Influence of root resistivity on plant water uptake mechanism,part I: numerical solution

The issue of water flow through the root zone of field crops represents a complex problem requiring knowledge of a large spectrum of phenomena from various disciplines. Although many investigations have been devoted to gain better understanding of water dynamics in the root zone, the problem is still insufficiently understood. The main objective of the presented work was to analyze the importance of root water resistivity in the plant water extraction process. The problem was solved numerically for a wide range of the soil–root conductivity ratio (SRCR). Two different types of root water uptake (RWU) mechanisms were obtained. The first one is related to low root resistivity or low SRCR, and, thus, exhibits a so-called “moving uptake front” (MUF) effect observed previously in several experimental studies. The second one is inherent in large values of root resistivity or high values of SRCR (larger than 10⁴), and is strongly dependent on the root density distribution. Deceased.