Vetiver Grass Hedgerows Likely To Be Key Solution For Stabilization Of Central American Watersheds
Tom Thurow of Texas A&M University leads a Soil Management Collaborative Research Support Program in Honduras. The pre Hurricane Mitch results are written up in Technical Bulletin No. 98-2 April 1998 (Technical Bulletin No. 98-1 also provides some background) available from: Department of Rangeland Ecology and Management, Texas A&M University, College Station, Texas 77843-2126 USA.
This research shows the effectiveness of vetiver grass hedgerows (in conjunction with mulch) on slopes ranging from 55 - 63% slopes for reducing runoff and soil loss. The reductions are very significant. Note the research was carried out on micro catchments of between 0.12 and 0.27 hectares -- these are much larger and more "real" than the standard 22m x 2m plots that are generally used.
Tom recently emailed me the following comment and feedback from farmers following the Hurricane Mitch devastation. Tom can be contacted directly at: "Tom Thurow" <[email protected]>
I don't have any recent pictures of our catchments and the surrounding areas, but I have some good quotes from the local farmers. I think USAID Frontlines may do something with them, but feel free to use them as well if of interest to people in the Vetiver Grass network. They tell the story best. I'll send by regular mail some of our publications which give an overview of what we are doing in southern Honduras. Briefly, I think the combination of mulch and vetiver grass is indeed a winner. Most of the erosion that occurs on these steep hillsides is associated with landslides. Mulch helps break the raindrop impact, but what is really needed is some mechanism to tie the soil into the hillside. Much research in the tropics only uses small plots (USLE size -- 22 m by 2 m) at largest. Such small plots show that leaving crop residue is a good solution -- such plots, however, do not detect the much more important aspects of soil erosion that occur on a field scale. It is an expensive and logistically imposing challenge to do field level work, but these field level data show best the realistic and important benefits of using a live barrier such as vetiver grass. Below are the quotes.
Throughout the text, LUPE refers to the USAID Land Use Productivity Enhancement project that was implemented in conjunction with the Ministry of Natural Resources. The LUPE program ended in Dec. 1998.
Cupertino Galindo, hillside farmer, Los Espabeles, Honduras
I am 84 years old and have seen many hurricane storms. I was happy to work with LUPE to install rock terraces on my farm 10 years ago because I know the benefits of keeping soil and water on the field. During the hard drought of last year, my neighbors envied me because my terraces produced enough basic grains to feed my family; the deep soils behind the terraces held enough scarce water to fill the heads of the maize and sorghum with grain. The heads of my neighbors crops did not fill because their crops ran out of water before the grain could develop. Their soils had washed away in previous years and could not hold enough water for the dry times. Now during this horrible flood, my fields have remained intact while many of my neighbors without conservation have lost their whole crop.
Neighbors took refuge in my house during the flood because they were afraid their (unprotected) fields would slide and crush their houses. My neighbor lost part of his house that way.
Questioner: If rock walls are so good, why doesn't everyone build them in their fields?
Cupertino: I am not sure you know how hard it is to build rock walls on these hillsides (60% slope)? It is damn hard to lift rocks and carry them on the hill and put them into place! LUPE organized a crew of farmers to work together therefore it was not so hard on any one person. They provided food to keep up our energy and allow us not to have to seek work off-site to earn money to buy things like sugar, cooking oil and beans. They also gave us sardines in cans. They did not have enough funds to help everyone get rock walls established. In fact, they ran out of money for the effort when the walls were only half way across my field. Everyone in these hills who had rock walls built has maintained them because we value them, but it is too insurmountable of task to start on your own.
Miguel Gomez, hillside farmer, Los Espabeles, Honduras
I have worked closely with LUPE and have seen the benefits of vetiver grass or rock barriers positioned on contour in the fields. Vetiver grass is easier to establish but we needed help in getting good grass into these hills. LUPE helped us establish plantations from which farmers could take grass and plant on their own. There were concerns about competition with crops and concerns about not being able to use fire or graze livestock during the dry season. There were concerns about having to prune the vetiver grass at a busy time of the growing season. These concerns have proven not be so serious in our experience over the past several years since we established vetiver. The fact that these sites held the soil during this flood has convinced many that having vetiver in our fields is good.
Forests are good too. Down the road there are very steep hillsides that had landslides which closed the road every time we would have a big rain. About 15 years ago a GTZ project reforested these hillsides. You see now that the forest had no landslides, but cropland on gentler slopes has covered houses. But people have to eat. Maybe forests should be replanted on exceptional slopes and projects should help us establish conservation structures on our fields.
Martin Guido, hillside farmer, Los Espabeles, Honduras
I like my rock terraces -- once soil accumulated behind them I planted fruit trees and make more money than growing basic grains. I grow basic grains on adjacent fields and am gradually extending my rock walls there. The field on which I left crop residue and did not burn according to LUPE recommendations washed away anyway. I need terraces on all my land, but during the dry season when there are not crops to tend, I must send my sons to work (out of the region) in the melon fields and chicken factories and thus do not have the manpower to make much progress on my own.
Simeon Gomez, hillside farmer, Los Espabeles, Honduras
On my field with vetiver grass contours the hillside remained perfectly in place. The fields without grass contours have had their crops and soil washed away. I have been trying to use vetiver cuttings from this field to plant on my other fields which are several kilometers away, but it is hard to transport the amount that I need. Now I have lost my crops and some soil on those fields, but I need to plant vetiver to save what is left. Does the project have a truck I can borrow to transport cuttings?
Hector Santos, former LUPE technical specialist.
When people realized that the USAID-LUPE project was terminating, and that no follow up was considered in the near future, they were very discouraged. In the situation these farmers, LUPE technicians that visited them were a source of hope and courage to continue with the hard work of stabilizing their hillside fields. People know it is important to conserve soils, but their primary concern is what they're going to eat this afternoon, tomorrow at the most. They have to work off-farm instead of installing the rock walls or Vetiver because they need the cash. They don't have time to think what will happen in ten years. A hurricane like this puts them in a great hazard for surviving next year. They lost their crops and don't have the money to buy their maize. That is the reason why they continue working on the hillsides. They do not have any other option, they need to feed their families. The farmers feel that now that LUPE is gone, they are abandoned on their own, orphans of the people who were showing them a light at the end of the tunnel. Just the technicians visiting these farmers gave them a sense of importance and pride, and the hope that we all need to keep working everyday towards a better living.
Downstream, the shrimp farmers are now realizing how much sediment from hillside farming goes into the rivers. This sediment eventually gets to their ponds, reducing their efficiency and increasing their costs. They don't think it is fair, they want a remedy, they are exploring solutions through the government, but the country is poor, and there are many needs.
It is interesting to note that in Ethiopia farmers say the same thing: "vetiver hedgrows are very effective, terrace building is costly and backbreaking!!"--- Dick Grimshaw