USC Dana and David Dornsife College of Letters, Arts & Sciences > Blog

September 25, 2011

California Wildfires

Soil biodiversity and conservation ecology has become a hot issue, specifically in Southern California, due to numerous factors. Due to anthropogenic factors such as human caused wildfires, and use of fertilizers on grasslands, Southern California’s soil is losing nutrient richness, and a decline in productivity is occurring. Other naturally occurring factors that contribute to the decline in suitable soil in Southern California are sediment deposits and high winds.

In the case of California wildfires, as explained in the article Ecological Effects of Southern California Fires Could Be Devastating,” human induced wildfires are much more harmful to flora and fauna than naturally occurring fires, according to Dr. James Danoff-Burg. “There are a lot of species that have adapted to a fire-dependent ecosystem,” Danoff-Burg says. “But there will be more mortality across the board, including in fire-adapted species, because these fires are more intense than normal wildfires.” Due to these intense fires, species are not only dying, but the microbes and soil productivity is decreasing.

The second anthropogenic problem in Southern California deals with fertilization. According to the abstract of “Effects of Soil Resources on Plant Invasion and Community Structure in Californian Serpentine Grassland” by the Ecological Society of America, fertilization with chemicals such as nitrogen and phosphorus have led to an increase in biomass of native vegetation initially, however by the second season the non-native grasses began to invade, and dominate areas originally inhabited by native grasses. In this instance species richness declined with fertilization due to the increase in biomass production by non-native organisms, and changes in community structure demonstrated that the invisibility of plant communities may be influenced directly by nutrient availability.

The Los Angeles Basin is where the majority of Los Angeles County inhabitants reside, and is an area high in sediment and low in stability. Due to the high deposits in sediment the area is more susceptible to ecological impacts from urbanization and urban sprawl of the Los Angeles Basin, as well as natural hazards such as earthquakes or winds. This means that one of the most densely populated regions in the United States is living directly on top of land that is very unstable, and very susceptible to earthquakes at a high frequency and high magnitude. Another effect of the instability is water supply. According to the U.S. Geological Survey, More than 10 million people live in the Los Angeles metropolitan area, and the majority depends on water pumped from beneath the surface of the Los Angeles Basin. In the central and west coast basins a third of the water consumed by the four million residents come from ground water. More than 30 monitoring wells have been drilled in an effort to better understand just how the instability of the basin could affect the future water supply.

Lastly, winds in Southern California are particularly dangerous because of the desert. Hot, dry winds blowing from the inland are very commonly called Santa Ana winds. These winds are responsible for the high frequency of wildfires in Southern California. This ecological impact is what causes the dry desert region to be so nutrient depleted. The drastically different terrains within southern California make it hard for conservation ecology to improve the soil biodiversity.

About the authors: Liam Sharkey and Katie Graves are undergraduate students in the USC Dornsife College of Letters, Arts and Sciences.

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.

September 19, 2011

Desertification in California

The Central Valley of California is a fertile bed of over 350 diverse species of agricultural crops, some of the major cash crops being rice, grapes, cotton, and almonds. California’s agricultural industry makes up 15% of the entire nation’s crops and made a profit of $37 billion in the year 2009.

Despite these numbers, desertification is an increasingly major problem.

Between 1998 and 2000, 10,000 acres of farmland were lost every year in Central Valley from urbanization alone—this doesn’t account for the acres of fertile farmland lost due to overgrazing, climate change, or poor farming practices. Currently, California is losing 178 km2 of arable, fertile land each year. Southern California especially, being a very arid and drought-inclined region to begin with, has a problem with increasing salinity and compound minerals in the soil, caused by overdrawing ground water (United States Geological Survey).

Desertification is not only the result of human activity. The UN Convention to Combat Desertification identifies the other major cause of desertification to be climatic variations—for example, erosion, drought and irregular rainfall, and violent winds.  Essentially it renders the soil infertile, not only for planting and agriculture but for any organic life. Desertification occurs on a global scale, particularly through deforestation and drought. Areas around the Amazons, for example, have undergone desertification because the trees are being harvested for wood and cleared for farmland, and much of the space lies fallow. Similarly, in California, trees are cleared using the “slash and burn” method to open fields for cheap soybean and livestock cultivation.

