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.

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.


photo credit:


the 15 principles of organic farming

Organic agriculture is the counter movement to conventional agriculture that supports a more natural relationship between production and the environment in which production takes place. In order to support this relationship and reduce the negative impact of horticulture and agriculture, 15 main principles rooted in common sense have been established. Any plant practitioner can choose to adhere to these standards regardless of certification. They are as follows:

  1. Avoid all synthetically-produced chemicals, including supposedly organic “icides” like pesticides, herbicides, and fungicides [they might be made with organic ingredients but they don’t really support soil health]
  2. Cultivate crop varieties with natural resistances and tolerances in suitable crop rotations
  3. Use beneficials for pest control
  4. Control weeds via mechanical [rather than chemical] methods
  5. Avoid the use of easily soluble mineral fertilizers
  6. Utilize nitrogen from manure and manure compost
  7. Practice green manuring with nitrogen-fixing plants [Leguminosae]
  8. Use slow-acting, natural fertilizers
  9. Preserve soil fertility via humus management
  10. Rotate crops with diverse varieties and long crop rotations 
  11. Abstain from the application of synthetically-produced chemical growth regulators
  12. Limit stocking density to improve animal welfare and reduce damaging effects to the soil, water, and air
  13. Restrict the use of purchased feed and focus on creating an on-farm or in-community production circle
  14. Use antibiotics on an as-needed basis
  15. Support biodiversity by embracing polyculture and intercropping 

Header Image Credit:

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.

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


EU Agricultural Economic Brief

the advantages and disadvantages associated with intercropping

Despite the fact that intercropping has ancient roots, it is only more recently that institutional attention has been paid to this growing method. The majority of formal research to date focuses on large-scale, rural production. Findings show that intercropping has both advantages and disadvantages, which are described in the table below.


– – – 

  • yield advantage
  • space maximization
  • pest deterrent and weed suppression → decreased pesticide and herbicide use
  • the potential for natural nitrogen use (less runoff)
  • reduced erosion via increased ground cover increased biomass production
  • informal crop insurance (reduced risk of complete crop failure)
  • competition for space, nutrients and sunlight → potential decreases in output
  • integrated management efforts essential
  • higher sowing and harvesting costs (non-machine) → higher labor costs
  • extensive planning required

However, the majority of issues related to intercropping can be overcome with proactive management, albeit harvesting without a machine is a great burden to producers, making the integration of intercropping on a large-scale difficult. Nonetheless, new research in this area is being conducted, and innovative, modular equipment is being developed in order to better facilitate the use of intercropping techniques.


Lithourgidis, A.; Dordas, C.; Damalas, C. A.;  Vlachostergios, D.N. (2011, April) Annual intercrops: An alternative pathway for sustainable agriculture. Australian Journal of Crop Science, 5(4) Retrieved from
Mousavi, S. R.; Eskandari, H. (2011, January). A General Overview on Intercropping and Its Advantages in Sustainable Agriculture. Applied Environmental Biological Sciences. 1(11). Retrieved from
Sullivan, P. (1998, November). Intercropping Principles and Production Practices. Agronomy Systems Guide.  Retrieved from
Wiley, R.W. and Rao, R.M. (1980, April) A Competitive Ratio for Quantifying Competition Between Intercrops. Experimental Agriculture, 16(02). Retrieved from

Zeman, F. (2012) Metropolitan sustainability: understanding and improving the urban environment. Oxford, Cambridge, Philadelphia, Delhi: Woodhead Publishing Limited

an introduction to intercropping

Intercropping is a growing method rooted in ecological diversity. In intercropped systems, two or more component crops are grown together for a given growing period. There are currently four types of intercropping systems:

  1. Strip: crops are grown simultaneously in independent rows within the same field
  2. Row: crops are grown together simultaneously and a minimum of one crop is planted in a row
  3. Mixed: there is no specific order to the crops
  4. Relay: the growing system is dependent on the lifecycle stage of the intercropped plants. Typically, the second crop in the intercropping schedule is planted after the first crop reaches the reproductive stage and before it reaches peak maturity

