18 June, 2004
Friday night at the Martz Farm. This was my last full week here in Belize. I managed to get everything done this week at both Minanhá and Baking Pot that needed to get done. I spent Monday and Tuesday mapping and photographing at Baking Pot. Wednesday through Friday I was at Minanhá mapping, taking core samples of a cross section of locations from the conductivity maps, and taking photographs.
The mapping at both locations consisted of mapping all visible surface features, that is trees, rocks, logs, mound and hillocks, depressions, and anything else that may affect the data as it is being collected. These field maps will be used during our analysis of the conductivity data. If we see an anomaly in the data, we will check the field maps, and our field notes, to see if, for example, there was a log or a rock or a hole in the ground that we had to stop at and move around. Any of these can cause bumps in the data- all surface features need to be carefully mapped.
Photographs are taken of some of these features when deemed necessary. For example, at Minanhá in M-OP1, M-OP2, and M-OP6 there are prehistoric terraces visible on the ground surface. These are mapped and photographed as well in order to have a better record of the size and shape of the terrace at the locations where they cross out survey lines.
The core sample locations at Minanhá were chosen based on variation in conductivity visible in the contour maps. Although upon initial analysis no cultural features were visible in the contour maps, we thought it important to take samples from areas of differing conductivity in order to confirm that what we see in the maps does in fact reflect what is found in the ground. The black dots on the contour maps below denote locations with sufficient variation from one another to warrant testing of the soil in these locations.
Taking core samples of these locations was quite easy. We brought along a corer that extracts a sample 2 ½ centimeters by 40 centimeters in size. The maximum depth with a single extension on the handle is 1.2 meters. This is the maximum depth I tested to.
The corer I used to sample survey grids M-OP1, M-OP2, and M-OP6.
The survey area at Minanhá has changed a lot in the last 2 weeks. Part of the reason that these locations were chosen for survey was the fact that they had been cleared and burned to make them ready for planting corn. Since we collected data in these grids they have been planted and the corn is already up.
BEMEP survey grid M-OP2, with corn plants growing along our survey lines- note the small green tufts visible in the blackened foreground.
Clearing, done by hand with a machete, and then burning, is a typical practice in this part of the world. By cutting the vegetation and burning it after it dries, the nutrients are added to the soil. Though this type of agriculture is not entirely sustainable, it does seem to work well enough if the land is left fallow for a number of years in between plantings. Of course, there does seem to be a bit of luck involved as well- cutting and burning must happen before the rains come, the corn cannot be planted too early before the rains, the rains must come, and there cannot be too much rain as this can cause the seed to rot.
Actual planting of the seed is different from the north American practice as well. From the following photo, taken at Pusilhá, you can see that a hole is made in the ground. This is done with a digging stick- a sharpened stick about 2 ½ inches in diameter. According to my source, 5 corn kernels are dropped in the hole- always 5. The hole is left as is- no soil is used to cover the seeds. This allows moisture to find the seeds and speeds up germination. Corn planted in this way can sprout in as little as a few days.