al., 1998). In marketing contracts, farmers retain ownership and use the contract to specify price, quantity and quality of product to be delivered. About 10% of all US farms use a contract of some sort, with almost 50% of large commer­cial farms involved in contract production (MacDonald and Korb, 2006). Contract usage varies among commodities. In 2003, nearly 60% of hogs and almost 90% of poultry and eggs in the U.S. were sold through contract production, primarily production contracts. Crops like vegetables, fruit and rice tend to have higher rates of contracting than corn, soybeans, wheat and sugar beets. Marketing contracts are much more prevalent in crop production while production contracts predominate in livestock production. While con­tracting can provide risk management for producers, con­tract farming can also pose risks to social structure when it creates the structural equivalent of factory or piece-rate workers who lose control over decision-making or assets; and to  family well-being given the contractor grower's asymmetrical bargaining power relationship with integrat­ing firms (Hendrickson and James, 2005; Stofferahn, 2006; Hendrickson et al., 2008).

2.4   Changes in NAE Cropping Systems Since 1945

2.4.1  Changes in soil AKST and use since 1945
Soil is one of the basic natural resources and is vital for ag­ricultural productivity across NAE, a region with extensive amounts of productive soils. Knowledge of soil is critical to agriculture, especially in low input agricultural systems, such as organic agriculture. Traditionally, knowledge of soil type on a particular farm passed from one generation of

farmer to the next and traditional practices of manure ap­plication were followed to improved soil productivity. Since the end of the WWII, development and availability of soil analytical techniques has led to a more science-based ap­proach for increasing and conserving soil productivity.
     Soil testing facilities have been developed largely in re­sponse to issues related to agricultural productivity. Con­cerns such as nutrient depletion and acidification led to the establishment of soil testing programs at publicly-funded in­stitutes in the late 1930s to the early 1950s. These provided services to help farmers make decisions about fertilizer and lime applications (e.g., Olsen et al., 1954; Mehlich, 1984). In recognition that saline and alkali soil conditions reduced the value and productivity of considerable areas of land in the US, the United States Salinity Laboratory was created in 1947 (Richards, 1954). During the 1970s soil testing ex­panded, providing additional tests and services in response to renewed emphasis on the efficient use of agricultural in­puts such as fertilizers, largely due to the energy crisis and an increased public concern for the protection of water quality and prevention of pollution from chemical fertilizers. Simi­larly, increased ability to analyze trace elements allowed rec­ommendations to be given to farmers concerning shortages, excesses or trace elements.
     Until the 1980s, there was substantial investment by governments in soil science research, predominantly focused on soil productivity and aimed to increase agronomic yields. However, since the 1980s, this investment has decreased and the institutional knowledge about analytical methods for soils, water and plant material is lodged more and more in the US private sector (Prunty, 2004). In contrast, follow­ing shrinkage in the 1980s, soil science is re-emerging as