Abstract
In this paper, an estimation of the transpiration and productivity with limited soil water is presented by using the experimental results which was described in the previous paper. A model to predict transpiration and production with soil water deficits was devised. It comprised three submodels dealing with transpiration, growth of leaf area and dry matter production. The transpiration submodel determined the potential transpiration from the leaf area. The growth of leaf area was estimated based on the relationship between the relative leaf area and relative cumulative transpiration, including the effect of soil moisture stress. Dry matter production was also calculated from relative cumulative transpiration. Solving the above three submodels alternately, the results gave transpiration and productivity at an arbitrary growth period for soybeans.
The estimated transpiration and production were compared with the experimental data which were measured under various soil moisture conditions. The estimated values were in close agreement with the observed results. As a result, the simplified model is useful for estimating the effect of soil moisture deficits on plant production.
