六、施用尿素后,不宜马上灌大水 试验和研究表明,尿素溶解后的尿素分子,土壤胶体微粒很难吸收保存,大量存在于土壤溶液之中,遇到大雨或灌大水,尿素淋失严重。其淋失程度并不亚于硝酸铵。但是,当它在土壤中转化为碳酸铵以后,胶体便可吸收,很少遇到淋失。所以,施入尿素后,应在其转化完毕后方可灌水。这种施肥技术要求,对水稻田基施尿素特别重要。一般来讲, Sixth, after the application of urea, should not immediately flood irrigation test and research shows that urea dissolved urea molecules, soil colloidal particles is difficult to absorb and save a large number of soil solution in the event of heavy rain or flood irrigation, urea leaching serious. The leaching degree is no less than ammonium nitrate. However, when it is converted to ammonium carbonate in the soil, the colloid absorbs and rarely leaches. Therefore, the application of urea, it should be completed after the conversion of irrigation. This fertilization technology requirements, rice paddy based urea is particularly important. usually,