March 19, 2013
Soil Biodiversity and Conservation Ecology: U.S. Soil Degradation and the Implementation of Organic Farming Methods
Many factors contribute to the classification of healthy soil which are comprised of, but not limited to, composition, fertility, nutrients, organic matter, as well as, diversity and abundance of soil organisms. These components combine to solidify basic definitions of what can be referred to as soil biodiversity and conservation ecology.
Soil Biodiversity is the composition, heterogeneity, and abundance of soil organisms for sustained soil fertility. Examples of this are microorganisms, nutrients, and organic matter. Conservation Ecology is the study of nature and the status of biodiversity on planet Earth. This field aims at protecting species, habitats, and ecosystems through such projects as landscape preservation and the prevention of species extinction.
The United States, in its current practice, implements industrial farming methods in order to maximize efficiency and decrease expenditures. A primary example of these methods is the segregation of crop production to single cash crops. Therefore, individual farms are responsible for specific agricultural sectors which increases efficiency, but constrains soil resources. According to Diana Wall of Colorado State University, “the use of insecticides, nematicides, and herbicides for control of soil pathogens and pests rather than on biocontrol of pathogens, herbivore-resistant crop varieties, or other management strategies has furthered the impression that soil biodiversity is of little relevance to agricultural production.”
Lack of crop rotation leads to soil degradation, resulting in unforeseen effects on soil quality. In the long run, soil degradation substantially decreases crop yields and quality, further exacerbating critical food insecurities. In addition to adverse effects on human nutrition and health, soil degradation increases environmental susceptibility to droughts and elemental imbalance leading to desertification and devastating events such as the dust bowl.
A bar-graph depicting the differences in erosion rates across four different land management techniques. http://www.eatwild.com/images/Soil%20erosion.jpg
An alternative to U.S. industrial farming methods is the use of organic farming. According to a 21-year study, that was published in Science, on various farming methods in Central Europe, researchers found that organic farms produced 20% fewer yields. Fertilizer and energy use, however, was reduced by 34-53% and pesticide use was cut by 97%. This led to increased soil biodiversity and fertility for future growing seasons.
Graph depicts increased corn crop yields with the implementation of pesticides and fertilizers but yields drop in most recent years. http://www.earth-policy.org/data_highlights/2012/highlights30
Organic farming differs from industrial agriculture methods because of its focus on decomposition and nutrient management. It emphasizes maintaining nutrient levels and soil fertility with the use of crop rotation practices. Organic farms are more dependent on soil chemical content and biological processes for nutrients to sustain crop health and yield than conventional industrial U.S. agriculture.
Integrated-livestock farming is the unification of livestock and grazing land in order to negate the impacts of industrial soil degradation. This purported solution is considered an alternative to organic farming methods in that it requires no change to current crop production and claims to show an improvement in soil quality.
A study conducted in central North Dakota sought to evaluate these claims due to the lack of documentation on the subject. A Soil Quality Index (SQI) was developed using the Soil Management Assessment Framework, and was used to judge treatment effects on soil conditions over a 9 year span. Aggregated SQI values over 9 years showed no significant change in soil quality, implying no differentiation in the capacity for each system to perform critical soil functions. As a result, the study concluded that integrated-crop management systems provide limited benefit to soil quality and nutrient abundance. However, the results of this study are specific to the geographic region to which they were performed, and the climatological as well as topographical characteristics of the region likely played a role.
About the Authors:
Sara Carlson is a sophomore at the University of Southern California studying International Relations Global Business and Environmental Studies.
Jacob Leonard is a sophomore at the University of Southern California and is currently pursuing a Bachelors of Arts degree in Mathematics with a minor in Environmental Studies.
Works Cited:
J.F. Karn, et al. “Integrated Crops And Livestock In Central North Dakota, USA: Agroecosystem
Management To Buffer Soil Change.” Renewable Agriculture & Food Systems 27.2 (2012): 115-124. GreenFILE. Web. 28 Feb. 2013. http://search.ebscohost.com/login.aspx?direct=true&db=8gh&AN=75166043&site=ehost-live
Lal, Rattan. “Soil Degradation as a Reason For Inadequate Human Nutrition.” Food Security
(2009): n. pag. Springer Link. Web. 28 Feb. 2013. http://link.springer.com.libproxy.usc.edu/article/10.1007%2Fs12571-009-0009-z
Mader, Paul, Andreas Filesbach, David Dubois, Lucie Gunst, Padruot Fried, and Urs Niggili.
