Modeling Plant Water Use and Response to Salinity, Drought, Nutrient and B Stress.

The unsustainable use of fresh water resources in arid regions means that we must utilize saline waters and soils for future crop production. Understanding the interaction of abiotic stresses on crop production is essential for management and optimization of resources as well as economic crop production. We evaluate plant response to interactive effects of combinations of salinity, drought, nitrogen and boron stress and the relation of water consumption to crop yield under conditions of single and multiple abiotic stress.   

Plant response studies and subsequent recommendations regarding water requirements and drought stress, salinity stress and management, boron toxicity and nutrient requirements are provided based primarily from single stress experiments. Under field conditions multiple stresses often occur simultaneously. Some recommendations are based on consideration of only the most severe stress when managing for yield loss. These have been shown to be unsatisfactory as has the concept of adding individual responses to abiotic stress to predict yield loss. There are conflicting reports regarding how multiple abiotic stresses interact. Many models now consider an interactive effect that is multiplicative of the response to individual stresses. Unfortunately there are a very limited number of controlled studies where individual stress response functions are developed and then multiple response models tested against data with multiple stresses. The present evaluation based on new data sets and evaluation of existing ones, indicates that although the multiplicative response model is the best available it is not adequate in many instances, resulting in overestimation of yield loss.  Estimation of water consumption based on reduction in biomass production is not adequate as it assumes that water use efficiency is constant under salt stress- an assumption that has been found to not be valid for many crops.