Soil Erosion and Nutrient Losses in Seasonal Tropical Agroecosystems Under Various Management Techniques

Abstract

(1) This study examined soil erosion losses in agroecosystems on the Pacific coast of Jalisco, Mexico, to develop erosion control techniques for this seasonally dry mountainous area that would be appropriate for the ecological and socioeconomic characteristics of the region. (2) Soil erosion and nutrient losses were measured for 2 years under seven management treatments: the undisturbed forest (control), maize, maize with forest litter as a protective mulch, guinea grass (Panicum maximum Jacq.), buffet grass (Cenchrus ciliaris L.), and 3 m and 10 m wide anti-erosion grass strips below the maize fields. (3) Plots were 20-40 m2 in size with an average slope of 22 5?. All but forest plots were burned after being cleared. (4) Most of the nutrients lost were adsorbed on soil particles which were eroded from the plots by surface water flow. (5) Soil erosion in the forest plots was almost negligible (less than 0 20 t hayear1), but was much higher in the maize and guinea grass treatments (up to 130 t ha'year1). (6) The most successful treatment for reducing erosion was the use of a mulch placed on maize fields. This reduced erosion by more than 90% and increased crop productivity by almost 30%. The use of anti-erosion grass strips did not reduce erosion significantly over the experimental period, but might if a longer time were allowed for their development.