Forest Lysimeter Studies Under Pine

In the region of podzolic soils there Is no portion of the forest soil profile which Is of greater Importance than the duff layer. While unquestionably there Is a mutual Interdependence between soil type, forest type, and the type of duff that accumulates, In this particular discussion we are interested not in the origin of the duff but rather In its effect upon the soil. One way to find out what this effect may be is to ascertain what constituents are leached out of the duff and what proportion of the leached material is retained in the underlying mineral soil. This information can be most readily and accurately obtained through the use of lysimeters. Many studies have been carried on In lysimeters using cultivated soils which are planted to the usual farm crops. In recent years some attempts have been made to carry on such studies in uncropped or virgin soils. Joffe (3) has Installed the Russian type of lysimeter in a hardwood stand, his primary purpose being to determine what materials come through the natural mineral soil horizons under virgin conditions. Both types of lysimeters have their place and lt is idle to say that either one Is superior to the other. The lysimeters we installed In Connecticut are designed to determine primarily the constituents leached out of the duff, and secondarily those leached out of the upper 4" of mineral soil.