Agriculture Reference
In-Depth Information
Table 3.2.
Comparison of alternate approaches for improving on-farm management of
weed variability
Ecological
Ecological
cropping systems
Precision
cropping systems
(hand tools and
monoculture
(mechanized)
animal power)
Goal ofweed
minimize/eliminate maintain easy-to-
maintain easy-to-
management
weed competition
manage weed complex manage weed complex
and reproduction
at acceptable levels
at acceptable levels
Tools ofweed
computerized sensing, cropping systems design cropping systems design
management
datalogging,and
and well-timed whole- and well-timed whole-
variable-rate
field practices
field practices and weed
application technology
patch control
Importance of
high
high
high
weed monitoring
Importance of
low
high
high
ecological
understanding
for success
Researcher-
technology transfer
participatory learning
participatory learning
extensionist-
for action
for action
farmer interactions
size, and production technology. However, they are similar in aiming for
greater land, labor, and capital productivity through flexible management
based on the quantification of local weed variability (Table 3.2). In each case,
farmers are trying to make better decisions by tailoring practices to weed
patchiness rather than using routine uniform practices. Decisions about what
practices to use are based on field-to-field and within-field monitoring for
timely matching of practices to weed composition and patches.
Precision agriculture employs computerized spatial information for crop
management (Lass & Callihan, 1993; Roberts, Rust & Larson, 1995; National
Research Council, 1997, pp. 26-43). In this approach, real time yield monitor-
ing on the harvester is connected with satellite-linked global positioning and
geographic information systems to produce a detailed yield map that can be
overlain on detailed soil maps. Variable-rate seeders and fertilizer applicators
make possible the within-field fine-tuning of seed and fertilizer rates accord-
ing to soil production potential. The more precise use of inputs may be
directed to reduced environmental pollution from fertilizers or to further
increase yields (Blackmore
et al
., 1995). Realization of either goal is subject to
weather unpredictability. For example, Jaynes & Colvin (1997) showed that
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