Land equivalent ratio explained
The land equivalent ratio is a concept in agriculture that describes the relative land area required under sole cropping (monoculture) to produce the same yield as under intercropping (polyculture).[1]
Definition
The FAO defines land equivalent ratio (LER) as:[2]
For a scenario where a total of
crops are intercropped, the land equivalent ratio LER can be calculated as
}
where
is the number of different crops intercropped,
is the yield for the
crop under intercropping, and
is the yield for the
crop under a sole-crop regime on the same area.
Example calculation
The table in this section provides yield values for a hypothetical scenario intercropping a grain crop with a fruit tree crop.
The first two columns state the yields for intercropping (IY) and sole yields (SY). The third column, equivalent area, column calculates the area of sole cropping land required to achieve the same yield as 1 ha of intercropping, at the same management level.
| Crop | Intercropped Yield IY (kg/ha) | Sole Yield SY (kg/ha) | Equivalent area (ha) |
|---|
| Grain | 4,000 | 5,000 | 0.8 |
|---|
| Fruit | 9,000 | 15,000 | 0.6 |
|---|
| Land equivalent ratio | 1.4 | |
The land equivalent ration can be calculated as
} = \frac + \frac = \frac + \frac = 0.8 + 0.6 = 1.4
An interpretation of this result would be that a total of 1.4 ha of sole cropping area would be required to produce the same yields as 1 ha of the intercropped system.
Applications
The land equivalent ratio can be used whenever more than one type of yield can be obtained from the same area. This can be intercropping of annual crops (e.g. sorghum and pigeonpea) or combination of annual and perennial crops e.g. in agroforestry systems (e.g. jackfruit and eggplant).[3]
It is also possible to calculate LERs for combinations of plant and non-plant yields, e.g. in agrivoltaic systems.[4]
The table below lists some examples for land equivalent ratios published in scientific journals:
| Crops | Country/region | LER | Source |
|---|
| | 2.17 | |
|---|
| | 1.36 | |
|---|
| | 1.23 - 2.05 | [5] |
|---|
| ginger, maize, soybean | Nepal | 2.45 | [6] |
|---|
| | 1.58 | |
|---|
| | 1.40 | | |
|---|
Notes and References
- Mead . R. . Willey . R. W. . The Concept of a 'Land Equivalent Ratio' and Advantages in Yields from Intercropping . Experimental Agriculture . 3 October 2008 . 16 . 3 . 217 . 10.1017/S0014479700010978. 84769811 .
- Book: Guidelines: land evaluation for irrigated agriculture . Food and Agricultization of the United Nations . 92-5-102243-7 . Glossary .
- Rahaman . Md. Abiar . Rahman . Atiqur . Miah . Md. Giashuddin . Hoque . Md. Azizul . Rahman . Md. Mezanur . Productivity and Profitability of Jackfruit-Eggplant Agroforestry System in the Terrace Ecosystem of Bangladesh . Turkish Journal of Agriculture - Food Science and Technology . 27 February 2018 . 6 . 2 . 124 . 10.24925/turjaf.v6i2.124-129.1330 . free .
- Majumdar . Debaleena . Pasqualetti . Martin J. . Dual use of agricultural land: Introducing 'agrivoltaics' in Phoenix Metropolitan Statistical Area, USA . Landscape and Urban Planning . February 2018 . 170 . 150–168 . 10.1016/j.landurbplan.2017.10.011.
- Amaducci . Stefano . Yin . Xinyou . Colauzzi . Michele . Agrivoltaic systems to optimise land use for electric energy production . Applied Energy . June 2018 . 220 . 545–561 . 10.1016/j.apenergy.2018.03.081. 116236509 .
- Chapagain . Tejendra . Pudasaini . Roshan . Ghimire . Bhawana . Gurung . Khem . Choi . Khem . Rai . Laxmi . Magar . Samjhana . BK . Bishnu . Raizada . Manish N. . Intercropping of maize, millet, mustard, wheat and ginger increased land productivity and potential economic returns for smallholder terrace farmers in Nepal . Field Crops Research . October 2018 . 227 . 91–101 . 10.1016/j.fcr.2018.07.016. 92717782 .
