The invention relates to the field of fertilizers for crops and particularly relates to a preparation process for a
urea formaldehyde slow-release and controlled-release compound
fertilizer. The preparation process is characterized by comprising the following steps of: (1) adding 430kg of
urea into a reaction kettle, adding water with the weight equal to 1.5-4 times of
mass of the
urea and stirring to dissolve the urea, regulating the pH to be 8-9 by utilizing
borax and
potassium hydroxide, and carrying out stirring reaction for about 1 hour at 75-80 DEG C; (2) adding oxidized
starch with the weight equal to 8-10% of that of the urea, stirring for 15-20 minutes, and regulating the pH to be neutral by utilizing
calcium oxide, so as to prepare a
urea formaldehyde slow-
release agent; and (3) weighing
solid materials which are crushed to be 80 meshes according to the weight ratio of
nitrogen to
phosphorus to
potassium to middle-trace elements being 4:1:2:1, putting the
solid materials into a stirring
machine to be uniformly stirred, putting the uniformly stirred materials into a pelletizer, and spraying the
urea formaldehyde slow-
release agent to carry out pelleting. With the adoption of the technical scheme, the novel slow-release and controlled-release compound
fertilizer has the advantages that not only can the
utilization rate of the
fertilizer be improved, the food security can be guaranteed, and the environmental
pollution can be alleviated; lifetime requirements of crops can be met after the fertilizer is applied once, the labor intensity of famers can be greatly alleviated, and the production inputs can be decreased.