Effects of Long-Term Application of Different Fertilizer Patterns on Rice Paddy Soil Phosphorus and Rice Phosphorus Nutrition

16-year experiment was conducted for revealing the long-term impact mechanism of fertilization on soil fertility and crop nutrition.Five treatments including blank(CK),organic nutrient recycling without NPK fertilizer application(C),NPK fertilizer application(NPK),organic nutrient recycling combined with NPK fertilizer application(NPK+C)and reducing fertilizer application(F+1/2C)were selected,and soil phosphorus fertility indicators and rice plant phosphorus content were measured.The results showed that long-term application of different fertilizer patterns changed the phosphorus fertility characteristics in 0–20 cm soil and rice phosphorus nutrition significantly,while did not vary the phosphorus fertility in 20–40 cm soil remarkably.Compared with blank,NPK fertilizer application increased Olsen-P and total phosphorus content in 0–20 cm soil by 108.8%and 31.9%respectively,meanwhile,the phosphorus contents in rice plant and grains of the two treatments had significant difference in all growth periods.In contrast with NPK fertilizer application,organic nutrient recycling combined with NPK fertilizer application increased Olsen-P and total phosphorus content in 0–20 cm soil by 84.3%and 19.4%respectively,meanwhile,the soil phos-phorus activation coefficient achieved 2.96,indicating that the phosphorus content of these two treatments in plant(except grains)had significant difference in all growth periods.There was no significant difference between treatments of organic nutrient recycling alone and blank on soil fertility indicators and the phosphorus contents in plant and grains in all growth period.And also, there was no obvious difference between treatments of reducing fertilizer application and NPK fertilizer application on soil fertilizer characteristics and phosphorus contents of plant and grains.Compared with NPK fertilizer application,reducing fertilizer application decreased rice plant phosphorus content slightly.Organic nutrient recycling combined with NPK fertilizer application improved soil phosphorus fertility characteristics prominently,raised soil phosphorus activation degree,and promoted the absorption of phosphorus in rice.