The formula $$\left( {\frac{{{\text{LER - 1}}}}{{{\text{LER}}}} \times {\text{Value}}\,{\text{of}}\,{\text{Combined}}\,{\text{Intercrop}}} \right)$$         represents

The above formula represents MAI which is Moisture Adequacy Index. It is the standardized measure used for assessing the degree of adequacy of rainfall and soil moisture to meet the potential water requirement of crops.
LER is Land Equivalent Ratio, which means the ratio of the area under sole cropping to the area under intercropping needed to give equal amounts of yield at the same management level.