During recent years the continued culture of orchards has been advocated in California and in all fruit-growing centres. But a change in belief is now apparent in all sections. In section (19. Root-protection) the subject of shading of orchard soils and the use of cover-crops are discussed. In this connection the combined system of culture and soil-shading will be noted. The orchard culture should begin early in the season. Early culture helps in saving the spring moisture and to start growth actively. The entire growth of the season of fruit trees is made early in the season. Hardy northern trees finish growth by the first of July and in the prairie States earlier. All cover- and catch-crops should be turned under in the spring as soon as the soil is in fair working condition. Some advise running the plough four or five inches deep, but a far better rule is to plough only deep enough to permit turning a flat furrow with levelling after culture.
The early culture answers the purpose of advancing growth and starting the fruit crop, and the after cover-crop is an advantage in shading the soil, permitting the nitrogen-feeding root-hairs to come near to the surface as an aid to fruit ripening and the perfect maturing of the cell-structure of the tree.
While the orchard is young and the supply of plant-food and humus yet ample, buckwheat answers well the conditions for keeping the soil shaded and relatively cool and moist. It covers the ground much earlier than any of the legumes, and is easier to turn under in the spring. If one half of a young orchard is sown annually to buckwheat about the first of July and the other half is cultivated, the owner will discover in a short time a surprising comparative thrift and vigor of growth on the buckwheat portion and also an increase of yield and increased size and smoothness of fruit. As the orchard attains greater age hairy vetch has proven best for a cover-crop in the Western States and cow-peas in the South. In south California the common field-pea makes a surprising growth in late fall and early winter in orange orchards and so far is a favorite cover-crop to supply the soil with needed humus and nitrogen.