The comparative plant availability of 32P myo‐inositol hexaphospha.te and KH2 32PO4 added to soils

Abstract

The comparative availability to Lolivm perenne of ³²P myo‐inositol hexaphosphate (IH³²P) and KH₂ ³²PO. added to soil could be determined unequivocally from the ³²P count of leaf material even when dry matter yields and total P content were not significantly different from the control.

IH³²P was equivalent to KH₂ ³²PO₄. in a soil with a low P retention at 200 p.p.m. P but not at 20 p.p.m. P. IH ³²P was totally unavailable in two soils with high P retention at 200 p.p.m. and 20 p.p.m. P, whereas uptake of KH₂ ³²PO₄. was observed in each instance.