intercropping in organic agricultural systems

organic farming

Genuine organic agriculture is rooted in four  main principles:

  1. ecology: both ecological systems and cycles should be supported
  2.  health: the well-being of both flora and fauna should be sustained
  3. fairness: providing common and just environment and life opportunities
  4. care: the management of natural resources that is both precautionary and responsible for the benefit of current and future generations, as well as the environment

These four principles are directly applicable to intercropping for many reasons. For instance, intercropping supports healthy ecological systems as it is based inherently on the incorporation of multiple species or varieties into a single system with various motivations for specific pairings or groupings. In this sense, biodiversity is encouraged in two ways. The first being that it prevents one particular variety of pest from aggregating by limiting their food source and ultimately reducing the risk of excessive loss due to one specific pest. The second is that more pollinators and predatory species are present as a result of a more diverse system that provides a habitat for pollinators and predatory species. This is accomplished by the relatively simple act of diversifying the crops grown. Similar benefits can be seen in reductions in total weed biomass. Further, intercropping supports the goal of closed-system production, i.e. nutrient cycling within a system, via the use of nitrogen-fixing legumes as component crops that benefit from their symbiotic relationship with Rhizobia.

640px-nitrogen-fixing_nodules_in_the_roots_of_legumes
nitrogen-fixing nodules from Rhizobia bacteria

The use of these crops also organically increases the soil nitrogen content, which encourages mycorrhizal fungus development, which can also improve phosphorus, copper, zinc, and molybdenum uptake. However, it is worth mentioning that these objectives may be best realized by polyculture farms that incorporate livestock manure as legume fatigue may occur if the soil becomes overly infested with pathogens caused by the over-cultivation of legumes.

When accounting for the above-mentioned factors, it may be supposed that intercropping is best suited for organic production systems because it serves to circumvent the need for synthetic, mineral and chemical inputs, i.e. fertilizers, herbicides and pesticides, that are commonplaces in conventional agriculture and restricted from use in organic agriculture. In a sense, this means that although intercropping is more closely related to historical approaches to agriculture, it is being adapted to modern circumstances that include a rising demand for organic food, increasing environmental stresses, and a growing societal awareness of food and food production processes. Concurrently, conventional agriculture is becoming increasingly cost-inefficient, both economically and environmentally speaking. This has the potential to support an agricultural transition towards organic production methods, especially if evidence substantiating assertions about the efficacy of intercropping continue to emerge. Moreover, the growing body of proof that demonstrates total system improvements in output produced by intercropped systems may help to counter the argument that organic production cannot be as productive as conventional agriculture, especially when comparing it to sole cropping systems. In turn, intercropping may enable organic production to become more competitive with conventional production and ultimately provide an opportunity for further organic market expansion through the establishment of a fairer economic playing field. Ultimately, these factors allow for the creation of more resilient food systems that provide modern day benefits that serve as the groundwork for a more sustainable future. Consequently, this element of foresight has the potential to benefit a wide variety of both human and non-human stakeholders.

sources:

photo credit:

  • geneticliteracyproject.org
  • commons.wikipedia.org

crop quality – when better is better

apple

There is no doubt about it – we like a shiny apple. It just looks so much more appealing than the odd, misshapen apple that has already been sampled by the local fauna. After all, we humans are visual creatures and the appearance of our food is what peaks our initial interest. Besides looking great, we want the apple to taste good and provide us with wholesome nutrition. After all, looks aren’t everything. Sellers also want a product that looks good, but their version of attractiveness comes from uniformity and bright colors that attract customers to their shelves. Just in case the product isn’t purchased right away, the product should also have a long shelf life. Producers, on the other hand, have completely different demands. They need a product that can travel from point A to point B [often thousands of miles] and not be bruised and mushy upon arrival. They want the apple to be dense so that they are paid the most for their wares.

In the end, beauty, i.e. quality, is in the eye of the beholder. In the case of crops, this generally means a favorable mix of appearance, texture, flavor, safety, and nutrition [see the table below]. To produce a crop more likely to please all parties involved, it must be of high quality. To grow a crop of high quality, it must have been produced with care, which means that a number of factors need to be considered during each phase of the production cycle.

Planning Phase

It is first important to understand your growing space. How much sunlight will it get? How much precipitation does your area receive? What are the average temperatures? What is the soil type? How big of an area will you be planting? Will you practice intercropping? How many seasons of the year are suitable for growing? Are you planning to grow annuals or perennials? Once these questions have been answered, a plan for the growing season can be made.

