Breakdown of Subsoil Fragipan By a Humic Product.

The fragipan is a cemented layer of soil that stops water movement and root growth. Its average depth is about 20-24 inches in these soil types. Therefore it reduces crop and forage production about 20 to 25% due to reduced water storage and saturated soils during periods of continuous rains. The fragipan is present in 2.7 million acres in Kentucky and about 50 million acres in the nation. We have identified one plant, 4 chemical compounds and one soil additive that may be able to dissolve the cement that binds the fragipan tightly together. Annual ryegrass was the first agent found to have activity on the fragipan. Therefore it has the most research history and its effectiveness has been verified in several ways. The last agent identified is humate. At the present time its activity on the fragipan has only been verified by one investigative method. The humate products were Menifee humate, raw leonardite, a gypsum/leonardite mixture and a gypsum/humic acid powder mixture. When these materials were combined with dried annual ryegrass residue and placed on an enclosed fragipan core and maintained in a moist condition for 3 to 4 months, a penetrometer could be pushed significantly deeper into the fragipan material than an untreated fragipan core or a dried annual ryegrass residue treatment. More research will be needed to verify its effectiveness but it shows promise at this time.