1906 FRUITS OF ONTARIO. 19 



land, where the rains quickly run off and snows blow off the high portions, a 

 growing crop tends to hold these until they have time to soak into the soil. (3) 

 Land covered by a growing crop dries out more quickly in the spring, owing to 

 the transpiration of moisture through the leaves, and consequently may be 

 plowed under earlier in the season than land which is bare. This is a very im- 

 portant point, as it enables the orchardist to gain several days in the busy season 

 of spring. (4) Ground covered with vegetation will hold the snows in winter and 

 thus prevent deep freezing, thereby avoiding the liability of root killing. 

 (5) A cover crop affords the most economical means of furnishing a sup- 

 ply of humus in the soil. (6) The roots of a cover crop assist the tree 

 roots in rendering available certain mineral plant food in the soil. 

 (7) A large amount of plant food is liberated in the soil after the tree 

 growth has ceased. This is taken up by the growing crop and held in a 

 readily available form for the following season. (8) Leguminous crops, such as 

 clover, vetch, alfalfa, peas, and beans, by virtue of certain bacteria which form- 

 nodules on the roots, are able to assimilate nitrogen from the air. As nitrogen 

 is one of the most expensive fertilizing elements, the value of this class of plants 

 cannot be too highly appreciated. 



Cover crops should be sown about the middle of July so that they may make 

 a good growth the same season, and in the colder parts of the Province, the seed 

 may be sown during the first week of July, as the season is shorter than in the 

 more favored sections. It is also wise to check the growth of the trees about this 

 time, so that they may mature their wood before winter sets in. The thorough 

 tillage which should have been practised up to this season, leaves the ground in 

 the best possible condition to give the young plants a start. The crop should be 

 plowed under as early in the spring as possible, and cultivation should begin at 

 once. If the crop is large and the soil rather dry, this is imperative, as the 

 large amount of vegetable matter turned under seriously interferes with capillary 

 action and leaves the surface soil unduly dry. 



That a cover crop may be of the greatest value, it should be capable of with- 

 standing the winter and continuing its growth next spring. This, however, is 

 not a necessity, as many of the ordinary crops which will not live through the 

 winter are valuable for this purpose. 



Different soils require different kinds of crops. This has led to a division 

 of cover crops under several classes. The most important are the nitrogen 

 gatherers, which through the agency of the nodules on the roots can make use 

 of the nitrogen of the air. Such plants as clover, vetches, alfalfa, peas, and 

 beans, belong to this class, and should be used where the soil is deficient in 

 nitrogen. Another class is known as the potash liberators, such as turnips and 

 rape, which, although they do not add anything to the soil, as do the legumin- 

 ous plants, yet change the form of the mineral potash so that it may be more 

 readily acted upon by the roots of succeeding crops. Thtn there is a third class, 

 commonly grown, such as rye, oats, and buckwheat, which are valuable chiefly 

 on account of the humus formed by their development. 



Hairy Vetch, sown at the rate of thirty-five pounds per acre, forms a verv 

 close mat over the ground. This is a valuable crop owing to the fact that it 

 collects nitrogen, lies close to the ground so that it does not inconvenience the 

 pickers when gathering the fruit, and also withstands the cold winter and con- 

 tinues its growth early in the spring. 



Red Clover and Mammoth Clover, sown at the rate of twenty pounds per 

 acre, are about equal in value, make a fair growth, are low growing, and winter 

 well on drained soil. 



