Interactive effect of nature of salinity and nitrogen on growth and nutrient composition of sorghum

A greenhouse experiment was carried cut to study the interactive effects of nature of salinity and N levels on growth and nutrient composition of sorghum. Four salinity levels, viz, ECe 3, 6, 9 and 12 mmhosjcm at 25°C along with a control, besides chloride to sulphate ratio of 1: 3 and 3: 1 in each level of salinity were maintained. The actual salinity developed were 2.8 (S1, 5.8 (S2), 8.8 (53), 11.7 (S4) and 0.364 mmhos/cm in control. Three levels of N (30, 60 and 90 ppm) were applied at each salinity through urea. Sorghum variety CSH-1 was grown in pots for 90 days. The dry matter production as welt as N,P and K concentrations in plants decreased with increasing levels of salinity, particularly in soils of ECe 8.8 mmhosjcm or more. The N levels were found to increase the dry matter production alleviating in part the adverse effect of salinity. Reduction in dry matter production as also in nutrient contents of plants was more pronounced under chloride than sulphate dominant salinity. Higher levels of N application increased the content of N, P and K at all the salinities.