Development of a low cost and productive nutrient formulation for simplified hydroponics using commercial grade chemicals.

In order to expand the productivity of agriculture in urban areas, low cost, simple technologies such as simplified hydroponics should be popularized. The major limitations in popularizing simplified hydroponics in Sri Lanka are the high cost of available nutrient packs and their drawbacks. The most popular and available nutrient pack “Albert’s Solution” is fairly expensive; the content is not completely soluble and does not carry adequate preparation instructions. This study was carried out to develop a low cost, completely soluble new nutrient formulation with a buffer system (to maintain the pH in the nutrient solution at 5.8 – 6.5) and to evaluate its suitability for simplified hydroponic system with low cost growing media such as rice hull and river sand. INTRODUCTION Simplified hydroponics is practiced under natural climatic conditions, utilizes space efficiently and conserve’s nutrients and water by a simple mechanism (Bradely, 2000). Two major limitations in popularizing simplified hydroponics in Sri Lanka are the high cost of nutrients and lack of proper guidelines on nutrient management. The most popular and available nutrient pack for hydroponics in Sri Lanka is “Albert’s Solution”. Main drawbacks of “Albert’s Solution” are high cost, inadequate instructions of preparation of working solutions, insufficient levels of some elements and presence of un dissolved matters in the working solutions. A buffer system in a nutrient formulation will be effective in obtaining the desired pH and also to withstand the pH changes in the growing beds (Morgan, 2000). Rice hull is a waste material that is not adequately exploited for use as a growing medium and rice hull mixed with other materials such as sand in a ratio of 3:2 is successful for use in simplified hydroponics (Bradley and Marulanda, 2000). The availability of ions to the plants in the growing bed will be as same as the nutrient supplied if the medium does not absorb or leach any nutrients, i.e. “inert”. Apart from the measurements of growth parameters, the decrease in EC in the solution of plant beds within a few hours after application of the nutrient solution (Harris, 1988) and the amounts of the nutrient ions absorbed by plants gives a direct indication on the nutrient uptake by plants. Hence the objective of this study is to develop a low cost, completely soluble new nutrient formulation with a buffer system and 1 Department of Crop Sciences, Faculty of Agriculture, University of Peradeniya, Peradeniya. 2 Department of Chemistry, University of Colombo, Colombo.