ANNUAL REPORT, 1937 13 



yields of tobacco and their respective crop indexes were materially increased by 

 the additions of nitrogen before plowing under the preceding crop. 



The Use of Nitrogen as an Aid in Decomposing Old Sod. (John M. Zak, 

 Karol J. Kucinski, and Walter S. Eisenmenger.) It is of interest to find out 

 whether the application of nitrogen to old grass sod before it is plowed under will 

 hasten decomposition and thus counteract the bad effects usually experienced 

 when crops are grown on newly plowed old sod. Applications of calcium cyanamide 

 at the rates of 100 and 50 pounds of nitrogen per acre on old sod before plowing 

 in the early spring proved to be effective in hastening decomposition. The 

 yields obtained on the treated area were higher than those obtained on the check 

 area of sod which received no nitrogen before being plowed. Another area that 

 received the same treatment but was plowed late in the spring showed similar 

 results but to a lesser extent. Determination of ammonia and nitrate nitrogen 

 throughout the growing season showed that the rate of decomposition of the old 

 sod was faster where nitrogen was plowed under. Study of the >ields and the 

 chemical analyses shows that the addition of nitrogen to old sods before plowing 

 them under will greatly aid in their decomposition and thus lessen their usually 

 harmful effects. 



Rate of Decomposition of Materials Used as Bedding for Animals. (Walter 

 S. Eisenmenger and John M. Zak.) The following bedding materials were 

 analyzed for total nitrogen: southern pine sawdust, southern pine shavings, white 

 pine sawdust, cedar sawdust, hemlock shavings, chestnut sawdust, oak sawdust, 

 birch shavings, peanut hulls, and cacao hulls. A mixture of one half bedding 

 material and one half soil (on a dry-weight basis) was placed in individual crocks 

 and sufficient nitrogen added to each to bring it up to one percent. Determina- 

 tions are being made of the rate of ammonification, nitrification, and decomposi- 

 tion of lignin. 



In another series, cow urine was added to each bedding to the point of sat- 

 uration, and the material allowed to decompose. Lignin and nitrogen determina- 

 tions are being made at the beginning and end of the process to study the com- 

 parative changes in the various materials. 



Magnesium Requirements of Plants. (Walter S. Eisenmenger and Karol 

 J. Kucinski.) Parts of a field known to be deficient in magnesium were used in 

 1936 to determine the relative response and tolerance of different crops to de- 

 ficiencies of this element. A mixed fertilizer, containing no calcium and no 

 magnesium was applied to the entire field, and magnesium sulfate and ground 

 limestone were added as shown in the table. Chemical analyses were made of 

 representative samples of crops grown on these plots. The results of analyses of 

 mangels, potatoes, and rutabagas would indicate definitely that wherever mag- 

 nesium is applied the amount in the plants is increased. Where calcium is applied, 

 not in all instances is the amount increased in the plant. 



Plot Treatment Analysis on Dry-Matter Basis, Percent 



A Check 



B Magnesium 



C Magnesium and lime 



D Lime 



