Page:Tree Crops; A Permanent Agriculture (1929).pdf/347

 dred feet apart. The roots would run under all the grass in the field and nitrate it. The honey locust trees (Chapter VII), besides feeding nitrogen to grass (page 65), would yield beans.

If such pastures had an open planting of honey locust interplanted with grafted walnut trees or grafted hickory trees, the honey locust could furnish nitrogen for the nut trees. If the run-off went into water pockets so that trees and grass could share all the water that fell, it would certainly result in a substantial increase of grass, wood, and tree crops. The water pocket would also catch and hold the fine earth particles which the rain would ordinarily carry away. Thus fertility would be increased, and the land would be built up. It should be remembered that both locusts and the black walnut have open tops letting much light through.

These differ but little from the steep land except that they are usually in better condition because they have escaped the scalping by a plow-mad race.

Under the heading of rough lands mention should be made of the hundreds of thousands of fruitless trees now standing in the rough limestone fields of the great Appalachian Valley which extends from southern New York to northern Alabama. In certain sections, such as the Cumberland Valley, Shenandoah Valley, and the valley of east Tennessee, which have long been famous for a rich agriculture, the traveler is amazed by the great amount of outcropping limestone making patches where farm machinery cannot go. Here the good soil makes good grass, and often good trees have sprung up without the aid of man.

This is prime walnut land, and the walnut is thoroughly