TFI is Working to Become Self-Sufficient | Intern Report |
TFI is Working to Become Self-Sufficient
Mary Jawlik, Project Manager
April 28, 2009
Agriculture in the humid tropics is something of challenge. With very infertile soils to begin with, the challenge deepens when we try to farm on land that had once been rain forest, but was cut down to make way for more than 30 years of cattle production. These abandoned pasture lands are severely degraded, with a high clay composition to boot! There is much work to be done and lots to learn, but we have started on the journey towards food self-sufficiency at TFI!
With student interns from 2008, we constructed a mini-greenhouse with wooden raised beds that reach to about hip height. Because it's a little bit more protected from wind and rain, we have had great luck growing more delicate crops such as tomatoes, herbs, as well as cucumbers, sweet peppers, and even lettuce.
Likewise, we have dug up several raised beds in the old pasture itself. Because the soil is so clay rich, roots are not able to penetrate very deeply. Little drainage leads to water pooling: no good for our plants. In an attempt to solve this problem, we have hauled several truckloads of sand from the nearby Rio Guabo. That, with some added manure from our buffalo farmer friends down the road, we planted our first round of crops.
Compost is a key ingredient of the mix, and we keep incorporating it into our garden beds in order to give them greater fertility and to improve overall soil structure. This hard work seems to be paying off, because we have already harvested some impressive squashes, radishes, green beans, and cukes.
Plans this wet season include planting about 2 dozen more fruit trees: starfruit, mango, avocado, mamon chino, lemon and orange. We hope to have a constant fruit source year round.
Shortly, we will be beginning a new experiment at TFI: dry-land rice cultivation. It is a practice that is slowly dying out at the local level, because in the past it was cheaper to buy rice from the grocery store than to grow one's own. However, with the change in the economy, more Costa Ricans are reverting to planting their own rice crops. We are going to do the same and see if we can grow enough to keep full all year round!
Peppers
Summer Intern Report
Dick Andrus, TFI Chairman and Intern Coordinator
June 1, 2009
The last several summers have seen some impressive results from our intern program. Each year we have had between 10 and 15 students who have worked hard on tree planting, research projects and learning tropical ecology. Each summer we have filled thousands of tree bags and planted thousands of trees. For many of the students, living in a rural Costa Rican community was the best part of their experience, as they got to develop an appreciation for the friendliness and the competence of our neighbors in Tres Piedras. We also visited Hacienda Barú, where we were privileged to hear from Jack Ewing, a conservation leader and writer (Monkeys are Made of Chocolate), who has given us his take on conservation in the area as well as the world. We also took side trips to Manuel Antonio National Park, Playa Ballena National Park and Aula Global, a cloud forest preservation project in the Santa Elena area.
Below is more detail about several research efforts that have spanned the two summers and will continue for probably several more.
1. Water infiltration study
TFI has always been very interested in the results of our plantings. In
other words, what have we accomplished in terms of enhanced ecosystem
services by our tree planting. We now have plantations up to 15 years
old so patterns are becoming clearer. We have been looking at several
categories of ecosystems on TFI land - primary forest, plantation forest,
briñon (the dense vine tangle that often develops on abandoned
pasture) and fern tangle (dense ferns). It turns out that the fastest
soil infiltration rates are in the fern tangles, with the vine tangles
and primary forest being similar to each other but slower than the ferns.
The plantations are clearly slower than either of the others. For comparison
we also looked at a neighbor's active pasture and found this to be very
slow--much longer than anything else.
The take home message here is that if all you're worried about is infiltration
(and erosion prevention), then a dense vine or fern tangle will work better
than planting trees. However, since biodiversity is almost absent from
vine and fern tangles, the story is more complicated. It is also obvious
that a vine tangle will not store much carbon either!
2. Vine and Fern Tangles
For several years now we have been investigating a fascinating successional
ecosystem that we have been calling a vine tangle. Vine tangles result
from pasture abandonment and are so dense that they seem virtually to
preclude successional replacement by trees. We have discovered by careful
measurement that some of the vine species can grow over 1 meter per year.
Such a growth rate quickly builds up both a deep organic soil layer as
well as a dense vegetation layer. Experiments in cutting back the vines
and planting trees have resulted in the trees simply being overwhelmed.
It is difficult to see what could cause the system to change. One of the
interesting things that we've figured out is that there seems no natural
process that would create such a tangle - all tangles appear to be a result
of past human land use. We have also discovered that cutting down the
vines close to the ground and then planting beans in the resulting mulch
will yield a great bean crop. Mary and Jairo have then burned the bean
patch in the dry season and have planted dry land rice. We may be self
sufficient in beans and rice.
3. Fern Tangles
Fern tangles are created by 1 or 2 species of bracken and Gleichenia ferns.
These create virtually impenetrable tangles through which nothing grows.
Ferns can be allelopathic so that could also be part of the story. Fern
tangles follow disturbance, but may in part come in after landslides.
We will be trying some new approaches to figure this out.
Coming up:
Mary has gotten orders for over 5000 trees to be planted so with our
research projects and tree planting this promises to be a good July.