WATER POTENTIAL CHANGE IN THE BEDS OF STRAWBERRY CULTIVATED UNDER DIFFERENT TYPES OF MULCHING

Abstract

A reduction of the soil temperature may help the development of strawberry plants during summer. This can be done with the use of opaque plastic tunnels and plastic film covering the beds to reduce the energy received by the soil. The work was carried out at Embrapa Clima Temperado, in Pelotas-RS, Brazil, from July to December 2006. Strawberry plants of the cv. 'Aromas' were grown under a plastic tunnel. Three different types of mulch were tested: black polyethylene film of low density with thickness of 30 micron (control) and black and white polypropylene films (called TNT or non woven) grammage 50 g/m 2 . We concluded that the plants' water consumption under various mulches indicated different patterns. At the beginning of the vegetative cycle, a low atmospheric water demand period, the evapotranspiration under the black TNT was similar to the other treatments. However under the white TNT it was the highest, returning to values close to the other treatments when irrigation was turned on or when it rains. Sixty days after planting, in high demand period, the evapotranspiration under the TNT covers was greater than under the plastic, especially the white mulching, which allows the development of weeds under it. With the advancement of the cultural cycle, leaky or inadequate rains to replenish the water lost in this area, the water potential in the soil treatments covered with TNT did not return to the levels of the soil covered with polyethylene. It is important to take into account the water management in tunnels with beds covered with white TNT films, without weeds control. The water consumption under these conditions is greater than the others.