Author : Patricio, Hope G.

Summary : The effect of salt and nitrogen on the soil solution EC and pH and on the growth, yield, and nutrient concentration of IR52 and IR26 rice varieties were studied in a pot experiment concluded in the screenhouse of the Department of Soil Sciences, University of the Philippines Los Ba¤os (UPLB), Laguna, on 17 December 1982 - 23 April 1983. Results showed that the soil solution EC increased, whereas pH decreased with increasing salinity. The different salt levels also significantly delayed flowering and harvesting; depressed growth and yields; generally increased the concentrations of nitrogen, phosphorous, sodium, and chlorine; and decreased potassium concentration in the straw of both varieties. However, varietal response to applied nitrogen differed. In terms of straw yield, IR52 responded more to the application of 90 kg N/ha to IR26 to 135 kg N/ha application. Furthermore, application of 90 and 135 kg N/ha increased the concentrations of nitrogen in the root and of potassium and sodium in the straw of IR52. The same nitrogen levels increased the concentrations of phosphorous in the grain and of potassium in the straw of IR26. The highest nitrogen rate (135 kg N/ha) increased chlorine concentration in the grain of IR52, but decreased it in IR26.