22 MASS. EXPERIMENT STATION BULLETIN 195. 



The choice of a cover crop depends on several factors, such as character 

 of soil, presence of Thielavia root-rot in the field, etc. Some leguminous 

 crop has often been advocated as a cover crop, but it is questionable if this 

 is advisable for tobacco, as so many of the legumes (clovers, etc.) are 

 also hosts of the Thielavia root-rot fungus, and would thus perpetuate it. 

 Any crop which will serve as a host for the root-rot fungus {Thielavia) should 

 not be employed as a cover crop for tobacco. 



Rye, barley and timothy have been used in many instances with varying 

 success, rj^e perhaps being most generally used up to the present time. 

 There is one objection to rye, particularly on light lands; i.e., if favorable 

 growing weather prevails in the spring and any considerable amount of 

 land is to be plowed, such a rapid growth of the rye top occurs that it is 

 difficult to turn under thoroughly, and consequently it does not decay 

 properly. 



Barley is not generally used, and its use is not advocated. • 



Timothy has been used by some growers with good success, and from 

 observation and trial on some soils the writer can recommend its use 

 strongly, as it usually makes a good root growth, and does not grow so 

 high as to be difficult of plowing under. 



Although no positive data are at hand, it is believed that rye as usually 

 planted will not furnish as much organic matter as timothy. Rye makes 

 more top growth, but not nearly as much root growth as timothy. 



According to our data, an ordinary cover crop of timothy will add to 

 the soil over 2 tons of dry organic matter to the acre. Some figures of 

 German investigators indicate even higher values, as much as 3 tons per 

 acre.^ 



In addition to the direct benefit to the soil in organic matter, such a 

 cover crop will aid in other ways. It will conserve nitrogen by preventing 

 leaching, and will bind light soils, consequently preventing the blowing and 

 washing which is so common in many fields. 



The cost, per acre, for seed is very little, as' the amount sowti should 

 usually be not over one-third bushel of good seed to the acre. The saving 

 in nitrogen alone would more than repay the cost involved. The seed 

 should be sown broadcast on stalk-cut fields, as soon as the tobacco is off, 

 and on primed and shade-grown Cuban fields should be sotvh after the 

 third pickmg at the latest. 



Every tobacco field in Massachusetts should have a cover crop each year, and, 

 so far as we can at present state, the choice should be timothy first, with rye 

 second. 



' Subsequent to the preparation of this report the Connecticut station and Hartford County 

 Farm Bureau published analyses showing that the average amount of dry organic matter returned 

 to the soil by a timothy cover crop amounts to 3}i tons per acre. This would be, so far as organic 

 matter content is concerned, the equivalent of 15 tons of manure. 



