Determination of the Water Requirements of Two Legume Species (Pueraria phaseloides L. (Kudzu) and Desmodium heterocarpon subsp. ovalifolium cv. Maquenque) Used as Cover Crops in Oil Palm Cultivation

The use of legume cover crops has become an established sustainable practice in agriculture due to their numerous benefits for soil conservation and their role in nutrient cycling and recycling. Additionally, it is essential to comprehend their role in crop water management, particularly in irrigated regions. This research was conducted at the Palmar de la Sierra Experimental Field in the Magdalena department of Colombia. The study aimed to determine the water requirements of the legumes Pueraria phaseloides L. and Desmodium heterocarpon subsp. ovalifolium cv. Maquenque and the evaluation of their development under three different soil moisture conditions: field capacity, 50% depletion, and 95% depletion. To achieve this, drainage lysimeters were set up using a completely randomized experimental design, and the water balance method was employed. The results indicate that both legume species are adversely affected by water deficit conditions, particularly P. phaseloides, which experiences a reduction in leaf area index of up to 12%. Under optimal soil moisture conditions, achieving more than 70% soil coverage, both legumes exhibited a similar average evapotranspiration rate of 3.2 mm day-1, with a range spanning from 1.2 to 4.8 mm day-1.