Differential impacts of climate variability on yields of rainfed barley and legumes in semi-arid Mediterranean conditions

Climate change has emerged as a major concern for crop production. This study used a field experiment to examine the differential yield responses of barley, lentil, common vetch, and bitter vetch to weather in the Mediterranean region. Crops were grown in a 10-year rotation trial in Lebanon. Precipitation and temperature were used as explanatory variables in simple linear correlation and standardized multiple-regression analyses. Grain yields were not correlated with annual precipitation. Barley grain yield was correlated positively with precipitation from March to May (r=0.70) and the rainfall distribution index (r=0.71), but negatively with mean May temperature (r=-0.62) and absolute minimum temperature in January (r=-0.91). Unlike barley, legume grain yield was not correlated with any rainfall parameters. Common vetch grain yield was negatively correlated with mean May temperature (r=-0.68). Grain yield of the two vetches were also correlated negatively with the absolute minimum temperature in January, but grain yield of lentil was not correlated with any weather variable. Standardized multiple-regression analyses showed that mean May temperature had the strongest influence on grain yield of barley, lentil, and common vetch, indicating that, under climate change, higher temperature may have a more deleterious effect on grain yield than lower rainfall. The negative correlation between common vetch and barley grain yields and temperature in May suggests that early sowing to induce earlier flowering and maturity to escape the hot summer may be an option to increase common vetch and barley grain yields.