Spatial variability of soil water content at the crop row scale with and without straw mulch inside a corn field in semi-humid Northeastern China

Abstract Soil water content (SWC) is an important but highly variable element of hydrological cycle. Understanding SWC spatial variability at the crop row-scale is critical for improving management of water, soils, and crops. This study investigated the SWC spatial variability at the row scale in corn (Zea mays L.) after the fields were treated with straw mulch (FPM) or without straw mulch (FP) in 2013 and 2014. The spatial variability in SWC was assessed from five horizontal measurement points (MPs), at 10-, 30-, 50-, and 70-cm depths using time domain reflectometry. The spatial variability in SWC among the five MPs was statistically significant for 19–75% of sampling dates and was most often different between the two treatments at 10- and 30-cm depths. Straw mulch most strongly affected the spatial variability of SWC at a 10-cm depth, but this effect differed between the two years. With respect to SWC, the FP treatment exhibited a higher range and lower maximum standard deviation and coefficient of variation compared to those of the FPM treatment. In the majority of sampling dates (more than 60%), the most representative SWC estimates were obtained at MPs positioned at one-quarter into the inter-row gap.