Temporal variability in water content, temperature, and electrical conductivity of sandy soil: Responses to soil-improving cropping systems (SICS)

Abstract

There is little information on the effect of soil-improving cropping systems (SICS) on the temporal variability of soil volumetric water content (WC), temperature (T), soil temperature amplitude (A_T), and electrical conductivity (EC) in low-quality sandy soils although they are increasingly being used in agriculture. The objective of this study was to determine the effects of the following SICS: liming (L), leguminous catch crops for green manure (LU), farmyard manure (M), and liming + leguminous catch crops for green manure + farmyard manure together (LLUM), and the control (C) on temporal changes in the three properties simultaneously in a field experiment on sandy soil established in 2016 in Poland. The monitoring was performed using TEROS 12 sensors in the soil layers of 5–10, 20–25, and 30–35 cm from 25 April 2019–30 April 2020 with spring wheat as the main crop. The results showed that the average WC over the entire investigation period in the 5–10 cm layer was 0.206 m3 m–3 in the control and increased in the L, LU, M, and LLUM variants to 0.245, 0.219, 0.241, 0.262 m3 m–3, respectively. The highest WC was recorded in the LLUM system during most of the investigation period. The average T in the 5–10 cm layer increased in L, LU, and M by 0.221–0.262 °C and in LLUM by 0.052 °C. The average monthly soil temperature amplitudes in the soil layer 5–10 cm tended to be higher under all SICS vs. C except LLUM vs. C. The average EC in the 5–10 cm layer in variant C (0.066 mS cm–1) increased in the L, LU, M, and LLUM systems to 0.067, 0.090, 0.151, and 0.107 mS cm–1, respectively. The shapes of the temporal variability of WC and EC were similar in all SICSs, while the increase in the response to the combined effects of the SICSs and precipitation during the growing season was greater for the EC. The temporal variability of all soil properties in response to the SICSs and weather course and their averages declined with depth. The amplitudes of soil T in all treatments were lowest in the 30–35 cm layer. This study provides helpful information for the selection of the most suitable SICS in terms of soil properties influencing productivity and other soil functions.