Soil crusts and cotton emergence relationships.
ABSTRACT RAIN-FORMED soil crusts annually necessitate the replanting of thousands of hectares of cotton. Therefore, we studied the relationships of cotton emergence characteristics and soil-crust strength (penetrometer resistance), and the relative crust-breaking efficiencies of two mechanical devices. As penetrometer resistance increased, mean emergence date was delayed, emergence percentage was decreased, emergence rate index was reduced, and seedling hypocotyl diameter was increased. The rotary hoe was superior to the small-disk device only when the crust-breaking operation was delayed until some seedlings had already emerged.