High temperature effects: On sugar beet germination in Imperial Valley
The imperial valley includes approximately 430,000 cultivated acres of fertile land located adjacent to the U. S.-Mexican border. Its climate is characterized by high summer temperatures and relatively mild, sunny winters. About 55,000 acres of this land is in sugar beet production and, because of the unique climate and processing requirements, seed must be planted between August and October. During this period when dry soil temperatures at ½-inch depth may reach 70°C, growers have difficulties establishing a satisfactory stand of sugar beets, especially in the late-August to early-September period. The problem decreases in plantings made during the period from mid-September through October–leading to the theory that high temperature might be the cause of the problem.