Effect of combined coated control-released fertilizer on winter wheat growth and soil available nutrient

Controlreleased fertilizer(CRF) improves fertilizer use efficiency, and reduces application time and environmental pollution. The effect of coated controlreleased fertilizer combined with weather coal on wheat yield, leaf net photosynthesis(Pn), plant nutrient and soil available nutrient was investigated. Three controlreleased fertilizers(MCRF, RCRF and WCRF), respectively coated with three releasecontrolling materials(modified starch, resin and water glass) combined with weather coal were established. The treatments are CK(no fertilizer), NPK fertilizers(NPK), CF(NPK combined fertilizer), CCRF(CF is only coated with weathered coal), MCRF, RCRF and WCRF. Results show that combined CRFs application increases leaf Pn during middle and late growth stages, increases filling rate, prolongs filling time, and increases 1000kernel weight, per spike grain, grain yield and protein content; decreases spike number compared with CK, NPK, CF and CCRF. Yield of combined CRFs increases 8.93%～16.05% and 5.34% ～ 12.23% over NPK and CF treatments respectively. Soil alkalized N, rapidly available P and K contents are low at early and middle growth stages and high at late stage with application of combined CRFs, which promotes accumulation and translocation of dry weight. Also plant dry weight, total N and K contents increase notably. WCRF has the most beneficial effect of increased grain yield, leaf Pn at middle and late growth stages, and plant dry weight, plant total N and K contents. Moreover, fertilizer release rate of combined CRFs is more in line with fertilizer need of winter wheat than that of conventional fertilizer.