Parâmetros agrometeorológicos de ambiente protegido com o cultivo de abóbora italiana sob adubação orgânica

Abstract

The growth of vegetable consumption has been demanding from the horticulturist, inside of a sustainable agriculture perspective, the utilization of techniques that make possible the production of food with larger productivity and quality. With summer squash cultivation under organic manuring in protected environment, the present work aimed to evaluate the microclimate behavior inside of the protected environment as well as to describe the radiation fluxes, to evaluate the fresh fruit biomass production under different doses of organic manuring, and to determine the conversion efficiency of photosynthetically activate radiation (PAR) in biomass. The experiment was carried out from September 2006 to December 2006, at Universidade Federal de Pelotas, using polyethylene greenhouse type "arched roof". The experiment was set up in an entirely randomized delineation, constituted of three treatments with five replications. The used treatments were one (1), two (2) and three (3) doses of solid bovine manure vermicompost. The meteorological variables of the internal environment were measured through electronic sensors connected to a micrologger. For the external environment, the meteorological observations were obtained in the Estação Agroclimatológica da UFPel/Embrapa. The average value of internal solar radiation was 14,6MJ m-2 day-1, and the medium transmittance to the global radiation was 75%. The internal solar radiation presented high correlation with the radiation fluxes of short wave and net radiation. Regarding the trofic limit of the culture, the internal solar radiation didn't impose limitations to the culture. The average daily value of the internal air temperature was 21,3ºC and the average of the maximum and minimum were 29,5ºC and 15,1ºC, respectively. For the period of day and night, the average temperature was 24,1ºC and 17,4ºC, respectively. The largest greenhouse effect caused by the protected environment was verified on the medium and maximum temperatures, mainly on the maximum. For the minimum temperatures, the internal and external values were similar during the whole cycle of the culture. Regarding the limits of air temperature and optimum strip for the culture, the protected environment favored the culture. The average daily value of the internal air relative humidity was 83% and the average of the maximum and minimum was 97% and 58%, respectively. Regarding the optimum strip of relative humidity for the culture, in general, the protected environment didn't favor the culture. The largest production of fruits and conversion efficiency of the incident PAR in fitomassa were obtained by the treatment 2, being of 1,79kg plant-1 and 0,950g MJ-1, respectively.