Abstract: | Geostatistical techniques were used to quantify the scale and degree of soil heterogeneity in 2 m2 plots around 9-year-old poplar trees and within a wheat field. Samples were taken during two years, on an unaligned grid,
for analysis of soil respiration, C and N content, available P, gravimetric moisture, pH, nitrification potential, and root
biomass. Kriged maps of soil respiration, moisture, and C content showed strong spatial structure associated with poplar trees
but not with wheat rows. All soil properties showed higher autocorrelation in June than in April. Isopleth patchiness for
all variates was less in June. This was associated with lower respiration rates due to lower litter decomposition. From the
degree and scale of heterogeneity seen in this study, we conclude that the main causes of soil heterogeneity at this scale
(2 m2) are likely to be found at micro scales controlled in part by plant root and plant residue patterns. These must be understood
in the evaluation of ecosystem processes.
This revised version was published online in June 2006 with corrections to the Cover Date. |