Soil salinity and nutrient availability influenced by silicon application to tomato irrigation with different saline water

Silicon can be used as a soil amendment to reduce deleterious soil salinity and improve nutrient availability under different irrigation water salinity levels. Four treatments of Si (0,150 and 300 kg Si ha-1 as nano-silica and 300 kg Si ha-1 as potassium silicate) along with four salinity levels of irrigation water (1.65,3,6and 9 dSm-1 ) were used to investigate their effect on soil salinity at three soil depth ( 0-15, 15-30 and 30-45 cm ) and availability of N, P and K in soil cultivated with tomato. The experiment was conducted under greenhouse conditions using a random complete block design with three replicates. According to the results, increasing irrigation water salinity level increased soil salinity and decreased available N, P and K to tomatoes. Si treatments decreased soil salinity and increased available amounts of N, P and K . Using 300 Kg Si ha-1 of nano-silica caused the lowest soil salinity of 1.89, 2.51 and 3.23 dSm-1 for 0-15, 15-30, and 30-45cm depth, respectively and increased availability of N, P and K with a percent of 19.4, 14.1 and 82.7 %, respectively. Keywords: nano-silica, soil salinity, available nitrogen, irrigation water salinity, tomato.