12 MASS. EXPERIMENT STATION BULLETIN 347 



latter family seem to have the virtue of being conducive to a good yield of to- 

 bacco when they precede tobacco. 



Distribution of Nitrogen in Soils Mixed with Different Plant Tissues and 

 Allowed to React for Two Months. (Walter S. Eisenmenger.) Tobacco planted 

 in rotation with corn and timothy is frequently subject to brown root-rot, while 

 tobacco following tobacco or certain weeds, as ragweed or horseweed. seems less 

 susceptible to the disease. 



It was found that tobacco, ragweed, and horseweed, when placed in the soil, 

 decomposed more rapidly and with a higher rate of nitrification or ammonifica- 

 tion than did red top, corn, and timothy. Clover, when placed in the soil, also 

 had a high rate of ammonification and nitrification, but it was similar to timothy 

 and corn in causing the brown root-rot to appear when planted in rotation with 

 tobacco. The intial rate of decomposition, therefore, is not the only indicator 

 of this trouble. 



Clover, timothy, corn, and red top are relatively high in lignin, while tobacco, 

 ragweed, and horseweed are relatively low in lignin. Those plants which are high 

 in lignin, or which maintain their physical structure fairly well during winter 

 weather, are the ones which are least desirable for crops in rotation with tobacco. 



Application of Calcium Cyanamide to Overcome the Immediate Harmful 

 Effects of Ligneous Tissue. (Walter S. Eisenmenger and Karol J. Kucinski.) 

 Attempts were made to overcome the bad effects which the residual portions of 

 certain preceding crops have on tobacco. Tobacco plants seem exceptionally 

 sensitive to the effects of the slowly decomposing portions of certain crop plants 

 in the soil. 



Applications of nitrogen in the form of calcium cyanamide were made in the 

 fall to plots of corn, red top, orchard grass, and timothy. Similar plots which 

 received no nitrogen were used as check plots. The red top, orchard grass, and 

 timothy plots were two-year-old sods of the respective grasses. Immediateh' 

 after the nitrogen was applied, all of the plots, including the checks, were plowed 

 under and seeded to a cover crop of rye. The following spring, tobacco was 

 planted on all of these plots. 



Yield and Quality of Tobacco 



Plot Treatment 



Acre Yield Grade Crop 



Pounds Index Index 



Cornfield 



Plowed — Check 1837 .489 898 



500 lb. per acre of calcium cyanamide added 



before plowing 2169 .555 1203 



Two- Year-Old Red Top Sod 



Plowed — Check 1782 .508 905 



500 lb. per acre of calcium cyanamide added 



before plowing 2432 . 538 1308 



Two- Year-Old Orchard Grass Sod 



Plowed — Check 1935 .524 1014 



500 lb. per acre of calcium cyanamide added 



before plowing 1877 .499 937 



Two- Year-Old Timothy Sod 



Plowed — Check 1793 .536 961 



500 lb. per acre of calcium cyanamide added 



before plowing 2185 . 508 1 1 10 



With the exception of the orchard grass plots, the table above shows that the 



