ALLEVIATION OF WATER DEFICIENCY EFFECT BY APPLICATION OF POTASSIUM SILICATE TO FABA BEAN INTERCROPPED WITH SUGAR BEET IN SANDY SOIL

Two field experiments were carried out at Ismailia Agricultural Research Station, Agricultural Research Center, Ismailia governorate (Lat. 30° 35' 30" N, Long. 32° 14' 50" E, 10 m a.s.l.), Egypt, during 2018/2019 and 2019/2020 growing seasons. The objective of this study was to determine the rate of potassium silicate that could mitigate the effect of water shortage on productivity of faba bean intercropped with sugar beet and its effects on water and land equivalent ratios, as well as farmer’s net revenue. In split plot design with three replications, three irrigation treatments i.e., 120, 100 and 85% Evapotranspiration (mm/d) (ETo) were assigned to the main plots, while three rates of sprayed potassium silicate (unsprayed (control), 200 ppm and 300 ppm) were arranged in sub-plots. The results showed that irrigation with 120% ETo and spraying with 200 ppm potassium silicate attained the highest yield and its components for both faba bean and sugar beet under their intercropping system in both growing seasons. For faba been and sugar beet, N, K and Si content were positively affected by irrigation levels at 100% ETo with foliar potassium silicate 200 ppm, but P content was positively affected by irrigation levels at 120% ETo with foliar 200 ppm potassium silicate. The available P and K in the soil were positively affected by irrigation with 120% ETo with foliar 300 ppm potassium silicate. N content was positive affected by irrigation with 100% ETo with foliar 200 ppm potassium silicate. The highest values of water and land equivalent ratios (WER and LER), as well as total and net return were obtained under irrigation with 120% ETo and spraying with 200 ppm potassium silicate. However, both WER and LER under application of 100% ETo and 200 potassium silicate were higher than irrigation with120% ETo and unsprayed plants in both growing seasons. The highest value of farmer net revenue was obtained when 120% ETo and spraying with 200 ppm potassium silicate were applied. Thus, to attain the highest faba bean with sugar beet in an intercropping system and highest water and land equivalent ratios, as well as farmer’s net revenue, 120% ETo and spraying with 200 ppm potassium silicate should be applied. However, in case of water shortage, 100% ETo and spraying with 200 ppm potassium silicate could be applied to mitigate the effect of water deficiency.