关键词: 菊花, 菊花, 干物质, 有效积温, 转捩点

Abstract:

Abstract: Yields of leafy vegetables tend to increase with temperature decreasing under high-intensity successive plantation in winter in Pearl River Delta Area. Under the condition of four successive plantation of leafy vegetables with the same amount of phosphorus and potassium, Urea, ammonium bicarbonate and their combined application with organic fertilizer experiment indicated that growth and yields of leafy vegetables in the urea treatment was better than those in ammonium bicarbonate treatment, but the difference declined with temperature decreasing. Little difference was obtained between treatments of Urea and ammonium bicarbonate combined application with organic fertilizer respectively. The nitrate content of leafy vegetables was affected by the difference in variety, temperature and fertilization, and Urea, ammonium bicarbonate combined application with organic fertilizer tended to reduce the nitrate contents. In addition, under continuous leafy vegetables cropping, combining application of organic and inorganic fertilizer could improve soil fertility.