Effects of slow-release compound fertilizer and mulched dry-farming on nitrogen use efficiency and quality of rice

Rice dry-farming and applying slow-release or controlled-release compound fertilizer could not only improve the use efficiency of water and fertilizer but also abate the environmental pollution. Under the condition of applying the same inorganic slow-release compound fertilizer (ISF), a field experiment was conducted in cold and rotten flooded paddy field to investigate the effects of three different paddy surface managements, i.e. conventional flooding(CF), dryland covered with plastic film(DF) and dryland covered with straw(DS) on the growth characteristics and yield of rice, nitrogen forms in leaf, fertilizer-N use efficiency, contents of amino acid and protein in rice. Results indicated that the rice agronomic characteristics (plant height, tillering capacity, straw weight, number of spike and grain weight) of DF were the best. Compared with the rice yields of CF and DS, the rice yield of DF was increased by 39.1% and 41.4%, respectively. At tillering stage of rice, the contents of amino acid, protein nitrogen and total nitrogen in rice leaf were in the order of DF＞DS＞CF. However, at tillering and booting stages, the contents of NO^{-₃-N for DF and DS were about twice as many as that of CF. The apparent recovery rate and agronomic efficiency and physiological efficiency of nitrogen for rice were in the order of DF＞CF＞DS. It was indicated clearly that the nitrogen nutrition in rice leaf at tillering stage affected the contents of amino acids and protein in rice and dryland covered with plastic film could improve the quality of rice.}