|Title||Fijnheid en verdeeling van een als meststof toegediend natuurlijk fosfaat|
|Source||University. Promotor(en): J. Hudig. - Wageningen : Veenman - 113|
|Publication type||Dissertation, internally prepared|
|Keyword(s)||natuurfosfaat - fosfor - bodem - kunstmeststoffen - samenstelling - onderzoek - proeven - rock phosphate - phosphorus - soil - fertilizers - composition - research - trials|
|Categories||Soil Fertility / Fertilizers, Fertilizer Application|
|Abstract||This study was to examine whether grinding of an insoluble fertilizer to different degrees of fineness produced a limit below which further grinding did not accelerate solution of the particles. Such a limit was indeed found. Below 30 mmu* the distribution of the particles became very uneven because individual particles tended increasingly to stick together. Mixing fine particles with coarser ones could improve the situation, but the percentage of coarse particles should not be too high.
Grinding natural phosphates to colloidal fineness was useless, since the colloidal state was lost during drying of the product. The smaller particles tended to aggregate thus preventing uniform distribution throughout the soil.
The availability of P in natural phosphates improved with the physiologically acid reaction of N fertilizers such as NH 4 HCO 3 and NH 4 NO 3 . A first requirement for rapid absorption of P from natural phosphates was a low concentration of Ca 2+ .