Modeling winter barley root distribution in flat and raised bed planting systems subject to full, deficit and rainfed irrigation

Abstract

In this study, we developed two new depth-decaying and depth-cumulative models for root length density and root mass density of winter barley. The performance of the new models was compared with the several existing depth-decaying and depth-cumulative root distribution models. The experimental treatments were the combinations of full, deficit, and rainfed irrigations under the raised bed and conventional flat planting systems. The two new models showed good performance in comparison with the other existing models. Further analysis based on the cumulative specific root length approach revealed that full irrigation resulted in thicker and thinner roots in the shallow soil depths of the raised bed and flat planting systems, respectively. In contrast, under deficit and rainfed irrigations, thinner and thicker roots were respectively developed in the shallow soil depths of the raised bed and flat planting system. This shows that under suboptimal soil water content, the crops in the raised bed planting system might be able to seek water by developing a network of thin and long roots in the soil matrix.