Analisis keseimbangan air pada irigasi bawah permukaan melalui lapisan semi kedap

Abstract

Under surface irrigation system was specially designed for irrigating crop planted in pots. The pots were made of burned clay-earth material with semi pervious base layer by mixing clay and sand in certain composition. The semi pervious layer enable water goes pass through the base of the pots to fulfill the water requirement of the crop for growth. Research experiment using this system was conducted in a green house to find out the performance of the pots specially designed for the irrigation system using spinach (Amaranthus sp.) for the experimental crop. The evapotranspiration in the greenhouse was measured and calculated by means of Fieldserver Instrument in real time. Growth observation was conducted by recording the change in crop height through a period of time. During the 50 day planting time, the water available for the crop in the pot ranged from 26% to 35% volume basis with semi pervious layer of 30% sand mixture. Potential evapotranspiration ranged from 0,61 to 0,75 mm/d. The actual evapotranspiration ranged from 0,58 to 0,71mm/d with crop coefficient ranged from 0,1 to 1,7 with the use of the semi previous layer (30% sand mixture).