Crop Response to Calcium Metaphosphate on Alkaline Soils¹

Hydrolysis and availability to plants of polyphosphates added to soils

“…The CMP compound was a mixture of undefined cyclic and chain polyphosphates. Results from a number of studies indicated that it is less available to plants on alka line soils than concentrated superphosphate (CSP), and nearly equal to CSP in neutral and acid soils (Tisdale and Winters, 1953;Terman and Seatz, 1955;Allamaras and Black, 1952).…”

Sorption of orthophosphate and nonorthophosphate phosphorus by soils

“…Generally, crop response to this material on acid and neutral soils have been comparable to those obtained from the use of ordinary superphosphate or p from concentrated superphosphate where sulfur is not limiting (Rogers, Pearson, and Ensminger, 1953). On alkaline soils, however, calcium metaphosphate frequently is less effective than superphosphate (Tisdale and Winters, 1953). Potassium and ammonium metaphosphates have been subjected to the same tests, but the scope of the tests is probably not sufficient to make such generalised conclusions.…”

Comparative value of calcium metaphosphate and superphosphate for plant growth on different soils

“…The evidence is as follows. Rather strong evidence is uniformly noted (Terman and Seatz, 1956;Tisdale andWinters, 1953» Pesek, 1955) that the effectiveness of CMP relative to CSP decreases as the particle size of CMP is increased.…”