[Effect of Phosphorus Addition on NO Emissions from Rice-Rapeseed Rotation Soils].

The red soils in southern China are generally classified as phosphorus-deficient, and therefore planting crops in these regions usually requires high applications of phosphate fertilizer. However, the effect of phosphorus addition on NO emissions in rice-rapeseed rotation soils is not clear. We carried out an incubation experiment with the rice-rapeseed rotation soil from Qianjiang and Xianning to explore the effect of different concentrations of phosphorus (0, 15, and 30 mg·kg) and different concentrations of nitrogen (0 and 100 mg·kg) on NO emission. Studies have shown that the addition of phosphorus has a significant effect on soil NO emissions, but the pathways of impact are varied:in the case of low nitrogen soil, the addition of phosphorus promotes the fixation of nitrogen in the soil by microorganisms and thus reduces NO emissions; in case of sufficient nitrogen content in soil, adding less phosphorus promotes the activity of nitrifies and thereby promotes the emission of NO, while adding more phosphorus also promotes fixation by microorganisms in the soil; when there is a high content of available phosphorus in the soil, whether the nitrogen is sufficient or not, the addition of phosphorus will inhibit the emission of NO.