Effects of particle sizes on segregation, chemical and physical properties of bulk blending fertilizers and their agronomic effectiveness under field conditions
1992
Prasert Soodmai
Bulk blending (BB) fertilizer grade 25-32-0 resulted from mixing of granulated urea with diammonium phosphate, granular sizes range between -6 + 8 to -10 + 14 mesh were let to move vertically in a hopper. Found that BB fertilizers prepared by blending of the matched size materials did not segregate in the process. The segregation of the blended fertilizers caused by the greater amount of finer particles rapidly pass through the coned hopper in the initial phase which result in the accumulation of coarser particles on the upper part of the pile in the later stage. The blended fertilizers having granule sized in a range of -6 + 8 to -10 + 14 mesh did not show segregation after being subjected to a truck transport over a distance of 100 kilometers. Bulk blending fertilizers of 16-20-0 grade prepared by using ammonium sulfate and diammonium phosphate could be kept more than six months without showing sign of excessive moisture accumalation. Prolonged storage under burden pressure could lead to caking. Fertilizer of 25-32-0 grade prepared by bulk blending of granulated urea and diammonium phosphate showed sign of moisture increase after one month storage. Fertillizers could also show off - standard moisture content if the plastic bags used for their storage were not sufficiently moisture resisted. The agronomic effectiveness trials with rice and maize grown on Rangsit and Lopburi soils. Poorly mixed BB fertilizer, good BB fertilizer, and compound fertilizer showed no significant difference in rice and maize yields. Incorporated into the soil with the application of diammonium phosphate (18-46-0) as basal treatment and top dressing with urea to rice gave atendency of higher yields than that of the compounds and the BB fertilizers. Economic aspect, BB fertilizers and using the straight fertilizers as basal and topdresing should have more advendtage over the compound fertilizers.
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