Annotated Bibliography

From Earlham CS Department
Jump to navigation Jump to search

Bibliography: My intent is to provide a brief summary of what I've read and a thorough analysis of the philosophy, design methods and biology outlined in the material.

The Omnivore's Dilemma :Michael Pollan This book is a journalistic project that traces several different paths that food travels in America today. The author follows the production of one meal from an industrial, an industrial organic, a small-scale pastoral, and a hunter-gatherer's perspective while providing the history and context for each in this country. The book provides a great overarching view the food system and dispels many of the mysteries and myths of how we as a nation feed ourselves and what that means for the environment, the people who make a living on food production and the people who consume this food. The book also provides a great starting place for people interested in making food production more sustainable in the section on small-scale pastoral.

The section of the book which directly looks at food production using Permacultural principles is the profile of the local Pastoral farm called Polyface farm in Swoope Virginia. The author spends a week working on the farm alongside Joel Salatin, a third generation inventor agriculturalist. The author thoroughly describes the systems that Salatin has implemented on his 550 acres of previously degraded farm land. Salatin is deeply philosophical in his approach to farming and describes himself as a “Christian-conservative-libertarian-environmentalist-lunatic-farmer.” His central dogma is that profitability is measured in the well-being of the land.

Salatin participates in a manner of pastoral farming meaning that the main crop that he cultivates is grass for various grazing animals to feed themselves on. The pastoral farmer’s mantra is that they are really grass farmers not beef or chicken farmers although those are the products of value. What sets Polyface farm apart from traditional pastoral farms is that it is “management intensive” which allows for a much higher productivity per acre than other practices. How Salatin explains management intensive partoral is that he’s “the orchestra conductor making sure everybody’s in the right place at the right time” and ensuring that the “the animals do most of the work on the farm” in how he organizes the movement in space and time of the various components of his farm. In other words, as he only deals with a limited amount of space, he finds ways to exploit as much energy as possible from each plot of land. He does this by mimicking the systems of fertility and energy transfer that occurs in natural ecosystems so that each component of the system contributes to the needs of another component in some way. The goal is to find a balance in the system where no one component is taking more from the system than it is giving back to other parts of the whole. Without this balance the system would be unsustainable by requiring external inputs of the over-used nutrients such as petroleum-based fertilizers to help grow more grass on an over-grazed plot. This is the main difference between industrial agriculture and sustainable practices in that industry strives solely for the highest yield, in contrast with the highest yield that the land can sustainably support under natural conditions.

The ingenious aspect of Permaculture is that its systems are designed to coax the highest yield possible off of a plot of land while simultaneously improving the fertility of the land so that yields will actually improve in the future rather than degrade and require external energy inputs. Salatin explains productive balance; “It’s all connected, this farm is more like an organism than a machine, and like any organism it has its proper scale. A mouse is the size of a mouse for a good reason, and a mouse that was the size of an elephant would not do very well.” He accomplishes this balance with the use of “holons” which mean “whole part” and can be imagined to be like an organ in a body because each one performs a distinct function while contributing to the function of the whole. Polyface farm is made up many of these systems, some of which I will explain in detail.

The basic premise of the pastoral system is called a “productive symbiosis” and works like this. Energy from the sun is trapped by grasses in photosynthesis and is transformed into glucose. Animals eat the grasses, taking up most of the transformed solar energy meeting their energy requirements and turning excess into body mass. Animal’s waste then returns many nutrients to the soil which in turn feeds the grasses many of the nutrients that they need. This is a very simple picture of the energy cycle found in a patch of grass. The reality is a much more complex web of relationships between species on a purposefully managed pasture. The beauty of this complexity is how once it exists it is self-regulated by other components of the system hence “animals do most of the work on the farm,” but that the farmer is “the orchestra conductor.” It’s hard to determine where the beginning of such a complex system is and it seems to be too perfect to have occurred naturally, hence the spiritual relationship of farmers to the systems on their farm; I will try to explain.

