engleski

Water dosage using the coefficient of irrigation in growing of the water-melon

The goal of the investigations was to determine the onset of irrigation using the coefficient of irrigation, which is based on the calculation of everyday evapotranspiration. The coefficient of irrigation represents the water consumption (mm) per one degree of mean daily air temperature (oC). Three-years investigation (1999-2001) were carried out at a water-melon plantation in Neretva Vally, on the soil type Eutric Gleysol, hydromeliorated. Irrigation was applied by means of drip system. Irrigation rate was calculated by the standard method and amounted to 15.6 mm, 31, 2 mm and 39, 0 mm. The coefficient of irrigation was estimated for ten-day periods (decades) according to the data on: soil moisture, precipitation, mean daily air temperature and the amount of water added with irrigation. Soil moisture was estimated gravimetrically. When soil moisture approached the value of lentocapillary moisture (0.625 MPa), irrigation was applied with the amount of water corresponding to the irrigation rate. The said data were processed to calculate the coefficient of irrigation, per decades, for the entire irrigation period. The average coefficient of irrigation ranged from 0.22 mm/oC in the second and the third decade of May to 0.45 mm/oC in the third decade of June. Water consumption for a particular day is calculated by multiplying the coefficient of irrigation by the mean daily air temperature (oC). When, in adding up the consumption of water per days, the previously added irrigation rate is spent, irrigation should be applied again. This fairly practical procedure of determining the onset of irrigation can be applied in water-melon production also in a wider area with equal or similar pedological and climatic conditions.

First Symposium on Horticulture

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