390 Modern Agricultural Reforms
field boundary bunds and drains with waste weirs, grasses on field bunds and
drains, short-term fallowing, criss-cross ploughing, seeding across slope, tied ridg-
ing, frequent interculture, deep ploughing in summer, and compartmental bund-
ing (Kerr and Sanghi, 1992).
One example of soil and water conservation measures used widely by farmers,
yet commonly ignored by professionals, are silt traps and gully fields. Stones are
placed across gullies or valleys to capture nutrients, silt and moisture. The princi-
ple is to capture run-off from a broad catchment area and concentrate it in a
reduced area, so transforming meagre rainfall into utilizable soil moisture. As water
slows, any suspended debris is deposited, helping to form organic-rich soils. These
gully or deposition fields have been recorded in India (Chambers, 1991; Shah
et al, 1991; Prem Kumar, 1994); Pakistan (personal observations (1992, 1994,
1995) in Punjab and northwest Frontier Provinces), Ethiopia (ERCS/IIED, 1988);
Mexico, known as atajadizos, trincheras and trancas (Johnson, 1979; Blackler,
1994); Nepal (Tamang, 1993); and Burkina Faso (Reij, 1988).
A well-maintained silt trap creates a flat, fertile and moist field with a micro-
environment quite unlike the surrounding area. Crops can thus be grown which
may be of higher value than field crops on nearby drylands, such as rice in India,
wheat and rapeseed in Pakistan, sorghum and rice in Burkina Faso, and chat and
coffee in Ethiopia. Agriculture in these gully fields is productive and dependable
(Griffin and Dennis, 1969; Shah et al, 1991). In Burkina Faso, sorghum yields can
range between 970 and 2670kg ha–1, and in some fields rice can be grown (Reij,
1988). Farmers in Gujarat have been able to grow high-yielding varieties of low-
land paddy, and in some cases achieve yields higher than irrigated regions in dry-
land areas (Shah, 1994). Farmers additionally benefit from these traps as
groundwater levels are raised and damage to crops on the downstream side is
reduced (Johnson, 1979; Reij, 1988).
The key element is that these technologies are intrinsically incremental sys-
tems, in which farmers add to the height of their structures year by year. Stones are
often bedded into the upper surface of spillway aprons and walls to provide sup-
port for the next layer, in order to keep the wall above the level of the accumulating
alluvium. Wilken (1987) reports the narrative account of an Otomí farmer of
Hidalgo, Mexico:
An atajadizo isn’t built all at once. Usually a farmer starts with a low wall across the path
of an arroyo (gully). It takes a few years until the water has brought down enough debris
and soil to level with the top of the wall. Then, the farmer will build up the wall a bit
more, and so on, little by little until s(he) has built up a tall strong wall and a large level
field. A well-made atajadizo is level so that the trapped water will cover all parts of the
field evenly. It may be necessary to level the field by hand and, also, to tear down parts
of the gully in order to enlarge the field. A well-made atajadizo always has a wall that is
higher than the field behind it. This is necessary because water must be trapped so that
it can soak into the field ... There is no need to fertilize an atajadizo because every rainy
season the water brings down new debris and soil.