自制的脲甲醛肥为白色粉末状 ,难溶于水 ,含氮 41%～ 43 % ,不挥发 ,不吸湿。施入农田后 ,其养分主要靠微生物分解而慢慢地释放 ,是一种缓释性肥料。农艺要求脲甲醛肥中氮素养分的释放必须与稻、麦的需求相适应 ,故在实验室生产出缓释性能不同的 6种脲甲醛肥。通过两年稻、麦轮作田间试验 ,筛选出效果最好的脲甲醛 4号肥 ,每亩施用 40 .5kg脲甲醛肥与 38kg尿素相比较 ,肥料成本增加 36 .2元 ,增产稻、麦 94kg。粮食价格按 1.4元 /kg计算 ,则每亩增收 131.6元 ,投入产出比为 1∶3 .6 6 ,氮肥利用率提高 12 .2个百分点 Homemade urea formaldehyde fertilizer is white powder, insoluble in water, nitrogen 41% to 43%, non-volatile, non-hygroscopic. After applied to farmland, its nutrients mainly by microbial decomposition and slowly released, is a slow-release fertilizer. Agronomic requirements Urea formaldehyde fertilizer nitrogen nutrient release must be consistent with the needs of rice and wheat, so in the laboratory to produce sustained-release properties of 6 different kinds of urea formaldehyde fertilizer. Through two years of rice, wheat rotation field trials, the best urea-formaldehyde 4 fertilizer was screened, 40.5 kg per acre urea formaldehyde fertilizer compared with 38kg urea, fertilizer costs increased by 36.2 yuan, yield of rice, wheat 94kg . Grain prices at 1.4 yuan / kg basis, the increase of 131.6 yuan per mu, input-output ratio of 1: 3. 6 6, nitrogen use efficiency increased by 12.2 percentage points