Fertilizing the Orchard 77 



humus for the satisfactory development of these 

 organisms. 



HUMUS AS A FERTILIZER. 



Owing to the aid of the nitrifying bacteria humus 

 contains all the ingredients necessary to promote 

 plant life, and may be considered as the one sub- 

 stance having in itself all the necessities of plant 

 life in a complete form. Therefore as long as humus 

 is plentiful in the soil vegetation will thrive. On 

 cultivated lands where quantities of plant food are 

 removed from the soil by the crop, the land is apt 

 to become poorer to the extent of the plant ingre- 

 dients removed, unless these are in some form again 

 restored to the soil. 



Humus may be added to the soil either by bring- 

 ing vegetable matter on to the land or by means of 

 cover crops. 



The cover crops which are usually grown in 

 orchards consist of various varieties of leguminous 

 plants, such as peas, beans, vetches, lupins, etc. 

 These plants have the property of taking up the 

 nitrogen from the air with the aid of the nitrogen- 

 fixing bacteria, and if they are again ploughed in 

 this valuable plant food is added to the soil. 



Peas are at present the favourite class of legumins 

 grown for cover crops on the Murray irrigation 

 settlements. They are usually drilled in -with super- 

 phosphate between the row r s in the early autumn 

 after the land has been watered. Usually only 

 alternate rows are sown each season, the implanted 

 rows being sown the previous years are kept bare, 

 so as to allow for one set of rows being used for the 

 removal of fruit or prunings. 



Peas are usually ploughed in during late winter 

 or early spring after having been allowed to flower. 



The weight of humus that may be added to a soil 



