Knowledge, science, and practice in ecological weed management: farmer–extensionist–scientist interactions - Ecological Management of Agricultural Weeds - page 101

Certain species, after undergoing initial domestication, subsequently lost
favor as food sources and lapsed back into the weed complex or into the col-
lected,but not cultivated,category.For example, Setaria in Mesoamerica (Minc
& Vandermeer, 1990) and Chenopodium (Smith, 1992, pp. 103-32) in North
America were domesticated early, but were abandoned as crops with the
domestication of maize.Today species in these genera are important weeds.
Over thousands of years since the first planted fields and in diverse climatic
zones, human society has continued to evolve techniques for crop production
and weed control. This development has resulted in widening landscape dis-
turbance and management, driven by increasing human population and
changes in technology from stone, bronze, and iron through steel,petroleum,
and computers.
Farmer and community learning has been central to the development of
technology for crop production and weed control. Recent studies of
farmer experimentation (e.g., Scoones & Thompson, 1994; Sumberg & Okali,
1995) indicate three important components in the farmer development of
technology.
First, farmers cultivating the land year after year under diverse conditions
of soils,crops,weeds,and weather accumulate a vast range of data on the effec-
tiveness of their agricultural practices. In each field in each new planting
season, farmers observe and adjust local crop production practices, although
they are not conducting experiments. Although the observations in a single
crop cycle only rarely lead to major changes in crop production or weed
control techniques,farmers'gradual adjustments in cropping techniques over
time have been the major force in the evolution of agricultural technology.
Second,farmers conduct tests or experiments in which they compare some-
thing new with their normal practices. In these experiments, farmers com-
monly test new physical inputs to crop production like crop species or
varieties, cover crops, tools and equipment, or soil amendments. For such
tests,farmers use the kitchen garden,a corner or strip of field close to their res-
idence, or even an entire field. They may also test variations in management
such as timing, spacing, or quantities of their usual inputs in a single or
several seasons.
A third area in farmer technology development is the multiyear organiza-
tion of the cropping system and the mix of activities that make up the farm
operation. Whereas the testing of new physical inputs is primarily suited to
planned experimentation, farmers use both planned testing and experiential
learning under variable weather and market conditions to develop their crop-
ping system organization and home consumption or income-generating
strategies.