Efficiency of various phosphate fertilizers on calcareous soil for alfalfa and sweet clover
1942
Hinkle, D.A.
Results of field tests comparing treble superphosphate, 20% superphosphate. Ammo-Phos (11-48-0), TVA triple superphosphate, and TVA metaphosphate as sources of phosphorus for alfalfa grown on Gila clay, an alkaline calcareous soil occurring in the irrigated valleys of the Southwest, showed that there was no significant difference in the yields from plots receiving treble superphosphate, TVA triple superphosphate, Ammo-Phoc 11-48-0, and 20% superphosphate. However, the Ammo-Phos 11-48-0 did yield significantly more hay than calcium metaphosphate. Fertilization with phosphates significantly increased the phosphorus content of the hay in all cases, the fertilized hay containing on an average about one-third more phosphorus than the unfertilized hay. In a greenhouse experiment using the same soil type, annual yellow clover failed to produce as much drv weight or to absorb as much phosphorus from calcium metaphosphate as it did from Ammo-Phos (11-48-0) or treble superphosphate. Application of nitrogen as ammonium sulfate slightly increased the absorption of phosphorus from superphosphate by clover in spite of the fact that the roots were inoculated.
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