It is defined as the productivity of an intercrop per unit area of ground compared was expected from sole crops sown in the same proportions (Azam Ali et al 1990). For each same then productivity in the intercrop can be expressed as a partial CPR.

Economic Viability:

The indicates like CEY, LER, RYT etc. give biological suitability of cropping system to an area. At the same time, cropping system should be economically viable and profitable following economic indicates can be used to evaluate profitability of cropping system.

**1. Net returns or net profit:**

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.

**2. Gross Returns:**

The total monetary returns of the economic produce such as grain, tuber, bulb, fruit, etc. and byproducts viz. straw, fodder, fuel etc. obtained from the crops included in the system are calculated based on the local market prices. The total return is expressed in terms of unit area, usually one hectare.

The main draw back in this calculation is that market price of the produce is higher than that actually obtained by the farmer. Generaly gross return calculated is somewhat inflated compared to the actual receipt obtained by the farmer.

**3. Return Per Rupee Invested:**

This is also called benefit-cost-ratio or input-m output ratio.

Return per rupee invested = Gross return

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Cost of cultivation

This index provides an estimate of the benefit derived and expenditure incurred by the farmer in adopting a particular cropping system. Anything above the value of 2.0 (meaning that the farmer can get RS.2 as return for every rupee invested) can be considered worthwhile.

**4. Per Day Return:**

This is called as income per day and can be obtained by dividing the net return by number of cropping period (days).

Per day return = Net returns

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Cropping period (days)

This gives the efficiency of the cropping system in terms of monetary value. If the system is stretched over one year, the denominator can be replaced by 365 days and per day for the whole year can be calculated.

No single index is capable of giving good comparision of different cropping system and so a number of indices are used together to assess the economic viability of the system.