EFFECT OF SUPPLY VOLUME AND WEATHER-BASED EC ADJUSTMENTS ON THE GROWTH AND YIELD OF GREENHOUSE TOMATO AND BELL PEPPER
Providing the required dosage and ideal balance of plant nutrients is a challenge for the farmers who practice hydroponics tomatoes and bell peppers under variable climates and weather conditions in Sri Lanka. Some recent work has led to identify incomplete wetting of the growth medium as a significant cause of under-feeding of roots in drip-fertigated grow bag cultures. It has also been revealed that higher water supply (with low EC) during regimes of overcast conditions reduces nutrient uptake due to low uptake volumes. Therefore, a replicated trial was conducted to examine the effect of supply volume and EC adjustment under weather-based changes in water uptake on the growth, yield and quality of greenhouse tomato and bell pepper. The treatments were over dosage of Alberts solution with extra supply volume in circulation (T1), recommended dosage with standard water supply without circulation (T2) and recommended dosage with weather-based variation in water supply without circulation (with variable EC levels) (T3). Significantly higher vegetative growth of tomato as well as bell pepper was found in the circulation culture (T1), compared to the control (T2). It was continued in terms of rate of flower initiation and fruit set in tomato and flower and fruit number in bell pepper. Weight, length and width of fruits and the overall yield were also significantly higher in the circulation culture in both crops. Higher compositions of macronutrients in leaf tissues of bell pepper together with EC and pH drifts and daily water uptake in both crops indicated the contribution of plant nutrition to higher plant growth under circulation culture. Meanwhile, comparatively higher early growth performances of T3 over the control in both crops stressed the positive effect of elevated EC levels in the liquid feed under regimes of low water uptake. Therefore circulation of excess nutrient solution (with high dosage) was more effective for production of tomato and bell pepper in drip-fertigated grow bag culture under humid tropical conditions while weather-based adjustments in supply volume, using the recommended dosage (subjected to variation in EC) was also a better fertigation option when compared to the standard method.
Weerakkody, W.A.P., Mayakaduwa, M.A.P. and Weerapperuma, K.N. (2007). EFFECT OF SUPPLY VOLUME AND WEATHER-BASED EC ADJUSTMENTS ON THE GROWTH AND YIELD OF GREENHOUSE TOMATO AND BELL PEPPER. Acta Hortic. 742, 105-111
circulation culture, drainage, EC, weather, drip irrigated grow bag culture, plant nutrients, supply volume