David Alexander Carroll II and Dr. Bryan Hopkins, Plant and Wildlife Sciences
In Haiti, widespread deforestation in mountainous and hilly areas has led to a diverse array of environmental problems, including biodiversity loss, habitat fragmentation, sedimentation of rivers, severe soil erosion and lower water content in mountain soils, flooding in coastal areas, bleaching and death of offshore coral reefs, and hotter, and drier microclimates in deforested areas. Socioeconomic problems related to deforestation include lower crop yields on mountain semi-subsistence farms, increased rates of poverty and malnutrition in rural communities, property damage and death associated with severe floods and landslides, and increased frequency of waterborne illnesses. Thus, environmental problems related to deforestation are perpetuating many of the country’s most serious developmental problems. Indeed, the vast majority of Haiti’s forests have disappeared, with only 1-3% of the country’s land area remaining under forest cover today1. The biggest driving force behind deforestation currently is Haiti’s dependence on woodbased charcoal as a cooking fuel for the majority of the population.
One strategy for combatting deforestation involves the establishment of community tree nurseries containing various species of native and non-native fruit and forest trees. Such community tree nurseries are often established by foreign nongovernment organizations or Haitian civil society groups, such as local farmer collectivities. The trees are then planted on mountain slopes, many of which are terraced and farmed actively. One possibility for an effective soil amendment for tree nurseries lies in the sugarcane industry, which is prevalent in the Léogâne area. Large piles of bagasse (the fibrous plant matter that remains after sugarcane stalks are crushed to extract their juice) are discarded outside of the many sugarcane mills found in the coastal plain of Léogâne and left to decompose. Some organizations purchase composts made from bagasse and manure by local entrepreneurs, while others take the bagasse directly themselves. The purpose of this study was to evaluate the nutrient content of bagasse in order to determine the amount of compost needed for meeting the nutrient requirements of saplings in reforestation nurseries. In order to do so, four soil-compost mixtures were created using various amounts of compost, and these mixtures were then tested for nutrient content.
The soil sample (sample name Duplaissy Sol) was taken from a hill slope on the property of Glaudine Auguste, a student at the Institut de Technologie Agricole et du Développement Local in Léogâne and a collaborator in the project. The property is located in the Duplaissy community of Léogâne and consists of a moderate foothill slope devoid of trees, shallowly terraced and planted sparsely with legume crops. The compost sample (sample name Nolivos Fumier) was taken from a sack purchased from a compost supplier in the Nolivos community of Léogâne’s coastal plain. The sample consists almost entirely of decomposed sugarcane bagasse taken from a local sugarcane mill. A sand sample was also taken (sample name Duplaissy Sable) from a riverbed below the home of Glaudine Auguste, also in the vicinity of the tree nursery. Four planting mixtures were then made. Each mixture had six parts compost and one part sand; the level of compost was varied between the mixtures, with zero (sample name 601), one (sample name 611), two (sample name 621), and four parts compost (sample name 641), respectively. The local agronomist recommendation for the mixture was two parts compost. Samples were then analyzed in the BYU Environmental Analytical Lab using standard lab procedures. Results of the analysis are presented below. 
Phosphorous content did not follow a linear pattern—the one part compost mixture had the least phosphorous content, while that with two parts compost had the highest. Nitrate content also did not follow a linear pattern, with the highest nitrate content observed in the mix with two parts compost. The mix containing four parts compost had lower nitrate content, possibly due to improper mixing of the different samples. Potassium content was positively correlated with compost content, as was organic matter—both potassium and organic matter levels were highest in the four parts compost mixture. Iron was also determined to be positively correlated to compost content. A large increase in soil iron is observed when using four parts compost in the mix as opposed to the agronomist recommendation of two parts. The increase in iron is essentially 5 ppm between the 621 and 641 mixes. Total nitrogen did not increase linearly with increased compost content, actually dropping between the 611 (one part compost) and 621 (two parts compost) mixes. However, using four parts compost in the mix was the most advantageous by far, with an increase of over 1,500 ppm between the 621 and 641 mixes. Parts per million of carbon did not change drastically among the mixes with one, two, and four parts compost, although a slight increase was observed in the mix with the greatest amount of compost.
In conclusion, it was found that the soil mixture with four parts compost had the highest content of major plant essential nutrients such as nitrogen, phosphorous, potassium, and iron. This sample also had the highest organic matter content of all the mixtures. Using four parts compost in soil mixtures for tree nurseries would be more advantageous to plant growth and establishment. This differs from the previously recommended level of two parts compost.
References
- Sprenkle, S. D. Community-based agroforestry as restoration; the Haiti Timber Reintroduction Project methods and framework. Ecological Restoration 26(3), 201-203 (2008).