AN ECONOMIC ANALYSIS OF THE BENEFITS OF
CHEMICAL WEED CONTROL ON HHEAt
By Charles K. Mann
Wheat Research and Training Project
Research in Turkey suggests that adding timely chemical weed control
to otherwise traditional wheat production practices in Anatolia can be
expected, on average, to produce 28 kg/decare more wheat. This represents
a gross return of TL 4.4 for one lira invested in weed control.
Not only does weed control have a high pay-off when used with
traditional practices; it is essential to success with the improved package
of practices which has been developed for Anatolia. A large scale weed
control program could provide the "leading edge" for a campaign promoting
use of the full package. Turkey's annual production of wheat could be
increased by one million tons by the application of timely weed control to
just over half of the dryland heatt area. The combination of strong farmer
demand and ample supplies of herbicide and equipment suggest that with a
forceful campaign the area of wheat treated with herbicide in 1976 could
be double that of 1975.
During the period 1970-1975 members of the Wheat Research and Training
Project and the USAID/Oregon State University Wheat Research Team conducted
experiments and demonstrations to evaluate the effects of chemical weed
control on wheat production on the Anatolian Plateau. Use of these
chemicals produced impressive yield increases. While the greatest gains
came from combining weed control with other elements of a recommended
package of practices, adding only chemical weed control to traditional
practices also produced significant and profitable yield improvements.
The main elements in the package of practices being recommended to
Anatolian Wheat farmers are: improved tillage to conserve soil moisture
through the fallow season; use of fertilizer responsive, disease resistant
varieties; fertilizing those reponsive varieties; timely control of weed
I wish to express my thanks to my colleagues in the Wheat Research and
Training Project for their help in developing the ideas expressed in this
paper. In particular I would like to thank Dr. Ahmet Demirliiakmak,
Cengiz Tezel, Mansur Bilgeo, Atakan Ginay, Nedrot Durutan and Dr. Homer
Hepworth. My thanks go also to Hikmet Alptekin for his assistance and
competition in the growing crop by chemical means. -'idespread adoption of
this total package would increase substantially Anatolian Wheat production.
However, given the cultural, technical, administrative and economic
environment some elements of this package may prove easier to implement
than others. For example, it may be more difficult to convince a farmer
to plow under weeds serving as fodder on fallow land than to kill weeds
obviously threatening a growing crop. In other instances, farmers may
appreciate the usefulness of increased tillage but may be unable to obtain
needed power or equipment at the proper times.
Without losing sight of the goal to implement a total package there is
some merit in focussing attention on individual elements of the package.
In the first year if the farmer does not have the resources to adopt all
elements of the package, what should he do? Both the informed judgement
of numerous wheat scientists and available experimental results suggest
that chemical weed control deserves special emphasis. Among the reasons are:
1) As discussed below its benefits are high relative to its cost.
2) Its results arc immediately obvious in the destruction of weeds.
3) It requires rnly an added operation with no change in the
timing of the overall crop cycle.
4) It comes lcgically before some othar elements of the package
in cases where all elements cannot be adopted at once. For
example, adding fertilizer without effective weed control may
simply produce more prolific weed growth.
5) A large scale campaign for woed control would appear feasible.
6) Weed control can be made available to farms af all sizes
relatively more easily than can the entire package of practices.
7) Yield and economic benefits received from one improved practice
encourages farmer acceptance and application of other improved
Because of the wide agreement on the importance of chemical weed
control, an economic analysis has been made of field experiment data.
First, the analysis deals with experimental results where yields under
traditional practices were compared to traditional practices plus weed
control. This analysis is followed by a discussion of the importance of
weed control within the package of improved practices.
WEED CONTROL ADDED TO TRADITIONAL PRACTICES
In this analysis, the cost of herbicides is calculated at TL 950
per 17 litre can. This is an approximation of the 1975 free market price
and is somewhat above the government price. Application rates are
2 litres/ha. Wheat prices are government floor prices for the 1975 crop
( 2.5 TL per kg. in Anatolia ). Data are based on the average of
experiments 1970-1975 which compared wheat yields on traditionally cultivated
fields with and without the application of 2,4-D herbicide. There are a
total of 18 observations.
Average yield without chemical weed control
Average yield with chemical weed control
Increase attributed to weed control
Value of increased what @2.50 TL/kg.
Cost of weed control
(of which materials)
(of which application)
(of which interest
5 months @10%)
Ratio of Benefits to Cost
: 124 kg/da.
: 152 kg/da.
: 28 kg/da.
: TL 70/da.
With a ratio of benefits to costs of 4.4 to one, weed control represents an
extremely profitable investment for the farmer and for the nation. Moreover,
the experience of wheat scientists with weed control suggests that these
figures may be quite conservative and that considerably higher benefit cost
ratios may be obtained that the 4.4 shown here.
