Excerpt from Humus and Humus-Nitrogen in California Soil Columns With ordinary green-manure crops and under field conditions it will probably require a much larger amount of green material to produce one part of humus, for there are losses from the incomplete turning-under of the material and the drying-out of the soil. It would naturally be supposed that as humus is formed by the decay of roots, leaves, etc., it would be found only where formed, whereas on the contrary, we find it quite evenly diffused through the surface soil; this even distribution is not easily accounted for without some outside agencies. Professor Hilgard, in discussing the subject,3 attributes it chiefly to the action of fungi, insects, and earthworms. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.