Productivity of high-yielding crops

The biological yield (Yb, glucose basis) of crops can be expressed by the following formula: Y b = E u × E a, and Y b = NAR × LAD, where E u is the solar radiation use efficiency; E a is the amount of solar radiation received by the plant canopy; NAR is the average net assimilation rate; and LAD is the leaf area duration. The results of parameter analysis obtained under various growing conditions were as follows 1. When the Y b values of all the crops were pooled together, the Y b was closely related to the E u and LAD parameters, but not to the E a or NAR ones.2. In rice and soybean, the Y b was low due to the low values of E u, E a, and LAD. In winter wheat and maize, the Y b was high due to the high values of E u and LAD. In potato and sugar beet, the Y b was high due to the intermediate or high values of E u, E a, NAR, and LAD in comparison with other crops.