Soil Hardness Measurements in Relation to Soil Moisture Content and Porosity

Abstract A method of adjusting penetrometer measurements so as to express soil porosity conditions is presented. The best simple function giving high correlations with macroporosity in the Decatur clay and the sandy clay subsoil of Greenville fine sandy loam was log (ϑH 1/2 ) where ϑ was field moisture percentage and H the hammer blows required to cut a soil core. The hardness function can be used to estimate macroporosity and compares favorably with the latter in relationship to depth of rooting, growth, and height of cotton plants.