Why might reduced emergence occur in fields heavily worked before heavy rains?

Reduced emergence in fields that have been heavily worked before heavy rains can occur due to crusting of the soil surface. When the soil is tilled or worked excessively, it can lead to a fine, loose soil texture. Subsequently, when heavy rains fall on this finely worked soil, the water can lead to the formation of a crust on the surface as it dries. This crust can create a physical barrier that hinders the ability of germinating seeds to push through the soil and emerge into the open.

The formation of a crust can trap moisture beneath its surface, which is advantageous for seeds initially but can later suffocate them and impede their growth. The crust makes it difficult for young seedlings to access the air necessary for respiration, ultimately leading to reduced emergence rates. Focusing on soil management techniques that prevent crust formation, such as using cover crops or conservative tillage practices, can help maintain optimal soil conditions for seedling emergence following rains.