Wind Erosion Control using Windbreaks and Crop Residues: Local Knowledge and Experimental Results

Abstract

Wind erosion in the Southern Sahelian Zone occurs during short monsoon storms  preceding rainfall events and leads to crop damage and loss of fertile topsoil. A survey with farmers was conducted near the ICRISAT Sahelian Centre (ISC) at Niamey, Niger, in order to learn about their knowledge of wind erosion and their strategies to reduce the wind erosion damage. Although 66% of the farmers have noticed wind erosion on their own fields within the last decade, it was not considered a main concern. Wind erosion caused inconveniences to millet according to 69% of the surveyed. Wind erosion changed the topography and decreased soil fertility, which resulted in spots with increased wind erosion damage within their fields. Farmers in the region have developed a strategy to deal with the restoration of these spots and used organic matter such as stover from more productive spots for mulching. A field experiment was conducted at ISC during 1991 to assess the effects of 3 year-old Andropogan gayanus and Bauhinia rufescens windbreaks and of a crop residue application (2 t/ha) on the quantity of eroded soil. A. gayanus and B. rufescens reduced the soil flux by 24% and 58%, respectively. Crop residues decreased soil flux by 59%. Maximum protection was given by a combination of both control measures. Control measures like windbreaks are difficult to establish and farmers have good reasons to use crop residues elsewhere. Thus, solutions must be found in close cooperation with farmers. Future research should be directed towards regional surveys and characterizations of the areas affected by wind erosion.