Soil stabilisation by water repellency under no-till management for soils with contrasting mineralogy and carbon quality

BEHRENDS KRAEMER, FILIPE; HALLETT, PAUL D.; MORRÁS, HÉCTOR; GARIBALDI, LUCAS; COSENTINO, DIEGO; DUVAL, MATÍAS; GALANTINI, JUAN

GEODERMA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2019 vol. 355

0016-7061

No-till soilmanagement is common around the globe, but the impacts on soilstructural quality varies depending on cropping practice and inherentsoil properties. This study explored water repellency as a driver ofsoil stabilization, as affected by soil mineralogy, granulometry andorganic carbon quality in three Mollisols and one Vertisol underno-till management and with different levels of cropping intensity.The studied soils were located along a west-east textural gradient inthe northern part of the Pampean region of Argentina. Croppingintensity treatments evaluated in each one of the soils were: PoorAgricultural Practices (PAP) close to a monoculture, GoodAgricultural Practices (GAP) involving a diverse crop rotation andmore targeted inputs, and the soil in the surrounding naturalenvironment (NE) as a reference. NE had the greatest aggregatestability (MWD) of all cropping intensities, with GAP being morestable than PAP for Mollisols and PAP being greater than GAP for theVertisol. This trend matched the Repellency Index (R index ), withgreater R index associated with greater MWD, including the differencebetween the Mollisols and Vertisol. However, the persistence of waterrepellency, measured by the Water Drop Penetration Time (WDPT) testfollowed the trend NE > GAP > PAP regardless of soil type. Theincreases in R index and MWD were related to higher intensificationas measured by the Crop Sequence Index, and decreased with greatersoybean occurrence in the sequence. Both WDPT and R index wereclosely related to aggregate stability, particularly for Mollisols.These results highlight the importance of considering the inherentsoil characteristics texture and mineralogy to understand aggregatestabilization mediated by water repellency. Good correlations betweensoil water repellency, organic carbon fractions and aggregatestability were found. Under no-till, crop rotations can be altered toincrease soil stability by inducing greater water repellency in thesoils. The findings suggest that water repellency is a major propertyinfluencing soil structure stabilization, thus providing a usefulquality indicator.p { margin-bottom: 0.25cm; line-height: 120%; }