MULTI-CROPPING: PRODUCING TWO OR MORE CROPS/PRODUCTS IN THE SAME SPACE AS ONE

Jac Smit - February 2009

In the 21st Century we are reading and hearing more and more about high yield small-scale urban-metropolitan agriculture production. However, one method I have not heard discussed is multi-cropping.

A well known historic method from pre-Columbian time, which also projects to the future, is the "Three Sisters". Three sets of seeds are planted at the same time: Corn, Squash and Beans. The beans climb the corn stalk and the squash covers the ground. The squash reduces weeding and reduces evaporation of soil moisture. The beans have relatively deep roots and return nitrogen as well as carbon the soil. The corn stalks are particularly good as a source of litter and compost. A recent experiment at Cornell University found that this combination produced as many calories per acre as the latest mono-cropping techniques in Iowa.

For the small-scale operator, three crops are better than one for the dinner plate or for Main Street.

For hundreds of years farmers in Vietnam have been producing rice and fish in the same field. This requires a bit more precision than the Three Sisters. Planting, feeding and harvesting have narrow time windows. The benefits of carbohydrates and protein are worth the effort. And the fish offal enriches the soil. Recent studies find that this practice is predominantly used in peri-urban areas - close to market. As would be the case in a small-scale urban site in Europe or America., irrigation is provided by grey water.

A similar method is common in Thailand's cities and in other countries including Taiwan. Here I refer to "Poultry over Fish Tank to Vegetable Raised Bed". Simply, chicken cages are built over fish tanks. The fish consume chicken waste (not their only nutrition source).  The bottoms of the fish tanks are cleared and used as compost/fertilizer for the vegetable beds. With the “multi-crops” including chicken, fish, rice and vegetables, substantial carbohydrates and protein are produced in a relatively small area. The technique is best suited to a quarter-acre backyard farm.

A common method in more temperate climates is "Chicken and Vegetable". This simple “lazy man” farming method uses the chickens to create compost and fertilizer. Season by season the poultry area and the vegetable area are switched with the vegetable growing area usually larger. The start of the process is known as "Chicken-Powered Composting".

Organic waste of many sorts is piled up.  As it becomes biologically active, crickets, worms, microbes invade and the birds scratch and feed, which accelerates and enriches the compost. Chicken offal can usefully be added. The next season compost is distributed or the chicken-compost space is taken over by the vegetables.

In my own background I worked for a farmer who raised goats. At night we corralled them. At the end of two years the corral was moved and the former space became a vegetable plot.

At simpler method is known as "Oats & Peas". Somewhat like the "Three Sisters", short climbing peas are planted with oats and the two crops are produced in the same space. The harvests occur at different times.  Additional benefits result from the carbon sequestering derived from the peas.

And some folks say you can't sensibly grow grains in the city.