Evaluation of super absorbent polymer (hipro-aqua) on the growth, yield and quality of tobacco (Nicotiana tabacum L.) under various irrigation regimes

Abstract

Drought is the most important limiting factor in the production of crops in agriculture; it is becoming an increasingly severe problem, sharpening its ends due to dynamic changes in climatic variables. Tobacco is one of the major cash crops that is being grown by many farmers, but its production potential is often constrained by the scarcity of water and poor productivity of sandy soil. In order to counteract the problem of water scarcity, the researcher hereby sought to investigate on the effects of a novel technology towards water conservation and potential production of tobacco in Zimbabwe. The addition of water-saving superabsorbent polymer (SAP) in soil can improve soil physical properties, crop growth and yield and reduce the irrigation requirement of plants. This experiment was conducted on a flue-cured tobacco variety ‘T75’ at Tobacco Research Board, Zimbabwe during the 2015-2016 season. The experimental design was a split-plot with two factors including four irrigation regime (providing 40%, 60%, 80% and 100% from consumptive (ET crop) of tobacco) as main plots and four levels of SAP (0, 75, 150 and 225 kg/ha) as subplots in a randomized complete block design with three replications. Irrigation level and SAP had significant effects on growth parameters of tobacco (leaf length and leaf width) of tobacco leaves, with the highest (77.19cm) leaf length at SAP rate of 150kg/ha under irrigation regime of 80% and the lowest (60.72cm) being at 0kg/ha SAP rate of under 40% irrigation regime. Also there was significant effect of the treatment application of different rates of SAP under different irrigation regimes on yield parameters (fresh and dry cured leaf yield), with the highest (2 017kg/ha) dry cured leaf yield of tobacco at SAP rate of 150kg/ha under 80% irrigation regime and the lowest (653kg/ha) dry cured leaf yield of tobacco at 225kg/ha under 40% irrigation regime. The quality of tobacco (% nicotine, % sugar content and grade index) was also influenced by the treatment applications of SAP rates under different irrigation regimes, with the highest (3.05%) nicotine content attained at an SAP rate of 150kg/ha under irrigation regime of 80%. The results indicate that 150 kg/ha of SAP under 80% irrigation regime produced the desirable outcomes on the growth, yield and quality of tobacco, signifying the importance and role of SAP in moisture retention and its positive contribution towards those parameters.