Effect of Phosphate Source, Lime, and Time of Phosphate Application on Absorption of Applied Phosphorus by Plants

Chin, N. L.; Ray, H. E.; Caldwell, A. C.; Hustrulid, A.

Effect of Phosphate Source, Lime, and Time of Phosphate Application on Absorption of Applied Phosphorus by Plants

1959

Chin, N. L. | Ray, H. E. | Caldwell, A. C. | Hustrulid, A.

Effects of P source, rate of liming, and time of contact between fertilizer and soil on the availability and uptake by plants of phosphatic fertilizers applied to several Minnesota soils have been studied in greenhouse experiments. Monocalcium phosphate resulted in significantly higher yields and lower P contents of wheat than dicalcium phosphate, and was more available to both wheat and alfalfa. Alfalfa yields generally increased with an increase in the rate of liming. Liming had no apparent effect on the total P content of wheat or alfalfa, but the uptake by alfalfa of P from applied monocalcium phosphate was increased by the 4-ton per acre rate of lime application. With both phosphate sources, alfalfa yields were highest on the alkaline soils, and lowest on an acid soil. Time of phosphate application had no consistent effect on growth rate or dry matter production of oats, although yield responses to phosphate fertilization were obtained on four soils. Phosphorus content of oats was generally increased when fertilizer was applied ahead of the planting date. Availability of applied phosphate tended to decrease on two high pH soils when fertilizer was applied 20 days or more ahead of planting.

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