Little information exists regarding the effects of field‐scale application of paper mill sludge on soil properties. A 5‐yr field study determined the long‐term effects of land application of paper mill sludge on an agricultural soil. The goal of this study was to determine the responses of soil chemical and physical properties to multiple applications of sludge. Five rates of sludge application were tested, ranging from 0 to 225 Mg ha−1 in multiple applications under three management protocols: applied once, applied in alternate years, or applied annually. Results indicate strong relationships between added sludge C and several soil physical properties. Increases or maintenance of soil C were observed when sludge was applied annually or biennially, but little residual effect of the single application was seen after 5 yr. Significant increases were observed in soil aggregation and moisture holding properties at higher rates of sludge application and when cumulative C additions reached 225 Mg ha−1 in other sludge application rates. It was concluded that long‐term paper mill sludge application can be managed to effect positive changes in soil physical properties that are correlated to soil quality.

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In many upland areas on glaciated landscapes, it is difficult to examine soil profiles and determine the depth to bedrock. Glacial rock fragments and irregular or weathered bedrock surfaces limit the effectiveness of auger techniques. While general trends can be inferred from the landscape, depth to bedrock or thickness of till cannot be accurately predicted from landscape position alone. Therefore, ground‐penetrating radar (GPR) was used to map the depth to bedrock for two study sites in Maine. Data were used to (i) determine the variability of the depth to bedrock in similar delineated areas of a map unit, (ii) compare the accuracy of GPR with auger methods, and (iii) evaluate the performance of GPR on a glaciated landscape in Maine. Results were confirmed by studying a trench excavated to bedrock. These results indicated that GPR techniques were more reliable and effective than conventional auger techniques for determining the depth to bedrock, and thus for determining the composition of map units that are based on soil‐depth criteria. Additionally, the screw auger was shown to be an unreliable tool for determining soil depths in moderately coarse‐textured tills having large amounts of coarse fragments.

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The effect of application methods on movement and degradation of aldicarb residues was studied in a typically stony, Maine potato field by comparing aldicarb applied in‐furrow at planting with aldicarb top‐dressed at emergence. At the end of the growing season, residues from the at‐planting application were found primarily in the top 0.6 m of soil and the residues from the emergence application were found primarily in the top 0.3 m. One year later, the residues were dispersed throughout the top 1.5 m of soil and had been reduced to about 5% of the original application. This study supports other work that has demonstrated that in the northeastern United States and Wisconsin, early aldicarb at‐planting applications generally result in greater aldicarb residue movement than do later emergence applications. The study is also useful in illustrating variability of soil samples, which exhibited an average coefficient of variation of 110%. The results indicate that little information is lost due to compositing samples, so that compositing samples appears to be an option for reducing analytical costs associated with soil studies.

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