Effect of straw mulching on water consumption components and crop coefficients in a maize field.

Clarifying the components and regulatory mechanisms of evapotranspiration is essential for irrigation scheduling. In this study, straw mulching and non-mulching treatments were set up in a maize field with drip irrigation, where the water use and related factors were determined in 2014 and 2015. Straw mulching slightly reduced evapotranspiration by 2.6% on average for the two years. However, transpiration of straw mulching increased by 10.0% and 9.0% and soil evaporation decreased by 36.0% and 31.1%, compared to the non-mulching treatment for 2014 and 2015, respectively. Straw mulching decreased the average crop coefficients of the entire growth period (from 1.03 to 1.01) while increasing them in the mid-growth period (from 1.20 to 1.22). The net radiation above the canopy for straw mulching was 92.3%–96.3% of that for non-mulching treatment, which could explain the lower evapotranspiration of the mulching treatment. The daytime canopy conductance of straw mulching was 30% higher than that of non-mulching treatment, which could potentially result in higher biomass. This study provided essential parameters for water management of drip irrigation maize fields with straw mulching in similar areas. [ABSTRACT FROM AUTHOR]