Mohamedin, A.A.M( 2012). Effect Of Leaching With Adding Gypsum And Rice Straw Compost On Improving Salt Affected Soil And Rice YieldMinia International Conference For Agriculture And Irrigation In The Nile Basin Countries, 26th -29th March 2012, El-Minia, Egypt
Abstract: This study was conducted to investigate the efficiency of leaching process with adding gypsum or compost and their combination on improving of poorly productive salt affected soil, the rice growth and nutrient uptake at El-Hamoul area which represent the salt affected soil in the northern part of the Nile Delta. The treatments were adding gypsum in rates of 0, 2.5, 5, and 10 (Mg fed.-1) or compost in rates of 10 and 20 Mg fed.-1 and combination of 2.5 gypsum with compost 10 Mg fed.-1. Rice was transplanted after the recommended soil preparation. Three successive leachate were done with the same volume of irrigation water. The discharged water through drain’s outlet and its electrical conductivity (ECd) were measured. Soil physical and chemical properties and plant analysis were done at harvesting. The results indicated that absolute differences in leachate volumes, due to leaching process, were relatively small for no amended soil and increased with gypsum application rates. The percolation of water through the gypsum treated soil profile was much faster than the control indicating that gypsum was the main factor to percolate process. Compost combined with gypsum treatment was more effective than compost alone. Salinity of the drained water (ECd ) values had sharply decreased until the third leaching, then a slight decrease was recorded with gypsum treatments. However, with compost treatments, the ECd values had the same trend, but the sharp decrease was retarded until the 4th leaching. The mean value of ECd in leachate was reduced from 32.50 to 5.17 dSm-1. This decrease was a function of the number of leachings of the soil. Consequently, leaching the soil treated with gypsum was more effective in removing the soluble salts. Leaching with adding compost reduced ESP at the end of leaching than the control. Increasing gypsum rates decreased ESP. Moreover, leaching with gypsum and compost decreased ESP value to 11.64. The results revealed that rice shoot dry weight was increased from 1890 to 2940 kg/fed. as gypsum rates increased from zero to 10 Mg fed-1. The corresponding value for compost increased from 2541 to 3801 kg/fed. at 10 and 20 Mg fed.-1, respectively. The combined effect of compost and gypsum treatment was greater than the individual one (4208 kg/fed.). Nitrogen and phosphorus content in rice dry matter was increased with compost application while they were not significantly affected by gypsum application rates. In addition, K content was not significantly affected by either gypsum or compost applications. The Na content was lower, however Ca and Mg content was higher in rice plants grown in gypsum treatments compared with compost ones. Thus, it can be said that leaching the salt affected soil with gypsum combined with compost was entirely safe. This treatment is more profitable than the leaching with water only (control).
Keywords: (Compost, gypsum, leaching process, salt affected soil, rice yield, componantes.)
