Page:Tree Crops; A Permanent Agriculture (1929).pdf/341

 between two terraces. With hogging down of non-tilled crops there is only soil preparation and seeding to be done on the winding little terraced fields (see Fig. 115)—another reduction of the handicap.

Hogging down also permits a variety of foods to be eaten by the pig, which has a distinct advantage.

If crop trees are on the terrace edge, hogging down permits trees to have the benefit of cultivation if the owner so desires and permits part of the hillsides to be cultivated. All parts can be profitable because that which is not cultivated can be covered by the trees and grass.

These new techniques—nitrate instead of cultivation, fertilization by legumes, irrigation from the rain-fed reservoirs on the spot, and hogging down, taken in combination with ordinary pasture suggest an entirely new era of heavier productivity of the unplowed and unplowable lands of the American farm. This is fortunate because over a large section of our country the greater part of the land as now arranged (page 10) can be regularly plowed only to its ruin.

The year after the Portuguese cork farmer strips his oak trees, the trees yield an enormous crop of acorns. Stripping the bark off injures the tree enough to scare it into yielding a big crop but gives no permanent bad result. This matter of crop stimulus through controlled injury is like whipping a horse. Its possibilities are for most crops unknown, but certainly