手法を比較

	Land Equivalent Ratio	Agroecosystem Analysis
分野	Food Agriculture Studies	Food Agriculture Studies
系統	Process / pipeline	Process / pipeline
提唱年	1980	1987
提唱者	Roger Mead & Roger W. Willey	Gordon R. Conway
種類	Descriptive index of relative land productivity	Systems-diagnosis pipeline for agroecosystem performance
原典	Mead, R., & Willey, R. W. (1980). The Concept of a 'Land Equivalent Ratio' and Advantages in Yields from Intercropping. Experimental Agriculture, 16(3), 217-228.	Conway, G. R. (1987). The properties of agroecosystems. Agricultural Systems, 24(2), 95-117.
別名	LER, Relative Yield Total, Land Equivalent Coefficient, Intercropping Land-Use Efficiency	AEA, Agroecosystem Properties Analysis, Conway Agroecosystem Analysis, Agroecosystem Diagnosis
関連	4	4
概要	The land equivalent ratio (LER) is the standard index for judging whether intercropping — growing two or more crops together on the same land — uses land more efficiently than growing each crop separately. Formalized by Roger Mead and Roger Willey in 1980, the LER expresses how much land would be required under sole cropping to produce the yields achieved by one unit of intercropped land. It is computed by dividing each component crop's intercrop yield by its sole-crop yield and summing these partial ratios across all components. An LER greater than one means the intercrop is more land-efficient than the corresponding sole crops, and the amount above one quantifies the land saved, giving agronomists a simple, interpretable, and widely used measure of the biological advantage of mixed cropping.	Agroecosystem analysis (AEA) is a systems-diagnosis framework, formalized by Gordon Conway in 1987, that characterizes any agricultural system through four properties: productivity, stability, sustainability, and equitability. Rather than judging a farming system by yield alone, AEA treats the agroecosystem as an ecological system shaped by human management and asks how much it produces, how reliably it produces it across seasons and shocks, whether it can maintain output over the long run, and how its benefits are distributed among the people who depend on it. The analyst bounds a system at an appropriate hierarchical level — plot, field, farm, watershed, or region — and uses interdisciplinary teams, ranked questions, and simple structured diagrams to surface the key relationships and the trade-offs among the four properties that drive design and policy choices.