Desertification is a challenge for California because it is a desert environment supporting an increasingly large population on limited water imports. The situation becomes more dire when the effects of global warming are considered, which dramatically expedite desertification. Owens Valley, California, for example, became a desert when all of the natural water resources were diverted to Southern California for drinking water and crop irrigation. The San Joaquin Valley is a region that has undergone natural desertification due to climate change, a result of surface crusting, salinization and waterlogging problems.

Most popularly considered solutions to desertification involve addressing problems of drought. Every 5 years in California a new Drought Contingency Plan (DCP) is released. In 2008, the last DCP, tactics included aggressive conservation, new groundwater and surface water storage facilities, and environmental restoration. GMOs also offer the possibility of growing crops that are resistant to drought, thus using less of the precious water resources to yield the same or greater amount of agriculture.

Similarly, Air-to-Water harvesters are a new technology that essentially takes the humidity in the air and convert it to usable water. This can slow desertification significantly.

From a more bottom-up perspective, education and conservation initiatives will also drastically reduce the human contribution to desertification. Programs teaching grey-water usage, water conservation, and the transformation of lawns into food forests can save a lot of water if it is implemented locally and broadly. Natural forests and wetlands need to be protected rather than cleared, farmed, and abandoned.

While desertification is in and of itself a natural process, the human factors can and must be reduced, especially in California, if we are to live harmoniously with the land and reap the benefits of its yield.

About the authors: Xueyou Wang and Kayla Duarte are undergraduate students in the USC Dana and David Dornsife College of Letters, Arts and Sciences.

Soil: The Underground Treasure

Filed under: Soil Sustainability — dginsbur @ 9:03 pm

Soil is one of the most diverse ecosystems on Earth, haven to not only insects, but also bacteria, fungi, nematodes, amoebas among many other organisms. However, the ecosystem and biodiversity is also understudied, which has resulted in the misuse and erosion of soil due to agriculture and a lack of government involvement to protect this resource in the US. Despite the significance soil has in supporting the majority of ecosystems that exist above it, the influence and financial benefits that agriculture has in the U.S. has led to poor farming practices at the cost of soil biodiversity.

An important aspect of conserving soil biodiversity is to understand the benefits soil biodiversity contributes. Soil biodiversity helps decompose plants such as trees and leaves that have fallen on the ground. Decomposition allows for nitrogen obtained from the decaying plants to be turned into an inorganic form to be used by plants and spreading nutrients, which allows vegetation to grow. Another service is storage and filtration, meaning that the soil biota filters water stored in the soil. The filtered water then flows into streams, providing clean water for many aquatic species to live in.

Yet, the efforts to conserve earth’s ecology have focused primarily on the loss of biodiversity above ground; degradation and loss of biodiversity in soil have gone fairly unnoticed. Land use, nitrogen enrichment and climate change have impacted soil through changes in physiochemical conditions of the nitrogen and carbon content of soil, losing functionally important organisms, and creating long term consequences in the nutrient cycling that makes it possible for plant dynamics and primary producers to exists in many ecosystems (Wall, Bardgett, et al. 2010).  Within the United States alone, soil preservation has not been an area of great importance due to the vital role that agriculture plays in US history and future.

“No comprehensive soils protection strategy exists in the United States”  (USDA).  The US EPA is the federal agency mainly responsible for implementing laws to mitigate polluted air and water, yet no legislative law has been implemented to protect soil biodiversity.  The goals for soil conservation within the U.S. as primarily have been interrelated with the greater goals for agriculture and the environment.  Agriculture has a deep history within America.  Both legislation and general social ideals form the basis of the U.S.’s conservation policy in agriculture.

Agriculture itself provides the food necessary to feed the population.  However, this deep seeded role that agriculture plays within American history has led to more than $40 billion annually lost from soil desertification (Ginsburg).  The U.S. has a difficult role in controlling erosion due to the large scale intensive agriculture dependency that has made up a profitable part of its economy for over 200 years.

