Influência de elementos Meteorológicos sobre o desenvolvimento da alface em diferentes ambientes.

Abstract

Plants cultivated within and outside the protected area (a covered shelter with plastic) during the same growing period, under different meteorological conditions occurred due to the plastic covering of the shelter. This research is conducted in protected (AE) and natural (AN) ambients. The objective of this work is to evaluate the development (growth) and quantity the effect of the meteorological elements on the growth of the Iettuce crop under to different ambients and in two different epochs. The research was conducted at the "Empresa Estadual de Pesquisa Agropecuária da Paraíba 8. A. - EMEPA", during the periods of 30!05 to 08/08/2007 and 10109 to 221112007, periods of winter and spring using two cultivars of Iettuce: "Elba" and "Americana Irene". The mean air temperatures in AE were higher than those in AN during both the experiments (21 .6 C and 228 C. respectively). The values of the mean daily relative humidity obtained in AN were more than those in AE during both the experiments (921% in Exp.1 and 813% in Exp.2). The levels of the photosynthetically active radiation (PAR) within the protected ambient (AE) accompanied the same pattern as the PAR in AN but with less intensity, due to the absorption of part of the PAR by the polyethelene cover. The protected ambient has favourable micro-climate to the crop growth, anticipating the harvest of the lettuce by one week in both the experiments. During the winter (Exp.1) the crop growth, development and production were higher in AE than in AN.