“Soil Fertility and Biodiversity in Organic Farming.” Science 296 (2002): 1694-697. JSTOR. Web. 28 Feb. 2013.
http://www.jstor.org.libproxy.usc.edu/stable/3076892
Stockdale, E. A., and C. A. Watson. “Biological Indicators of Soil Quality in Organic Farming
Systems.” Renewable Agriculture and Food Systems 24.4 (2009): 308-18. ProQuest
Research Library. Web. 28 Feb. 2013.
http://search.proquest.com.libproxy.usc.edu/docview/220383136
Wall, Diana H. “Chapter 10: Making Soil Biodiversity Matter For Agriculture.” Microbial
Ecology in Sustainable Agroecosystems. By Tanya E. Cheeke and David C. Coleman. Boca Raton: CRC, 2013. 267. Print. http://books.google.com/books?hl=en&lr=&id=92fbRsUSWTgC&oi=fnd&pg=PA267&dq=definition+of+soil+biodiversity&ots=-OyVeDJUoW&sig=-2klu3oSseuuhhaS7YXDFEx7RA8#v=onepage&q=definition%20of%20soil%20biodiversity&f=false
March 13, 2013
It’s Not Just Dirt: Using Sustainable Agriculture and Soil Biodiversity to Feed Earth’s Growing Population
Currently the world’s population is estimated to be slightly over 7 billion, increasing at a rate of about 1.1% per year. Developed countries tend to produce the most agriculturally, while less-developed countries produce fewer crops, but have the densest populations. Even though we produce enough food to feed all 7 billion people on Earth: 19 million people in developed countries suffer from starvation, while 906 million people in under developed countries around the world suffer from starvation (Worldhunger.org). Currently there is an unequal distribution of food across the globe. If we can’t feed the current world population, how will we sustain Earth’s continually increasing population?
The current agricultural crisis is not only a U.S. problem, but also a world problem. Current agricultural practices deplete the land’s natural resources and will not be able to sustain Earth’s increasing population; the only way to mitigate this issue is through the use of Sustainable Agricultural Practices (SAP).
Sustainable Agricultural Practices are not a defined set of agricultural practice, but rather methods that aim to maintain long-term production without degrading natural resources (Rodriguez, Molnar, Fazio, Syndor, and Lowe). The most common sustainable agricultural practices include conservation tillage, crop rotation and diversity, integrated pest management, water management, and soil diversity and testing. The most important and central component towards maintaining sustainable agriculture is maintaining soil biodiversity.
Without maintaining soil resources issues such as erosion, poor nutrient content, and inability to produce necessary crop yield can occur. Approaches to these issues have been widely studied and programs have been instituted in almost every country by a government or local agency that produce guidelines and regulations on maintaining good soil biodiversity. Despite the global importance of soil management different countries take varied approaches to the issue and some have much more stringent requirements for things such as nutrient content and erosion control.
In the United Kingdom the Department for Environmental, Food, and Rural Affairs, or DEFRA, has requirements for ranchers and farmers known as the Good Agricultural and Environmental Conditions, GAEC. The main goals of DEFRA is to prevent soil erosion and particulate runoff from fields, maintain organic matter, and allow for good soil structure. DEFRA focuses on a preemptive approach rather than one that deals with issues after they have occurred. Their literature warns of the dangers of “poached soil”, that is, soil that has been compacted by hoofed animals, as well as consequences and ways to mitigate waterlogging. An interesting factor was a legal limit on nitrogen use in areas that have been defined as Nitrate Vulnerable Zones (NVZ’s).
In comparison, the United States has information released by the USDA. While the literature focuses more on solutions rather than maintaining natural balances, the USDA does stress the idea of interconnectedness and relationships between soil management, water, and air quality. It also links biological, physical, and chemical properties of soil to create a holistic view of soil management.
