121 



cartlicnware pots i)rovi(le(l witli airangoinents for aJTatiou and the 

 collection of drainage water. In each pot were placed 22 kg. of soil 

 containing 22.41 grams of nitrogen, to \vlii(;li were added dried blood 

 containing ().r)l gram of nitrogen, and snli)hate of ammonia containing 

 1 gram of nitrogen, making altogether 23.98 gramsof nitrogen. Calcium 

 sulphate and inUnral phosphate were also added. The pots were divided 

 into three lots of two each, designated A, a; Jj,i; C, c. The experiment 

 continued two years, from March, 1888, to March, 1890. Grass was 

 sown and harvested each season in B and b and red clover in C and c. 

 In i)ots A and a no plants were allowed to grow. Determinations were 

 made of nitrogen as ammonia and nitric acid in the drainage waters of 

 each season; and of the nitrogen in the soil and fertilizers at the begin- 

 ning of the experiment in the crop of each season, and in the soil at the 

 end of the experiment. The results so far as the gain of nitrogen by 

 the soils is concerned, are recai)itulated in the table herewith, in which 

 averages of duplicate trials are given. The nitrogen gained of course 

 came from the air. 



Nitrogen statistics. 



Nitrogen— 



Witlioiit Witli 



plaiitB, I grass, av- 

 average or prngo of 

 A and a. 1 B aud b. 



Keniaining in .soil at end of oxpnimcnt* . .. 



Ucmovod l>y crops of two seiisons 



lloiuovfd in drainage water of two seasons. 



Total 



Amount in soil at beginning of experiment 



fJro.ss gain by soil and crops , 



Loss ill drai::ago 



Not gain l>y soil and crops .., 



lifiiiovod in crops 



.Net gain by soil 



Grams. 

 24.20 



Qrams. 



26.95 



1.47 



0.U8 



28.50 

 23.98 

 i.52 

 0.08 

 4.44 

 1.47 

 2.97 



WiUi 



clover, 



average 



ofCandc. 



Qrams. 

 30.80 

 4.20 

 0.20 



35.20 



23.98 



11.22 



0.20 



11.02 



4.20 



6.82 



* Including nitrogen of roots of plants. 



The surface area of the soil in each pot was 7,54 square dm. Estimated 

 per hectare, the net gain of nitrogen by the soil after the removal of the 

 crops would be, without plants 29 kg., with grass 394 kg., and with 

 clover 904 kg. ; or per acre without ])lants 2G.1 pounds, with grass 354.0 

 pounds, and witli clover 813.0 pounds. 



As results of this investigation it appears that, (1) the loss of 

 ammonia hy drainage was inconsiderable in the soil either with or 

 without plants; (2) the loss of nitric acid was quite large, especially in 

 the soil without vegetation (taking the loss of nitric acid in the experi- 

 ment with grass as 1, with clover it was 3, and without plants 17) ; 

 (3) in the second year the soil without plants lost less nitric acid, and 

 the soils with crops more than in the first year; (4) the crops of the 

 second year were smaller than those of the first year, notwithstanding 

 the greater apparent nitrification and thegaiu iu nitrogen. — [W. O. A.] 



