The mulch dilemma: Trade‐offs between soil water conservation and microirrigation water retention

Abstract Mulching is widely used worldwide to reduce soil water evaporation, but it can also intercept and retain rain or irrigation water, limiting infiltration into the soil and thereby altering the soil water balance. Microsprinkler irrigation in dwarf coconut orchards applies water in small, frequent doses, producing shallow, near‐surface wetting bulbs vulnerable to evaporative losses; under such conditions, mulch water retention becomes proportionally more critical to meeting crop demand. This study evaluated the trade‐off between microsprinkler irrigation water retention by mulch and soil water evaporation reduction and assessed their effects on soil wetting patterns in dwarf coconut systems. Treatments included bare soil, raffia, and coconut leaf mulch (10, 30, and 50 leaves), combined with two irrigation doses of 50 and 100 L plant − 1 day − 1 . Irrigation water retention was quantified using a highly absorbent surface methodology, and soil water profiles were monitored during the dry season with a capacitance probe. Coconut leaf mulch retained 51%–87% of irrigation water, compared with 6%–11% for raffia. Although greater retention reduced infiltration, coconut mulch provided more favorable soil moisture distribution for root uptake than raffia or bare soil. This paradox highlights the dual role of mulching: while reducing irrigation efficiency through interception, it enhances soil water conservation. These findings underscore the need to optimize irrigation management in sandy soils, particularly in coconut systems where leaf residues are readily available as mulch.