Types of Intercropping, Source: own, Adapted from Mousavi and Eskandari (2011)

Regardless of the intercropping pattern selected, the plants grown together should be complementary in nature in that they have different “rooting abilities, canopy structure, height and nutrient requirements” which produce a yield advantage. This occurs when resources that could not be utilized by a single crop are utilized by an additional crop growing in the same space.  One of the best-known examples of intercropping is the three sisters method developed by Native Americans in the United States, where Maize, pole beans and winter squash are grown together. The Maize provides a form for the beans to climb and shades the squash. The beans stabilize and fix nitrogen for the Maize plants. The squash provides ground cover, effectively maintaining moisture levels and suppressing weeds.

In order to develop an advantageous intercropped system, five fundamental principles must be adhered to:  

  1. A detailed plan must be developed, including an understanding of the characteristics of the component crops
  2. Crops must be timely sown
  3. Adequate fertilizer must be applied at the appropriate time
  4. A weed and pest strategy must be in place
  5. Harvesting must be efficient

If the wrong types of plants are grown together or the spacing is incorrect, the output will decrease.  To determine whether an intercropped system is effective, the land equivalent ratio [LER] is typically used, where:  (INTERCROP 1 / PURE YIELD 1) / (INTERCROP 2 / PURE YIELD 2). Results > 1.0 indicate an advantageous pairing. Results < 1.0 indicate a disadvantageous pairing.


Lithourgidis, A.; Dordas, C.; Damalas, C. A.;  Vlachostergios, D.N. (2011, April) Annual intercrops: An alternative pathway for sustainable agriculture. Australian Journal of Crop Science, 5(4) Retrieved from
Mousavi, S. R.; Eskandari, H. (2011, January). A General Overview on Intercropping and Its Advantages in Sustainable Agriculture. Applied Environmental Biological Sciences. 1(11). Retrieved from
Sullivan, P. (1998, November). Intercropping Principles and Production Practices. Agronomy Systems Guide.  Retrieved from
Wiley, R.W. and Rao, R.M. (1980, April) A Competitive Ratio for Quantifying Competition Between Intercrops. Experimental Agriculture, 16(02). Retrieved from

Zeman, F. (2012) Metropolitan sustainability: understanding and improving the urban environment. Oxford, Cambridge, Philadelphia, Delhi: Woodhead Publishing Limited

vertical farming: when high-tech meets food production

In 2008, Dickson Despommier published the book ‘The Vertical Farm’. His vision of growing up rather than outwards intrigued the world and ignited the imaginations of innovators who would build on his ingenuity to create sustainable, agricultural production systems even in the most land poor locations. Since the release of his book, his creativity has become a source of inspiration for those who believe in his dream for the future in which cities are no longer resource-hungry, environmental destroyers, but self-sufficient landscapes capable of producing enough food for each citizen. The non-profit organization the Association for Vertical Farming (AVF) has also since come together to help support this effort and help transform Despommier’s dream for the future from fantasy to reality.

While there are many varying concepts related to the realization of the vertical farm concept, a basic conceptual framework is nonetheless present: Vertical farms are isolated ecosystems that engage in a practice referred to as Controlled Environment Agriculture (CEA) that is arguably ideal for edible food production, particularly leafy greens. These systems, which can exist in a variety of locations ranging from old warehouses to newly designed multi-use urban farms, can grow food 24/7/365 regardless of the outside climate conditions. They are efficient in that production per square meter is increased and the outputs are highly nutritious due to the controlled nature of the growing environment. Production in such an environment requires also fewer chemical inputs, allows for water and nutrient cycling and recycling and eliminates the need for pesticides. Likewise, the issue of agricultural runoff is removed and arable land is not required for production. Explained more concisely, vertical farms are plant factories, which apply many of the concepts of traditional, technology-based manufacturing to food production.

