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Improving water use efficiency is increasingly important as California agriculture confronts water shortages. Changing tillage and crop residue practices could help. In regions of the world where no-tillage systems are common -– such as Brazil, Argentina, Paraguay, Canada, Western Australia, the Dakotas, and Nebraska -– generating and preserving residues are an indispensable part of management and sustainable production. Residues reduce erosion, provide carbon and nitrogen to soil organisms, and reduce soil water evaporation, along with other advantages and drawbacks. The water conservation value of crop residues and conservation tillage has not been evaluated in the warm, Mediterranean climate of California. This study measured the effects of residues and no-tillage on soil water evaporation in California conditions.
California tomato producers need profitable technologies that guarantee long-term viability in the marketplace and on the farm. Production practices used by tomato farmers need to be affordable and also preserve or improve the long-term sustainability of production fields. Two practices that can help producers with economic and sustainability goals are covercropping and conservation tillage. While widely used in the 1940s, cover crops were not a mainstay of California production systems during the last half of the twentieth century. In recent years though, their potential benefits have received renewed attention by researchers and farmers, and there is interest in integrating them into tomato production systems. Cover crops provide soil cover, scavenge and recycle nutrients, break up monocultures, and add organic matter to production fields. But they require additional costs and careful management to be successfully integrated into tomato production systems. Conservation tillage (CT) practices include a number of tillage management approaches that reduce overall operations and costs. CT systems are also frequently associated with adjunct benefits such as lower dust and diesel emissions, reduced equipment maintenance, and lower total labor requirements. CT systems also require management “know-how” and up-front planning.
Cotton production in California’s San Joaquin Valley (SJV) relies on soil tillage for seedbed preparation, weed control, and postharvest pest management. Intensive tillage practices throughout the production season contribute to the crop’s yield and help producers manage risk. But these practices are costly, requiring considerable labor, specialized tillage implements, and adequate tractor horsepower. Despite incentives programs through the Farm Bill and USDA encouraging tillage reduction, along with rising costs of tillage, most SJV cotton continues to be produced using traditional, heavy tillage practices. Cotton is one of the most tillage-intensive agronomic crops produced in California; tillage systems for cotton have changed little over the past 50 years.
California farmers face increasing challenges due to labor and water availability, environmental regulations, and competition. Cheaper and more resource-conserving systems that rely on less labor are needed for profitable and sustainable production. Reducing tillage may significantly cut fuel use, labor, and costs in intensive production systems. However, most California farmers have little experience with these techniques.
Sustainable crop production in California’s San Joaquin Valley (SJV) relies on efficient management of increasingly scarce irrigation water and farm labor resources. SJV producers face powerful pressures for new, cheaper, and more efficient water-conserving cropping systems. A potential means for achieving greater farm production efficiencies may result from the merging of two new technologies that are widely used in other parts of the world, but not yet in California. Coupling overhead low-pressure center pivot irrigation with no-till practices may be a “systems” means for achieving the kinds of production efficiencies that will be required in the SJV in the future. The merging of these technologies is common in several regions of the world including the Pacific Northwest, throughout the Ogallala Aquifer region of the U.S. Great Plains, and in Brazil and Argentina, but neither technology is currently used much in California.
Conservation tillage (CT) production systems have been developed in a number of regions around the world for crops such as corn, wheat, cotton, and soybeans . Widespread adoption of CT practices for these crops is common in South Dakota, Iowa, Georgia, Australia, and Brazil; however, CT currently is used on less than 2 percent of California's annual cropland. CT production may be a means for improving production economics of farming systems while also sustaining air, water, and soil quality; but, little research-based information and experience about CT is available that addresses California’s diverse production environments.
Rising fuel and labor costs oblige growers to carefully cut production costs. Reducing intercrop tillage typically associated with bed preparation operations is a promising means to cut costs in tomato production systems. A variety of “conservation tillage” (CT) crop production systems have been developed in other regions for crops such as corn, wheat, soybean, and cotton. To what extent, though, might CT principles and practices be adapted to tomato production in California?
The US Environmental Protection Agency designated the San Joaquin Valley (SJV) a serious non-attainment area for PM10, particulate matter with an aerodynamic diameter less than 10µm. PM10 can bypass the body’s respiratory defense mechanisms and has been linked to cardiac and lung diseases. Because air quality violations occur during periods of intense tillage activity, row crop agriculture has been pinpointed as a major contributor of PM10. Conservation tillage (CT) production systems that reduce or eliminate tillage have been developed in other regions. Less than 2 percent of California’s annual acreage uses CT approaches. Do CT production practices reduce dust and can they be developed for California crops?
Diversifying crop rotations may be a means for reducing disease pressures and improving long-term productivity in California’s annual crop production valleys. Using “off-season” or intercrop cover crops might be a useful crop diversification strategy that also could add organic matter to the soil and improve soil function and quality. In general, farmers have little experience with cover-cropping practices and have been reluctant to use them.