Response of cauliflower to phosphate fertilizer placement and soil test phosphorus calibration on a Karrakatta sand

Abstract

Abstract The effect of placement (broadcast versus banded) and level of phosphorus (P) applied as superphosphate at 0 to 450 kg P/ha was measured using the yields of cauliflower (Brassica oleracea var botrytis) on newly cleared Karrakatta sands of low natural P fertility. While there was a significant (P<0.01) yield response to level of P, there was no significant response to fertilizer placement. Phosphorus recovery efficiency by curds (P uptake curds/P applied both in kg/ha) decreased from 0.35 at 20 to 0.09 at 320 kg applied P/ha. Phosphorus recovery efficiency by whole plants decreased from 0.58 at 20 kg P/ha to 0.18 at the highest level. Bicarbonate‐soluble P extracted from the top 15 cm of soil was determined on residual P sites from experiments over two years where P was applied from 0 to 450 kg P/ha. These soil test values were related to yield. The critical soil test values required for 95 and 99% of maximum yield were 40 and 55 (μg/g, respectively. The level of freshly‐applied P required for eit...