
TY  - JOUR
A1  - Helyar, KR 
A1  - Spencer, K 
T1  - Sodium bicarbonate soil test values and the phosphate buffering capacity of soils
JF  - Soil Research
JO  - Soil Res.
Y1  - 1977
VL  - 15
IS  - 3
SP  - 263
EP  - 273
KW  - 
UR  - https://doi.org/10.1071/SR9770263 
N2  - Fifty-one field experiments dealing with responses of subterranean and white clover pastures to applied phosphate at a range of soil phosphorus levels, were carried out. The level of sodium bicarbonate extractable phosphorus above which little or no response to applied phosphate occurs (critical level), increased from 22 to 48 pg phosphorus/g soil with increases in soil phosphate buffering capacity (at solution [P] of 0.3 pg phosphorus/ml) from 1 to 20 ml/g x 10-1. On the few highly buffered soils occurring outside this range critical levels up to 60 µg phosphorus/g soil were indicated. A preliminary estimate is made of the way yield/soil test functions vary with changes in soil phosphate buffering capacity. 
ER  -

