Enhancing Resource Efficiency by Integrating Legumes and CoProducts Into Modern Agricultural Systems
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The world population is expected to exceed 9 billion in 40 years (United Nations, 2011). Soil conservation and improved efficiency of resource (water and fertilizer) use is critical to feeding this growing population. The pressure that agriculture is facing to produce more food while conserving natural resources such as soil, water, and nutrients is compounded by an increase in the middle-income population and the related demand for food, fuel, and fiber. Conservation agriculture and resource efficient technologies are available in the United States, but are only regionally adopted. Advances in plant genetics and machinery, and availability of cheap energy and inorganic fertilizer greatly improved agricultural productivity during the Green Revolution. The Green Revolution resulted in a shift from diverse agricultural enterprises into highly mechanized and specialized production units. Today, a growing awareness is emerging that the stability and resiliency of agricultural lands appear to be impaired by specialization, concentration of operations and expansion of scale which have compartmentalized and disrupted nutrient cycling far removed from natural ecosystem cycling (Gates, 2003; Franzluebbers, 2007).In the South Texas Plains, the primary agriculture commodities produced are cotton, corn, and cattle. Steadily decreasing water availability, more frequent and severe drought conditions, and increasing costs of fuel, fertilizer, and labor require maximum efficiency for economically and environmentally stable agricultural systems. As a result of these economic drivers, land tracts are still large, but average acreage is decreasing and where cattle are produced, the primary profit is shifting from beef cattle production to wildlife hunting leases. New management practices that maximize resource efficiency and conserve natural resources are necessary in order to maintain agriculture production in south Texas. One of these management shifts is the replacement of introduced forages with native forages in pastures. Besides providing nutrition for grazing livestock, forages in the region are also important for maintaining water quality and providing erosion control along waterways and near the Gulf of Mexico. Using forages for soil remediation caused by salt contamination and in rotation with traditional row cropping systems also have potential for this region in the future. Another management shift is the introduction of conservation tillage into the region, which may increase the potential success of cover crops, which reduce soil erosion. Conservation tillage has been shown to decrease soil erosion, soil temperatures, and evaporative water loss, and increase water infiltration (Pimentel et al., 1995; Reeves, 1997; Kay and VandenBygaart, 2002). Since increases in soil organic C (SOC) and decreases in mechanical soil disturbance are two hallmarks of conservation tillage systems, a conservation tillage system is expected to improve water capture and availability over the long-term timeframe.........