Abstract
A field experiment was carried out in sandy soil at the Research and Training Station at King Faisal University, Al-Hassa, Saudi Arabia, during the 2016–2017 season, to study the effect of five rates of silica nanoparticle (Si-NP) treatments on soil soluble Si4+, water characteristics curve, yield and water use efficiency of cucumber (Cucumis sativus L.) after harvesting. A randomized complete block design with three replicates was used to conduct the study in the greenhouse where the amount of irrigation water was at 100 % evapotranspiration 78 L Plant−1 at the end of the season. The nano-silica particle (Si-NP) treatments were Si-NP0 (0 mg kg−1), Si-NP100 (100 mg kg−1), Si-NP200 (200 mg kg−1), Si-NP300 (300 mg kg−1) and Si-NP400 (400 mg kg−1). The results revealed that the Si-NP had a significant effect (p < 0.0001) on the soluble silicon (Si mg kg−1), field capacity (Fc, cm3cm−3), welting point (WP, cm3cm−3), available water (AW, cm3cm−3) and moisture content (θs, cm3cm−3), of the soil after harvesting crop and also, yield (g plant−1) and water use efficiency (WUE, g cm−3). The values of all parameters in the study increased with increasing the rates of silicon-nano particles. The main results can be summarized as follows: An increase of soluble Si4+ in the soil according to the application of Si-NP leads to a rise of all behaviour water properties in the soil such as FC, WP, AW and θs, which caused the increase in cucumber yield and water use efficiency by 178% as compared with Si-NP0. The higher mean values of all properties were found in plants exposed to Si-NP400 treatment.