Effect of Super Absorbent Polymers (Saps) on Irrigation Interval of Betel (Piper betle L.) at Nursery Level

Abstract

Water scarcity is considered as one of the most important limiting factors in expanding betel farming under predicted climatic change. Therefore, optimization of irrigation water usage is given higher attention. As such application of Super Absorbent Polymers (SAPs) to increase soil moisture holding capacity was evaluated. A pot experiment was conducted to evaluate the effect of SAPs on growth of betel plants under different irrigation intervals. The experiment design was a factorial layout based on a completely randomized design with two main factors (application of SAP and irrigation interval). Application of SAP had two levels, with SAP (ASAP) and without SAP (NSAP) and there were four levels in irrigation intervals as 2, 4, 6, 8 days. Results showed that media with SAP significantly enhanced plant growth parameters including plant height, average internodal length, total leaf area, root to shoot ratio and total dry weights during the 6 day (ASAP6) irrigation interval compared to the NSAP 2 day (present farmer practice) irrigation interval. Moreover in all ASAP treatments, moisture holding capacity increased by 39 % and bulk density decreased by 25 %. Further it has been shown that the application of SAPs increased water usage efficiency by 88 % in ASAP6 treatment with 55 % less water consumption and 40 % more biomass production compared to farmer practice. Therefore, it is evident from the results that the application of SAP at a rate of 2 g kg-1 of potting media could increase the irrigation interval up to 6 days without any negative effects on betel plant growth compared to the farmer practice.