Polyculture for pest control, high yield & food diversity

 Polyculture - alley, strip, cover, inter, mixed or three sister cropping systems

Polyculture is an agricultural system were multiple crops are planted on the same piece of land to provide crop diversity which mimic the diversity of natural ecosystems. This does not only provide food, but sustain life as a whole. As opposed to raising single crop/animal (monoculture), polyculture is raising more than one species of plants or animals at the same time and place. Polyculture is an old system of farming which is still carried out in sub-Sahara Africa and has regained popularity today because of its environment and health benefits. It is a sustainable form of agriculture because of its ability to control pests, weed and diseases without major chemical inputs. There are different types of polyculture systems such as intercropping, cover-cropping and alley cropping. The type of polyculture carried out depends on the types of plants grown, the spatial distribution and the time they spend growing together. The type of plants or animals that can be raised in a polyculture system has no limit.

Three sister crops (Maize, beans and pumpkin)

Intercropping or mixed cropping – This occurs when two or more crops are planted together e.g legumes and cereals mixtures. The legumes fix atmospheric nitrogen into the soils at its root noddle in a process called nitrogen fixation. This soil nitrogen acts as fertilizer for the other plants and therefore eliminates the need for man-made fertilizers. A typical example is the ‘three sister crop’ system of planting maize, beans and squash (e.g pumpkin) in a group to provide mutual benefits to each other. The maize provides support for the beans to grow on, the beans provide nitrogen to fertilize all the plants while the squash suppresses the weeds. These crops thus sustain each other with little or no human intervention.

Cover cropping: - This is when a crop is grown alongside another plants that is not a crop e. grass & legumes. Cover crops can help to prevent erosion, suppress weeds, improve water retention or fix nitrogen. It can also be called weedy culture if the non-crop element is a weed.

Strip or alley cropping

Strip or alley cropping: - This involves growing different crops in alternating rows. Though it doesn’t involve a complete mix of the plants, it also prevent soil erosion and aid nutrient cycling. 

Permaculture: - This is a polyculture of perennial plants such as cocoa, coffee, timber, fruit trees etc. This system increases soil fertility, decreases soil erosion, conserve soil nutrient and increase soil organism and water retention. Agroforestry is a popular form of permaculture where trees and crops are grown together. The trees provide shade and organic nutrients when they share off their leaves and also provide extra commodities like timber, medicine, firewood etc. Shade loving crops like coffee and cocoa are well suited within such a system.

Advantages of polyculture

Pest and disease control: - Pest are less predominant in polyculture due to crop diversity. Specialized pest that prefers a concentration of a single crop type often gets confused as they find it difficult to locate a favorable host in a polyculture. Common general pest moves from one plant to another within a polyculture system to the surrounding environment because they look alike, thereby reducing the effect on a particular crop. This diversity of plants attracts natural enemies or predators which help to further suppress pest population without causing harm to the plants. Different plants are susceptible to different diseases so the spread of diseases can be contained in polyculture.

Weed control: - the high density of plants reduces available space, sunlight, water and nutrients for weed to develop as resources are fully utilized by crops. The few that do grow can host arthropods (pest enemies) that are beneficial to other crops.

 Sustainability: -

A bunch of plantains at Suzy-Farms

A polyculture system doesn’t depend on pesticide, but can be boosted with minimal use of organic fertilizers as diverse plants are planted together. This greatly reduce eutrophication of fresh water, hence good health and wellbeing. Reduce tillage conserves microbes and soil nutrients. This saves money as farmers can grow multiple crops and animals on same piece of land with little or no machinery. It increases local biodiversity which attract different pollinators, hence increase pollination and fruits harvest. Polyculture addresses human subsistence needs because food security doesn't just depends on quantity, but on diversity and quality of available food. Polyculture is diverse in nature and provides both nutritional and economic resilience  because if one plant fails, the other crops may support the household with food and income.

Polyculture is more effective when the diverse plant species have distinct biological needs such as absorbing different nutrients and requiring different amount of sunlight (no competition). Our modern lifestyle is negatively impacting our land and ecosystems. Restoring these systems will lead to food abundance to support human life and culture as well as restore the ecosystems. It is our duty to secure a rich permaculture for future generation. So let’s do it...

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