A New Soil Testing Programme for the Evaluation of Intensity and Quantity Factors of Iron

Deficiency of Fe in rice mainly occurs under upland condition, particularly in alkaline and calcareous soils. The plants respond directly to changes in the activities of ions in the soil solution. Baker soil test (BST) is a new approach to soil testing which not simply determine the concentrate bioavailability but also provides the activity of an ion. A greenhouse experiment was conducted with special reference to iron for relating the data with content of efficient and inefficient cultivars of aerobically grown rice for iron availability. Alkaline, calcareous, acid and lime-treated soils could be rated as normal in respect of labile Fe status. Intensity parameter of Fe (pFe) for alkaline and calcareous was rated to be low, while it was normal for other two soils. Comparison of pFe values of Fe(III) in different soils with plant Fe content reveals the positive impact of intensity parameter of Fe(III) in soil is reflected well in plant Fe content data in both the rice cultivars. Similar were the relationships of intensity parameter of Fe with grain and straw yield of rice. BST, particularly intensity parameter of Fe, can be a good index of availability of Fe in soils.