Regarding the important question of the investment risk for the farmer,
in only one case in 18 (6%) did the increased value of the production fail
to cover the cost of the treatment. (To recover costs an increase in wheat
yield of 6.3 kg/da. was needed). In 14 out of 18 observations (78%)
increased returns were greater than twice the cost of weed control.
It must be noted that these experimental results are based upon timly
application of herbicides. If the application is made too late the benefits
drop significantly. To illustrate this point, data from Ankara trials
1970-73 show that yields with early weed control ( March 1 April 10 )
were 154 kg/da. in contrast to only 104 kg/da. on untreated fields.
This represents a benefit-cost ratio of 7.9 to one. In fields where weed
control was applied later (traditionally in Anatolia April 15 May 15)
yields were only 122 kg/da. With a benefit-cost ratio of 2.8 to one, this
is still a profitable increase over the untreated fields but less than the
full potential. If weed control is applied to a field after the weeds have
already given the wheat severe competition, the benefits of weed control may
be less than its cost.
WEED CONTROL WITHIN THE "PACKAGE OF PRACTICES"
While data are not conclusive, there is considerable evidence to
suggest that omitting weed control from the package of improved practices
can rob the farmer of the benefits of the rest of the package. That is
to say, without weed control, the added soil moisture and fertility
resulting from the "package" may simply go into producing more weeds
rather than more wheat. For example; in two of the 1975 demonstrations
a part of the demonstrator's field was left untreated by herbicide.
In other words, these areas had the full package except for herbicide.
On the part with the whole package including herbicide the yield average
was 322 kg. per decare. On the portion with the whole package except
for herbicide the yield was only 242 Kg. per decare. Omitting the herbicide
caused a drop of 80 kg. per decare in the yield. Because weed control is so
fundamental to the success cf the package, a strong weed control program
could serve as the "leading edge" of the attempt to promote the package
ECONOMIC BENEFITS OF LARGE SCALE WEED CONTROL PROGRAM
In Turkey approximately 8.5 million hectares of wheat are sown
annually. According to a recent estimate herbicides are currently used
on about 12 percent of this area (see reference 1). Some 6.5 million
hectares of wheat are located in dryland regions. An additional million
tons could be added to Turkey's wheat production by the application of
timely weed control to about 3.6 million presently untreated hectares.
This figure represents about 55 percent of Turkey's annual dryland wheat
area. The gross value of this increased production would be TL 2.5 billion
in domestic prices and $150 million at current international prices. The
net value in domestic prices (after deducting weed control cost) is TL 1.9
This large production increase could be obtained even in the absence
of the rest of the package of improved practices. Still greater increases
would follow as the rest of the package was adopted. Moreover, this practice
can be applied on farms of all sizes. Hand-operated as well as tractor
and aircraft sprayers are already in use. To reach an expanded area,
government supervised contract operations could complement government programs.
Not only could weed control alone easily add a million tons of wheat to
Turkey's production but it could do so with both efficiency and equity.
A GOLDEN OPPORTUNITY
There is reason to believe that 1976 represents a golden opportunity
to realize the economic potential of weed control. First, farmer awareness
of the practice is increasing rapidly. Having herbicides in use on 12
percent of the wheat land may not seem impressive from the point of view
of production. Viewed as a demonstration area, however, the impact is
enormous. Farmers are quickly learning by their own observations of the
great profitability of weed control. The high black market prices paid by
farmers for herbicide in 1975 gives concrete evidence of the desire to
adapt this practice. Second, in contrast to 1975 when herbicide supplies
Were very short in Turkey, supplies for.1976 are abundant. Whereas in
1975 one million hectares were treated, in 1976 there will be available
enough herbicide in Turkey to treat nearly two million hectares. An
adequate equipment supply is also believed to exist to support such an
expansion in area treated.
The combination of strong farmer demand and ample supplies of herbicide
and equipment suggest that 1976 could be a breakthrough year for weed
control in Turkey. To realize this potential for a doubling of the area
treated a dynamic and well-organized campaign will be needed. To be
effective, planning for that campaign should begin at once. The staff
of the Wheat Research and Training Project are ready to assist in any
way they can in such a campaign.
1) Hikmet Alptokin, "Bugday Uretimimizde Herbisit Sorunu". Oda Haberleri
2) Cengiz Tczel and Homer Hepworth, "Wooeed Control on the Anatolian
Plateau in Turkey". Paper presented at the Third Regional Wheat
Workshop, Tunis, Tunisia, May 1975.
3) USAID/OSU Team, "Nore Wheat from Fallow Farming". 2nd. ed. Ankara,1975.
4) Wheat Research and Training Project, Unpublished data. 1970-75.
December 2nd. 1975