Model outputs are usually value-added parameters that are more closely linked to crop yield than the inputs. For instance, crop soil moisture is more relevant to crop growth than is rainfall, as rainfall might run off without entering the soil, particularly on hilly terrain. The outputs are empirically related to crop yield through standard regression techniques.
Crops require solar energy to develop and grow.
However, exposure to the sun also tends to increase the temperature of leaves, sometimes to such an extent that plants would die if they did not evaporate water to maintain their temperature at acceptable levels. In fact, the amount of solar energy that plants can accumulate is directly linked to amount of water that can be evaporated. The main aim of the crop model and water budget described here is to estimate the amount of water consumed which, in turn, is very closely related to crop yield. For each dekad, rainfall, crop water requirements and crop stage are known. At the same time, the water stress that could affect the crop during its development is also calculated in a cumulative way.