Consistent plant residue removal causes decrease in minimum soil water content in a Mediterranean environment

Residue retention and no-till farming have been widely adopted to reduce erosion risk, but residue retention in particular is becoming less common due to issues with weed control, and competing markets for residue such as bioenergy production. For this reason, the impact of residue removal on soil water contents in a sandy soil in a Mediterranean-type environment was evaluated. Crop residues were removed by burning or conventional tillage annually in autumn (April or May) from 2008 until 2011. Surface residue cover and soil water contents were measured in summer (February-March) every year from 2008 until 2012, at the time of minimum soil water content (approaching air-dry). After three years of residue removal, average ground cover in the subsequent summers (2011 and 2012) decreased from 78% to 51%, and surface soil water contents decreased from 5.1% to 3.1%. Tillage also significantly decreased ground cover (from 72% to 58%) and soil water (from 4.2% to 3.9%) during the same time period. Changes in surface cover and soil water content indicate that residue removal will have implications for soil health and sustainable crop production.