Grain yield efficiency of dry land wheat in Israel: a high-resolution coupled crop-climate modeling approach

Wheat crop provides a quarter of global calorie consumption. In dryland regions like Israel, spring wheat is grown under rain-fed conditions across a wide diversity of soils and agroclimatic zones. As a result, wheat grain yields suffer from high year-to-year and regional variability. With the projected climate warming intensifying water scarcity in the Eastern Mediterranean region and the global food demand rising, there is a need to develop new crop strategies for future needs.

Regional crop models allow us to assess yield and water use efficiency under future regional projected climate conditions, and thus can be used to develop such crop strategies. The current study uses a climate model (WRF) coupled to a crop model (Noah-MP-Crop) to simulate at high spatial resolution (3 km²) wheat crop growth in Israel. This approach allows accounting for feedback between the climate and the annual crop, which, in the case of widespread crops like wheat, might be significantly important. After calibration of model parameters for Israel’s commercial spring wheat fields, we run the coupled model over a 30-year period, finding a good match between model predictions and recent field observations.

Our results reveal a strong non-linear dependency of yield and water use efficiency on soil moisture. Notably, water stress exceeding 30% can trigger a rapid decline in the potential yield. Clayey soils show more resilience to moisture variability, whereas sandy soils can sometimes outperform clayey soils under greater water stress if other growth factors are optimal. This apparent yield advantage of sandy soils can be attributed to more optimal agroclimatic conditions of these soil locations. Overall, these findings demonstrate that climate-informed, site-specific management strategies, including the selection of appropriate crops and cultivars, can substantially improve yield efficiency under future climate conditions.