No abstract

Fertile soils are essential for human health and nutrition and formed the foundation of human economies for millennia. Soils deserve close attention from environmental and economic historians and sustainability scientists. Most soil history literature addresses failure: misuse of soil, uncontrolled erosion, and the resulting collapse of past civilizations. More important, however, and of urgent interest for our present and future prosperity, are the mundane ways that historical farm communities sustained soil health, even while cultivating the same land for centuries. This article explains five strategies by which European and North American farmers accessed, recycled, replenished, and sustained soil fertility over 250 years. By evaluating inputs, extractions, transfers, and annual balances of potassium, phosphorus, and, especially, nitrogen, it models historical soil management in a variety of agroecosystems in various geographical settings and through time. This biophysical environmental history, based on socioecological metabolism methods borrowed from sustainability science, reveals ongoing adaptation to shifting social and environmental contexts. As industrialization, global trade, and population accelerated, farmers adjusted their soil fertility strategies to keep up with new pressures and opportunities. Each solution to existing soil fertility constraints created new obstacles and bottlenecks. Through the past quarter millennium, farm sustainability meant constant readjustment to new circumstances. As farmers innovated crop choices and rotations, corralled livestock, adopted new technologies, deployed novel energy sources, and expanded into new lands, they increased food productivity to feed growing world population and supply expanding markets, while maintaining the supply of soil nutrients necessary to fertilize next year’s crop.

Caregiver reciprocity is the collective affective and behavioral expression of exchanges given and received between a caregiver and care receiver, and among family members. This psychometric investigation was designed to further examine the reliability and validity of the revised Caregiver Reciprocity Scale II (CRSII). Items were rewritten to reflect valued exchanges and balance among the entire family network, including spouses. An alpha of .83 for Warmth and Regard; .73 for Intrinsic Rewards of Giving; .83 for Love and Affection; and .75 for Balance Within Family Caregiving indicated acceptable internal consistency. The study, conducted with 176 spouse or adult children caregivers, provides additional support for the conceptual model of the four-factor solution. Construct validity was supported by the standardized factor loadings and goodness-of-fit indices obtained from confirmatory factor analysis. The results of the analysis of the measurement model, taken as a whole, demonstrate that the CRS II has adequate psychometric properties. Model parsimony was supported by an AGFI of .87, combined with an adjusted chisquare between 1.0 to 3.0. All but two item loadings were greater than .50. This, combined with the fact that all standardized loadings were twice the standardized errors and t-values were greater than 2.0, contributes to concluding that convergent validity was strong. Discriminant validity, evaluated by variance extracted estimates, and confidence interval (± two standard errors) around the correlation estimate between factors, was adequate. This study provided evidence to support the reliability and validity of the CRS II.

Using a socioecological metabolism approach to analyze data from the Census of Agriculture, this article examines the underlying soil fertility of two case study areas in the Canadian province of Saskatchewan through the calculation of soil nitrogen balances. The Rural Municipalities of Wise Creek and Livingston are 300 miles apart and therefore have different topography, soil types, and rainfall levels, even though both are within the northern Great Plains. Over 85 years, from first settlement in the 1910s until the beginning of the twenty-first century, Wise Creek agriculture focused increasingly on livestock production while in Livingston farmers began to grow a greater variety of crops, most notably incorporating canola into rotations. Despite the differences between the two case studies, the pattern of soil nitrogen losses was remarkably similar, with biomass yields declining along with soil nitrogen. The addition of chemical nitrogen fertilizers since the 1960s did not produce yields matching historic highs, nor did a renewed focus on livestock. Wise Creek and Livingston showed two different responses to declining yields, but neither one ultimately provided a long-term solution to the problem of soil nutrient depletion and consequent productivity declines.