Vertical farming is of interest to many different industries due to its novel nature, which provides an opportunity for innovation and new products for manufacturing. Technology companies are particularly keen on this technology because of the inherently high-tech nature of this strategy for food production. In Japan, the global epicenter of vertical farming, there are already 370 vertical farms (as of 2014) and the demand currently heavily outweighs the supply despite products costing more than double their conventional counterparts, albeit this is arguably a result of Fukushima which has engendered a great deal of fear related to food safety. Success has been so great that major technology companies, such as SONY and SHARP, have invested in vertical farms and begun adapting inactive infrastructure to suit growing consumer demand. Other successful endeavors can be seen in the Netherlands with the Plantlab, in Sweden with Plantagon, and in the United States with Farmed Here and Green Spirit Farms.

However, despite some demonstrated successes, there are still questions as to the economic feasibility of vertical farming operations – especially due to the high technology and energy demands. However, it can be contended that as this practice expands and renewable energy becomes more readily available, the costs of the technological components will decrease as is the case with most technological advancements, indicating that vertical farming will likely be a permanent component of the urban agriculture family.


Loesel, M. (2014). Vertical Farming: From Concept to Reality. Urban Agriculture Magazine, 28. p. 62-64.

zero acreage farming (zfarming): what it is and how it can change the future of (urban) agriculture

It is not uncommon to hear about the challenges that will be faced in feeding the growing population of the world. One of the main concerns is the lack of arable space, an issue that can be attributed to land-use changes, especially urbanization. Subsequently, the rapid growth of cities contributes to a number of issues, with the overwhelming demand for resources, e.g. food, that must be imported from outside systems being among the most relevant. This long-distance between urban-dwellers and agricultural production creates ecological problems in the form of inhibited nutrient cycling, high costs, and emissions problems.

Despite these issues, it is also well-documented that cities are efficient hubs of innovation. Accordingly, cities have birthed the idea of zero acreage farming, or ‘Zfarming’, which is defined as a form of agriculture that does not use farmland or open space, rather it uses otherwise unused spaces. Zfarming can take the form of, for example, rooftop farms/gardens, edible walls, indoor farms, or vertical greenhouses. As the competition between food producers and various interests is alleviated, the conflict related to land-use in urban spaces is resolved. Moreover, urban spaces supportive of Zfarming practices can be considered to have added-value as there is a unique component to said spaces.

Additional potential benefits associated with Zfarming include, for instance, the potential to shift towards new frameworks for food supply systems via input from evolving customer and social demands, and income generation – especially when higher value crops are grown. Furthermore, Zfarming can help address issues related to urbanization by providing economic opportunities which incentivize the transition towards more sustainable, resilient and efficient urban spaces.  

At present, Zfarming is almost exclusive to middle-class spaces with operations often catering to the needs of higher end restaurants or supermarkets with the use of mid- and long-term contracts in order to establish income consistency. This is arguably necessary due to the higher startup and maintenance costs. However, Zfarming is also associated with social/educational centers, efforts to improve the quality of urban life, and supporters of innovation focusing on alternative, i.e. not soil-based, methods for growing. It can, therefore, be assumed that as innovative practices are disseminated, they will gradually become integrated into lower-income spaces.

To encourage and promote Zfarming in more locations and further foster development in existing venues, the following supportive infrastructure is needed:

  • Modern and adaptive policy that is reflective of modern societal demands
  • Financing programs to allow for a shift away from top-down approaches to startups
  • Greater involvement (human capital)
  • Knowledge sharing to address the issue of a lack of practical experience which results in difficulties in the planning and implementation phase, something that can hinder the longevity or establishment of any Zfarming operation

In promoting Zfarming, innovative practices that may contribute to sustainable urban agriculture may be developed and implemented. Supplementary to the practical benefit of growing food, Zfarming also aids in the advancement of new forms of resource efficiencies, farming technologies and the practical application of such innovation, making it a trend worthy of further investigation.