Sustainable Agriculture – A Historical Perspective
This month I would like to discuss sustainable agriculture. The following comments are my own and do not represent the official policy of the Lodi Winegrape Commission. I am sharing them in order to stimulate further discussion on this topic.
I believe that “sustainable agriculture” is an easy concept to define. It is simply agriculture that can continue indefinitely without depleting the resource base upon which it depends. In my opinion we don’t need to make it any more complicated than that.
Sustainable agriculture is simply agriculture that can continue indefinitely without depleting the resource base upon which it depends.
For example, agricultural practices that erode the soil are not sustainable because they deplete the soil resource upon which agriculture depends. Similarly, agricultural practices that increase soil salinity are not sustainable for the same reason.
Another example would be that agricultural practices that reduce the quantity or quality of irrigation water are not sustainable because they deplete the water resource upon which irrigated agriculture depends. In fact, virtually every agricultural practice which is not sustainable involves either soil or water.
It is currently believed that agriculture began 10,000 to 12,000 years ago in two locations: present-day Iraq and present-day Mexico. Since that time no human society, having developed agriculture, stopped farming and returned to being hunter-gatherers. Most, but not all, agricultural systems have been sustainable. When they haven’t been, it has usually been due to the depletion of soil or water resources.
In recent times when agricultural practices have not been sustainable it has led to mass human migration rather than a return to a hunter-gather society. Examples include the Irish potato famine of 1845-1852 and the Dust Bowl of the U.S. and Canadian prairies during the 1930s. Both areas have since returned to agricultural production but for a period of time their agricultural practices could not be sustained. Another example of non-sustainable agriculture would be the urbanization of Santa Clara and Los Angeles counties in California which led to a dramatic reduction in fruit production in both of those areas.
One prominent California winery cites their use of barn owl boxes as an example of their commitment to sustainable agriculture. Barn owl boxes, however, by my definition are not a factor in agricultural sustainability. They may be beneficial for controlling vertebrate pests, or for marketing purposes, but they neither deplete nor augment the resource base upon which agriculture depends. In all of human history no system of agriculture has ever gone out of production because farmers either used or didn’t use barn owl boxes.
Some definitions of agricultural sustainability are actually expressions of modern values rather than explanations of what sustains agriculture. For example, one commonly used definition of sustainable agriculture includes the statement that sustainable agriculture “enhances the quality of life for farmers and society as a whole.” However, different people have different sets of values so sustainable agriculture means different things to different people.
Today we use petroleum products to supply most of the energy used in agricultural production. This practice is not sustainable because world petroleum reserves are finite. However, in light of the fact that the entire global economy runs on oil I don’t think that it would be fair to single out agriculture for using the same source of energy that the entire world uses.
To the best of my knowledge the agricultural practices commonly used in the production of wine grapes in the Lodi appellation do not seriously deplete the resource base upon which it depends. Because most Lodi vineyards are not planted on hillsides there is little soil erosion. Because of the extensive use of drip irrigation groundwater levels have not been dropping as rapidly as in other parts of the state.
There are, however, areas of California in which wine grape production practices are depleting the resource base upon which they depend. Specifically, there are areas where the groundwater used to irrigate the vines contains high levels of salts. As the vines use this water the soil becomes increasingly saline. In above normal rainfall years the rain can leach these salts beyond the root zone but in dry years the salts accumulate and can harm the vines. If wine grape production is to be sustainable in these areas I believe that the growers will eventually have to desalinate the groundwater before using it for irrigation in order to prevent excessive salt levels in the soil.
To continue our 10,000-year history of sustainable agriculture we must continue to protect the soil and water resources upon which agriculture depends. I believe that vague and complicated definitions of sustainable agriculture only serve to distract us from the more proximate and practical focusing on preserving our soil and water resources.