| Long-term experiments were conducted to study the effects of continuous plastic film mulching and controlled-release coated urea on paddy soil fertility properties and nutrition uptake of rice on different soils under non-flooding condition. The experiments started in 2001 and 2008 at Duntou Town of Jinhua city (Jin Qu basin) and in 2010 at Jingshan Town of Yuhang (plain region) in Zhejiang Province, China with one rice crop annually. The results were as follows:1. Compared with traditional flooding management (TF), rice at mature period absorbed more nitrogen by 3.0%, phosphorus by 5.8%, there's no difference in potassium uptake, the rice fertile panicle were significantly increased by 15.0% and the number of grain per ear, filled grain reduced by 5.7% and 3.2% respectively, there's no significant difference with grain yields under non-flooding plastic film mulching condition (PM) at the same amount of nitrogen. Compared with non-flooded and no plastic film mulching cultivation (UM) at mature period, rice uptook more nitrogen, phosphorus and potassium by 11.9%,8.4% and 5.6%, the rice fertile panicle, filled grain, filled grain rate and the grain yields were increased by 29.9%,7.2%,4.2% and 6.1%. Rice straw incorporation could promote the nutrient content in shoot of rice and grain yields. After continuous 10 years PM the grain yields in different years showed great differences for the growing environment changed. The results showed that the grain yields increased from 2001, and the highest one were in 2003, decreased from 2004 to 2006, but increased in 2007, and reduced in 2010, the UM were the worst one. Continuous non-flooded plastic film mulching influenced the soil chemical characteristics more obviously. Continuous PM regime decreased soil organic matter content. After ten years application, the soil organic matter content under straw returned or not in PM decreased by 23.7% and 27.6%, in TF by 12.1% and 16.1%, in UM by 8.3% and 9.7% compared with the harvest stage in 2001. The soil organic matter content in PM reduced by 5.6% and 2.2% in contrast with TF and UM. The PM increased soil available P and available K by 23.1% and 18.3% and decreased soil hydrolysis N by 10.4%. Compared with UM, the PM decreased the soil available P and available K by 6.6% and 6.4%, and soil hydrolysis N were almost not be affected. Rice straw returned increased the paddy soil organic matter content, hydrolysis N, available P and available K by 6.4%, 7.7%,8.5% and 87.1% than no straw returned. Therefore, rice straw returned was important to enhance paddy soil fertility under continuous PM regime.3. The nutrient release pace of controlled-released coated urea could coordinate with the law of crop needing. Compared with prilled urea (PU), polymer-coated urea (PCU) improved the rice fertile panicle, filled grain rate, grain yields and nitrogen use efficiencies. On average, the rice fertile panicle, filled grain and filled grain rate were increased by 4.9%,6.0% and 2.4% with PCU under TF and PM compared with PU after three years at Duntou town. Meanwhile, the grain yields, agronomic nitrogen use efficiencies and nitrogen use efficiencies were significantly improved by 7.5%,3.3% and 13.9%. Controlled-release coated urea were in certain release effects on rice paddy soil fertility degradation phenomenon caused by PM, and the effects of short-term test were not very apparent, so long-term tests are necessary. At Jingshan town the rice fertile panicle, filled grain, grain yields, agronomic nitrogen use efficiencies and nitrogen use efficiencies were notably increased by 24.8%, 17.9%,7.7%,3.1% and 22.8% under single basal application of sulfur-polyester resin-coated urea (SPCU) compared with prilled urea (PU). |
PDF Full Text Request