Soil moisture variability affected by sand mulch: An isotope-based assessment of irrigated farmland in Northwest China

As a practical agricultural technique in Northwest China, the sand mulch reduces the soil moisture loss of irrigated farmland under an arid setting. To understand the soil moisture variability affected by sand mulch, we selected an irrigated orchard of peach (Amygdalus persica L.) in Northwest China and examined the soil moisture movement conditioned by irrigation using a stable water isotope method. Based on the isotopic variability of continuously collected soil, plant, and irrigation water samples, the infiltration and evaporation of soil moisture were assessed. The results showed that (1) during the sampling period, the average soil water content and infiltration volume of the sand mulch plot were 1.63% and 6.82%, respectively, which are higher than those of the uncovered plot, indicating a better soil water retention after sand mulch. (2) The slope of the evaporation line of the sand mulch plot (4.79) was greater than that of the uncovered plot (4.11), and the average evaporation loss of the sand mulch plot (0-30 cm) was 10.29% lower than that of the uncovered plot. The average evaporation rate of the sand mulch plot was 5.02% per day, which is lower than that of the uncovered plot 8.41% per day. The isotope-based evidence shows that sand mulch effectively reduces soil water evaporation, which provides a theoretical basis for agricultural water management and optimization of water-saving methods for arid land.

Automated summary

Research shows that sand mulch can reduce the evaporation loss of soil moisture in farmland and improve soil water retention. This provides a theoretical basis for agricultural water management and water-saving methods in arid regions.