250 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



taken up by the soil water. This solu- 

 tion is then able to dissolve many in- 

 soluble minerals from the soil which are 

 necessary as plant food. Such substances 

 as rock phosphate and limestone, which 

 are practically insoluble in pure water, 

 are made soluble and available as plant 

 food by the action of this carbon dioxide 

 in water. 



Humus is partially decomposed vege- 

 table matter. When the vegetable matter 

 forms humus, or the humus breaks down 

 to form still simpler compounds, heat is 

 liberated. Whether a pile of leaves is 

 burned or allowed to rot, the same amount 

 of heat is given off in either case. This 

 means that the decaying organic matter 

 in the soil makes it warmer and drier in 

 the spring. Thus growth will start ear- 

 lier and be faster throughout the entire 

 season. 



Bacteria working in the soil, especially 

 during warm weather, are continually 

 setting free food in the form of nitrates. 

 and other minerals are also changing to 

 soluble form. The nitrates, unless used 

 immediately, are liable to be lost by 

 leaching away in the drainage water. 

 There are some minerals also more or 

 less soluble that may be lost by washing 

 away in drainage water. However, their 

 loss is not so great as that of nitrogen. 

 To avoid this, a crop is necessary dur- 

 ing the whole growing season. At the 

 first of the season, the orchard while 

 growing can handle and use all of this 

 available plant food. Later on. when 

 the orchard growth is less active, it is 

 necessary to have a cover crop of some 

 sort to use this food and get it in a form 

 that can be carried over until the next 

 season without loss. Such crops as clover 

 are especially good. They not only use 

 all the available nitrogen in the soil, but 

 they add more from the air. and in the 

 spring they decay readily, liberating their 

 contents to be used by the trees. 



The ideal cultivation for orchards in 

 the Central West is, we believe, inten- 

 sive, clean culture from early spring to 

 June, then seed to cow peas — either drill- 

 ing and cultivating or broad casting. In 

 this connection, the Western Fruit Grower 

 says: 



"Regarding cover crops for the Middle 

 West, will say that we agree with you 

 that nothing is better than cow peas, ex- 

 cept that lots of orchards are on hills so 

 steep that it will not do to give them cul- 

 tivation in early spring, during the rainy 

 season. We think that very soon we shall 

 have to adopt a plan of cultivating two 

 rows and leaving the next two rows in 

 clover and alternating this treatment." 



There are numerous and various vari- 

 eties of cow peas adapted to the different 

 orchard regions. Occasionally, we have 

 followed a crop of cow peas with a crop 

 of corn. During the last cultivation of 

 the corn more peas are sown or hairy 

 vetch. The vetch supplies a fine crop 

 for plowing under in the spring. Vetch 

 also becomes a profitable pasturage crop 

 for hogs when their age and size will per- 

 mit pasturing them without injury to 

 young trees. On this subject of hairy 

 vetch, Agrostologist F. Lamson Scribner 

 in 1895 reported: 



"Hairy vetch sown in autumn will cover 

 the ground and prevent washing during 

 the winter. It is one of the best crops to 

 turn under as green manure. Do not 

 commence to feed hairy vetches until they 

 have begun to bloom. Like most of the 

 bean and clover family they are some- 

 what diuretic if fed in large quantities 

 before mature. Use caution in feeding 

 until the animals have become accustomed 

 to the change of feed." 



Peas may be utilized in the same way 

 — just as you would clover. We have occa- 

 sionally used a crop of red clover but its 

 use is too familiar to need further com- 

 ment here. We have also used alsyke 

 clover, which in some cases is better than 

 red clover. 



Some sort of cover crop throughout the 

 winter not only prevents washing, which 

 is so disastrous, but holds the winter 

 snows, and lessens the depth of alter- 

 nate freezing and thawing. Also in gath- 

 ering the crop in the fall, it makes pick- 

 ing and hauling of fruit a much cheaper 

 and cleaner job. 



The rapid growth induced by cultiva- 

 tion through the first of the season is 

 inclined to make the new wood of the 

 trees soft and tender. To check this 

 growth and harden the wood for winter, 

 a cover crop is necessary. The weeds 

 or volunteer grasses might be allowed to 



