An energy-based aggregate stability method is more management-sensitive than commercial methods in coarse-textured, subtropical orchard soils

Abstract

Aggregate stability impacts important soil functions, including carbon/water storage and soil structure. Macroaggregate stability tests, using rainfall simulation or wet sieving, are commonly used, but microaggregate stability tests may be more applicable to subtropical, coarse-textured soils. We compared different cover crops in two sites of different maturities within a commercial citrus orchard in southwest Florida to test the applicability of four aggregate stability methods for coarse-textured soils. Macroaggregate stability tests (i.e., volumetric aggregate stability test, Cornell sprinkle infiltrometer, Eijkelkamp wet sieve apparatus) did not significantly respond to cover cropping. In contrast, all soil dispersion (SD) curve indicators significantly responded in one orchard, with more favorable values in the weedy grower standard relative to the non-legume mixture. Also, most SD indicators were significantly and positively associated with soil protein, total carbon, and carbon mineralization. This study highlights the potential of SD indicators to inform soil health management in coarse-textured, subtropical soils.

Core Ideas

• The management-sensitivity of four aggregate stability methods was tested on coarse-textured, low carbon soils.
• Cover crops did not significantly impact macroaggregate stability indexed by wet sieving and rainfall simulation.
• Microaggregate stability indicators were responsive to management and correlated with carbon cycling indicators.