Evaporation of maize crop under mulch film and soil covered drip irrigation: field assessment and modelling on West Liaohe Plain, China

Abstract Due to existing problems related to drip irrigation under the conditions of mulching and the vigorous promotion of soil covered drip irrigation without film, drip irrigation experiments were conducted in 2017 and 2018 in order to explore the mechanism of water conservation. Three different irrigation treatments were adopted in this study: high, middle, and low irrigation quotas. In addition, two different experiment areas were selected: Taking mulching as an example, Zone I (film covered area) and Zone Ⅱ (bare soil area). For comparison, the division of zone with soil covered drip irrigation without film was the same as that with the mulching film. The two zones were designed to analyze soil evaporation regularity based on a calibrated SIMDualKc model under the conditions of both mulched drip irrigation and soil covered drip irrigation without film, respectively. The results showed that the SIMDualKc model could potentially be applied to simulate the soil water content and evaporation rates with a higher accuracy. The soil evaporation in high-water treatment was 13% higher than that in medium-water treatment, and that in low-water treatment was 5% lower than that in medium-water treatment under the soil covered drip irrigation without film conditions. The evaporation rates were only 0.67 mm and 36.18 mm in the Zone I and Zone II areas under mulched drip irrigation conditions, respectively. The water conservation had mainly occurred in the mulched area (Zone I) where mulched drip irrigation methods were utilized, and the evaporation was much less than that of the areas where soil covered drip irrigation without film methods were implemented. The results obtained in this study may provide a theoretical basis for future maize production under the conditions of both mulched drip irrigation and soil covered drip irrigation without film processes.