Plants cover with a nonwoven polypropylene protection comprises one of the most recent techniques for protecting horticultural crops. Four experiments have been conducted at the experimental area of the "Centro de Investigación y Desarrollo Agrario" in Córdoba, Spain. The aim of this study was to evaluated the air and soil temperature amplitudes and the photosynthetically active radiation and its effects on the production of chinese cabbage, table beet, spinach and lettuce grown under nonwoven polypropylene protection (PP) and also at environment conditions (AN) during the spring, autumn and winter of 1995/1996. The experiments were carried out in a randomized blocks design with four replications. Air and soil temperatures under PP were higher than those ones at AN conditions during initial growth period for all studied species, with differences up to 5.5 and 2.2ºC for air and soil temperature, respectively. However, with crops growth, temperature values under PP trended to be similar to AN for both air and soil. For chinese cabbage and spinach, air temperature under PP was lower than AN after middle and final cycle, respectively. For chinese cabbage and spinach, air temperature under PP was up to 3.1ºC lower than the observed at AN condition after middle and final stage of the cycle, respectively. For chinese cabbage, table beet and spinach grown under PP, such microclimatic modifications have promoted a higher precocity and production compared to AN conditions. However, for lettuce crop the higher temperature under PP did not result in a higher final production. In this case, low incidence radiation levels under PP and also a prolonged precipitation period during the winter months interfered negatively with crops growth, where PP protection should be removed in this climatic conditions.
Brassica pekinensis; Beta vulgaris; Lactuca sativa; Spinacia oleracea; chinese cabbage; table beet; lettuce; spinach; soil temperature; air temperature; radiation; nonwoven; plant protection; leaf area; vegetable biomass