In a more stark comparison the government agency of the Kenya Agricultural Research Institute (KARI) brings a much more basic approach to soil management. In Kenya, due to low food supplies and variable soil conditions the focus of the information given to the people is that of utilizing the best suited crops to their area, directions on spacing and when to fertilize, and how to use pesticides and natural alternatives, all in the hopes of increasing food security. While much simpler than the guidelines and regulations of more developed countries like the US and UK, KARI is making steps towards giving subsistence farmers food and water security while teaching sustainable soil practices and not further degrading the land.
As a nation the United States is extremely apprehensive towards the adoption of SAP such as maintaining soil biodiversity. Barriers to adopting SAP include lack of knowledge, social, and economic factors. There is not a lot of access to information on cropping systems, machinery, soil management, and government funding available to farmers. Many farmers wrongly assume SAP will yield fewer crops; they do not have the money to hire more workers and purchase new equipment. Farmers also feel societal pressure to adopt the same systems used by their peers.
The United States has programs such as The Environmental Quality Incentives Program (EQIP) that provides financial and technical support to agricultural producers who would like to adopt SAP for up to ten years. Most farmers are not aware that programs such as this exist. In order to remedy this problem in the United States government and the private sector must get involved in making SAP a priority.
With the world population on the rise it is critical to find a way to feed and sustain the increasing population. The only viable option to remedy this global issue is for nations to raise awareness about the issue by educating farmers and consumers on soil practices and to implement standards for sustainable agricultural practices that will provide a steady and high-yield food source that does not degrade the environment or deplete the soil.
Authors: Ashley Brady is a sophomore at USC working towards a bachelor degree in Environmental Studies and Ryan Gobar is a junior at USC also working towards a bachelor degree in Environmental Studies.
Hyperlinks:
http://soils.usda.gov/sqi/assessment/files/sq_assessment_cp.pdf
February 27, 2012
Which Came First: Soil Conservation or Sustainable Agriculture?
Agriculture requires fertile soils and is therefore dependent on a high level of soil biodiversity. However, agriculture itself has a major influence on biodiversity. For sustainable farming, a farmer should manage his soil’s health, ensuring that the soil will support crops for years to come. The FoodandAgricultureOrganization has historically encouraged scientists and farmers to share research and experiences for the benefit of agricultural development programs and farmers. As soil is fundamental to agriculture, it is also fundamental to human health and food security. It is important that we conserve soil biodiversity and the manage soil for the value of its ecosystem services.
One common agricultural practice, the use of fertilizer, is advantageous to the soil biota. For example, mineral fertilizers can increase the abundance of nematodes. However, because soil biodiversity is very sensitive to the changes in soil pH and the concentration pore water salts, using fertilizer might decrease the soil biodiversity. It is important to use the appropriate amount of fertilizer to avoid damage to the soil organisms.
Pesticides are also commonly used, and can affect soil biota. Soil organisms can be exposed to applied pesticides, so it’s important that the pesticides don’t harm the soil organisms. Testing has led to the development of regulations to ensure that when used properly, pesticides will not cause unacceptable harm to the soil organisms. When planning for fertilizer and pesticide use, a farmer can work towards improving soil biodiversity. By using an appropriate amount of fertilizer and pesticides, the farmer can stimulate plant and soil organism growth while decreasing the risk towards soil organisms.
The farmer can use several physical techniques to manage his soil. The first is planting his crops. By providing plant cover for the soil, the farmer protects his soil and the organisms with in his soil from wind or water erosion. Further, cultivation of row crops such as sugar beet, maize, potato and vegetables provides only partial soil coverage and protection, leaving the land vulnerable to erosion. Large field areas are often devoid of any morphological structures, such as hedges, that could potentially mitigate erosion from wind or water. The farmer might also reduce or even stop tilling the fields. Intense mechanical soil treatment that disturbs the soil pore system is a common cause of erosion. Reduction may improve soil structure, increasing water capacity, and decreasing erosion. The consequence of the erosion is usually the loss of humus and nutrients from the upper soil, leading to reduced fertility.
As such, agricultural practices and following natural processes can have tremendous influences on soil and soil biodiversity. To maintain adequate food supply, and reach sustainable agriculture, conservation of soil is the most important factor in today’s agriculture business. Farmers can conserve soil biodiversity by using contemporary agricultural techniques that cause fewer disturbances to the soil than traditional techniques. Although soil analysis may be an extra cost to production, the benefits would outweigh the cost. With analysis and proper planning, the farmer will be able to enjoy his soil for a lifetime. Through effective soil management, the farmer can avoid stripping the land of nutrients.
