Agro-Food Systems and Agroecology Chapter 11
What we will cover Human-environment interactions Agro-food system evolution How the system is trying to provide for global demand How the system is affecting social and ecological interactions Land use and land cover changes The growing changes from globalization and food trade Feedback loops The future of the agro-food system
Humans have had a 1/3 impact on the biosphere Agriculture is only a small percentage of Gross World Product If you include all processing, transportation and retail= 8 percent NPP= net primary production Growth of vegetation which depends on location, soil quality, elevation, precipitation, temperature, as well as other factors Rural populations are most common at medium NPP areas- less completion but enough food GDP per capita generally tends to be positively correlated with NPP
Income tends to increase with distance from the equator Human distribution can be mapped using 4 parameters Altitude, nearness to rivers and coasts, temperature and precipitation Anthromes a type of biome that reflects the changes humans have made 80% of all people live in densely populated urban and rural villages 1 in 4 people live in agricultural villages Social Ecological systems An integrated human- environment system with feedback and interdependence Used to explore sustainable pathways based on the identified local varieties and contingencies
Agro food systems In an urban setting, the natural environment is usually restricted to natural parks and rural areas. Intensive agriculture in a few highly productive areas The rest of the world relies on the natural world right around them for sustenance, survival, and enjoyment Figure 11.4 This shows how agricultural practices have evolved over time but also how each stage has gained a niche in the overall agricultural system
There are still a couple hundred thousand hunter gathers that exists in remote areas of the world. Because they are vulnerable to external shocks they will diversify A subset of the nomads are commercial grazing operations. Where land was scare- large, intensified manufacturing plants process dense populations of animals for supermarket consumption. Shifting cultivation is done by around 500 million people but rising population density and food demand have pushed more of these farmers into permanent agriculture and cash crops
For intermediate, modern, and mechanized farming there are two main categories: Wet rice culture and mixed farming Wet-rice relies on lots of water (usually from natural floods) and labor vs lots of soil and less labor or livestock. However in many cases much of the rice grown is consumed by the household and so it is technically considered subsistence farming
The modern methods of mixed farming Started in the early middle ages Reduction of the fallow period, Elimination of common rights, Greater need for livestock, Need for more intensive use of inputs Shift from cereals to high value crops. Modern agriculture has become dependent on science, manufacturing, and technology Globalization has only increased these factors and has forced farmers to comply with standards
Food needs and demands The consumption need is determined by the amount of people and their nutritional requirements. The number of food units as well as amount of income spent on food can track the food needs Engel’s Law The proportion of staple foods consumed decreases with rising income but the consumption of luxury foods increases with increasing income Liebig's law- the weakest link For the food system A population is not limited by the total resources in the system but rather by the availability of those resources during the time of highest scarcity
Another way to look at the system is at biophysical resource potential- or how food can be supplied Based on soils, temperature, and precipitation- variable can be made to see the potential yields of crops in certain places. Figure 11.5 shows the potential yield of some crops but the potential doesn't equal actual and The difference is called the yield gap. A different agro-economic method is to define efficiency of crops as the difference between the actual yield and the growth defining variables
How the system supplies more food Much of the increase in food production comes from yield improvements and intensification But will it take a increasingly large toll on the environment? In order to track this the inherent fertility of soils is looked at This is to preserve the ability of a soil to grow plants as it was before humans interacted with it To do this the nutrient flow and pollutants must both be net neutral flows Figure 11.7 shows the flows
The effects of over- intensification land degradation in densely populated areas Water use is at unsustainable levels Chemical inputs are disrupting phosphorus and nitrogen cycles leading to eutrophication Methane and carbon dioxide emissions from meat production mean climate changes This can be beneficial for some but generally causes severe consequences such as droughts or extreme rainfall
Cases Nomads in Mongolia Rural farmers were growing a lot of facai grass The mass harvesting of the grass quickly desertified a great portion of the landscape that one was grassland. This led to the farmers pushing rural herders off their land by force and also created dust storms that affected surrounding areas
Rural France Farms in France have decreased over the last 40 years and is expected to decrease further in the future The global competition for produce have pushed prices so low that the costs outweigh the returns Many farmers are being forced to look for other opportunities of work in order to stay afloat Those farms that remain have turned into mega-operations with razor thin margins In order to save the rural farmers many suggest to push trends that: Rely on food ideals centered on local quality and flavor, agritourism, or allowing farmers to be the main managers of the landscape and surrounding nature However, many say it is doubtful that these trends will arise and with steep global competition, the question of whether to actually save rural France comes into question
Land use changes Land change occurs in low-income areas places that are rapidly urbanizing and industrializing Deforestation is one of the most common examples and has been occurring around the world at different areas in different stages Europe, Northern India, and China in the 18 th century, North America and Russia in the 19 th century, South America and south east Asia in the 20 th century Africa for the 21 st century
Land use/ land cover transitions Are reversible change processes with many economic, ecological, and social feedbacks Different areas of the world are in different stages of land use/cover transitions There are many direct and indirect causes behind what makes land use/cover transitions 5 fundamental underlying causes Resource scarcity and a pressure on production of resources Changing opportunities by the markets Outside policy intervention Loss of adaptive capacity and increased vulnerability Changes in social organization in resource access and attitudes Most important is the behavioral responses to perceived opportunities and constraints of markets and policies Many issues arise because top down government strategies don’t take local biogeography into account
Modelling Land use/cover changes and transitions Usually done at a top down aggregate level for land categories over time But because these changes and transitions are so complex down to a local level, it is necessary to have a bottom up approach Unit of production= family farms Microclimates, seasonal variations, soil erosion Landscape= communities Altitude, topography, soil and water basins Region=social, economic, cultural, and biophysical aspects of communities Colonization, migration, major infrastructure, world food prices, trade opportunities, climate parameters, and crop potentials
CLUE (Conversion of Land Use and its Effects) Input the suitability and food availability Urban expansion, technology availability, management level, and values Translate demand into actual land use changes Food security and technological adaptation Explores how to achieve sustainable food for all
Example of CLUE model at the local scale in the Philippines- See Figure 11.9 The San Mariano municipality 48,500 hectares and 20 villages near a large protected area Logging deforested a big part of the area Logging Moratorium But even with the change, agricultural trends using CLUE have shown to be at unsustainable levels and is still about one-third that of the previous rate So in order to help design policies to stop the deforestation, the model must show the forces action on the situation at different scales of local, regional, and global in an integrated way
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