Field-scale variability of topsoil dehydrogenase and cellulase activities as affected by variability of some physico-chemical properties

Abstract

We have studied spatial field-scale variability of soil dehydrogenase (DH) and cellulase activities (CEL) and their relationship with variability of some physico-chemical properties at the surface horizon of the agricultural field. Soil samples were collected at 50 points from the upper 20 cm of soil. The activity of DH ranged between 0.77 and 1.5 μM TPP·g-1·h-1 while CEL activity ranged from 0.8 to 1.94 μM glucose·g-1·24 h-1. Concentrations of CORG and TN varied from 8.5 to 31.7 g·kg-1 and from 0.94 to 3.56 g·kg-1, respectively. The soil data showed that spatial variability and semivariograms describe spherical and linear models with the nugget effect (DH, CEL, CORG and TN). Dehydrogenase activity was in the strong variability class, while cellulase activity was situated in the week variability class. Both CORG and TN concentrations and pHKCl values were strongly spatially dependent with the percentage of total variance (sill) presents as nugget variance ranging from 8.9% to 16.1%. Kriged maps displayed the lowest values of CEL activities in the north-east of the area, while the south area showed the highest CEL activity. The DH activity values were irregularly distributed in the surface horizon of the studied soil and this behaviour did not correspond with the spatial distribution of other properties. © 2010 The Author(s).