VARIOUS RATES OF K AND Na INFLUENCE GROWTH, SEED COTTON YIELD AND IONIC RATIO OF TWO COTTON VARIETIES IN SOIL CULTURE

Cotton is generally grown on alkaline calcareous soils in arid and semi-arid areas of the country. Sodium can interact with other earth cations like K, Ca and Mg. Therefore, a pot study was conducted to investigate the growth, yield and ionic response of two cotton varieties. Four levels of K and Na were developed after considering indigenous K, Na status in soil. The treatments of K+Na in mg/kg were adjusted as: 105+37.5, 135+30 135+37.5 and 105+30 (control). Control treatment represented indigenous K, Na status of soil. The experiment continued until maturity. Application of K and Na increased seed cotton yield and boll weight significantly (p 0.01). Both varieties varied non-significantly with respect to K:Na ratio in leaf. The beneficial effects of Na with K application over control on seed cotton yield and boll weight were greater in NIBGE-2 than in MNH-786. Increase in seed cotton yield was attributed to maximum boll weight of both varieties. Significant negative correlation (r= -0.89, - 0.76, n= 4) was found between K:Na ratio and K use efficiency in shoot of NIBGE-2 and MNH-786, respectively.