Abstract
Deviation in the horizontal distribution of air and soil temperature beneath film mulch was studied in relation to meteorological conditions in a greenhouse and upland field. The following results were obtained. (1) From measurements of solar radiation of 10 points in the greenhouse with east-west direction, standard deviation of 10 sky solar radiations was 122% that of direct solar radiation. Changes in air temperature at 150 cm height as measured at the same position that of the solar radiation increased considerably with approach to gable side equipped with a ventilation fan. For relative humidity at 150 cm, no characteristic tendency was observed. (2) For the greenhouse and upland field, large differences were found between standard deviation in 10 soil temperatures at 10 cm depth in daytime and that of nighttime. Diurnal range of the deviation in the greenhouse was about twice that of upland field. (3) Standard deviation in 10 air temperatures and 10 soil temperatures in a horizontal direction in broad bean field and soybean field was investigated by multiple regression analysis using predictor variables of 5 principal meteorological factors and LAT. The deviation of air and soil temperatures was significantly influenced by solar radiation in the broad bean field, and by solar radiation and LAI in the soybean field. (4) Amount of heat load in the greenhouse and daily variation in heat transfer in the soybean canopy were calculated in relation to deviation in air temperatures in a horizontal direction.
