 During the past decade,
numerous erosion control experiments have been conducted at experiment stations and in FPR
trials on farmers’ fields. CIAT has developed a simple methodology to measure the
effect of soil/crop management treatments on erosion, using plastic-covered ditches dug
along the lower edge of each plot to trap eroded sediments. With this simple methodology,
many soil/crop management and erosion control practices can be compared in terms of yield,
gross and net income, and soil losses through erosion.
Most experiments
have shown that soil losses through erosion can be markedly reduced by practices such as
zero tillage, contour ridging or staggered mounds, closer plant spacing, intercropping,
mulch application, fertilizer application, and planting contour hedgerows of grasses
(e.g., vetiver grass, lemon grass, elephant grass, Paspalum atratum, or Brachiaria
brizantha) or legumes (e.g., Arachis pintoi, Chamaecrista rotundifolia,
Gliricidia sepium, Leucaena leucocephala, or Calliandra calothyrsus).
Some of these practices have been long adopted by Asian farmers, such as zero tillage
on steep slopes in Hainan, China. Contour ridging is sometimes applied on gentle slopes,
but up-and-down ridging is more common, especially in areas where land is prepared by
tractor. Intercropping is practiced in Indonesia, staggered mounds and bunds in
Kerala, India, and closer plant spacing and fertilizer or manure application in many
areas. Mulching has been shown to be highly effective, but is seldom practiced as mulch is
often not available and/or its transport is too labor intensive.
The planting of contour hedgerows to control erosion is seldom practiced as it requires
additional labor for planting and maintenance, takes land out of production, and may
create competition with nearby crop plants. Moreover, in areas where land is prepared by
tractor, contour hedgerows interfere with the commonly used practice of up-and-down
tillage in straight lines. In the Claveria area of northern Mindanao, Philippines, farmers
have accepted the use of contour strips of natural grasses (weeds) to control erosion as
that requires fewer inputs in planting and maintenance, provides some cut-and-carry fodder
for cattle, and does not interfere with plowing with carabao (water buffalo).
By conducting these
FPR erosion control trials in their own fields farmers become directly involved in
developing and disseminating more sustainable practices. Practices selected by farmers are
likely to be effective in controlling erosion, be appropriate for local conditions, and
may provide substantial short-term economic benefits. Through these trials farmers
become aware of the problem of soil erosion and the need for better soil conservation
practices. When farmers do their own FPR trials (in collaboration with the facilitators),
they realize that, while erosion may be a serious problem, the practices that they
themselves have tested and selected can be easily adopted to reduce erosion on their
fields.
The farmer
participatory approach seems to be the best way to markedly enhance the adoption of soil
conservation practices.
|
