Low temperature control by fixed sprinkler irrigation in the Bolivian central highland

Marco R. Vargas, René Chipana Rivera

Abstract

In the present work we have evaluated the control of low temperatures by sprinkler irrigation ERA (effect of sprinkler irrigation) and the effect due to the humidity of a plot irrigated one day before by irrigation by sprinkler ESH (wet soil effect) . Twenty-two trials were carried out, at an irrigation intensity of 5 mm h^-1, operating pressure of 200 kPa and overlap between sprinklers of 12 x 12 m². Relative humidity sensors have been installed at spatial level and at three heights above ground level (0.1, 0.25, 0.5 and 1.0 m). These trials were subjected to different intensities and times of frost exposure in the colder period. The model proposed by Gerber and Martsolf (1979) and the approach by Campbell and Norman (1998), for a freezing of radiation, were used for the calculation of the irrigation sheet. The evaluations were carried out at the Patacamaya Experimental Station of the Faculty of Agronomy of the Universidad Mayor de San Andrés. The results show that at exposure times of frost 0 to 3; 3 to 6; 6 to 9 and greater than 9 hours show an increase in temperature (ΔT °) of: 1.2 °C; 1.4 to 2 °C; 1.2 to 5 °C and 1.1 to 2 °C respectively for the ERA. The increases in relative humidity (ΔHR) were: 12%; 7 to 26%; 16 to 35% and 18 to 32% respectively. Thus, the temperature increase (ΔT°) for all the tests carried out due to the ERA goes from 1 to 5 °C and the increase in relative humidity ranges from 7 to 35%. The increase in temperature due to ESH is in the range of 0.7 to 1.1 °C and 12 to 18% for the ΔHR.