Referencing your plan and a guide for plant spacing, select seed varieties suited to the local climate and growing conditions. If possible, opt for local seed banks or nurseries, cooperatives, or reputable seed catalogs that can provide this information or are already adapted to local conditions. If a particular seed variety is particularly successful, consider saving your own seed for future growing seasons.

bean-varieties

Planting and Growth Phase

When planting the crops, make sure to follow the recommended spacing suggestions. By doing so, the plants are sure to get the appropriate amount of light and there is enough space for air to circulate which reduces the likelihood of disease and pest problems.

As the plants are growing, opt for manual methods of weed management and monitor pest populations to help prevent any major infestations. Having healthy soil helps to reduce the likelihood of pest infestations and provide the plants with the nutrients it needs to remain healthy and bear nutritious fruits.

If possible, protect the plants from extreme temperatures to avoid premature flowering, damage from frost or snow, and leaf scorch.

Harvesting & Post-Harvest Phase

The moment a product picked, it begins to deteriorate in quality. Accordingly, it is important to have a plan and system in place for processing the harvest. The essential parts of this process involve cooling, cleaning, sorting, and packaging. How far a product will travel impacts the approach to packaging. Having a system in place for post-harvest handling also contributes to overall food safety.

General Tips

  • Pay attention to the details and to be consistent.
  • Keep track of the growing process to learn from successes and mistakes

At present, the quality of fresh fruits and vegetables is based on the following factors:

crop quality

For more information about the horticultural production system, click here.

additional resources:

photo credit:

  • sknaturalsadoor.com
  • sciencmag.com

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.

hoophouses-clay-bottom-farm
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/

sustainable agriculture defined and discussed

Sustainable agriculture has become increasingly supported by citizens and farmers alike. According to the United States’ 1990 Farm Bill, for agriculture to be sustainable agriculture it meets the following requirements:

  • The production must satisfy the human need for food and fibers.
  • The environmental quality and natural resource base that the agricultural economy depends upon must be enhanced.
  • It must improve the quality of life for farmers and society as a whole.
  • The economic viability of farm operations must be sustained.
  • Integrated natural biological cycles and control methods must be employed.
  • Non-renewable and on-farm resources must be efficiently used.

Sustainability is often associated with organic agriculture. An organic agricultural system is designed to maintain the health of the soil, ecosystems, and people. It is structured to mimic ecologic processes in order to preserve biodiversity, limit the input of non-natural resources, and adapt to local conditions. Land must be free of chemical use for three years before it can become organically certified. Organic growing generally produces lower yields, approximately 80% of those using technological inputs, although with good conditions organic crops can compete to within 5%. The discrepancy is attributed to limited nitrogen in a given system. However, productivity typically increases over time due to soil improvement and agricultural management skills. Methods used in traditionally rural settings can include, for example, crop rotation, cover crops, compost and the application of manures as fertilizer.

The employment of organic agriculture practices also requires more space as it is not dependent upon large quantities of outside inputs for its functionality (see what is the difference between intensive and extensive agricultural systems as they relate to livestock production?). Accordingly, there are typically a greater variety of activities practiced, i.e. polyculture, on a given piece of land. When employing low-intensity methods on more diversely populated plots, several benefits have been shown to emerge, including increase in forest cover, larger and fuller hedge-groves, more crop diversity and more vegetation strata. These effects have resulted in an increase in natural vegetation cycles and biodiversity levels.

Sustainability is also a major theme in alternative agriculture systems, particularly in urban spaces, where practices, such as vertical and hydroponic, are driving the competitiveness of food grown in non-traditional spaces.

However, there are obstacles to the transition from 20th-century agriculture to sustainable agriculture. For example, a study surveying sustainability practices of farmers in 12 states it was found that:

  • 84% of farmers were aware of soil testing;
  • 76% knew about crop rotation;
  • 75% were knowledgeable about conservation tilling;
  • 74% were familiar with soil cover;
  • 64% had knowledge of Integrated Pest Management (IPM)
  • 52% were aware of diversification.

However, researchers also noted that awareness does not necessarily transfer to use as only 18% of farmers practiced water management, 13% engaged in nutrient management and 7% employed erosion control. The top three concerns related to issues associated with sustainable agriculture are:

  1. Cost and fear of crop/profit loss during transitional periods;
  2. A lack of education on how to integrate complicated alternative options, coupled with a lack of resources and support necessary to the transition;
  3. Resistance to change.

