question: what are small farms, how do they contribute to society, and what challenges are they faced with?

Producing a vast amount of the world’s food, small farms are valuable assets that contribute to long-term economic sustainability and food security. What actually constitutes a small farm is hard to specify as there are extreme variations in societal structure, ergo many definitions exist. In the United States, a small farm is defined as any farm earning a minimum of $1,000 and a maximum of $250,000. In Canada, a small farm is considered a farm that doesn’t sell commodities in a market with set prices. The FAO has a much more complicated definition: “small farms are complex interrelationships between animals, crops and farming families, involving small land holdings and minimum resources of labour and capital, from which small farmers may or may not be able to derive a regular and adequate supply of food or an acceptable income and standard of living”, while the European Union has no concrete definition.

Despite a lack of a universal definition, small farms contribute a great deal to society – even beyond food production. It could even be argued that small farmers are some of the most underappreciated members of society even though they add genuine and unselfish value to the world. For example, small farms support rural employment as well as maintain and accommodate social connections in rural areas. This is especially important in an age of widespread urbanization as it contributes to the goal of more balanced development. Likewise, it provides diversity in societal structural. Such diversity is particularly essential to maintaining diversity in ownership in an era when the consolidation of power is a major issue facing society. In this respect, they provide also a basis for community empowerment. In doing so, small farms are a symbol of regional identity.

The benefits provided by these farms are threatened by a variety of factors, with the aforementioned issue of the consolidation of ownership and power being at the forefront of concern. This issue is catalyzed by unfavorable government policies (see Everything I Want to Do Is Illegal by Joel Salatin) that have been developed in favor of large agricultural conglomerates with the financial resources to influence government officials. A lack of societal sympathy and support for small farms due to false perceptions, for example, the belief that small farms are unproductive, further contributes to the problems faced by small farmers.

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This is a picture of Clay Bottom Farm in Indiana that produces 30 varieties of vegetables to feed 200 families on one acre of land. Photo Credit: Clay Bottom Farm

sources:

EU Agricultural Economic Brief

http://www.fao.org/docrep/003/t0757e/T0757E02.htm

http://articles.extension.org/pages/13823/usda-small-farm-definitions#.UsV_8ifCYx4

http://www.sciencedirect.com/science/article/pii/S0305750X15002703

www.foodfirst.org

http://smallfarmcanada.ca/2014/10-years-8-questions/

environmental management defined

It is not difficult to argue that the environment can manage itself in the event that humans are not available to intervene. However, humans are at present an integral part of the natural environment and our interactions with the environment often negatively impact the environment by altering its normal functionality, subsequently resulting in the emergence of a need to engage in environmental management practices.  

Based on the principles of ecology, environmental management is a decision-making process that relates to natural resources, pollution and the modification of ecosystems. This is achieved by analyzing and monitoring the way that the environment changes in relation to human activities, indicating that environmental management focuses on human interaction with the environment. The information garnered from this process is used to predict future changes in order to maximize human benefits while reducing the negative impact of human presence.  Through the management process, resources and their use are organized. Accordingly, activities are controlled in order to conserve and avoid the pollution of physical resources.

When deciding on what management activities should be engaged in, there are several questions that must first be posed:

  • What are the possible environmentally desirable outcomes?
  • What are the physical, economic, social, cultural, political and technological constraints for achieving the outcomes?
  • What are the most feasible options for achieving those outcomes?

Moreover, it should not be forgotten that conditions change over space and time. This fact must be anticipated and incorporated into any prescribed efforts via the development of dynamic management strategies. Concurrently, the structure of the management efforts must be enforceable and equitably employed.

Should environmental management efforts be successful in nature, there are four types of benefits that can be enjoyed:

  1. Ethical: knowing that the ‘right’ thing is being done
  2. Legal: knowledge that the practices being engaged in are not illegal or in conflict with any laws
  3. Commercial: environmentally-friendly business practices are often seen favorably by consumers
  4. Economic:  practices that are favorable are often money-saving in nature, e.g. via a reduction in energy costs

The fourth benefit of environmental management noted above states that effective environmental management should result in economic benefits. However, this is (unfortunately) not always the case. This may manifest in the form of opportunity costs or increased investment in capital or infrastructure. Typically, a cost-benefit analysis is performed in order to determine the potential (positive or negative) of any sort of new development plan. However, such an estimate – which is undoubtedly pragmatic in nature and representative of current economic needs – begs the question: How do we put an accurate price tag on the environmental system that sustains the world. Likewise, it is necessary to examine the morality of actions taken and work towards conflict resolution as a means of promoting investment in positive growth (i.e. sustainability), rather than negative growth (i.e. reactive).

question: what is the difference between plant resistance and plant tolerance?

