Intensive cultivation in a potato/grain rotation system in southeast Idaho has reduced soil organic matter and subsequently crop yields and potato tuber quality. Application of soil amendments (e.g., compost and manure) can improve yield potential and increase soil fertility and organic matter content. A study was conducted to determine the effects of soil amendments on organic matter (OM), nitrogen (N), phosphorus (P), yield, and tuber quality. A four year rotation (winter wheat, winter wheat, alfalfa, and potatoes) with compost added before planting was compared to the same rotation without soil amendment. The compost source was steer feedlot manure (11.2 g kg^-1 N and 7.0 g kg ^-1 P) and was applied before planting at the rate of 6.7 Mg ha^-1 for wheat and alfalfa and at 11.2 Mg ha^-1 for potatoes. Research plots were located on two intensively cultivated soils which were a Blackfoot silt loam and a Pocatello variant silt loam near Rexburg, Idaho. Soil samples were taken before planting and compared with native soils which included undisturbed soils from the same soil type as the research plots and similar soil types under native vegetation. For the research plot soils, CEC ranged from 12 to 15 cmol_c kg^-1 and historical yields of 4.0 to 6.7 Mg ha^-1 for wheat and 33.7 to 39.3 Mg ha^-1 for potatoes. Soil OM varied from 15 to 20 g kg^-1 for the research plots and from 20 to 50 g kg^-1 for the native soils. This study is on going, and data for composting effects on yield, tuber quality, OM, and fertility levels will be collected during or following fall harvest.  It is expected that composting will increasing soil carbon levels and provide nutrients to the plant which will reduce the amount of fertilizers need to obtain optimal crop yields and quality.