RAINWATER HARVESTING ON GREENHOUSE ROOF AND USE IN IRRIGATION

Rainwater collection systems are alternative water supply methods providing environmental and economic benefits compared to traditional water supply methods used in arid and semi-arid climates with water shortages. Rainwater harvested in greenhouse roof by rain gutters can be used to irrigate and grow the plants cultivated in greenhouses. However, rain gutters and storage tanks in greenhouses should be of sufficient size to collect rainwater. Water consumption of plants in the greenhouse should be calculated correctly to determine the storage size in greenhouses. The amount of annual irrigation water harvested from rainfall in Kirsehir province where total rainfall is 388.3 l/m2 was determined as 349.57 l/m2 based on rainfall factor of 0.9. Total amount of irrigation water needed by the plants in the unheated greenhouse between April and September for single crop cultivation was 568.33 l/m2. The results revealed that 61.49% of irrigation water needed for plants can be met by rainwater harvesting. In addition, 47.74% of the total water demand of plants in the heated greenhouse where crops are grown throughout a year can be met by rainwater harvesting. The storage capacities needed for unheated and heated greenhouses were determined as 0.21 m3/m2 and 0.30 m3/m2 depending on the amount of rainwater harvested. The results showed that rainwater harvesting may contribute to the improvement of agricultural activities in water-scarce regions.