Plant tolerance is the characteristic of a plant that allows a plant to avoid, tolerate or recover from attacks from insects, among other things, under conditions that would typically cause a greater amount of injury to other plants of the same species. These inheritable characteristics are what influence the ultimate degree of damage caused by a pest. Tolerance in terms of agricultural production means that despite stress from a pest or disease, the production levels will remain above the economic threshold.

Resistance means that a plant completely immunizes itself from a particular stress.  This is typically a biotrophic pathogen infection. The host has a resistance gene which prevents the proliferation of the pathogen. The pathogen typically contains an avirulence gene which triggers plant immunity.

Resistance and tolerance are the best defense mechanisms of plants against pests. 

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developing new plants that are resistant to freezing  photo credit: phys.org

There are two main types of resistance: ecological resistance/pseudo-resistance and genetic resistance. Ecological resistance is resistance related to favorable environmental conditions at a given location at a particular time. This type of resistance can be broken down into 3 forms:

  1. Host evasion – this phenomenon occurs when a host passes through the susceptible stages very quickly or during a period when pests are fewer.  This type of resistance applies to an entire species population.
  2. Induced resistance – this type of resistance is the result of some type of changed condition for the plant, such as an increase in available nutrients or water
  3. Escape – this is more or less luck as there is an absence of infestation or injury to a host plant as a result of incomplete infestation.

Genetic resistance is resistance related to (you guessed it) plant genetics.  There are several types of genetic resistance:

Resistance based on the number of genes

  • Monogenic – controlled by a single gene which makes it easy to both incorporate and exclude in plant breeding programs
  • Oligogenic – controlled by a few genes
  • Polygenic – controlled by several genes
  • Major Gene Resistance – controlled by one or a few major genes (vertical resistance) 
  • Minor Gene Resistance – controlled by many minor genes; the cumulative effect of minor genes is called adult/mature/field/horizontal resistance

Resistance based on biotype reaction

  • Vertical Resistance – specific resistance against specific biotypes
  • Horizontal Resistance – effective against all known biotypes; nonspecific resistance

Resistance based on miscellaneous factors

  • Cross-Resistance – when resistance against a primary pest results in resistance to a secondary pest
  • Multiple-Resistance – different environmental stresses (e.g. insects, diseases, nematodes, heat, drought, etc.) results in a new resistance

Resistance based on evolution

  • Sympatric Resistance – resistance that is acquired through the coevolution of a plant and insect (which is why it is important to protect our native pollinators!); governed by major genes
  • Allopatric Resistance – not governed by a co-evolution; governed by many genes

There are three mechanisms of resistance in plants.

Antixenosis (non-preference) resistance mechanisms are those by which host plant has characteristics that result in non-preference for insects in terms of shelter, oviposition, feeding, etc. There are morphological or chemical factors that influence insect behavior and results in the poor establishment of insects. Plant shape and color can also be an important influencing factor.

Antibiosis is the negative effect of a host plant on the biology of an insect. This can include decreased rates of survival, development and/or reproduction and is a result of biochemical and biophysical factors. Antibiosis may be a result of the presence of toxic substances, the absence of essential nutrients or a nutrient imbalance. Physical factors, such as thick cuticles, glandular hairs and silica deposits, also contribute to antibiosis.

Tolerance is a plant’s ability to grow and produce an acceptable yield despite a pest attack. Tolerance is typically attributed to plant vigor, regrowth of damaged tissue and a plant’s ability to produce additional stems/branches.

Both plant tolerance and plant resistance are extremely important to IPM efforts as it helps to reduce costs and amount of other control tactics that need to be implemented. This includes improving the efficacy of insecticides and promoting non-chemical benefits like shifts in predator-prey relationships and reduced pest populations.

The benefits of the use of resistant cultivars are numerous as this method has a high level of specificity, is eco-friendly, lower cost and adaptable to a given situation. The benefits are limited only by the amount of time required to develop new cultivars in breeding programs and by a lack of known resistance genes that can be used. To identify and capture relevant genes, crop wild relatives are often used.

biological control via entomophatogenic viruses: baculovirus

Entomopathogenic viruses are those that infect and kill insects.  They are superior to regular pesticides in that they are not harmful to humans or other vertebrates. Furthermore, each viral strain attacks only a limited number of insect species which helps to mitigate unpredicted damage.

baculo
Photo Credit: aibn.uq.edu.au

There are two types of entomopathogenic viruses:

  1. Baculoviridae (ds DNA)
    1. Nucleopolyhedrovirus
    2. Granulovirus
  2. Reoviridae (ds RNA)
    1. Cypovirus

However, the Baculoviridae viruses are the ones that are most commonly used.  They are found only in invertebrates and despite rigorous testing have not been shown to negatively affect vertebrates and plants.  They also have a narrow host insect range which is typically restricted to the original host genus.  

