The invention discloses a blended controlled-release
fertilizer for
flue-cured tobacco in southwest Hubei province. The blended controlled-release
fertilizer is composed of a coated
nitrogen-potassiumcompound
fertilizer with a controlled-release period of 50-70 days,
coated urea with a controlled-release period of 30 days, a quick-acting
ternary compound fertilizer, granular diammonium phosphateand granular
potassium sulfate in a
mass ratio of (14-28): (2.3-5.5): (33.5-41): (8-10): (23-33.5). The coated
nitrogen-
potassium compound fertilizer with the
controlled release period of 50-70 days is prepared by the following steps: mixing
urea,
potassium chloride and stone
powder in a
mass ratio of (28-32): (58-62): (8-12) to form a
raw material mixture,
water vapor is introduced, and the mixture is granulated, and then is coated with
polyurethane. The compound fertilizer with different release periods provided by the invention can ensure sufficient supply of nutritional ingredients of tobaccos in the early stage, the middle stage and the later stage, the quality of the tobaccos is improved, and the labor output of later topdressing is reduced; and through reasonable matching of the
nutrient elements and control of the release period, unnecessary loss of the
nutrient elements is reduced, the
utilization rate of the fertilizer is increased, environmental
pollution is reduced, and theproduction cost is reduced.