Temporal variability of soil water content and penetration resistance under different soil management practices

Abstract

This study analyzed the temporal induced variability of soil penetration resistance (PR) and soil water content (SWC) of eight soil treatments, which ranged four tillage systems (conventional tillage [CT], reduced tillage [RT], no-tillage [NT], and fallow no-tillage [FNT]), to four soil management treatments (abandoned soil [that is, control], compacted soil, CT on compacted soil [tilled], and application of super absorbent polymers [SAP] on abandoned soil). The treatments were arranged in 20 × 4 m (65.6 × 13.1 ft) plots with four replicates. The temporal variability of soil PR and SWC was determined using four measurement repetitions over time, from 2014 to 2015 (December, February, April, and June). A total of 64 soil samples (four replications × eight treatments × two soil depth layers) were collected for the analysis of the temporal variations of SWC at four different times. According to the study, soil PR and SWC were influenced by soil management and tillage systems. Also, the study indicated that PR and SWC varied over time. For different treatments, a second degree polynomial correlation between PR and soil depth was observed during all measurement times. Tillage practice on compacted soils resulted in a decrease in PR during all measurement times and in both depths. In general, for most of the investigated soil treatments, a low variability of SWC between treatments was obtained at a given measurement time. It was discovered that the effect of soil management and soil depth was significant for SWC, but the interaction between depth and management was not statistically significant for any measurement time. The effect of soil treatment and soil depth, and the interaction between them, was significant for PR at p < 0.01. Moreover, the effect of soil management and time, together with the interaction between them, was significant for both PR and SWC at p < 0.01. Consequently, the average of the values of PR and SWC indicated a clear temporal behavior.