Department of Soils, Punjab Agricultural University, Ludhiana, Punjab, 141004.
The Pi soil test uses strips of hardened filter paper impregnated with iron oxide to measure plant available P. In a greenhouse study, estimates of available P by different extractants were correlated with dry matter yield and P uptake by wheat. Among all the extractants, strip embedding P had the highest correlation coefficient with dry matter yield, P uptake, Bray's per cent yield and Bray's per cent P uptake, followed by strip shaking P and Olsen P in control pots. Other methods gave significant but lower values of correlation coefficients. Also in the soils supplied with various P levels, the strip embedding P before sowing of wheat gave the highest coefficient of correlation with dry matter yield, and P. uptake.
Pi soil test, critical P level, iron oxide impregnated filter paper, strip shaking, strip embedding
