Long-term impact of soil solarization on cucumber production under cold greenhouse conditions

Soil solarization (SS) was carried out on a glasshouse (0.5 ha area) and a fiber-house (0.25 ha area) during the summer season (2003) at Shahania farm, Arab-Qatari Agricultural Production Company (AQAPCo), Doha, Qatar. Another two identical houses were left without SS as control. Cucumber hybrid cultivar (Bazz) was grown in the three subsequent seasons (fall 2003, winter and summer 2004) in both soil-solarized houses as well as in the 2 houses used as the control. The cooling system of the used greenhouses was ceased only during the period of SS. As compared to the control, SS treatment significantly increased cucumber yield and markedly prolonged its harvesting period by eliminating the visual symptoms of nematode infection in all three subsequent seasons of both greenhouse sorts. In this work, it was evident that the positive impacts of SS lasted for three subsequent seasons (more than one year) since the achieved significant increase in cucumber yield was accompanied by the absence of the visual symptoms of nematode infection up to one year after the application of SS. These data emphasized the reality of the proposed hypothesis of this work and proved that SS can be applied every other year, rather than annually, as it was previously programmed in the rehabilitation programs of AQAPCo. Therefore, AQAPCo can reduce the cost of SS by about 50% since SS can be applied on only 50% of its greenhouses/year during the summer season. Furthermore, this 50% of AQAPCo greenhouses can be soil-solarized in two equal halves during the summer season since SS can he applied twice/each summer season as 25% during the early summer (May and June) and 25% during the late summer (June and July). Following such program will enable AQAPCo to follow an applicable program for SS by increasing the number of greenhouses used for cucumber production during the summer season from 50 to 75% of its total greenhouses and to all greenhouses throughout the rest of the year. This will maximize cucumber net cash return of the AQAPCo the whole year around, particularly during the summer season (off-season) that has the highest cucumber prices compared to the other growing seasons.