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The article focuses on the use of agricultural lands and soil carbon in the U.S. It mentions that land management and productivity were restored after the Dust Bowl and the World War II including the use of agricultural chemical, the improvement in crop varieties and the greater mechanization. It also underscores the development of several land conservation programs such as the Soil Bank Program in 1956. The role of soil organic carbon in the country's agricultural land is also explored.

Tolerable soil toss (T) is defined as the maximum rate of annual soil erosion that economically and indefinitely will continue to sustain a high level of crop productivity. Currently a T value is assigned to a soil based on its current functional state and structural integrity. However, in India a default T value of 11.2 Mg ha-1 yr-1 (5.0 t ac-1 yr-1) is being followed. Our objective is to provide adjusted T values for India's Northwest Himalayan region by incorporating bulk density, water stable aggregate measurements, infiltration rate, soil carbon, and fertility status into the assessment. A quantitative model was used to sum up overall soil performance to define the current state of soil resource. Scaling functions were used to convert soil parameters to a 0 to 1 scale. The normalized values were then multiplied by appropriate weighting factors based on relative importance and sensitivity analysis of each indicator. A categorical ranking of soil 1, 2, or 3 was given to a soil group based on the overall assessment. A general guideline developed by the USDA-Natural Resources Conservation Service (NRCS) was followed to calculate soil loss tolerance for each soil group using effective soil depth. Adjusted T values for the area ranged between 5.0 and 12.5 Mg ha-1 yr-1 (2.2 and 5.6 t ac-1 yr1) compared to 11.2 Mg ha-1 yr-1 (5.0 t ac-1 yr1). Use of the adjusted T values will improve conservation planning, help meet erosion control regulations for development of sustainable farm operations, and improve watershed management in this portion of India. [ABSTRACT FROM AUTHOR]

The threat of global climate change has provoked policy-makers to consider plausible strategies to slow the accumulation of greenhouse gases--especially carbon dioxide (CO2)--in the atmosphere. One such idea involves the sequestration of atmospheric carbon (C) in degraded agricultural soils as part of the Conservation Reserve Program (CRP). While the potential for significant C sequestration in CRP grassland ecosystems has been demonstrated, the paired-site sampling approach traditionally used to quantify soil C changes has not been evaluated with robust statistical analysis. In this study, 14 paired CRP (> 8 years old) and cropland sites in Dane County, Wisconsin, were used to assess whether a paired-site sampling design could detect statistically significant differences (ANOVA) in mean soil organic C and total nitrogen (N) storage. We compared 0 to 10 cm (0 to 3.9 in) bulk density and sampled soils (0 to 5 cm, 5 to 10 cm, and 10 to 25 cm [0 to 2 in, 2 to 3.9 in, and 3.9 to 9.8 in]) for textural differences and chemical analysis of organic matter (OM), soil organic C (SOC), total N, and pH. The CRP contributed to reducing soil bulk density by 13% (p < 0.0001) and increased SOC and OM storage (kg m-2 [lb ft-2]) by 13% to 17% in the 0 to 5 cm (2 in) layer (p = 0.1). We tested the statistical power associated with ANOVA for measured soil properties and calculated minimum detectable differences (MDD). We concluded that 40 to 65 paired sites and soil sampling in 5 cm (2 in) increments near the surface were needed to achieve an 80% confidence level (a = 0.05; b = 0.20) in soil C and N sequestration rates. Because soil C and total N storage was highly variable among these sites (CVs > 20%), only a 23% to 29% change in existing total organic C and N pools could be reliably detected. While C and N sequestration (247 kg C ha-1 yr-1 and 17 kg N ha-1 yr-1 [220 lb C ac-1 and 15 lb N ac-1]) may be occurring and confined to the surface 5 cm (2 in) as part of the Wisconsin CRP, our sampling design did not statistically support the desired 80% confidence level. We conclude that usage of statistical power analysis is essential to insure a high level of confidence in soil C and N sequestration rates that are quantified using paired plots. [ABSTRACT FROM AUTHOR]