EFFECTS OF REGULATED DEFICIT IRRIGATION AND PHOSPHORUS FERTILIZERS ON YIELD, WATER USE EFFICIENCY AND TOTAL SOLUBLE SOLIDS OF TOMATO

摘要

A field experiment was carried out on a sandy clay loam soil at the experimental field of Cairo University, Egypt. The experiment consisted of 4 drip irrigation water levels (1,: 1.0 ETc (potential crop evapotranspiration), l2: 0.9 ETc, l3: 0.8 ETc and l4: 0.7 ETc) accompanied with two kinds of phosphorus fertilizers (F^. Super phosphate calcium and F2: El-Mowfer-Bio). Yield was significantly (P ￡ 0.05) affected by irrigation level, fertilizers and their interaction. The highest fruit yield, equal to 75049.33 kg ha~(-1) was recorded for F^U, while the lowest fruit yield, equal 58524.20 kg ha~(-1), was recorded under F2U. IWUE values varied from 4.326 to 4.730 kg m 3 in 2010-2011 and from 3.893 to 4.247 kg m3 in 2011-2012. WUE values varied from 4.266 to 4.643 kg m'3 in 2010-2011 and from 3.893 to 4.180 kg m'3 in 2011-2012. The highest values of IWUE and WUE increased with water shortage till l3 (80% ETc). The effects of deficit irrigation on fruit quality were conversely of those on fruit yield, whereas the amount of water applied through drip irrigation increased, the percentage of solids level decreased, so the lowest TSS (5.867 % Brix) corresponded to the full irrigation and SUPER PHOSPHATE CALCIUM fertilizer (F1I1). The results suggest that the crop does not benefit from the water when the last is supplied to fulfill total crop requirements (100% ETc). Indeed, it is possible to save water, improving its use efficiency in processing tomato at a low rate (80% ETc), to achieve adequate fruit yield, minimizing fruit losses and maintaining high fruit quality levels. Tomato yield under SUPER PHOSPHATE CALCIUM was higher than of those under El-Mowfer-Bio while the qualityparameters like TSS and hardness was higher under El-Mowfer-Bio so it is recommended to use it if the main purpose is the quality.