Priprema zemljista
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Transcript of Priprema zemljista
sajt sa objasnjenjima ne engleskom> http://www.epa.gov/oecaagct/ag101/crop.html
moldboard – pluzna daska
plow- plug
sowing-setva
tiling- oranje
Drills - are implements used to plant crops in closely spaced rows (typically four to ten inches); drills
are commonly used for cereal crops such as wheat and can be used to plant soybeans. Grain drills are
typically equipped with disks to open a small trench in the soil, a metering system to deliver a
measured, controlled amount of seed to drop tubes which guide the seed to the seed trench. There
must be some means (wheels or drag chains) of gently closing the seed trench with soil to cover the
seeds.
Planters - are implements used to plant row crops (typically in row spacings ranging from 10 to 40
inches). Planters open a seed trench, meter seeds one-at-a-time, drop seeds into the seed trench,
and gently cover the seed. Some planters can cut through residues and till a small strip of soil in
each row at the time of planting. Planters can also be equipped to apply fertilizer, pesticides, and
herbicides during planting. Planters come in sizes as large as sixty feet wide - that is twenty-four
rows with a typical 30-inch row spacing, or thirty-six rows with a narrower 20-inch row spacing. Such
large planters can cost in excess of $140,000.
Pesticides are used to control pests, which include insects, mice and other animals, unwanted plants
(weeds), fungi, or microorganisms like bacteria and viruses. Though often misunderstood to refer only to
insecticides, the term pesticide also applies to herbicides (that control weeds), fungicides (that control
fungi), and substances used to control other pests.
The label includes information on when the product should be applied. Labels often list the minimum
number of days which must pass between the last pesticide application and harvest of crops or grazing
by livestock. These are intervals set by EPA to allow time for the pesticide to break down in the
environment, preventing residues on food, feed, or animal products.
Sprayers - are implements or vehicles used to apply liquid crop chemicals, most often herbicides, and
increasingly, fertilizers. Sprayers typically include a tank, pump, plumbing, valves, a boom, and nozzles.
Sprayers can be mounted on a tractor or other implement, pulled by a tractor, self-propelled, or
mounted on airplanes or helicopters. Large self-propelled sprayers that incorporate technologies to
vary application rates within a field can cost more than $250,000.
Aerial application of pesticides has several advantages for the modern agricultural producer.
When properly managed, aerial application offers speed of dispersal, accessibility to crops on
areas where ground equipment cannot operate, and reasonable cost. In many cases, aerial
application also allows more timely applications and, therefore, better utilization of pesticides.
Aerial application programs require good cooperation between the pilot and grower. It must also
recognize the potential dangers to people, other crops and the environment.
Limitations on aerial application include weather hazards, fixed obstacles such as radius towers,
field size and shape, the distance from the point of application to the landing area, and the danger
of contamination of nearby areas due to drift or misapplication. Careless applications can be
harmful to the crop, the grower and the applicator.
The federal government has regulated pesticides since the early 1900s.
The use of synthetic pesticides in agriculture is the most widespread method for pest control.
"...Farmers spend approximately $4.1 billion on pesticides annually. They justify this high cost
by a direct dollar return of from $3 to $5 for every $1 spent on pesticides." (1991 edition of the
Handbook of Pest Management in Agriculture.)
Environmental and human health problems related to the use of synthetic pesticides have created
an increasing pressure against their use. In recent years, non-chemical alternatives for pest
control have been developed and modern pesticides have become safer and more specific.
Technical developments of the application equipment have also improved to enable their proper
application. However, their proper professional use has not always been transferred satisfactorily
to field practice.
Alternative approaches to pest control are used more and more and the concept of integrated pest
management where synthetic pesticides are only applied as a last resort is now considered
common practice in professional agriculture. The non-chemical alternatives include cultural
practices, choice of resistant varieties, creation of an environment favorable for natural enemies
of pests, and use of biological products and agents, including beneficial insects.
Likewise, synthetic pesticides have undergone a development process to match today's
requirements. They have become less toxic for humans, though not necessarily for the
environment, they have become more specific to act as a useful contribution within an IPM
concept and they have become more powerful. While 40 years ago pesticides were applied in
kilograms or liters of active ingredient per hectare, modern pesticides only require grams or
milliliters to achieve the same or better result.
On the other hand, the new pesticides require a more sophisticated technology for a safe, even
and efficient application. Modern application equipment (including backpack sprayers) allow a
fairly safe and efficient application of pesticides of all kinds. "The design of equipment has
impact mostly on the operator and environmental safety preventing unnecessary contamination,
accidents, loss and spills and allowing an even distribution of the product." Modern electronics
have improved the accuracy of dosing, distribution, and application. The use of global
positioning systems (GPS) allows precise tracking of the application. Spray nozzle technology
greatly affects spray coverage, which is second in importance only to the selection of the
pesticide in determining the success of an application.
Originally, the purpose of pesticide laws and regulations was to protect consumers from
fraudulent claims about product performance. The focus now has shifted to the protection of
health and the environment, including:
Providing for the proper and beneficial use of pesticides to protect public health and
safety.
Protecting the environment by controlling the uses and disposal of potentially harmful
pesticides.
Assuring safe working conditions for farm workers, commercial pest control personnel,
and consumers.
Assuring users that pesticides are labeled properly and are appropriate for their intended
use, and contain all instructions and precautions necessary.
Encouraging the use of integrated pest management (IPM) systems that emphasize
biological and cultural pest control techniques with selective use of pesticides.