Improvement of Salinity Soil Properties and Rice Productivity under Different Irrigation Intervals and Gypsum Rates

Abstract

The study was carried out in of 2015 and 2016 seasons at the Experimental Farm of El-Sirw Agriculture Research Station, Damietta Governorate, and Egypt. The main objective of an attempt was to determine the effect of short, medium and prolong irrigation intervals (irrigation every three, six and nine days) and gypsum rates (0, 0.5,1.0 and 1.5 t ha-1 CaSO4) on some soil prosperities, some plant elements, plant growth and grain yield of Sakha 104 rice cultivar, under saline soil conditions. A strip plot design, with four replicates, was used. The horizontal plots were devoted to irrigation intervals, however, the gypsum rates were allocated in the vertical plots. The soil of the experimental site was clayey and salinity levels were 7.5 and 7.3 dSm-1 in 2015 and 2016 seasons, respectively. The results obtained could be summarized as follows: Irrigation every three days increased chlorophyll content, LAI, plant height, number of tillers, panicle length, number of panicles, filled grains/panicle, panicle weight, 1000-grain weight, grain and straw yields as a compared with irrigation every nine days, which recorded the highest values of unfilled grains. Irrigation every three days significantly increased soil bulk density as well as Ca++ and K+ (in the soil and plant). However, it decreased the soil EC, Na+ (in the soil and plant) and Na/K ratio in the plant. Irrigation every three days consumed the highest amount of irrigation water, while prolonged irrigation intervals up to six and nine days tended to decrease the amount of water used. Furthermore, nine days treatment recorded the highest water use efficiency. Gypsum (as a soil amendment) rated 1.5 t1 CaSo4 ha- significantly raised all studied growth parameter (except plant height), grain yield and its components without any significant differences with 1.0 t ha-1 CaSo4 in some traits in both seasons. Gypsum at the rate of 1.5 t ha-1 CaSo4 mitigate the hazardous effect of salinity by decrease soil EC, Na+ (in the soil and plant) and Na/K ratio in the plant. Generally, under the same condition, irrigation every three days and gypsum at the rate of 1.5 t ha-1 CaSo4 are favorable for improve soil properties and enhance rice productivity under saline soil conditions.