Chemical Thickening of Biogas Digestate Slurry from Anaerobic Digestion

Understanding crop water requirements (CWR) is essential for the better irrigation practices. Scheduling and efficient use of water since the water supply through rainfall is limited. The main objectives of the research were estimated crop water requirement and irrigation scheduling for rice crops, in addition, to increase agricultural productivity and improving irrigation efficiency uses. The irrigation schedules and water requirements were simulated using CROPWAT, and the model result was verified with field values in the Maliana Irrigation Scheme, Bobonaro District of East Timor. The results indicated the wider applicability of CROPWAT in calculating water requirement as well as developing irrigation schedules for rice irrespective of the agro-climate conditions. The specific objectives were (i) to estimate reference evapotranspiration (Eto), (ii) to an estimate of the effective rainfall from the Maliana stations, (iii) to estimate of crop water requirements for rice crops, (iv) to estimate irrigation schedule. The average value of reference evapotranspiration of the crop was 4.98mm/day. It ranges from 4.21mm/day to 5.90mm/day. The maximum evapotranspiration of crop was accorded in the month of September and the minimum were January. The maximum effective rainfall of 155.2mm in the month of January and a minimum of 5.3mm during August. The total irrigation water requirement for the rice crop the season from December to April was 435.3mm. This low water requirement for rice is mainly due to higher effective rainfall in the site of study. The net irrigation applied to the field varies from 90mm to107.8mm with an average net irrigation of 486.9mm. The gross irrigation water requirement ranges from 128.57mm to 154mm with average gross irrigation water of 695.6mm.