Vetiver Soil Conservation Buffers at the Pioneer Machete Farm

Initial barrier

We are happy to say that the Vetiver Soil Conservation Buffers project at the Pioneer Machete Farm has met its objectives and our plants are now containing sediments that would otherwise be affecting coral reefs south of Guayama in Puerto Rico. This project, funded by a grant from the National Resources Conservation Service (NRCS) of the US Department of Agriculture, is a good example of simple bioengineering used in the agricultural industry.

Pioneer, a DuPont company, has several locations in Puerto Rico where research on new seeds for corn, soybean, sorghum, and sunflower is taking place. They are very interested in the application of the Vetiver technology, for controlling soil erosion, managing waterways, reducing runoff, trapping sediments, and stabilizing soils during intense rainfall and floods. A small pilot project at one of their Salinas locations was the stepping stone to this ambitious project.

Barriers along waterway

A visit on July 20, 2011 by Luis Pascual Ramos from Pioneer, Edwin Mas from NRCS, and Alberto Rodriguez and Carmen I. Ruiz from Agriflora, found the Vetiver hedges to be developing very rapidly after they were replanted in March 2011. The replanting using hardened, well-rooted, plugs was needed because the original bare root slips could not survive the severe drought that occurred from November 2010 to February 2011. The new planting, with an installed drip irrigation system, is now fully rooted and the hedges are already trapping a substantial amount of the sediment carried by the waterway.

Although this land looks fairly level to the eye, evidence of strong sediment flows could be seen throughout the fields. The waterway running across Finca Machete was creating a large gully due to the effect of water running through the soft soil with no protecting vegetation. The silt being dragged down the waterway was finding its way to an urban area at the southern end and to the coastal area beyond that. Pioneer had been establishing trenches and dikes to direct and collect the water flows in a manner which protects the production fields as well as the community. These mechanical barriers and channels require extensive maintenance and do little to prevent the main waterway flow from reaching the coast where coral reefs are known to exist.

A vegetative conservation system, as built, forms a series of protective barriers along the waterway, which slows the run-off water causing sediment to be deposited. Since the barriers only filter the runoff and do not block it, water seeps through the hedge, reaching the bottom of the slope at a lower velocity without causing any erosion and without being concentrated in any particular area.

The objectives of this proposal have been achieved and the project is considered completed. The Vetiver filter strip system established is composed of:

One initial barrier of 500 feet north of the start of the waterway
Thirty (30) barriers along the waterway - placed every 100 feet
One final barrier, 1000 feet wide, at the southernmost edge of the waterway

Trapped sediment

All the barriers were seen trapping vegetative mass along the waterway and deposits of loose soil accumulations are evident within each segment of the waterway. It was noted that hedges closer to the beginning of the waterway show greater development that those towards the end. This would be consistent with the expectation that the Vetiver will trap and use the excess fertilizer that would otherwise flow along the waterway.

Agronomist Luis Pascual Ramos, Sr. Research Associate at Pioneer, made a presentation about this project in a Pioneer meeting in Hawaii where operations from several countries were represented. The results of the project will continue to be shared with these locations and it is expected that similar measures could be implemented by other stations. In Puerto Rico, Pioneer is still interested in expanding the use of Vetiver to other areas of the Machete Farm. We will continue to work closely with them to define and design these additional objectives.

A full set of pictures can be seen in our Picasa album Pioneer Finca Machete Sediment Control