追肥是在作物生长期施用的肥料,目的是满足作物生育期间对养分的需求,一般多施用速效性化肥。腐熟良好的有机肥料、化学性质稳定的氮肥可用作追肥。作物明显表现缺磷时,可追施过磷酸钙补救。为了充分发挥追肥的增产作用,应做到: 深施覆土:为了保证作物及时吸收所需要的养分,减少肥分损失,追肥一般应深施在根系密集层附近。磷肥在土壤中移动性小,更应注意施用深度。施用化学性质不稳定的氮肥(如碳酸氢铵)或化学性质稳定的氮肥(如硫酸铵或尿素)均应深施覆土,以免造成挥发损失,降低肥效。据测定,碳酸氢铵深施6 Top dressing is a fertilizer that is applied during the crop growth period to meet the nutrient requirements during crop growth and is generally applied more than the quick-acting fertilizer. Well-matured organic fertilizer, chemically stable nitrogen can be used as top dressing. Phosphorus deficiency can be apparent when the crop phosphorus deficiency can be traced overshoot. In order to give full play to the role of fertilizer to increase production, should be done: deep soil cover: In order to ensure timely absorption of crops needed nutrients, reduce fertilizer loss, top dressing should generally be applied in the vicinity of the root system. Phosphate fertilizer mobility in the soil is small, but should pay attention to the depth of application. Application of chemically unstable nitrogen (such as ammonium bicarbonate) or chemically stable nitrogen (such as ammonium sulfate or urea) should be deep soil cover, so as to avoid volatile loss and reduce fertilizer efficiency. According to the determination of ammonium bicarbonate deep facilities 6