Abstract: More than half of wheat residues are burnt or discarded for years in China, which not only wastes organic fertilizer source, but also pollutes the environment. Meanwhile, heavy use of nitrogen fertilizer has become a serious problem in rice production, especially in Jiangsu province. The purposes of this study were to investigate the effects of wheat straw application and site-specific nitrogen management (SSNM) on the absorption and utilization of nitrogen (N), phosphorous (P), and potassium (K) in rice plants. A mid-season japonica rice cultivar of Yangjing 9538 was field-grown. Three treatments of farmers’ N-fertilizer practice (FFP), SSNM based on chlorophyll measurement (SPAD) readings, no nitrogen application, and with or without wheat residue application (the straw was incorporated to soil) were conducted. The results showed that wheat-residue incorporation re-duced N content and the accumulations of N, P, and K in plants at the early growth stage, increased P and K contents in plants during the whole growth period, and increased nitrogen use efficiency, harvest index, and biomass production efficiency of N, P, and K when compared with the straw removal treatment. Under the same amount of straw incorporation, SSNM reduced the amount of N and P absorption in plants, and increased transportation percentage of N, P, and K from heading to maturity and N and P harvest index. There was no significant difference in the amount of K absorption between SSNM and FFP. The results indi-cated that both wheat-residue application and SSNM can increase absorption and use efficiency of N, P, and K in rice plants.

Key words: Rice, Wheat residue incorporation, Site-specific nitrogen management, Phosphorous, Potassium, Use efficiency