Influence of Moisture Regimes on the Transformation of Recently Appplied Phosphate in Soil and its Availability to Rice Crop

Experiments were conducted to study the influence of three soil moisture regimes, viz., (i) continuous submerged, (ii) continuous saturated, and (iii) alternate submerged-saturated on the transformation of recently applied water soluble phosphate in two alluvial rice soils of West Bengal. The results showed that continuously saturated moisture condition could maintain a higher amount of applied P in the saloid-bound and Bray's available form as compared to the other two moisture conditions. The continuously saturated moisture condition also caused higher transformation of applied phosphate into Al-P, whereas transformation into Fe-P was less under this moisture condition. Transformation into Ca-P was practically negligible in both the soils, and as such no effect of moisture regimes could be observed. The results of the pot-culture experiment showed that the increase in dry matter yield, the increase in P concentration in the plant material and the increase in P uptake due to phosphate application over no phosphorus control were highest under continuously saturated moisture condition.