Grazing animals and the plants that they eat co-evolved in nature. Grazing animals are specially adapted to eat grasses because they have a symbiotic relationship with bacteria in their gut that allows them to metabolize the cellulose in grass which other animals can’t. Grazers thus allowed certain favorable species of grasses to prosper by clearing competing species and spreading seeds in their feces. Grazers and grass co-evolved to the cycles of sheering and re-growth that occurred in newly formed grass plains. As grazers usually stay in great herds as a mode of protection from predators, they would move into patches of land and completely sheer the grass and then move on to the next patch of new growth. The patch they had just been on then had time to re-grow until the next time the herd came around. This cycle of growth and sheer actually improves the fertility of the soil and the quality of the grasses.

Responsible grazing improves soil fertility by the top-down build up of the topsoil with organic matter. Plants naturally seek equilibrium of above and below ground growth so that there is not an imbalance of energy requirements in different regions. When they are grazed, grasses will lose an equal amount of root growth to what was eaten above ground adding organic matter to the soil in pastures. Root litter is then broken down by decomposers in the soil which releases nutrients back into the soil and creates channels in the soil for oxygen, water and below surface creatures. After the “first bite” leaves recover from nutrient stores so that they can obtain energy by photosynthesis and provide for root recovery. New root growth in turn increases soil stability, which reduces erosion and draws water up to the surface from deeper in the soil which benefits many organisms.

Management intensive pastoral farming exploits the natural benefits of grazing by taking the needs of each of the components into account. Firstly conducting how often an area of grass is grazed prevents over-grazing, a major problem with other grazing practices. Breaking the rule of the “second bite” as Salatin calls letting grazers go over a patch of pasture before the grass has recovered fully cancels the benefits of grazing. Interestingly the same is true for under-grazing. Salatin says that a pastoralist must “pulse the pasture” to optimize the cycle of re-growth that grass undergo. Salatin manages his grazers by rotating them over pasture on a very specific schedule. Grass recovers from grazing on a growth curve of a certain length of time. There is a point where the grass is just right for optimizing the benefits of grazing to the animals as well as the plant and soil. Grass begins to grow back slowly for several days until it hits a “blaze of growth” where the blades and roots have reached equilibrium and then undergo rapid growth. This slows down after several more days up until the plant is ready to flower and seed. After this happens grasses become woody which is not preferable for grazers. The optimal time to let grazers over a pasture is right after the major blaze of growth and before it seeds and flowers. This is the point when grass has finished growing and is the most nutritious because all of the plant’s energy has been expended on growth and has not yet been transferred into producing seeds and flowers.

Another of the main benefits of management intensive pastoral is the maintenance of grass diversity in a pasture. This has multitude of benefits to the system the most obvious being that diversity maximizes the photosynthetic potential because different grasses are adapted to different niches in natural plains. There are a wide range of heights of grasses in a pasture, tall grasses as well as shade tolerant grasses that grow close to the ground. This allows more total solar energy to be stored in a certain plot than the same size of a grass monoculture such as corn. The occupancy of different niches in a polyculture also allows plains to be more resilient to environmental shocks as well as optimizing the growing season and the amount of the year that a pasture can be grazed. Different grasses have different growth cycles as well as different propensities to cope with environmental conditions such as drought. The overall affect is the security of grazer’s food source so the health of the system is maintained even through scarce times.

Diversity in a pasture that is grazed responsibly is also directly beneficial to the soil and to the grass itself. Grazers prefer specific species of grass that they find delectable. Size is a big factor to their preference. Cow’s jaws allow them to only eat grasses of a certain height so they’ll gravitate to the tastiest grasses that they can eat giving the ones that they can’t reach, the ground huggers a chance to grow. A sign of a well grazed pasture is a high number of ground hugging grasses which also allows them to provide a very valuable service to the pasture. Several grasses (legumes such as clover) have the ability to fix atmospheric nitrogen, a critical nutrient to plants. This ability is really a symbiotic relationship between the roots of the plant and bacteria that attach to the roots in “nodules” and fix the nitrogen in return for glucose. The availability of nitrogen in a well managed pasture is another example of how a natural system manages its own fertility because it cuts down on the inputs of fertilizer that a less diverse field would require.

Salatin’s farm is enormously productive for its size. It consists of the following.

 (450 acres, restored woodlands)
(100 acres, pasture, structures, garden, etc.

