Pedotransfer functions to estimate proctor test parameters under different tillage systems

ALVAREZ, CARINA R; MICUCCI, FEDERICO; BUSTINGORRI, C.; TABOADA, MIGUEL A

REVISTA BRASILEIRA DE CIêNCIA DO SOLO

SOC BRASILEIRA DE CIENCIA DO SOLO

Año: 2010 vol. 34 p. 1787 - 1793

0100-0683

The Proctor test is time-consuming and requires sampling of several kilogramsof soil. Proctor test parameters were predicted in Mollisols, Entisols and Vertisolsof the Pampean region of Argentina under different management systems. Theywere estimated from a minimum number of readily available soil properties (soiltexture, total organic C) and management (training data set; n = 73). The resultswere used to generate a soil compaction susceptibility model, which wassubsequently validated using a second group of independent data (test data set;n = 24). Soil maximum bulk density was estimated as follows: Maximum bulkdensity (Mg m-3) = 1.4756 - 0.00599 total organic C (g kg-1) + 0.0000275 sand (g kg-1)+ 0.0539 management. Management was equal to 0 for uncropped and untilledsoils and 1 for conventionally tilled soils. The established models predicted theProctor test parameters reasonably well, based on readily available soil properties.Tillage systems induced changes in the maximum bulk density regardless of totalorganic matter content or soil texture. The lower maximum apparent bulk densityvalues under no-tillage require a revision of the relative compaction thresholds fordifferent no-tillage crops.