Although there are range of motivations for choosing to intercrop in a farming system, strong production and output are undoubtedly main priorities. Accordingly, a means to measure the efficacy is necessary. This allows a farmer to objectively evaluate the outcome of their cropping plan and adjust their practices, e.g. spacing and cultivar use, accordingly.
The land equivalent ratio [LER], is the most common approach. LER is a helpful tool for measuring the max production criterion, the least area criterion, crop combination comparisons, and the agronomic practice comparison.
The income equivalence ratio [IER] uses a similar approach, but it measures yield in terms of net income rather than plant productivity and will fluctuate according to crop prices. Accordingly, it may not be as accurate of a gauge for measuring productivity.
Using the LER, the competitive ratio [CR] can be determined in order to measure the competitiveness of the two [or more] crops planted by accounting for the sowing proportions.
Likewise, the monetary advantage index [MAI] provides an indication of the economic advantage of an intercropping system.
To incorporate the time component by accounting for the duration of crop growth into the evaluation process, the area time equivalent ratio [ATER] is used.
- Bantie, YAYEH BITEW (2014). DETERMINATION OF EFFECTIVE SPATIAL ARRANGEMENT FOR INTERCROPPING OF MAIZE AND POTATO USING COMPETITION INDICES AT SOUTH WOLLO, ETHIOPIA. In International Journal of Research In Agriculture and Food Sciences, 2(8), pp. 9-19.
- CIAT (Centro Internacional de Agricultura Tropical). (1986). Principles of Intercropping with Beans; study guide to be used as a supplement to the audio-tutorial on the same topic. Scientific content Jeremy Davis, J. B. Smithson. Production Oscar Arregocés. Cali, Columbia. CIAT. pp. 40. (Series 04EB-12.05)
- Ghosh, P.K. (2004): Growth, yield, competition and economics of groundnut/cereal fodder intercropping systems in the semi-arid tropics of India. In Field Crops Research, 88, 227-237.
- Leihner, D. 1983. Manual and Evaluation of Intercropping Systems with Cassava. CIAT. Cali, Columbia, 70pp.