It has also been noted that there is often an incompatibility between growing conditions and sustainable growing practices, such as when the climate makes growing nitrogen fixing plants difficult, if not impossible. Such fears and obstacles to sustainability have the potential to be overcome via the use of education practices and more equitable public support and financing for food production.

sources:

https://www.nal.usda.gov/afsic/sustainable-agriculture-information-access-tools
Rodriguez, J. M., Molnar, J. J., Fazio, R. A., Sydnor, E., & Lowe, M. J. (2009). Barriers to adoption of sustainable agriculture practices: Change agent perspectives. Renewable Agriculture and Food Systems, 24(1), 60-71.
https://www.researchgate.net/publication/231888132_Barriers_to_adoption_of_sustainable_agriculture_practices_Change_agent_perspectives
Karp, D. S., Rominger, A. J., Zook, J., Ranganathan, J., Ehrlich, P. R., Daily, G. C., & Cornell, H. (2012, September). Intensive agriculture erodes ß-diversity at large scales. Ecology Letters, pp. 693-970.
http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2012.01815.x/abstract;jsessionid=BCD212E8E234B5D0CD57708401BD85E9.f03t01

question: what is the difference between intensive and extensive agricultural systems as they relate to livestock production?

Intensive livestock production systems are those that use higher amounts of labor and capital relative to the land area.  The best-known examples are Concentrated Animal Feeding Operations (CAFOs) which house large numbers of animals in small spaces.  These operations are dependent on food that was likely produced thousands of kilometers/miles away which increases demand for fossil fuels.  They also create large amounts of concentrated waste, CO2 and methane which is damaging to the environment and cannot be reintegrated into the ecological system of a farm because of the monoculture nature of these types of production systems.

intensieve-veehouderij1
Photo Credit: thinkability.com

In contrast, extensive farming systems are dependent on the carrying capacity (soil fertility, terrain, water availability, etc.) of a given piece of land and often responds to the natural climate patterns of an area.  It does not depend on a large amount of pesticides, fertilizers or other chemical inputs relative to the land area being farmed.  This is how most livestock production takes place int he world.  Herders are the classic example.

mongolian-grasslands
Photo Credit: oregonstate.edu

The main difference between the two types of agriculture is that extensive agriculture requires much more land for production and profitability than intensive production.  As such, extensive agriculture is often practiced where population densities are low and land is inexpensive.

The danger of intensive agriculture, apart from environmental degradation and animal welfare issues, is that prices can be depressed by overproduction when extensive tracts of land are used for production – despite the intense nature of agricultural practices.  Low prices do not reflect the actual price of food production and can result in poor market results.  It can also be argued that because of the extremely low price of food, it is a commodity that is taken for granted and often wasted – especially in the western world.

the purpose of agricultural irrigation and the advantages and disadvantages of mainstream methods

Irrigation is defined as the artificial application of water to the soil through various systems of tubes, pumps, and sprayers.  Approximately 20% of the world’s agricultural land is irrigated, yet 40% of the world food supply comes from irrigated lands with 70% of the world’s freshwater reserves being used for irrigation purposes.  

The main reasons for irrigation are:

1. Not enough rainfall to support crop growth.  

This may be due to rainy and dry seasons, drought or arid or semi-arid climate conditions.  Irrigation systems may also be used to maintain consistent moisture levels even in areas with moderate precipitation levels as it has been shown to improve crop performance.

and

2. High soil salinity levels.  

High soil salinity levels can be a natural occurrence which is the case in many semi-arid and arid locations or a result of poor agricultural practices and ineffective drainage.  In cases impacted by salt levels in the soil, irrigation must often be coupled with drainage in order to achieve the desired benefits.  

There are two main types of agricultural irrigation – gravity powered and pressure driven systems.  Gravity powered systems are, as the name implies, driven by gravity.  Pressure driven systems require an electrical pump in order to provide the irrigation system with water.

Examples of gravity powered systems include:

  • Furrow irrigation systems, basin irrigation systems and hand irrigation systems.

