Report 15. An explorative approach for assessing soil movement on hillsides. Application for hedgerow performance

Abstract

This report describes a methodology for studying soil movement on hillsides in Haiti. Hedgerows are one of the methods used in Haiti to prevent land degradation, and the method described here can be used to assess its efficiency. Observations need to be made on the parameters influencing soil movement in order to propose the best agroforestry practice to stabilize or even increase agricultural output. The most effective spacing of these anti-erosive structures, as well as the impact of climate and human activities on soil movement, are also discussed. Most of the procedures were developed during on-farm survey research conducted by Haiti Agroforestry Research Project (HARP) researchers. This methodology is based on the following two considerations: (1) Soil accumulation observed above the hedgerows is due to the presence of vegetal barriers and, (2) The physical arrangement of these barriers affects the amount of soil lost from a hillside field. The soil volume displaced is estimated in a strip parallel to the slope using a topographical survey and simple formulas. However, estimating soil displacement within a heterogenous zone requires a careful assessment of the procedures used. It is necessary to evaluate the methodology by comparing the figures of actual soil loss measured from runoff plots to those of the soil volumes estimated empirically. The methodology developed here consists of taking measurements on a graduated non-elastic rope tied between two stakes driven into the ground. At least three measurements must be taken at three critical times of the agricultural calendar: before tillage, one or two weeks after germination, and after the harvest. More measurement are taken as needed. Applying the methods described here provides information to the researcher regarding the place of soil departure and the areas where soil accumulates. It also provides a clearer concept of possible anti-erosive management practices.

Rapo sa-a décri youn fason pou étidyé mouvman té bo-koté ranp vivan en Ayiti. Ranp vivan se youn fason pou consevé té-a. Pou bay youn bon rekomandasyon sou pi bon pratik agwoforestri ki ta ka fé youn alemye nan renman agrikili, obsévasyon te fet sou ki kantité plas ki fet pou geyen ent batiman anti-ewosyon yo, sibyen ke éfé zact crétyen vivan é zanimo tou. Plipa métod sa yo te devlopé pendan reshech tap fet sou fem planté pa Haiti Agrofoestry Research Project (HARP). Metod pwoposé-a bazé sou plizyé idé: (1) Nou sipozé ke té ki akimilé anwo ranp vivan-an reté poutet ranp la baré rout li, é, (2) li afekté ranjman barikad sa-yo ak kantité té ki pedi sou pant la. Estimasyon volum té ki deplasé-a fet sou youn ban paralel a pant-la ak youn rélvé topografic é kek formul semp. Esimasyon deplasman té nan youn zon mandé youn bon jen evalyasyon dé metod kap sevi-yo. Li mandé youn comparezon ent chif té ki pedi nan ban yo é chif volum téki te éstimé pa obsevasyon. Metod sa-a mandé ke mezi yo fet sou youn kod red maré ent de piket ki fouyé nan té-a. Fok twa mezi empotan fet: youn avan plantasyon, youn de ou twa semenn apré plant-you lévé, é youn apré rekolt-la. Plis mezi kapab fet si nesesé. Si metod sa-yo apliké nan youn ban, li bay infomasyon sou ki koté té ap pedi é ki koté té ap akimilé. Li bay tou, youn bon idé sou ki pratik anti-éwozyon ki ta posib. Aplicasyon métod sa yo sou youn ban complet bay infomasyon sou plas koté té kon pati é koté té reté. Li bay, tou, youn bon idé sou pratik anti-ewosyon ki posib.