FORTY-FIRST ANNUAL REPORT. 95 



THE USE OF COYER CROPS. 



M. T. MUNN. 



The use of cover crops in connection with the growing- of fruit is 

 closely allied Avith the fertilizer problem, inasmuch as they are both 

 fundamental factors in soil fertility. The producing capacity of the 

 soil is as much dependent upon its physical or mechanical condition 

 as it is upon the amount of i)lant food it may contain. The chief factor 

 governing- the physical condition of the soil is the amount of humus or 

 decaying vegetable matter it contains. 



Xitrogen occurs in the soil in a combined form in humus and decay- 

 ing vegetable matter and in that form thru the action of bacteria it is 

 changed into nitric acid which unites with other substances and will dis- 

 solve soil salts. There are two methods of adding humus to the soil, 

 first, by the application of barnyard manure, and second, and perhaps 

 the better of the two methods is by growing a cover crop upon the soil 

 and jiloAving it under in the spring. 



The principal uses of a cover crop in the orchard or vineyard are as 

 follows: Their growth helps to check the tree growth and ripen the 

 new wood. A cover will catch and hold the leaves as they fall from the 

 trees and will afford some protection. The cover crop itself will make 

 a blanket over the ground and by holding the snow fnmi blowing off, 

 will prevent deep and severe freezing of the roots, and the alternate 

 freezing and thawing which causes serious loss in Michigan orchards 

 located upon the lighter and more porous soils. A cover of vegetable 

 growth over the soil, supplemented by the root system will prevent the 

 washing of the valuable top soil by the heavy fall and spring rains as 

 is liable to be the case on knolls and hillsides, (/over crops also en- 

 courage deep rooting of the trees, also catch soluble plant food in early 

 spring before root action begins in the trees, but the most valuable re- 

 sults from the use of cover crops is that they add hunuis and plant food 

 to the soil. 



The selection of a suitable cover crop will depend somewhat upon 

 various factors; a cover crop must make at least a fair growth during 

 late summer and fall ; it must be able to withstand the winter and 

 grow vigorously in the spring; it must be able to stand the tramping 

 necessary at picking- time, and it should have the power of gathering 

 nitrogen from the air and holding it in the roots. If the soil needs 

 more nitrogen one of the legumes, such as vetch, peas, or the clovers 

 should be sown as they have the power to gather nitrogen from the air 

 so that when they are plowed under and decay the soil is actually 

 richer in nitrogen than it was before. If the maintenance of humus is 

 necessary with soil protection then a non-legumious plant such as rye, 

 oats, or buckwheat will serve although they leave the soil but little 

 richer than it was before, though the presence of the decaying vegetable 

 matter thus added to the soil improves its physical condition and makes 

 it more productive. 



Winter Vetch (Vicia A'illosa) sometimes called sand or hairy vetch 



