WATER SOILS. 



537 



thron|j;li was very great, the iiu-rease for tlic iiiixcd soil licinjf 84.5 per cent, the soil 

 losinjj; more nitrates tluin was formed ihiriiij,' tlie period. As in tlie previous year, 

 the poorer soil lost a smaller percentage of nitrates than the better soils. 



Calculating the results for the 2 years to kilograms per hectare, the following 

 data are obtained : 



Nitric nitrogen mixhrd aitt of one hectare of different xoilx. 



In 1896 an experiment was also made to compare the nitrifying capatdty of the 

 soil No. 1 and its accompanying subsoil. The samples were taken as follows: First, 

 the soil layer was cut out by a cylinder, then the opening was enlarged, and a layer 

 of subsoil was removed by means of another cylinder. Both cylinders were fixed 

 in th<; ground in the way described above. The experiment was begun at tlie end of 

 June and finished at the end of October. During that period the nitrate contents in 

 the water percolated through a kilogram of the soil was for the soil 59.95 mg., for the 

 subsoil 9.04 mg. 



The author also carried out in 1896 a series of experiments in which various plants 

 were cultivated on the soil. The cylinders used in these experiments were of a 

 wider diameter, viz, 20 cm. One cylinder remained without plants, for control. 

 In 3 others were placed germinated seeds of oats, barley, and black vetch. Of the 

 15 seeds sown originally in each cylinder only 10, the strongest, were allowed to 

 develop. The experiments were begun June 15 and were discontinued September 

 25 on account of cold weather, although the oats and Ijarley had only reached the 

 milk stage and the vetches, though of normal size, were still green. 



As was to l)e expected, the control soil allowed the largest quantities of water 

 to percolate (1,402 cc, containing 373.7 mg. of nitric nitrogen per liter). The least 

 amount of water percolated through the soil under oats (467 cc, containing 6.1 mg. 

 of nitric nitrogen per liter), which agrees with the experiments of various inves- 

 tigators (Haberlandt, Hellriegel, Sorauer, etc.), showing oats to be a plant consum- 

 ing large quantities of water per unit of dry matter as compared with other cereals. 

 Oats also consumed the largest amount of nitrates, then follows barley, under which 

 the percolation was 534 cc. of water, containing 6.2 mg. of nitric nitrogen per liter, 

 and lastly, vetches, under which the percolation was 616 cc, containing 103.2 mg. of 

 nitric nitrogen per liter. 



The results indicate that the amount of nitric nitrogen lost by soils covered with 

 plants is inconsiderable. — p. fike.man. 



The humidity of the soil and denitrification, E. Giustini.xni {An)i. Agron.,27 

 {1901), Xo. 6, pp. 262-285, Jig. 1). — .\n account is here given of 3 series of experi- 

 ments to test the influence upon nitrification and denitrification of (1) temperature, 

 in a licjuid medium; (2) proportion of water, in an artificial solid medium; and (3) 

 humidity in the sf)il. In the earlier exiteriments of the first series the medium used 

 for oh.-ervations iin nitrification was made up as follows: .Vmmoniiuii sulphate 94.5 

 mg., potassium i)hosphate 20 mg., calcium carbonate I gm., water 100 cc; that used 



