Influence of Exchangeable Sodium on the Chemical Composition of Important Crops at Different Stages of Growth

Some common winter season (Rabi) crops, viz., wheat, barley, oats, pea. gram, lentil and rainy season (Kharif) crops like cotton, jowar, maize and paddy were grown on soils artificially alkalized to varying levels of exchangeable sodium ranging from 2 to 99 per cent. Plants were analysed after one and two months and at the stage of maturity for their cationic composition. It was observed that the total cationic uptake and the absorption of sodium increased with rise in the levels of ESP, whereas the uptake of calcium, magnesium and potassium generally exhibited a reverse trend. Values of the individual as well as the total cationic absorption, in general decreased with the progress of plant growth beyond one month stage. Interrelationship between different cations indicates that ratios of Ca/K and Na/K increase, whereas that of Ca/Na decreases with rise in the levels of ESP. Crops which had a narrower Ca/Na ratio under normal soil conditions were observed to be more tolerant to soil alkalinity than those which had a broader ratio, the cotton crop being an exception to this observation.