As a result, agriculture has led to numerous farming practices that have led to loss in soil biodiversity:  soil erosion, fertilizer and pesticide pollution, deforestation, salinization, desertification, loss of biodiversity of some of the few sources of loss in soil biodiversity.

There are ways to prevent loss of soil biodiversity while maintaining the agricultural dependency our economy relies on.  Soil erosion can be reduced by seasonal plowing, crop rotation, multi-crop farming and a plethora of ways to reduce the anthropogenic impact on soil.  And, a deeper understanding of the true value of soil—as a basis of almost all primary ecosystems on this planet to create a sentiment of how critical soil is.  Yet, like all natural resources provided by this planet it is important to recognize that no matter what measures we take to restore any resource it will never return to its original state of biodiversity.

About the authors: Victoria Chu and Mabel Nevarrez are undergraduate students in the USC Dana and David Dornsife College of Letters, Arts and Sciences.

California Soon to Suffer the Environmental Costs and Impacts of Desertification

It is believed California is currently undergoing desertification. The long-term impacts and environmental costs associated with this process will take a devastating toll on the environmental future of the state. According to an article from Remote Sensing by Doris Lam, Tarmo Remmel and Taly Drezner, the present conditions of the majority of California’s lands are arid and semi-arid, which makes California highly susceptible to climate changes and anthropogenic impacts leading to desertification.

There are a combination of factors that when placed together can have the potential for disaster. During the 1930′s in Oklahoma, the combination of drought, arid climate, and land misuse led to the dust bowl resulting in depression, a mass exodus of people, poverty, hunger, high economic costs, loss of biodiversity, and unusable land for agriculture. Currently, because of California’s arid climate, land erosion and misuse, and rising global temperatures, the potential for disastrous environmental impacts is on a greater scale and drawing near.

U.S. Secretary of Energy, Steven Chu, projects the future of California’s agricultural lands to decline. According to the climate reports Chu has reviewed, global temperatures are only expected to reach staggering heights. Along with these increases in temperatures come major environmental impacts such as shortages in water supplies and loss of agricultural land. Without a secure water supply, agricultural processing and more importantly food production, could be in danger. In an article from Nature Geoscience, Diana Wall warns that the lack of water will cause great damage to the essential functions of healthy soil, which include providing proper environments for crop growth with various nutrients and other levels of biodiversity.

The rise in temperatures will also affect levels of precipitation and perhaps even cause valuable lands to lose their ability to sustain abundant crops for California’s growing population. A twenty-five percent drop in precipitation levels beginning in 2007 and lasting through 2009 is an example of this situation. The consequence of this occurrence was that the stream flows were forty percent below normal standards.

As a result, farmers pumped groundwater as a short-term answer to their water problems. However, in the long run, the groundwater resources were depleted greatly and a valuable resource was used unsustainably. A total reduction in groundwater during the drought proved to be 48 times worse than reductions in a comparable period earlier in the decade. A continuation of similar events in using water resources unsustainably will eventually force the water-deprived grounds of California to move quickly towards desertification.

The state of California’s economy relies heavily on its agriculture. A report from the 2010-2011 edition of the California Agricultural Resource Directory states that in 2009, California agricultural exports reached 12.4 billion, which was a 66 percent increase over a length of seven years. A sudden plummet to California’s agricultural productions due to the presence of desertification would result in not only a decrease in harvested crop acreage but also in jobs for Californian residents.

California’s success in farming over the years has earned the state the title of “the agricultural powerhouse of the United States.” The state’s economy is heavily dependent on the profits of their agricultural productions. The environmental impacts and costs of desertification in California will have a huge toll on millions of people. Not only will it do damage to the state’s economy but it will also cause a great increase in unemployment rates. Moreover, the total cost of attempts toward restoring the deteriorated agricultural lands will most likely continue to rise since the chances of restoring those lands to its native standards are close to impossible. The desertification of California agricultural lands will be detrimental to the entire population of the state.

About the authors: Ticia Lee and Wendy Whitcombe are working towards their bachelor’s degrees in Environmental Studies in the USC Dana and David Dornsife College of Letters, Arts and Sciences.

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