Tuesday, September 13, 2011

Bolivia Diaries: Day 5, Part 3 - A Biointensive Garden

This diary is part of a series describing my trip to Bolivia to study food sovereignty, agroecology, and climate change. We spent our fifth day in Yungas, the warmer and greener region just down the mountains from the Altiplano. After lunch, we visited a biointensive garden that the students maintain to provide their own food supply. John Jeavons aficionados, buckle up!

One look at the garden told me much of what I needed to know about it. If you've ever used John Jeavons methods, as outlined in the book How to Grow More Vegetables, then you know what I'm talking about. I asked where they learned the methods they used, and sure enough... They learned from an Argentinian expert, but the Argentinian learned from John Jeavons.

As you can see here, the beds here are one to one and a half meters wide (3-5 ft), which is just wide enough so that someone can reach from either side into the middle, and so that you don't have to walk on the bed, compressing the soil in it. The beds can be as long as you want them to be. Here, they prepare the soil by double digging it (as outlined in the Jeavons book) down to 60 cm from the walkways (about 2 ft), which is closer to 70 or more cm below the top of the raised beds. Double digging is a way to aerate compressed soil, and you typically add soil amendments to the soil when you do your double dig. After an initial double dig, you can simply mix future amendments into the top few inches of the soil.

The idea behind planting in beds instead of rows is that you can plant more in the same space and thus derive more productivity from it. The chard (below) is a great example of the recommended plant spacing.

Don Desiderio shows us his chard

Floating row covers used on a broccoli plant

Don Desiderio began his tour by telling us the most important part of biointensive gardening was living soil. Initially they used chicken litter, but then it became very popular and now they cannot get enough of it. Now they make their own amendments - compost tea and compost.

Compost tea

Compost tea

This compost tea is created by putting kitchen scraps in buckets. Each bucket has small holes in it. On the top, he put yogurt and urine. He also adds oats and molasses to stimulate the fungi and bacteria, respectively. The scraps break down after a few weeks and they come out the bottom as a compost tea. He mixes a cup of the tea with 2 liters of water and then sprays it on the plants. He said it's a very fast system so you need to constantly add more food on top. You can add a little meat and fat and you can add eggshells, but no plastic and no bones. To create a bit of an organic insecticide, he adds spicy pepper seeds to the mix.

Compost pile

To make compost, they want to mix materials both rich in nitrogen and rich in carbon. They strive for a mix of 30:1 carbon to nitrogen. Dry material like leaves, straw, and wood are carbon rich, whereas food scraps are typically nitrogen rich. With too much carbon, the compost pile doesn't break down quickly. With too much nitrogen, it can go anaerobic.

To build the pile, they begin with carbon rich material, then a layer of nitrogen rich material, and then a layer of soil. That's because the soil has the microorganisms that are needed for composting. They continue to build the pile, layering it like this. Then they add water. The big plastic tube is for aeration. They turn the compost every month or two (ideally every month) and it takes six months to be ready. Don Desiderio said they just always need more compost than they have, but for a small family growing a garden, this would be a good system. They use about 5 to 6 kilos (11-13 lbs) of compost per square meter in the garden. (If they have chicken litter, they use 1-2 kg per square meter as an amendment.)

They also grow peanuts, beans, and other legumes to add fertility to the earth. And they have a small scale worm composting operation going too.

Many of the plants are started in trays and then transplanted into the ground. This allows them to maximize their use of space. They make their own potting soil by mixing soil (which has a lot of clay in it) with sand and compost.

A student mixing potting soil.

Plant starts.

The entire garden is done on a slope, so it is all terraced in order to retain nutrients and moisture and to prevent erosion. The bricks that line some of the terraces heat up during the day and radiate the heat back at night.

A view of the terraces, from below.

Several rows of trees (citrus trees, plantain trees) are grown as windbreaks. The plantains are eaten green and boiled, not raw. They accompany every meal here, often as a bread substitute. I noticed that one of the trees is a legume, which puts nitrogen into the soil.

A row of trees that serves as a windbreak.


Plantain trees

Leguminous tree

Near the compost pile, Don Desiderio pointed out wild relatives of some native plants - wild amaranth and ground cherries.

Wild amaranth growing near the compost pile. Good food for birds, says Don Desiderio.

Physalis peruviana, a.k.a. ground cherry, growing wild

Lemongrass, which they call hierba luisa, is used as an insecticide. I asked if they also used neem and he said they don't have it here, although it is grown in Bolivia (he said in Alto Beni, which is closer to the Amazon compared to Yungas).

Lemongrass - the essential oil is used as an insecticide.

Next, Don Desiderio showed us a solar dehydrator. It was something the students built and worked with but then sort of abandoned. Don Desiderio said it's very good to use for drying herbs, tomatoes, bananas, or even fish.

A solar dehydrator.

A solar dehydrator.

One of the crops here, locoto peppers, are very special and loved in Bolivia. Recall that chiles are native to this part of the world and there is great biodiversity of chiles here. These are the ONLY crops in this garden that grow from saved seeds. Here, the locoto are flowering and the peppers will be ready in 2 months.

Locoto peppers

Locoto flowers

One very disturbing detail that came out during our visit to this garden was that they are forced to buy seeds that have already been treated with pesticides. As noted before, the only saved seeds are the locoto seeds. Those have always been saved and they aren't available commercially. Untreated seeds are available to buy but are much more expensive, too expensive. Treated seeds are affordable. And, very unfortunately, most or all of the seeds sold are hybrids, which means you can't really save them - although they are trying. So even in this beautiful, organic garden, all of the seeds except for the locoto seeds already have pesticides on them.

A student shows me his agroecology book.

A hoophouse that provides partial shade.

Oops, looks like the pests had a good meal here.

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