-Farm products (per year)

Sweet corn
25,000 lbs beef
50,000 lbs pork
12,000 broilers (chickens)
800 turkeys
500 rabbits
30,000 dozen eggs


Orchard grass
red/white clover (legumes)
lupines (legumes)
queen annes lace

-"below decks"

fungi mycelium

Polyface Farm “Holons” :systems with a specific purpose (part) that add in achieving this end add to the overall fertility of the entire system (whole). Each individual system provides benefits to all parties involved in the relationships that they exploit. The big picture benefits are typically reduction of farmer’s expense of productivity in decreasing the need for expensive inputs like fertilizer, pesticides, parasiticides and feed while at the same time improving the health (and the nutritious value for humans) of the animals involved, in a way that also improves the health of the land that these relationships depend on for future use. By managing farm this way farmers also produce higher yields from a certain area of land of each product of the system then the land would support if they were all raised on it individually. This is the principle that “stacking” of different species on the same land is a more ecologically efficient way of producing food. The classic example of stacking and exploiting symbiotic relationships on the farm is the “three sisters” of corn, squash and beans which each provide a valuable service to each other while producing more of each on the same land then if only one was planted on the same area. There are numerous other examples of this found on Polyface farm.

Ex:1 Chickens and Cows These animals are the players on a farm that have a market value to humans, they are supported however by a long cast of other species and a complex web of relationships with each.

Birds and grazers have a symbiotic relationship in nature: Birds follow grazers which provide them with food and protection in exchange for various cleansing services. This mutually beneficial relationship is easily emulated and has other specific benefits on a well-managed pasture. On any stretch of pasture on Polyface farm, a herd of around 70 cows contained by movable electric fences will graze for a day. They will sheer the grass to a certain uniform height and will leave beyond mountains of poop. They will then be moved to graze in the next patch of pasture. Three days later the egg mobile arrives which is a giant movable trailer housing 400 laying hens. These are allowed to graze the cow patty laden pasture. The hens eagerly scratch at the pies in search of fat grubs and tasty morsels of fly larvae. The separation of time between the cows and chickens allows the fly larvae enough time to fatten up, optimizing their nutrition and protein content. In the process of spreading the nutritious manure, the hens feed themselves and eliminate parasites from the cow’s waste that could spread diseases the next time the cows graze on that pasture. The cow’s also provide the chickens with access to the ground-hugging grasses which only they can eat. In the end the chicken’s waste adds valuable nitrogen back to soil. Salatin refers to this system as his chicken cleanup crew because it lessens the need to medicate the cows against sickness which improves the quality of the meat and cuts a huge cost in industrial beef processing. Keeping this system moving on a finely-tuned time table is what allows it to optimize each of the various services provided as well as allow for the rest and re-growth period that pastures need.

Ex:2. Reforestation of 450 acres of degraded farm land.

The decision to reforest the majority of land on the Salatin farm was initially a first step to improving land that had been horribly degraded by generations of farming practices that deteriorated the topsoil. It also was a strategic decision because it has many side effects that benefit many other areas of the farm. The service of reforestation is counter-intuitive to many in regards to a farm’s productivity, but the net effect is improvement of the ecosystem. Recreation of natural ecosystems helps growing crops and farm productivity in several ways. Firstly a forest in the highland of a property pumps water up hill because of root action which helps all of the plant live in all the way up the slope. Roots also improve soil stability, hold moisture well and allow organic material to build up in the forest by preventing their run-off from rains. Trees provide a wind shield that prevents soil erosion from pastures as well as improving plant growth in fields because grass expends less energy standing up against wind and can focus energy on growth. In summer forests act as air conditioners, cooling air and reducing the stress on animals which improves their health. Probably the main benefit of forests to a farm which is typically overlooked is that it is good for the overall productivity of the farm by increasing the biodiversity of surrounding ecosystems. This is because forest provides habitats for wild animals which has multiple benefits. With a healthy ecosystem predators and herbivores are more likely to find food in the forest as opposed to finding food on a farm in livestock and crops. This is specifically useful on the border between forest and farm because here occurs the “edge effect.” On the border of two different types of ecosystems is where the highest level of diversity of species is found. Birds especially dwell in high numbers of species in this region which has the effect of less insects on a farm because birds feed on insects which can be harmful to crops. Another obvious benefit of a forest to a farm is that they provide raw materials for building, mulching, heating and sale on top of their intangible benefits to productivity.