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Open Access Publications from the University of California


California Agriculture is a quarterly peer-reviewed journal reporting research, reviews and news on California’s agricultural, natural and human resources.

Volume 56, Issue 1, 2002

Issue cover


Agricultural easement programs . . . Saving agriculture or saving the environment?

California has 34 local conservation organizations, land trusts and open space districts that seek to protect farmland through conservation easements. In an examination of their mission statements and interviews with managers, we found variations in the extent to which the same easements protect both agricultural production and natural resources. Because they frequently protect farm operations that involve intense cultivation, cropland easements tend to be seen as incompatible with natural resource purposes such as riparian areas, habitat, wetlands and recreational trails.

Agricultural easements limited geographically

A review of conservation programs in the state shows that agricultural easements are concentrated in central coastal counties. Many of these counties, such as Marin and Sonoma, are not top agricultural regions, while some of the state’s most productive agricultural counties have no easement programs at all. To date, there are approximately 120,000 California farmland acres in easements, nearly 80% of them grazing land and the rest in crops. Our review shows that state coastal conservation programs and sentiments among local populations are major reasons why easements are plentiful in some counties and not in others.

Landowners, while pleased with agricultural easements, suggest improvements

We extensively interviewed 46 landowners in two northern Bay Area counties and nearby Yolo County to assess their satisfaction with agricultural conservation easements. The landowners in most cases were enthusiastic sellers of the easements; their motivations included cash, keeping land in the family and conservation. They reported generally satisfactory experiences with the easement programs. To a lesser degree they expressed concerns about certain aspects of the easement process, especially negotiations and monitoring, and suggested ways that easement programs can improve their relationships with landowners.

Eradication costs calculated . . . Red imported fire ants threaten agriculture, wildlife and homes

The red imported fire ant, a pest newly introduced into California, threatens households, agriculture and wildlife. This study estimates the costs and benefits of a public program to eradicate the ants. The results show that almost all agricultural activities would be affected should the ants become established; however, households would incur the majority of costs. The total estimated cost if red imported fire ants become established would be between $387 million and $989 million per year in California. Given current funding levels for eradication of red imported fire ants, for the expected benefits to be at least as great as the expected costs, the probability of successfully eradicating the ants needs to be at least 0.65% if the annual costs of establishment are $989 million and 1.67% if they are $387 million.

Minimum tillage practices affect disease and yield of lettuce

Vegetable growers have been experimenting with reduced tillage practices to increase soil organic matter, limit compaction, and reduce fuel and labor costs. We studied soil properties of different tillage practices and compared deep minimum tillage (chiseling and ripping) with shallow minimum tillage for lettuce on a farm in the Salinas Valley. We found that periodic deep minimum tillage is recommended for long-term retention of semipermanent, raised beds in lettuce production. Over a period of several years, deep minimum tillage increased lettuce yield and decreased symptoms of lettuce drop disease, as compared with shallow minimum tillage. Continuous shallow minimum tillage, despite a trend toward higher active and total organic matter in the surface layer of soil, is best used with intermittent deeper tillage to avoid disease and yield losses.