Effects of Different Colored Mulch Polyethylene Covers on Solarization and Soil Temperature in Greenhouses

Abstract

The solarization applications performed by means of sun is effective in disinfection of the soil in greenhouses. A trial was completed in a plastic covered greenhouse for determining the effect of solarization on soil temperature and disinfection. In this trial, temperature values were measured from May to September in parcels covered with 0,15 0,01 mm thick transparent and black polyethylene and soil parcels. In these months, the surface temperature on the black polyethylene covered parcels was measured between 49.0 degrees C and 57.7 degrees C. These values are 5.0 degrees C to 6.1 degrees C higher than the transparent polyethylene covered parcel (44.0 degrees C - 51.6 degrees C). As for the soil parcel, the maximum soil temperature varied between 44.1 degrees C - 46.9 degrees C. The temperatures, which were measured as a result of the solarization and exceeded 45 degrees C - 50 degrees C, are significant values for soil disinfection. It was determined that temperature of surfaces with black cover increased up to 57.7 degrees C when the air temperature in the greenhouses exceed 40 degrees C. However, the surface temperature of the soil under the black cover was around 43.6 degrees C and thus 14.1 degrees C lower than the surface temperature of the black polyethylene cover. The difference between the low greenhouse temperatures might be lowered down to 2 degrees C - 3 degrees C. The temperature of the soils under the polyethylene covers resistant to solar rays is lower than the soils under the transparent polyethylene cover. The soil surface temperature of the transparent polyethylene covered parcel might be 2 degrees C to 3 degrees C higher than the polyethylene covered parcel. The maximum temperatures measured at 10 to 15 cm depth of the soil were between 32.12 degrees C and 40.7 degrees C in the parcel covered with transparent polyethylene and thus 1.1 degrees C to 4.9 degrees C higher than the parcel with black polyethylene cover. These values varied between 23.2 degrees C and 35.2 degrees C on the soil parcel and thus were lower than other covered parcels.