The mode of action for Baculoviridae is as followed:

Baculovirus is sprayed onto foliage –>  Caterpillar consumes the virus  –> The protein encapsulating the Baculovirus DNA dissolves and the DNA enters the stomach cells –> Baculovirus DNA is replicated by the stomach cells until the stomach cells rupture –> The caterpillar stops eating  –> Baculovirus is spread throughout the caterpillar causing a general systemic infection    –> The caterpillar dies within days

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Photo Credit: Leo Graves, Oxford Brookes University via oetltd.wordpress.com

 

The biggest issue related to the use of this method is the amount of time required before the pest dies.  This is noted as being the number one reason why this method is not used on a more wide scale basis.

Baculoviruses are created in vivo and production is often automated which makes it predictable and inexpensive because of the use of inexpensive growing mediums and the natural process of fermentation.  It is estimated that application in the USA costs $6-10/acre which is competitive with prices for industrialized chemical pest control options.

In order for the use of Baculovirus to expand the following improvements must be made:

  1. Genetic engineering must result in a 50% increase in the speed of the kill time
  2. Residual activity of the virus must be increased from 2 – 4 days to >7
  3. The role of Baculoviruses must be strengthened within successful IPM programs
  4. More cost-effective cell culture for the mass production of wild type and genetically modified Baculoviruses must be developed

A major example of success using a Baculovirus is the control of the Gypsy Moth (Lymantria dispar) using the entomopathogenic virus LdMNPV.

sources:

https://www.researchgate.net/publication/233795389_Genomics_of_Entomopathogenic_Viruses_Insect_Pathogens_Molecular_Approaches_and_Techniques

http://www.fao.org/docs/eims/upload/agrotech/2003/active_agents.pdf

https://www.researchgate.net/publication/263765284_Entomopathogenic_Viruses

http://web.entomology.cornell.edu/shelton/cornell-biocontrol-conf/talks/georgis.html

http://www.biopestlab.ucdavis.edu/files/131018.pdf

an introduction to integrated pest management (IPM)

Integrated pest management (IPM) is a long-term pest prevention program that focuses on ecosystem-based strategies for the control of pest related issues. This is accomplished through a combination of techniques including biological control, habitat manipulation, modification of cultural practices and the use of resistant cultivars. The use of chemical pesticides is then restricted to applications only after strict monitoring that is based on established guidelines indicates that stronger measures are required for pest management. In the event that chemical agents are required, they are applied in a targeted manner intended to minimize risks to the environment, other organisms (especially beneficial and non-target organisms) and to human health.

The 8 principles of IPM are as followed:

  1. In an effort to prevent and/or combat pests, the following intelligent production practices shall be used: crop rotation, sustainable cultivation techniques, resistant/tolerant cultivars and certified seed production systems, balanced fertilization, irrigation and drainage techniques, proper hygiene measures and the protection and proliferation of beneficial organism.
  2. The use of biological, physical and non-chemical control methods must be preferred to chemical options as long as the non-chemical options provide acceptable pest control.
  3. In the event that pesticides must be applied, they shall be target-specific and strategically applied in an effort to reduce negative health outcomes.
  4. Pesticides shall be used only on an as-needed basis and the frequency and intensity of use  should be minimized in order to reduce the risk of resistance populations.
  5. In cases where pest resistance has been established and repeat pesticide application is necessary, anti-resistance strategies should be integrated into control efforts.  
  6. Record keeping is essential and should be based on detailed records in order to determine the efficacy of pest control programs – especially in the case of chemical inputs.
  7. Monitoring efforts are essential in order to track pest presence.  This can be accomplished via observations, forecasting and early diagnosis systems and information, as well as information from professionally qualified .  
  8. The information garnered by monitoring efforts shall be used to determine when and which plant protection measures will be taken.  There should be scientifically supported threshold values upon which to base decision making.  Said values should be adapted to local conditions including climate, crop type and topographical qualities.

sources:

https://www.nap-pflanzenschutz.de/en/practice/integrated-plant-protection/general-principles-integrated-plant-protection/
http://www.ipm.ucdavis.edu/GENERAL/ipmdefinition.html
http://www.fao.org/agriculture/crops/thematic-sitemap/theme/spi/scpi-home/managing-ecosystems/integrated-pest-management/ipm-how/en/

 

