FIELD CROPS. 141 



per cent. " The maximum from a single pot is 3.45 where 4 gm. nitrate of soda 

 was applied ; the raaxiraura average, 3.348, occurs where 10 gm. calcium car- 

 bonate was used, and the average with 25 gm. is only slightly less. The lowest 

 average, 3.12G, is found with 4 gm. calcium sulphate. These pots, however, 

 gave the highest yield of dry matter, thus placing the yield of total nitrogen in 

 second place, the highest occurring with 4 gm. nitrate of soda. It is of es- 

 pecial interest to note that tlie limestone gives higher percentages of nitrogen, 

 on an average, than the nitrate of soda, thus emphasizing the value of an 

 abundant supply of limestone in the accumulation of atmospheric nitrogen, and 

 also making it clear that it is not necessary to add nitrogenous fertilizers in the 

 growing of soy beans, provided the soil is well supplied with lime." 



Analysis of 11 varieties of soy beans harvested at about the same stage of 

 maturity as forage shows that " there is a rather wide variation in the per- 

 centage of nitrogen in the different varieties. The Medium Yellow, El)ony, and 

 Guelph show above 3.25 per cent of nitrogen ; the Edna and ^Manhattan show 

 an average of more than 3 per cent. The Ohio 9035 and Swan show an average 

 of more than 2.75 per cent, the Claude and Wilson more than 2.5 per cent, and 

 the Tarheel shows an average of more than 2.25 per cent. It should be ob- 

 served that in most cases the percentage of nitrogen in a particular variety 

 runs quite constant. It is of interest to note that the Tarheel, which gives the 

 highest yield of dry matter, shows the lowest percentage of nitrogen. Since this 

 variety does not mature well in this latitude it would not be well adapted for 

 growth if seed were desired. If, however, it were to be used as a forage or 

 green manure crop, its rank growth would probably result in adding to the 

 soil more nitrogen than would be added by some of the smaller varieties. Cer- 

 tainly this was true in this case, for there was recovered in the crop 3.01 gm. 

 [per pot] as against 2.56 gra. for the Swan, which was the next highest. The 

 [Hollybrook], with a recovery of 2.45 gm., stands third. The Ebony and Man- 

 hattan both produced small plants, and have this much against them if one is 

 considering the enrichment of the soil. The Tarheel, Swan, Hollybrook, and 

 Ohio 9035 all show a recovery of nitrogen in the crop of above 2 gm." 



Tobacco investigations, E. K. Hibshman (Pennsylvania Sta. Rpt. 1912, pp. 

 455-|79, pis. 15, figs. 5). — In this report are given notes and data secured in 

 the selection and breeding of Pennsylvania Broadleaf tobacco during 1909, 1910, 

 and 1911 in an effort to improve and purify the type that was being planted in 

 Lancaster County. Data show the number, length, and width of leaves, the 

 number and size of suckers, and the yield of leaf per plant. 



Experiments in high and low topping and normal (28 by 42 in.) and close 

 (28 by 36 in.) planting of tobacco showed in 1910 and 1911 that " with the same 

 planting distances high topping produces more weight per acre than low topping. 

 Furthermore, they also indicate that close planting Avhen accompanied by high 

 topping produces more weight than normal planting with high topping. It was 

 observed that the leaf on the closely planted and high topped plats was not as 

 heavy in body nor as uniform in color as that from the normal planted plats 

 topped high. It was also far more difficult to sucker the closely planted plats 

 without breaking leaves. The high topped plats were of cour.se slow to ripen; 

 and apparently the closely planted and low topped plats ripened later than those 

 normally planted and low topped. 



" It is not safe to conclude, however, from these experiments that tobacco 

 should always be topped high. The best height of topping depends upon a num- 

 ber of factors. The grower must first take into consideration the number of 

 leaves a plant would naturally develop if allowed to go to seed. He must also 

 consider the time of the season when the plant is ready to be topped ; if it is 

 early, he can top high ; if it is late, he must top low in order that the plant may 



