Abd El-All, A.E.:, A. K. Abdelhalim and A. El-Namas ( 2017). Assessment of deficit irrigation and foliar application of salicylic acid and potassium silicate on performance of drip – irrigated onion crop in sandy soilMenoufia J. Soil Sci., Vol. 2 February (2017): 29 – 40
Abstract: The present experiment was conducted during 2011/2012 and 2012/2103 winter seasons to study the effect of irrigation regimes e.g. 60, 80 and 100% ETo and foliar application of Potassium Silicate (PS) and Salicylic Acid(SA) in 250 and 400 mgL-1for both and interactions. The adopted treatments were assessed a split – plot design with 3 replicates. The irrigation regimes were represented in the main plots, whereas foliar application of PS and SA treatments were allocated to the split plots. The obtained results could be summarized as follows:
1- Water saving reached to 20 and 40% under irrigation onion crop at 80 and 60% ETo regimes, comparable with 100% ETo regime. Total onion yield and both Bulb diameter and Single bulb weight were significantly affected due to the adopted treatments in 1st and 2nd seasons. Under100% ETo regime, higher values of total onion yield, Bulb diameter and Single bulb weight were recorded, comparable with those under 80 and 60% ETo regimes in 1st and 2nd seasons. Higher values of total onion yield, Bulb diameter and Single bulb weight were observed with PS500 foliar application, comparing with those under PS250, SA250 andSA500. Interaction of100% ETo regime and PS500 foliar application resulted in higher figures of total onion yield, Bulb diameter and Single bulb weight
2- Total Soluble Solids (TSS), marketable bulb yield% and dry matter % were significantly increased under 60% ETo, whereas the assessed foliar application e.g. PS or SA treatments did not significantly increase such parameters. nteraction of 60% ETo regime and SA250 exhibited higher TSS %, Dry matter content% and marketable bulb yield%%
3- Values of IWUE tended to increase with reducing irrigation rate and vice versa. Additionally, foliar application of Potassium Silicate at 500 mgL-1 concentration (PS500) exhibited higher IWUE figures, comparing with PS250, SA250 and SA500. The 60% ETo irrigation regime as interacted with foliar application of Potassium Silicate at 500 mgL-1 (PS500) exhibited higher IWUE figures.
4- Under the present experiments circumstances, it is advisable to irrigate the onion crop at100% ETo regime combined with foliar application of potassium silicate at 500mgL-1 concentration. However, in water constraint situation irrigating at 80 or 60% ETo regimes and foliar application of potassium silicate at 500 mgL-1 concentration is recommended due to irrigation water saving(20 to 40%) and acceptable onion bulb yield with higher quality and efficient water use as well.
Keywords: (Deficit irrigation, Onion yield and quality, Potassium Silicate (PS) and Salicylic Acid SA), IWUE)
