Relative Performance of Different Iron Carriers on Rice Growth and Nutrient Uptake in Calcareous Soils

In a pot culture experiment conducted to ascertain the effect of readily soluble and sparingly soluble iron carriers on rice growth and nutrient availability in calcareous soils (37.6% CaCO₃) lime induccd chlorosis was noted in early stage of plant growth. The dry-matter yield of rice decreased from 31.6 to 22.2 g/pot with increasing degree of calcareousness of soil. Pyrite and biotite were more effective in increasing the yield of rice than ferrous sulphate. The effect of iron sources on the uptake of Fe, Mn, Zn, Cu, Ca, P and K were significant. Fe/Mn and K/Ca ratios were increased whereas P/Fe ratio was decreased with increasing levels of CaCO₃ in soils.