October 31, 2011
Where would California agriculture be without the carbon cycle?
The amount of global carbon outputs have increased with the industrial revolution and rising need for agriculture, brought about by a rapid population growth. Agriculture over the years has become a major contributor to the global carbon cycle, especially as it now accounts for approximately 14% of global land use. It tends to deplete soil carbon because land used for agriculture has a lower net primary productivity than land that is kept in it’s natural state with undisturbed soil and processes.
In order to better understand the ways in which we are emitting carbon and effecting the carbon cycle, one must better understand the cycle itself. Carbon is absorbed by plants during photosynthesis in the form of carbon dioxide, along with sunlight and water. Plants then produce glucose and oxygen. When plants decompose, the carbon is transferred to the soil, where it is stored along with mineral carbon. Additionally, when animals eat plants, the carbon is passed from one to the other. Therefore this carbon can be released into the atmosphere during the respiration of plants and animals, the burning of fossil fuels, or, in the case of farming, when soil is tilled (Soil Science and Management 5th Edition, Plaster).
California’s agriculture tends to differ from that in the rest of the US in that it grows a large amount of perennial crops and specialty crops such as vegetables, nuts and fruits. California’s climate makes it the ideal provider of specialized high value crops to the rest of America, and much of its economy has been built on this industry. Perennial orchards and vineyards account for roughly a third of agricultural land (Kroodsma and Field). Since California has long hot summers, irrigated soils go through distinctive wet and dry cycles between water applications, which impacts the amount of dissolved organic carbon in soils. For these reasons, it’s evident that the carbon cycle is particularly vital in California industries and agriculture (Kroodsma and Fields).
California has smaller levels of carbon sequestration, most likely largely due to warmer temperatures, irrigation, and a strong lack of conservation tillage. This practice disturbs the soil less, but is not practiced as much in California because there is less of a risk of erosion than in the rest of the US. However, carbon storage in California is improved by the growth of perennial agriculture. It agitates the soil less and decomposes faster than annual plants.
There are practices, both farming and industrial, that can be put into effect in California’s agriculture to reduce carbon emissions. Farmers can implement increased use of conservation tillage to leave soil undisturbed and reduce emissions. They can also return pruning of plants to the soil as mulch. It has been proven that if soil is mulched, rarely tilled and has plants growing, loss of CO2 is decreased. Waste wood from orchards and vineyards can be used in biomass power-plants, both to reduce waste and the burning of fossil fuels. California has already begun decreasing field burnings, as that releases CO2 (Kroodsma and Fields). These practices implemented together would reduce carbon emissions while simultaneously improving crop yields and productivity.
About the authors: Lily Phillips and Ariana Verdu are working towards their bachelor degrees in the USC Dornsife College of Letters, Arts and Sciences.
September 25, 2011
Sustainable Agriculture: the new face of agriculture in America
Agriculture is an important multi-billion dollar industry in the United States that plays an important economic and social role. In recent years, the concept of sustainable agriculture has emerged out of the increasing concern for long-term farm productivity and the effect of agricultural practices on the environment. Sustainable agriculture is an alternative approach to agriculture that incorporates integrated farming systems to produce environmental goods while protecting resources and enhancing future environmental quality. The key to creating sustainable agriculture is improving and maintaining soil biodiversity, but this cannot be done until the economic and social issues related to farming are addressed.
Soil biodiversity is a central component of sustainable agriculture since without it the availability of arable soil would decrease, therefore making soil management techniques crucial in sustainable farming. Soil is the home for a myriad of organisms, bacteria, fungi, and microbes, which all play key roles in soil quality and health, in turn affecting agriculture. The function of these soil biota are “central to the decomposition processes and nutrient cycling” and therefore “affect plant growth and productivity, as well as the release of pollutants in the environment.” Soil biodiversity is key in sustainable agriculture’s goal of producing adequate amounts of nutritious food while maintaining environmental quality and conserving natural resources.
Sustainable farming is extremely intertwined with three variables: environment, economy, and society. Environmental factors sustainable farmers must take into account are biodiversity, recycling of nutrients, waste, and avoidance of pollution, to name a few. Although most attention is usually places on the environmental facet of sustainable agriculture, the economic and social influences play increasingly crucial roles in its success. Economically, concerns of profitability, especially compared to other farms, and maintenance agricultural raw materials are important for farmers to take into consideration. The social dimension includes the “retention of an optimum level of farm population, the maintenance of an acceptable quality of farm life, and the equitable distribution of material benefits from economic growth.” The struggle for many sustainable farms is that environmental, economic, and social factors do not always coincide and therefore priority must be given to certain interests over others. For example, sustainable agriculture techniques such as crop rotation, conservation tillage, cover cropping, nutrient management, and multicrop farming can become costly and do not necessarily yield the biggest profit margin. Conversely, due to competition from other farms, sustainable or not, in order to stay in business farms must have a maximum output of crops.
Organic farming is a type of sustainable farming that prohibits the use of synthetic products, including fertilizers and pesticides, and stresses maintaining soil productivity and quality. In 1995, the National Organic Standards Board defined it as “an ecological production management system that promotes and enhances biodiversity, biological cycles and soil biological activity.” Since organic farms do not use unnatural pesticides and fertilizers, they tend to rely more on natural nutrient cycles than do conventional farms. These types of farms must be creative in the ways they replace chemical fertilizers and frequently practice crop rotation, maturing, cultivation, and mineral fertilizers. Since many of these practices are more time consuming and costly than traditional chemical fertilizers, organic farms rely on higher prices for their produce in order to ensure profitability. By increasing their prices, organic farmers do not have to choose between being environmentally sustainable and making an economic profit.
Due to the increasing global population rate and more demand on agricultural resources, sustainable agriculture is becoming more important and necessary, however it is crucial to remember the role of soil biodiversity in its success and how economic and social factors play an important role in its effectiveness and implementation.
About the authors: Ariana Verdu and Lily Phillips are working towards their bachelor degrees in the USC Dornsife College of Letters, Arts and Sciences.