than those of spring maize production. The CF and functional unit-scaled CFs decreased as planting year increased. In addition, increasing SOC storage and grain yield were benefit for decreasing CF. The results of this study showed NT/ST rotation produced the highest grain yield and SOC storage with the lowest CF and functional unit-scaled CFs and was thus determined to be the best tillage practice for balancing sustainable production with the environment in the Loess Plateau. (C) 2019 Elsevier Ltd. All rights reserved.