 

the importance of annual grasses

The family Poaceae is considered the most economically important plant family due to the fact that they produce the world’s food staples including domesticated cereal crops such as maize (corn), wheat, rice, barley and millet.  Poaceae plants also provide forage, building materials (bamboo, thatch, straw) and fuel (ethanol).  

cereals
Photo Credit:  oxfordlearnersdictionaries.com

Agricultural grasses grown for their edible seeds are called cereals or grains (although the latter term, agriculturally, refers to both cereals and legumes). Of all crops, 70% are grasses.  Three cereals – rice, wheat, and maize (corn) – provide more than half of all calories eaten by humans.  Cereals constitute the major source of carbohydrates for humans and may also be the major source of protein.  Rice is the dominate crop in southern and eastern Asia, maize in Central and South America, and wheat and barley in Europe, northern Asia and the Americas.  Sugarcane is the major source of sugar production. Many other grasses are grown for forage and fodder for animal feed, especially for sheep and cattle which indirectly provides more calories for humans.

Flowering Poaceae plants are among the 5 most numerous families in the world.  There are an estimated 10,000+ species within family Poaceae that originate from Gondwanan more than 80 million years ago.  The grasses grow on every continent in the world in varying climates from deserts to riparian.  There are two types of grasses – C3 and C4.  C3 grasses are cool season grasses and C4 grasses are warm season grasses.  It is estimated that at least 20% of the world’s surfaces are covered in grasslands.  

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The plants  are typically wind-pollinated and have hollow stems called “culms” plugged at intervals by solid leaf-bearing nodes. Grass leaves are nearly always alternate and distichous (in one plane), and have parallel veins. Each leaf is differentiated into a lower sheath hugging the stem and a blade with entire (i.e., smooth) margins. The leaf blades of many grasses are hardened with silicaphytoliths which discourage grazing animals.  Some plants also produce silica crystals in their leaves to deter predation.  

It is theorized that the evolution of large grazing animals during the Cenozoic period contributed greatly to the spread of grasses.  Trampling grazers killed or consumed seedlings, but not grasses.  This prevented the colonization of fire-cleared areas by trees which prevented the shading out of grasses.

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Photo Credit: nature.org

Grasses also serve very important environmental purposes including erosion protection, nourishing and providing a habitat for animals and insects, cooling, water retention and nutrient enrichment via the dead root litter that is decomposed in the soil.

crop wild relatives – what they are and why we need them

Nature has been doing her thing for billions of years (maybe longer, I’m not sure).  It is only since about 200,000 years ago that humans entered the picture and it is only since about 15,000 years that humans have figured out agricultural production.  It is safe to say that nature may have a few tricks up her sleeves that we Homo sapiens cannot even begin to fathom – although our incredible brains are trying.

For the first 14,850 years of the human agricultural experience, seeds were simply saved from the plants that were growing.  Some cultures chose to save the seeds from the best-looking plants and others chose to save seeds from the smallest plants, so they could eat the best-looking seeds.  The latter was not the best decision and eventually all cultures began saving the seeds from the best and strongest plants.  This helped to improve production somewhat.

Then in the 1890s, we human folk decide that it might be wise to breed two plant types together in order to get even better production.  This gave birth to modern plant breeding. Soon after, during the Green Revolution, new types of staple crops were developed that were not sensitive to the number of daylight hours, produced larger amounts of above ground biomass and saved billions of people from starvation.  It was quite an accomplishment.

However, as a result of these scientific efforts, modern crops cannot grow without inputs from humans.  They lack the necessary defenses from the many surprises that the wild world has to offer.  This brings us to Crop Wild Relatives (CWR).  These are the wild relatives of the current crops.  They contain the valuable genetic information needed to maintain genetic diversity.  Such a quality is essential as monoculture practices continue to dominate the agricultural production landscape.  CWRs also continue to evolve in adaption to natural conditions – something that domesticated crops are incapable of doing.

cwr-richness
Photo Credit: agro.biodiver.se

The information provided by the CWRs also contribute the development of more desirable qualities in domesticated crops. Pest resistance is one of these important factors, as in the case of three peanut crops that helped in the development of a crop variety resistant to the root-knot nematode that previously cost growers an estimated $100 million annually.

Furthermore, even in their wild state, some CWRs provide valuable nutrition for humans and other animals in areas that are not suitable for cultivation. Strong examples include the use of wild cowpeas and yams in Africa to help sustain the large population, and the consumption of wild fruits, such as apples, throughout Asia.  CWRs also provide valuable fodder, fiber and medicines.

origin-species-world-map

sources:

http://www.cropwildrelatives.org/cwr/importance/

http://www.bioversityinternational.org/cwr/