Effect of straw biochar application on soil carbon, greenhouse gas emissions and nitrogen leaching: A vegetable crop rotation field experiment
Jining Zhang, Huifeng Sun, Jia Ma, Xianxian Zhang, Cong Wang, Sheng Zhou
Abstract
Abstract Intensive vegetable crop systems are rapidly developing, with consequences for greenhouse gas (GHGs) emissions, nitrogen leaching and soil carbon. We undertook a field trial to explore the effect of biochar application (0, 10, 20 and 40 t ha −1 ) on these factors in lettuce, water spinach and ice plant rotation. Our results show that the 20 and 40 t ha −1 soil treatments resulted in the SOC content being 26.3% and 29.8% higher than the control (0 t ha −1 ), respectively, with significant differences among all treatments ( p < .05). Biochar application caused N 2 O emissions to decrease during the lettuce and water spinach seasons, by 1.5%–33.6% and 12.4%–40.5%, respectively, compared the control, with the 20 t ha −1 application rate resulting in the lowest N 2 O emissions. Biochar also decreased the dissolved nitrogen (DN) concentration in leachate by 9.8%–36.2%, following a 7.3%–19.9% reduction in dissolved nitrogen in the soil. Similarly, biochar decreased the nitrate (NO 3 − ) concentrations in leachate by 3.9%–30.2%, following a 3.8%–16.7% reduction in the soil nitrate level. Overall, straw biochar applied at rate of 20 t ha −1 produced the lowest N 2 O emissions and N leaching, while, increasing soil carbon.