As the world’s population grows and its food needs increase, we must work to relieve population pressure on food supply. Soil biodiversity is the key factor for sustainable agriculture, and thus the practices to conserve soil biodiversity are important. As the soil biodiversity and agriculture are the basis of human food supply, we need to take action to preserve our soils.
Sources:
www.fao.org/ag/agl/agll/soilbiod/docs/CGRFA_SoilBiodSustAg.doc
http://www.fao.org/ag/agl/agll/soilbiod/default.stm
http://www.europeanlandowners.org/files/pdf/soil_bio_and_ag_009.pdf
Wonho Jung and Christopher Miranda are undergraduates in the USC Dornsife College of Letters, Arts and Sciences.
February 14, 2012
California Coastal Sage Habitat: On the Brink of Extinction
Many residents of Southern California are unaware of the growing threat to the California coastal sage habitat. This widespread ecosystem ranges from central to southern California. The habitat is known for its high species and soil biodiversity as it houses a wide range of organisms and diverse soil levels. This region is threatened by human and agriculture expansion and consists of diverse habitats that range from forests to woodlands to grasslands and salt marshes. Because of this variety of habitats, the soils in these regions have to be able to support the growing habitats and ensure their survival.
The eco-region of the coastal sage habitat is home to about 200 species of butterflies, the widest range of native bees in the United States, and a wide variety of other organisms that rely on this region for their home. The California legless lizard and the rosy boa are just some of the reptiles and amphibians that belong to this certain Southern California region. The Channel Islands also take part in this eco-region, but because they are isolated, they house certain rare plant and animal species that are only native to that island.
Because of anthropogenic development, native habitats in this region are threatened. Human air pollution, specifically smog, reduces production and growth in the environment. When humans introduce outside species, such as sheep, cattle, and deer, their grazing and physical presence on the land reduces the productivity and fertility of the land. Agricultural practices do not allow for healthy regrowth of the soil and plants. Only about 15% of the coastal sage habitat is intact because of the growing expansion of agricultural lands and housing. Human invasion of this land has altered the physical makeup of the region enough to affect the organisms that live on and in the soils. Invasive plants, brought in by humans, displace native species, which change the flora and fauna of the specific eco-region.
Since humans have started to develop the land, the larger habitats are divided into smaller regions. These small habitats are more vulnerable to outside threats of animal and human predators. Humans use processes such as grazing, herbicides and burning to convert the land to their specifications. However these methods alter the soil composition, which affects the organisms that live in the soil and the organisms that rely on the soil. These unfamiliar conditions destroy the native seed beds and organisms within the soil, which negatively impacts soil productivity. Unhealthy soil leads to overall ecosystem degradation.
Because of these huge environmental impacts and risks, conservation ecology is crucial to preserve this eco-region from becoming extinct. Not only are the organisms threatened, but the diversity of the soil relies on the preservation of this coastal sage habitat. Many humans are only concerned with development and expansion, but for human society to thrive, the environment surrounding humans needs to thrive as well. With population increasing, we can’t ignore human needs, however there has to be a balance between human and environmental needs. Destroying this coastal sage habitat threatens the ecosystem services that communities depend on, such as water, oxygen from the wide range of trees, food, and other vital resources. There needs to be a bigger focus on soil preservation and protection of organisms in this region because many of them are so rare and specific to this coastal sage region. Without this eco-region, a whole group of organisms would become extinct. We might not even know the benefits of all of these organisms, and to destroy them in order to expand our agricultural land, would be a huge loss to this treasured habitat in Southern California.
Links:
http://www.eoearth.org/article/California_coastal_sage_and_chaparral
http://www.laspilitas.com/nature-of-california/communities/coastal-sage-scrub
http://audubon2.org/watchlist/viewSpecies.jsp?id=57
http://www.ncbi.nlm.nih.gov/pubmed/10801992
http://www.treesearch.fs.fed.us/pubs/27020
http://www.jstor.org/pss/3235887
Chantal Morgan and Alanna Waldman are undergraduates in the USC Dornsife College of Letters, Arts and Sciences.
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.