QUANTIFYING COCOA CROP WATER REQUIREMENTS IN SABAH, MALAYSIA TO SUPPORT PRECISION IRRIGATION
Authors: Ilahi, W. F. F1,2*, Rosdi, N. S. I.1 and Samsury, M. D. A-D.1
Journal Issue: Malaysian Cocoa Journal, Volume 17 2025
Keywords: Crop water requirement (CWR), Penman-Monteith method, evapotranspiration, precision agriculture, cocoa
Published On: 5/11/2025
Abstract
This research explores the crop water requirements (CWR) of cocoa (Theobroma cacao) using the FAO-56 Penman-Monteith method to estimate reference evapotranspiration (ETo). Precise calculation of CWR is essential for improving irrigation efficiency, particularly in regions like Sabah, Malaysia, where cocoa farmers are increasingly affected by unpredictable weather and poor water management. The study focuses on two major cocoa-producing areas in Kota Kinabalu and Tawau. Climate data such as temperature, humidity, wind speed, and solar radiation were collected from the FAO CLIMWAT 2.0 database and processed using FAO CROPWAT 8.0 software. ETo values were then used alongside crop-specific coefficients (Kc) to determine the crop evapotranspiration (ETc) of cocoa at its fully developed stage. The results showed similar ETo and ETc patterns across both regions, with no statistically significant difference between them (t(11) = 1.72, p-value = 0.116, α < 0.05). The estimated irrigation need ranged from 35 to 44 L tree-1 day-1 for 3 x 3 meter planting spacing throughout the year with no interference from rainfall. These findings emphasize the need for irrigation strategies that are tailored to local conditions while maintaining overall consistency, supporting more efficient water management. Integrating such data-driven approaches into precision agriculture can help reduce water waste, maintain soil moisture balance, and enhance crop productivity, thereby improving the resilience and sustainability of cocoa farming systems in Sabah.