Onion plant development under different soil and climate conditions. II Growth and water use efficiency

Abstract

This paper, is a continuation of the part l of the present study. It refers to the onion crop development in the field and greenhouse conditions for two soil, under different minimum soil water potentials: -15.0; -0.8; -0.3; -0.15 bars, and daily irrigation in the field, and -15.0; 0.2 bars, and daily irrigation (with and without drip) in the greenhouse. In the field, the biggest heights of the leaves occurred on the soil B (thinner texture) and on the treatment with minimum soil water potential of -0,15 bars; there was a tendency of increases from the first to third collects, and decreases in the fourth collect. Un the greenhouse conditions, the increases occurred from the first to the fourth collects, mainly under the highest Ψs, and on the soil B. The growth of the leaves at night was 3 to 5 times higher than during the day time, with evidence for the drip irrigation, where the biggest growth occurred with the least atmosphere water needs. The growth of the leaves among the treatments began to differentiate about the 18 cm of length. The soil 8 was more efficient in the water use than the A, in both climates. The treatments -0.15 bars on the field and the drip in the greenhouse were the most efficient. The plants were around three times more effective in the water use in the field conditions than in the greenhouse conditions.