Advantages of Gravity Powered Irrigation Systems

  • Low-cost – gravity is free and simple irrigation systems can be developed to use this wonder of physics
  • Promotes social interaction – many community members need to work together to ensure the success of irrigation systems, particularly those dependent on water that comes from long distances (ex. mountain runoff)
  • Can be used indefinitely as long as the irrigation system is well-maintained

Disadvantages of Gravity Powered Irrigation Systems

  • Requires constant monitoring to ensure that the crops are not damaged by too much/too little irrigation water
  • Difficult to adapt to the specific needs of plants

irfurrow
Furrow Irrigation

irrigation-9
Basin Irrigation, Photo Credit mit.edu

 

Examples of pressure powered irrigation systems include:

  • Drip irrigation systems, sprinkler irrigation systems and pivot irrigation systems.

Advantages of Pressure Powered Irrigation Systems

  • High water efficiency
  • Very adaptable to the needs of the plants which allows a wider variety of crops to be grown – especially those of higher value

Disadvantages of Pressure Powered Irrigation Systems

  • High use and maintenance costs (parts replacement, electricity costs)
  • Expensive to install
  • Requires a high level of education and training for use (the most advanced system in the world can be installed, but if the people don’t know how to use it, it’s useless.)
  • Needs to be replaced every 10 – 20 years as the technology becomes outdated

drip-irrigation-system-for-trees-2
Drip Irrigation System, Photo Credit: heritageoakfarm.com

re1finding_new
Sprinkler Irrigation System, Photo Credit: ers.usda.gov

13sept_datafeature_schaible_photo
Pivot Irrigation, Photo Credit: ers.usda.gov

 

 

reasons for and benefits of agricultural drainage

Agricultural drainage serves two purposes. The first is for the removal of excess surface and subsurface water.  The second is to remove excess soluble salts with the (excess) water from the drained soil profile. 

drainage
source:  bae.ncsu.edu

There are two options for drainage systems. The first is a surface drainage system. A surface drain removes excess water from the surface of the land.

The second is a subsurface drainage system. A subsurface drainage system is used to control the water table in the soil. They can be open drains, which are open ditches with an exposed water table, or pipe drains which are buried pipes.

water table drainage
source: ohioline.osu.edu

Both types of drainage are employed to direct excess surface water to a collector drain in order to prevent ponding.

ponding
source: purdue.edu

The three main components of drainage systems are as followed:

  1. A field drainage system
    This system is used to control the water table and prevent ponding. This component is the most important part of the drainage system. It is comprised of a network which gathers excess water from the land. This is accomplished with the assistance of field drains. Supplemental measures to direct water to the drains may be taken.
  2. A main drainage system
    This part of the drainage system brings the water away from the farm to the outlet point. The water comes from the field drainage system, surface runoff and groundwater flower using a main drain known as a canalized stream. This means that there was an existing stream that was altered to improve the flow.
  3. An outlet
    This is where the drainage water is led out of the area and discharged into another body of water (lake, river, sea). An outlet will either be gravity powered or require a pumping station.  If it is gravity powered,  the water levels rise and fall.  An outlet will require a pumping station if the water levels in a drainage system are lower than the levels of the receiving body of water.

outlet
source: bae.ncsu.edu

There are several benefits of agricultural drainage.  The biggest and most important being the improvement of aeration within soils which results in better yields. This is due to the fact that:

  1. The crops can root more deeply
  2. The choice of types of crops that can be planted is expanded
  3. There will be fewer weeds
  4. Efficiency in fertilizer use will be improved
  5. Denitrification will be reduced
  6. Grass swards will be better

There are also additional benefits not related to aeration. They include:

  1. Easier access to the land
  2. Greater bearing capacity in the land
  3. The soil has better tilth and workability
  4. Tillage operations can take place over a longer period of time
  5. A better environment for micro-fauna (ex. Earthworms) is created which improves permeability
  6. Crops can be grown earlier due to increases in soil temperature

Drainage also makes it possible to inhibit soil salinity.  Soil salinity levels indicate the amount of salt presence within a soil. If there is too much salt, plant growth will be retarded.  To remove the excess salts from the soil, leaching is encouraged.  Leaching is the process of nutrients or salts being removed from the soil with water.  Leaching can occur naturally or as a result of irrigation and drainage systems. Sometimes leaching is necessary to repair land that has been negatively impacted by agricultural activities. It is also used to protect the root zone from being salinized by the capillary rise of saline water. Such safeguards allow for a wider variety of crops to be grown.

sources:

https://www.bae.ncsu.edu/topic/drainageadvisory/background.php

https://www.researchgate.net/publication/272507858_Drainage_of_Irrigated_Lands

http://www1.frm.utn.edu.ar/laboratorio_hidraulica/Biblioteca_Virtual/Subsurface%20drainage%20practices/Part_1.pdf