Introduction: One of the biggest problems in cotton farming in the Comarca Lagunera, Mexico, is the low efficiency of irrigation, since the large quantities of water used for this crop result in water shortages.
Objectives: To determine the response function of the cotton crop to different soil moisture contents, as well as the water use efficiency.
Methodology: Seven treatments were evaluated in the field: 40-40, 40-80, 60-60, 60-100, 80-40, 80-80 and 100-60 % of available moisture consumed (AMC) by the cotton plant at two phenological stages. Treatments were distributed in a randomized block design with four replications.
Results: The highest cotton yield (8.7 Mg∙ha^-1) was obtained with the treatment that developed under 63 and 62 % AMC at the first and second stages of development, respectively, by consuming 97 cm of water.
Limitation of the study: The models do not predict satisfactorily when extrapolating outside the range of moisture levels considered in the study.
Originality: No studies have been reported on extreme favorable and unfavorable conditions of soil moisture content in cotton to know its productive response.
Conclusions: The obtained model maximizes cotton production (8.74 Mg∙ha^-1) with a water deficit of 59 and 56 % AMC. The highest water productivity (0.945 kg∙m^-3) was obtained with 81 and 82 % AMC and 78 cm of water consumption.