The results secured on 13 cooperative soil experimental fields on the Grundy silt loam in Southern Iowa have shown that the Iowa System of Soil Management when put into, operation on that soil type, will definitely increase the yields of general farm crops.

Occasionally the Grundy silt loam is not adequately drained, especially on some of the broad, level to flat areas of the type, and tiling is the first treatment needed to make such areas satisfactorily productive.

Ordinary farm practice usually provides satisfactory cultivation, and this is especially important on this type because it stimulates the production of available plant food.