FARMEfRS' INSTITUTES. 27 



of certain fQrms of bacteria. These changes can only go on when the soil 

 is fairly porous, and when there is a certain amount of humus present. 

 I make this prefatory statement in order to emphasize the necessity, 

 from the fertility standpoint, of keeping up the store of humus. We 

 are coming to believe in the East, that orchard tillage includes in the 

 meaning of the term the cultivation of the soil in the fore part of the 

 season, and the covering of the soil in the latter part of the season 

 with some crop which, when it is returned to the land, will leave it in 

 better condition, and with more fertility than it found there. This 



1 



H 



liifiiipigliiiiiltfnlW^^ 



Fig. 1. Showing Good Tillage 



is termed the cover cropping system, and it does not imply that the 

 orchard ?oil is cropped in a sense that is suggested by the growing of 

 a field of wheat, where such field is grown primarily for the yield of 

 grain and straw. The cover crop is grown, not as a competitor, but 

 as a cooperation with the fruit crop. It is put on the soil after the 

 period of greatest vegetative activity of the tree has taken place. 

 The growing season, then, of the cover crop and the tree is not coincident, 

 although it may overlap that of the orchard crop, but it should be 

 successive. 



What, then, may we consider an ideal system of tillage? Perhaps it is 

 most nearly approached when the fruit grower stirs the soil as early 

 as practicable in the spring, when he maintains thorough surface tillage 

 until the trees form their terminal buds, and when he then seeds with 

 a cover crop. The ideal cover crop plant is one which germinates 

 promptly, is not readily killed by a frost, lives over winter and makes 

 early growth in the spring, when it should be turned under. 



Classes of cover crops. — These are practically two : The ''nitrogen col- 



