Study on the Fertilization Effect of Nitrogen, Phosphorus and Potassium in Post-tobacco Rice and the Fertilizer Utilization Efficiency in Yongding District

In order to clarify the fertilization effect of nitrogen, phosphorus and potassium and the fertilizer utilization rate of post-tobacco rice variety in Yongding District, the field experiment was carried out in Qingxi Village of Kanshi Town and Daxi Village of Daxi Town combined with the soil testing fertilization ″3414″ test. The results showed that when 150 kg·hm^-2 N, 43.5 kg·hm^-2 P₂O₅ and 100.5 kg·hm^-2 K₂O were applied in the whole fertilizer area, the overall economic characters of post-tobacco rice was the best, and the yields of paddy rice and straw were the highest. The yield of paddy rice increased by 11.1%, 9.4% and 4.6%, respectively, compared with that in the areas with nitrogen deficiency, phosphorus deficiency and potassium deficiency. The contribution rates of nitrogen, phosphorus and potassium fertilizers were 10.0%, 8.6% and 4.4%, respectively. The fertilizer application correspondingly increased the contents of nitrogen, phosphorus and potassium in paddy rice and straw, which were respectively increased by 10.5%, 4.7% and 1.1% in paddy rice and 44.4%, 0.8% and 2.4% in straw in the whole fertilizer area. The single-cropping utilization rates of nitrogen, phosphorus and potassium were 25.9%, 16.7% and 50.5%, respectively. The above results showed that the post-tobacco rice in Yongding District was the most sensitive to nitrogen fertilizer, with the largest contribution rate of applying nitrogen fertilizer to the yield, while was the least sensitive to potassium fertilizer. Therefore, the application rate of potassium fertilizer in the post-tobacco rice should be appropriately reduced and the application ratio of nitrogen, phosphorus and potassium should be further optimized.