Effect of weathered coal-based coated fertilizer on winter wheat growth and soil enzyme activity

Controlled-release fertilizer (CRF) has emerged as a potential approach to solving the problems associated with the application of conventional fertilizers. It can improve fertilizer use efficiency, reduce application times and environment pollution. Three controlled-release fertilizers coated with three controlled-release materials, modified starch, resin and water glass, combined with weathered coal were called as MCRF, RCRF, and WCRF, respectively. The treatments were, no fertilizer (CK), NPK fertilizers (NPK), MCRF1, RCRF1, WCRF1 (which used equivalent NPK rate to NPK treatment), MCRF2, RCRF2, WCRF2, (which used 80% NPK rate to NPK treatment). Effects of weathered coal-based coated fertilizer on wheat yield, leaf net photosynthesis (Pn), plant dry weight, plant nutrient content, soil available nutrients and soil enzyme activity were studied. Results showed that，CRF application improved yield components, and so yield was increased compared with CK and NPK treatments. Compared with NPK treatment, CRF decreased spike numbers per hectare, but increased 1000-kernel weight and grains per spike. Yield of CRF1 (included MCRF1, RCRF1, WCRF1) were increased 6.69%–16.92% over NPK treatment. CRF increased leaf Pn in middle and later stage of wheat, plant dry weight and nutrient contents, and increased grain protein content over NPK treatment. WCRF increased soil enzymes activity, soil nutrient contents, leaf Pn in middle and late growth stage, plant dry weight, plant nutrient contents, and wheat yield. Its nutrient release was more synchronized with nutrient need than other treatments.