Intercrop Productivity & Land Equivalent Ratio
Introduction
The most common goal of intercropping is to produce more yields on a given piece of land by making use of resources or ecological processes that would otherwise not be utilized by a single crop. Intercrop is grown simultaneously with main crop.
The productivity of intercrop is assessed through the method of LER.
In order to assess intercrop performance as compared to pure stand yields, one grows mixtures and pure stands in separate plots. Yields from the pure stands and each separate crop from within the mixture are measured.
Land Equivalent Ratio
From the above yields, the land requirements per unit of yield can be determined and also the yield advantage the intercrop has over the pure stand, if any. They then know how much additional land is required in pure stand to equal the amount of yield achieved in the intercrop. The calculated figure is called the Land Equivalency Ratio (LER).
To calculate an LER, the intercrop yields are divided by the pure stand yields for each component crop in the intercrop. Then, these two figures are added together.
Here’s the equation for a corn pea intercrop where the yields from pure corn, pure peas, and the yields from both corn and peas growing together in an intercrop are measured.
(intercrop corn / pure corn) + (intercrop pea / pure pea) = LER
When LER measures 1.0, it tells us that the amount of land required for peas and corn grown together is the same as that for peas and corn grown in pure stand (it means there was no advantage to intercropping over pure stands).
LERs above 1.0 show an advantage to intercropping while numbers below 1.0 show a disadvantage to intercropping.
See also…
Intercropping- Definition, Example, Benefits
CROPPING PATTERN-CROPPING SYSTEM
STRIP CROPPING-DEFINITION,USE&TYPES