68 Report of the Department of Ageonomy of the 



Tennessee experiments. — At the Tennessee station comparative 

 experiments with ground limestone and caustic lime have been 

 conducted for four years with a variety of crops, including corn, 

 wheat, oats, barley, sorghum, clover, grass, cow peas and cotton. 

 The results of the experiments are summarized in the following 

 paragraph quoted from Tennessee Station Bulletin 97: 



" The most important feature of these experiments consists, how- 

 ever, in the comparative returns from burned lime on the one hand 

 and ground limestone on the other. A study of Table V shows that 

 the returns are very close. If the increased yields of all hay attribut- 

 able to liming be summed up, we find an average increase for each 

 crop harvested of 0.G7 ton per acre for the burned lime and 0.69 

 ton per acre for the ground limestone. If the increased yield of all 

 kinds of grain crops be averaged in a similar manner we find an 

 average increase of 4.5 bushels for the burned lime and 5.5 bushels 

 for the ground limestone. We would conclude, therefore, that in 

 these trials two tons of ground limestone proved somewhat superior 

 to one ton of burned lime." 



Particular mention is made in the bulletin that the burned lime 

 was strictly high grade. 



Maryland experiments. — Eleven years of comparative experiments 

 with burned lime and carbonate of lime have been reported by the 

 Maryland station. Each form of lime is tested on duplicate plats. 

 On one plat the burned lime is from limestone and on the other 

 from oyster shells. The carbonate is from marl in one case and in 

 the other from ground oyster shells. 



Caustic Lime vs. Carbonate of Lime: Maryland Experiments; 11 Years' 



Results. 



Produce per acre in eleven years. 



Corn 

 4 crops. 



Wheat 

 3 crops. 



Hay 

 4 crops. 



Caustic lime 1400 lbs. per acre applied once in 11 

 years 



Carbonate of lime 2600 lbs. per acre applied once 

 in 1 1 years 



No treatment 



Bushels. 



128.6 



148.4 

 97.5 



Bushels. 



33.7 



42.3 

 31.9 



Pounds. 



7,637 



7,930 

 5,200 



Attempt has been made to discredit these experiments because the 

 marl used on one of the carbonate plats may have contained as 

 much as 3 per ct. potassium and .15 per ct. phosphorus. These 

 percentages are but little higher than potassium and phosphorus are 



