California mirrors national development trends that found one third of all of land ever developed in the lower 48 states has been developed in the last 25 years.
The finding comes from the National Resources Inventory (NRI), a national land use survey released every five years. Results were just released for the period 2002-2007.
The NRI is a survey of the nation's non-federal lands conducted by the USDA Natural Resources Conservation Service in cooperation with Iowa State University since 1982. It documents natural resource conditions and trends, including the conversion of agricultural land to developed uses, and is the most comprehensive natural resource database in the nation.
California converted 2.1 million acres to urban uses between 1982 and 2007. At the same time losses were experienced in cropland (900,000 acres), rangeland (1,600,000 acres), and forestland (500,000 acres).
The rate of urban gains has not been equal over time and the seven percent increase in development for the just-released 2002-2007 time period is lower than for other five-year periods since the survey began.
Within the overall story of development and farmland loss there are other trends of note. The loss of prime farmland, those soils best suited to produce food with the fewest inputs and the least erosion, is particularly troubling.
California ranked fourth nationwide in losing such soils between 1982 and 2007. However, between 2002 and 2007 the loss of prime farmland in California stabilized and even experienced a minute increase.
Another trend shows a significant change in the make-up of California agriculture regarding cultivated (typically annual) crops versus non-cultivated crops (fruits, nuts, hay, and horticulture).
In 1982, cultivated crops represented 68 percent of California's 10.5 million acres of cropland. In 2007, non-cultivated crops with 4.8 million acres became the majority (51 percent) of California's cropland. The increase in non-cultivated crops was due to minor increases in vineyards and berries and large increases in nuts and hay land.
Positive trends in wetlands and erosion in California are also reflected in the data. California wetlands, as measured by NRI, had modest increases, growing by about 19,000 acres since 1997. Sheet and rill erosion on cropland has experienced significant decreases — a 57 percent drop on cultivated crops and a 43 percent drop on the non-cultivated crops.
To view the complete report and survey and sampling methodologies, visit www.nrcs.usda.gov/technical/NRI/.