Ammonia emission of paddy was reduced by the combined action of soil and plants under long-term rice-based cropping system

Abstract Aims In order to reveal the influence of different cropping system on ammonia volatilization in paddy field and be helpful to the sustainable development of agricultural system. Methods Two long-term paddy-upland rotations, garlic-rice (GR) and wheat-rice (WR), were conducted to investigate the influence factors and difference of ammonia volatilization in paddy using in situ ventilation method in field and pot experiments. Results Although the soil nitrogen level was higher under GR, the loss amount of ammonia volatilization decreased by 13.9% compared with WR, which mainly attributed to the 28.9% and 12.4% reduction in spikelet-developing fertilizer and base fertilizer, respectively. Dry matter accumulation and rice yield under GR was 8.2% and 8.9% higher that under WR respectively, which leading to a 14.8% increase in nitrogen uptake by rice plants and 15.3%-24.7% decrease in the average ammonia volatilization rate of spikelet-developing fertilizer. Ammonia volatilization of base fertilizer was significant positively correlated with ammoniacal nitrogen concentration in paddy water. The soil C/N ratio increased by 4.2%-13.3% under GR, which increased the adsorption capacity of ammoniacal nitrogen and decreased the concentration of ammoniacal nitrogen in paddy water, leading to the average ammonia volatilization rate of base fertilizer under GR decreased by 12.0%-16.4%. Conclusion The increase of soil carbon and nitrogen content and C/N ratio reduced ammonia volatilization of base fertilizer, and meanwhile promoted plant growth, increased rice yield and nitrogen uptake, which in turn reduced ammonia volatilization of spikelet-developing fertilizer.