FIGURE 101.—Fertilizer and fuel—valuable by-products of the farm woods
FOREST Litter a Good Fertilizer of Farm as Well as Tree Crops
About a ton of leaves, or needles, and other organic matter falls yearly to the ground in an acre of well-stocked pine woods. In some of the hardwoods like the oaks, the yearly cast-off of such leaves, twigs, flowers, and fruit probably amounts to about 2 tons. This material goes to make up nature’s protective blanket over the forest floor. It is well known that the woods litter, if not destroyed by fire, gradually changes to humus, or decomposed organic matter, rich in plant food.
We know that trees grow faster with a deep accumulation of leaves and humus. A pure, even-aged loblolly pine stand in eastern Maryland was raked for many years on one side of a dividing road. The growth of the trees was measured on 2 acres lying on opposite sides of the road. Each had the same number of trees. The acre raked yearly had a stand of 18,600 board-feet, while the other with its accumulated straw had 24,800 board-feet. The trees were 55 years old, and the blanket of organic matter had added over $1 an acre yearly in the value of the growth.
Unburned woods of short-leaf and loblolly pines in central and eastern North Carolina were found to have on the ground an average of a pound of dry organic matter per square foot, or a total per acre, eliminating-area occupied by tree trunks and a few bushes, of net less than 18 tons. A chemical analysis of samples consisting of both the fresh and the decomposed forest organic matter revealed the fact that each ton contained about 12.1 pounds of ammonia (NH4), 2.8 pounds of phosphoric acid (P2O4), and 3.9 pounds of potash (K2O). At prevailing wholesale prices, this is the equivalent per acre of $39.20 for the ammonia, $2.52 for the phosphoric acid, and $4.21 for the potash, a total value per acre of $45.93.
A farmer raked all the litter from beneath the trees on a measured acre of heavy oak woods in Gibson County, Tenn., and plowed it under on an acre of field crop land. For three years he measured the yields of corn and cotton on the treated and on adjacent untreated acres, with some interesting results. The first year his crops on the treated acre were worth $20.65 more than on the untreated land, the second year $14.80, and the third year $13 more. Although a marked effect was shown at the end of the third year, the farmer was unable to take more records, so the story of the value of the woods fertilizer is incomplete, at a total, however, for the first three years of $45.45 per acre.
The high water-holding value of woods mold when applied to the soil should be considered along with the value of its chemical fertilizing materials. In the Southern States large amounts of pine straw, or litter, are raked for stable bedding, for mulching strawberries, and as a general crop fertilizer. In the opinion of forestry experts the value of woods litter as a crop fertilizer is greater than ifs value as a means of stimulating increased growth of forest trees if it is allowed to remain undisturbed in the woods.