Assessing the effect of conventional and conservation tillage methods on soil moisture under drought progression

Tillage is an agricultural practice that aims to create a favorable environment for crop production. Nonetheless, the intense field traffic by tillage, in the worst-case, is considered a detrimental anthropogenic practice to the soil. By impeding soil water movement, tillage might exacerbate the impact of droughts. To limit drought impacts, adapting tillage practices is one management option.

In this study, we aimed to evaluate the effect of tillage practices on soil moisture. For this purpose, we deployed 28 point-based plant care soil moisture sensors at 20 and 40 cm soil depths, in a farm field in Lower Saxony, Germany on silt loam divided into three different sections based on tillage type with different tillage depths (moldboard – 30 cm, chisel plow – 25 cm and disk harrow – 10 cm) implemented consistently for more than twenty years. The effect of tillage types on soil moisture was analyzed for different crop development phases of sugar beet and drought severity levels in 2022. For the latter, the soil water deficit index was used, which is computed based on soil moisture content at field capacity and permanent wilting point. Additionally, we ran DSSAT model simulations to evaluate the potential of nature-based solutions, such as no tillage and mulching, on maximizing soil moisture conservation during drought period.

Our result showed a temporal variability in soil moisture content between the three different mechanical tillage depending on the drought severity level. Moreover, our DSSAT simulation indicated that mulching tends to improve soil moisture content and to reduce runoff and soil evaporation.