Capacity and Intensity Indicators to evaluate the effect of different crop sequences and cover crops on soil physical quality of two different textured soils from Pampas Region

SALAZAR, M.P.; LOZANO L.A.; VILLARREAL, RAFAEL; IRIZAR, A.; BARRACO, M; POLICH, NICOLAS; SORACCO C.G.

SOIL & TILLAGE RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2022

0167-1987

Soil physical degradation is a current problem in Molisols of the Pampas Region underno-tillage (NT), that has been related to over-simplified agricultural systems with scarceor no rotations and long winter bare fallows. Soil physical quality (SPQ) is a key factorof soil health and productivity, as it controls root development and air and water fluxesand storage in the soil, which in turn affect nutrient uptake and plant growth. Covercrops have been proposed as a companion agricultural practice to improve NTperformance and SPQ. The aim of this study was to evaluate the effect of the inclusionof winter cover crops in different cropping sequences on capacity and intensityindicators of SPQ in two soils of different texture under NT and to compare it withdifferent traditional crop sequences, including non-agricultural plots. SPQ wasevaluated at two different sites, one with a silty loam Argiudoll and the other with asandy loam Hapludoll. Treatments included plots with and without cover crops, withdifferent summer crop sequences (continuous soybean and corn ? soybean rotations).Also, a corn ? wheat/soybean rotation with and without pastures was evaluated. Alltreatments had more than 15 years under the same management. We measured soilorganic carbon (SOC), and capacity SPQ indicators (bulk density, total porosity, poresize distribution, air capacity, plant available water, relative field capacity and S index).We also measured dynamic SPQ indicators derived from field infiltration tests(saturated and near saturation hydraulic conductivity, effective macro andmesoporosity, and porosity connectivity indexes for different pore families). On the siltyloam Argiudoll, cover crops increased SOC but failed to improve SPQ. This wasrelated to soil physical degradation and the low ability of these soils for structureregeneration. On the sandy loam Hapludoll, cover crops had mixed effects on SOCand pore size distribution, but increased near saturation hydraulic conductivity, in thecase of the corn ? soybean rotation with cover crops, reaching values similar to thoseof a natural grassland.