This document discusses the cost-benefit analysis of integrated weed management in rice cultivation. It explains that weed control measures should only be implemented when the cost of control is lower than potential losses from weeds. The total cost of cultivation includes variable costs like seeds, fertilizer, labor as well as fixed costs like land rent. Economic costs also factor in opportunity costs. Marginal costs refer to the change in total costs from small production quantity changes. Weed management options are evaluated based on their gross returns, net returns, and marginal benefit-cost ratios to determine the most economically viable strategies.

1. Cost and benefit analysis of
Integrated weed management

2. Economic Weed management
• Weed management is to reduce the weed
population to a level where their presence
has no negative effect on the areas of
economic use.
• The most important principle is to resort to
weed control only when it is absolutely
necessary. In other words, more presence of
weeds should not be taken very seriously
unless they cause economic losses.

3. Rule in weed management-
• The cost of weed control should not be more
than the loss caused by the weeds.
• The recent shift from transplanting to direct
seeding of rice in Asia has resulted in dramatic
changes in the types and intensity of weeds and
their distribution.
• Additionally, higher fertilizer usage by farmers,
for realizing higher grain yields of modern semi-
dwarf HYVs and hybrids, are also conducive for
weed proliferation and their intense growth.

4. Effective And Economic Weed Control
• systems combine preventive,
• cultural,
• mechanical,
• chemical, and
• biological method

5. Non-Chemical Methods
• Judicious combination of appropriate rice varieties.
• crop husbandry practices that enhance robust seedling
growth and stand establishment.
• need based nutrient use.
• cultural practices that reduce weed proliferation and clean
cultivation practices.
• biological control that breaks the weed life cycle and
reduces environmental pollution.
• using weed-free seed, crop rotation, leveling of land,
seedbed preparation, selecting the proper seeding method.
• managing water and fertilizers properly.

6. Chemical Methods
• The use of herbicide treatments that
selectively control weeds in rice when applied
correctly.
• Indiscriminate as well as continuous use of
herbicides, may lead to development of
herbicide resistance in weeds as well as
increasing public concern about its effect on
environment and human health.

7. Cost and benefits of weed
management

8. Introduction
• Weeds should be controlled by least expensive but effective
available technology.
• Any weed control measures should be used only when its
results are expected to be more economically beneficial than
without using any control measure (Moody 1993).
• Farmers compare time and cost of weed control and usually
select management tactics having the lowest cost.
• Therefore, choice of weed control inputs depends not only on
its efficacy but also on its cost (De-dutta and Foster 1977).
• In order to work out the most profitable treatment, the
economics of each treatment is worked out on the basis of
prevalent market prices of the inputs and output.

9. Cost of cultivation
• Cost of cultivation is obtained by adding all
the costs involved in each operation or input
(seed bed preparation, seed and sowing,
fertilizer, irrigation,weed control, plant
protection, harvesting and postharvest
operations, land rent etc).

10. Types of cost
• Total cost
Fixed cost
Variable cost
• Economic cost
• Opportunity cost
• Marginal cost
Total cost
Variable cost
Fixed cost
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Unit
Relationship between fixed cost
and variable cost

11. Total Cost
• In economics, the total cost (TC) is the total
economic cost of production. It consists of
variable costs and fixed costs. Total cost is the
total opportunity cost of each factor of
production as part of its fixed or variable
costs.

12. Variable costs
•Variable cost (VC) changes according to the quantity of a
good or service being produced.
• Includes inputs like labour and raw materials. Variable
costs are also the sum of marginal costs over all of the
units produced (referred to as normal costs).
•Eg: Clothing manufacturer, the variable costs would be
the cost of the direct material (cloth) and the direct
labour.
•The amount of materials and labour that is needed for
each shirt increases in direct proportion to the number of
shirts produced. The cost "varies" according to
production.

13. Fixed Costs
•Fixed costs (FC) are incurred independent of the quality of
goods or services produced.
•They include inputs (capital) that cannot be adjusted in the
short term, such as buildings and machinery.
•Fixed costs (also referred to as overhead costs) tend to be
time related costs, including salaries or monthly rental fees.
•An example of a fixed cost would be the cost of renting a
warehouse for a specific lease period.
•However, fixed costs are not permanent.
•They are only fixed in relation to the quantity of production
for a certain time period.
• In the long run, the cost of all inputs is variable.

14. Economic cost
.
•The economic cost of a decision that a firm
makes depends on the cost of the alternative
chosen and the benefit that the best alternative
would have provided if chosen.
•Economic cost is the sum of all the variable and
fixed costs (also called accounting cost) plus
opportunity costs.

15. Opportunity cost
• The cost of an opportunity forgone (and the loss
of the benefits that could be received from that
opportunity); the most valuable forgone
alternative.
• The cost of any activity measured in terms of the
value of the next best alternative forgone (that is
not chosen).
• The value of investing in the next best alternative;
the value forfeited by taking a particular route.

16. Marginal cost
• The additional cost from taking a course of action.
• The increase in cost that accompanies a unit increase
in output; the partial derivative of the cost function
with respect to output.
• The additional cost associated with producing one
more unit of output.
• Marginal cost is the change in total cost that arises
when the quantity produced changes by one unit.
• That is, it is the cost of producing one more unit of a
good.

17. Gross returns
• The total monetary returns of the economic
produce such as grain, tuber, bulb, fruit, etc. and
by products viz. straw, fodder, fuel etc. obtained
from the crops are calculated based on the local
market prices.
• The total return is expressed in terms of unit
area, usually one hectare.
• Generally gross return calculated is somewhat
inflated compared to the actual receipt obtained
by the farmer.

18. Net returns
•This is worked out by subtracting the total cost of
•cultivation from the returns.
•This value gives the actual profit obtained by the
farmer.
•In this type of calculation only the variable costs
are considered.
•Fixed costs such as rent for the land, land revenue,
•interest on capital etc. are not included.
•For a realistic estimate, however, fixed costs should
also be included.

19. Net returns per rupee invested
This is also called benefit cost ratio or input: output ratio.
Net returns per rupee invested were obtained by dividing
net returns with the treatment-wise cost of cultivation.
Gross/Net returns
Net returns per rupee invested = -----------------------
Cost of cultivation
—
This index provides an estimate of the benefit derived
and expenditure incurred by the farmer in adopting a
particular practice. Anything above the value of 2/1.0
(meaning that the farmer can get rupee 2/1 as additional
return for every rupee invested) can be considered
worthwhile.

20. Cont.,
• Conveniently, the economic viability of a
treatment can be assessed by the
methodology given as below
• Cost of weed control - Here only the control
cost is estimated.
• Gross return due to weed control GRwc =
Gross return of treatment – Gross return of control

21. Cont.,
• Net return due to weed control ,
NRwc = Net return of a treatment- net return of control
NRwc = GRwc – cost of weed control
Marginal benefit cost ratio
MBcR = NRWC/COST OF WEED CONTOL (CWC)