Suchergebnisse

AbstractIn contrast to most long-settled agricultural landscapes, the US Great Plains presents a rare example of well-documented agricultural colonization of new land. The Census of Agriculture provides detailed information about evolving grassland farm systems from the beginning of agricultural expansion and then at some two dozen time points between 1880 and the present. From early sod-busting, through drought and depression, and into late-twentieth-century modernization, it is possible to track how farmers used their land in any county. Treating farmland as an agroecosystem, a hybrid human-natural landscape, this article asks how farmers captured, altered, and replenished soil fertility. Did they extract more soil nitrogen than they returned, or did they maintain a balance? The article assesses land use from a soil nutrients perspective in several plains environments to capture variation in climate (especially rainfall), native soil quality, and availability of irrigation water. It traces farm management strategies through time to understand agricultural crises, growth periods, and technological transitions in the context of soil fertility. Soil management on an agricultural frontier was markedly different from that in places that had been farmed for centuries. A shortage of people and livestock and an abundance of deep, rich soils in the plains informed farmers' calculations as they juggled labor, capital, and market forces against family and financial strategies. Uniform methods of estimating and representing soil nutrient processes make possible a direct comparison of the relative sustainability of historical agroecosystems.

AbstractFertile 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.