Temporal variation of soil physical quality under conventional and no-till systems

SORACCO, CARLOS GERMAN; LOZANO, LUIS ALBERTO; VILLARREAL, RAFAEL; MELANI, E.; SARLI, GUILLERMO OLIVERIO

REVISTA BRASILEIRA DE CIêNCIA DO SOLO

SOC BRASILEIRA DE CIENCIA DO SOLO

Lugar: Vicosa; Año: 2018

0100-0683

The objective of this study was to assess the effects of no tillage (NT) and conventional tillage (CT) on temporal variation of capacity (bulk density, BD; macroporosity, Pmac; Air capacity, AC; plant available water capacity, PAWC; Relative field capacity, RFC; Dexter´s S; and Structural stability index, SSI), and dynamic soil physical quality (SPQ) indicators (Field saturated hydraulic conductivity, K0; Water-conducting macro and mesoporosity, εma and εme; and pore continuity indexes based on water flux of total porosity, macroporosity and mesoporosity, CWTP, CWmac, Cwmes). Additionally, the effect of soil management system on corn yield was evaluated. Soil sampling and infiltration runs were carried out in four different moments of corn growing season (BS: before seeding, V6: six leaf stage, R5: physiological maturity, and AH: after harvesting). Capacity SPQ indicators were derived of soil water retention curve determined using sand box and pressure chambers, and dynamic indicators were derived of field infiltration data measured using tension disc infiltrometer. Most capacity SPQ indicators were affected by sampling moment, but followed similar trends and presented similar values under both treatments, particularly AH. Dynamic SPQ indicators varied differently during the growing season depending on the management system. Under NT most dynamic indicators increase from BS to V6, decreasing again AH, while under CT follow a different trend, decreasing from BS to V6, remaining constant until R5, and increasing AH. Corn yield was higher under NT (NT: 10939 kg.ha-1, CT: 8265 kg.ha-1). These results emphasize the need of including dynamic SPQ indicators, and its temporal variation when evaluating cropping systems intending to model crop yields. The capacity SPQ indicators were not able to distinguish between treatments. Future studies, following years with different weather conditions (rainfall and temperature), would be useful to improve the knowledge on this topic.