55 / 2016-01-27 17:24:13

Slow-release fertilizer: a good choice to reduce paddy runoff phosphorus in plateau lake area

Erhai watershed, paddy, phosphorus, runoff, slow-release fertilizer, rice grain yield

Rice is the main cereal crop in the Erhai watershed located in southwest China. Rapid population growth and a continuous decline in areas available for cultivation has resulted in an almost 3-fold increase in chemical fertilizer use compared to 20 years ago. Agricultural non-point pollution became the main source of water quality deterioration in the area, which contributing 92.5% of the total phosphorus pollution to Erhai. We investigated the effects of applying slow-release fertilizer, while various other fertilizer (no fertilizer, chemical fertilizer, mixtures of organic and inorganic fertilizers) to paddy fields on phosphorus pollution in runoff in Erhai watershed. The objective was to identify an environmentally friendly fertilizer that resulted in both higher rice grain yields and reduced nutrient pollution. Applying the slow-release fertilizer resulted in the highest rice grain yield (p < 0.05) copared with other methods, while rice plants that received no fertilizer had the lowest grain yield. Compared to conventional fertilizer treatment, application of slow-release fertilizer resulted in 53.77%, 42.17%, and 63.26% lower concentrations of total phosphorus, dissolved phosphorus, and particulate phosphorus, respectively, in the runoff (p < 0.05). Application of slow-release fertilizer treatment also reduced loss of total phosphorus, dissolved phosphorus, and particulate phosphorus into the runoff by 55.86%, 43.89%, 65.43%, respectively. Thus, we found that slow-release fertilizer treatment promoted higher rice grain yields while reducing non-point source pollution in paddy fields. Slow-release fertilizer should be recommended in Erhai watershed and other lake zones on the plateau with similar characteristics.