THE IMPACT OF LAND USE PRACTICE AND HISTORY ON THE PHYSICAL AND HYDROLOGIC PROPERTIES OF SOME CONNECTICUT SOILS

An experiment was designed to observe the soil physical and hydrologic properties across several land uses and determine their recovery following historical agricultural use. These land uses include a cornfield (CF), a wooded area (WA), and hay/pastureland (HP); each located on the floodplain of the Housatonic River in Salisbury, Connecticut. Three 5x5 meter grids were designated for each land-use, and soil samples and cores were requisitioned from each to analyze soil moisture (SM), soil texture, aggregate size distribution, bulk density, and soil carbon/organic matter (SOM) in the lab. The soil infiltration rates and surface penetration resistance (SPR) were measured in the field. Bulk density results indicate that the CF and HP had near identical average values at 1.361 to 1.358, while WA yielded an average bulk density 35% lower. The SPR of WA ranged from 40-100 lb/in² at each depth interval (0, 10, 20cm), while the CF and HP readings at 20cm depth frequently exceeded 250 lb/in². A CF plot yielded the highest average SPR at over 300 lb/in². At the shallowest depths, the SOM values for the HP and CF plots were 4-5% of the total mass, whereas the WA plot contained about 9% SOM which decreased with depth to values similar to the CF and HP plots. The higher WA SM content appears to be correlated with the higher SOM content, with 38.2% moisture by weight at the surface, dropping drastically to 27.4% with depth. The CF and HP SM values did not vary significantly and stayed in a fine range (~13-17% for HP, ~20-21% for CF). Infiltration rates were similar for HP and WA plots while the rates in CF plots were slower. In general, soil textures were similar in preliminary analysis. The samples were fine sandy loams to silt loams at the surface, coarsening with depth. Observation of the samples collected for soil aggregation indicated a greater amount of macro-aggregates and micro-aggregates in the WA samples, with the HP and CF samples appearing similar. These data sets correlate and represent a significant reduction in soil quality for values yielded from samples in agricultural settings. Furthermore, recovery of the HP samples from corn cultivation was statistically insignificant over 6 years. This experiment is unique to the locale, and provides insight into hydrologic changes stemming from agriculture that may be applicable on a global scale.