112 SUCCESSFUL FARMING 



for different crops and different soils, and would also be influenced by the 

 character of the manure and its rate of application. 



GREEN MANURES 



Green manuring consists of plowing under green crops for the benefit 

 of the soil. The practice results in increasing the organic matter in the 

 soil. If legumes are used for this purpose the nitrogen content of the 

 soil may also be increased. Preference should be given to legumes for 

 this reason. The choice of a crop for green manuring purposes will depend 

 on a number of factors. Other things equal, deep-rooted crops are prefer- 

 able to those having shallow root systems. Plants with deep roots gather 

 some mineral constituents from the subsoil and upon the decay of the 

 plants leave them in the surface soil in- an organic form. Deep-rooted 

 plants are also beneficial because they improve the physical condition of 

 the subsoil. In general, crops that will furnish the largest amount of 

 humus and nitrogen-bearing material for the soil should be selected. 



When is Green Manuring Advisable? — The practice of plowing 

 under crops for the benefit of the soil is not justified in systems of live- 

 stock farming where the crops can be profitably fed and the manure 

 returned to the soil. There are many localities, however, where the farm- 

 ing systems are such that but little manure is available to supply the 

 needs of the soil. Under such conditions green manuring crops are often 

 resorted to with profit. They are especially to be recommended in case 

 of sandy soils low in organic matter, and for heavy soils in poor physical 

 condition. In addition to serving the purposes above mentioned, green 

 manuring crops, if properly selected, occupy the soil at seasons when it 

 would otherwise be bare of vegetation and subject to erosion. They also 

 prevent the loss of nitrogen by leaching. This is later made available for 

 other crops as the green manures decompose in the soil. 



Green manuring is most applicable on fruit and truck farms. It is 

 quite extensively practiced in orchards during the early life of the trees. 

 It is also economical in the trucking regions where the winters are mild. 



Objections to Green Manuring. — The objections to* green manuring 

 lie chiefly in the fact that green manure crops are grown and plowed 

 under for the benefit of the soil and no direct immediate return is secured. 

 The green manuring crops generally take the place of money crops. 

 When it is possible to grow legumes and feed them to livestock with profit, 

 the stubble and roots of such crops, together with the manure which 

 they will afford, make possible nearly as rapid improvement of the soil 

 as is the case when the whole crop is plowed under. Whether or not a 

 green manuring crop should be fed or plowed under must be determined 

 by the cost of harvesting and feeding, together with the cost of returning 

 the manure, as compared with the returns secured in animals or animal 

 products in feeding it. 



