Impact of Different Concentrations of Municipal Wastewater on Rice Seed Germination and Seedling Performance
Abstract
The major challenge faced by developing countries is to produce adequate food for their growing human population under the shortage of freshwater for agricultural activities. Laboratory experiment was conducted in a completely randomized design using sand medium with municipal wastewater and MR253 rice seed with the aim to evaluate effects of municipal wastewater (treated and untreated) at different concentrations (0, 2.5, 5, 10, 25, 50 and 100%) on seed germination and seedling performance. Significant (p<0.05) difference was observed between untreated and treated municipal wastewater for seedling length (SL), root volume (RV), seedling vigour index (SVI) and root: shoot ratio (R:S) while no difference were observed between untreated and treated municipal wastewater for germination percentage (GP) and the seedling phytotoxicity. The concentrations of N, P, K, Ca, Mg, Zn, Fe, Cu and Mn were higher in the untreated municipal wastewater compare to treated municipal wastewater. Seeds imbibed with untreated municipal wastewater have high seed germination and seedling performance compare to treated municipal wastewater. Inhibitory effect on chlorophyll content was observed at concentration >50% of both untreated and treated municipal wastewater while promoting effects were observed at lower (<25%) concentrations. However, all the nutrient elements were negatively and highly correlated with quantity of different municipal wastewater concentration. The study showed that seeds imbibed with untreated municipal wastewater have high seed germination and seedling performance compare to treated municipal wastewater. Municipal wastewater of <50% concentration could be recommended as a good source of water and nutrients for rice seed germination without affecting seedling performance.
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Introduction
Potential means to secure rice productivity is to ensure that the quality of the seeds for sowing is good. A good and quality seeds are free of weed seeds, seed-borne diseases, pathogens, insects, or other matters and it possess high germination, vigor, viability and seedling performance (Chhetri, 2009). On the other hand, water is a major factor on earth and top priority for the existence of human life and crop production. The global demand for water in agriculture will have to increase with rising human population, escalating incomes, and deviations in nutritional favorites. Growing demands for water by industrial, urban users will deepen competition (de Fraiture and Wichelns, 2010). The use of domestic wastewater for agricultural production is increasing, especially as domestic wastewaters are rich in plant nutrients and organic matters which are essential for plant growth and development (Dash, 2012). The practice of using municipal wastewater will help reduce the pressure on freshwater for watering or irrigation of agricultural activities. Crops irrigated with wastewater have the potential to give a higher yield as the water helps to reduce the need for chemical fertilizers (Haussain et al., 2002). The macro and micro-nutrients in the wastewater assist as a good basis of plant nutrients and the organic constituents furnish helpful soil conditioning properties (Singh and Agrawal, 2008). Generally, wastewater (treated and untreated) is extensively utilized in farming because it is a rich basis of nutrients and provides all the moisture vital for crop growth. Water is a vital factor in agriculture and it plays an influential role in the growth and development of plants. Therefore, actions must betaken to reinforce irrigation farming, safeguard the rural environment and support water resource sustainability with good water management (de Juan et al., 1999). Meeting the trials of feeding the ever-rising human populace, proficient uses of water and land resources is extremely vital in crop production. As the demand of wastewater is increasing, this study was conducted to evaluate the impact of untreated and treated municipal wastewater on rice seed germination and seedlings performance.
Conclusion
The use of wastewater in plant nourishment would be beneficial water resources for irrigation due to its nutrient contents. Municipal wastewater contains essential nutrients for plant growth and development. The promotion of seeds and seedlings quality parameters at lower concentrations of the wastewater is due to the presence of optimum levels of plant nutrients in the wastewater. Seedlings imbibed with lower concentration of untreated municipal wastewater showed better seedling performance compare to treated municipal wastewater although untreated wastewater contains some hazardous toxic elements. Thus, municipal wastewaters can be used for irrigation purposes in agricultural practices after proper dilutions. It is also suggested that, treatment of municipal wastewaters is necessary to minimize the pollution effects before irrigating the crops.
