普通尿素在施入土壤后虽然可以迅速溶解于溶液中,但被作物根系直接吸收的数量很少。尿素只有在土壤脲酶的作用下,水解成铵态氮后才可被大量吸收。一般农田土壤都有一些脲酶存在,尤其是那些含有机质多的高肥力土壤更是不缺少脲酶。所以普通尿素施入土壤后会较快转化成铵态氮供作物吸收利用。当然,温度高低和不同季节对土壤中尿素转化的速度影响是很大的。尿素一经水解成铵态氮后,如果作物尚处于苗期吸收氮很 Although ordinary urea can be quickly dissolved in the solution after being applied to the soil, it is rarely directly absorbed by the crop roots. Urea only in the role of soil urease, hydrolysis into ammonium nitrogen can be a large number of absorption. General farmland soil has some urease, especially those with high organic matter and more fertile soil is no shortage of urease. So ordinary urea into the soil will be quickly converted into ammonium nitrogen for crop absorption and utilization. Of course, the temperature and the different seasons have a great influence on the rate of urea conversion in the soil. Once the hydrolysis of urea into ammonium nitrogen, if the crop is still in the seedling stage to absorb nitrogen is very