Do conservative agriculture practices increase soil water repellency? A case study in citrus-cropped soils

Water repellency is a property of soils that inhibits or delays infiltration. Long-term conservation practices as no-tillage, manure addition, application of herbicides may contribute to increase soil organic matter and, hence, soil water repellency. In this research, we have studied the effect of long-term addition of plant residues and organic manure, no-tillage and no chemical fertilization (MNT), annual addition of plant residues and no-tillage (NT), application of conventional herbicides and no-tillage (H), and conventional tillage (CT) on soil water repellency in Mediterranean calcareous citrus-cropped soils (Eastern Spain). Slight water repellency was observed in MNT soils, which may be attributed to the input of hydrophobic organic compounds as a consequence of the addition of plant residues and organic manure such has been demonstrated by the soil organic matter measurements. CT reduced the organic matter content and soils remained wettable. Subcritical water repellency (with water drop penetration times below 5 s) was observed in soils under NT and H treatments.