BOTANY. 1011 



The potassium phosphate increased growth, while the ferric phosphate 

 had some little influence in increasing growth, but in large quantities 

 it caused a change in the color of the leaves. 



The effect of the salts on the dry weight of the plants is shown, and 

 statements made relative to the effect of different quantities of each 

 salt, the optimum quantity for plant growth being sought. 



The summary statements in the paper must not be considered as gen- 

 eralizations, but to apply only under the conditions of the experiments. 



Concerning the nitrogen nutrition of plants, L. Richter (Landw. 

 Vers. Stat, 51 (1898), Xo. 2-3, pp. 221-241, pi. 1).— The author reports 

 an extensive series of experiments with peas, buckwheat, mustard, and 

 oats to study the effect of continual cropping upon the exhaustion of 

 the soil nitrogen. The pots in the experiment each contained 3,600 gm. 

 sand and 1,200 gm. garden soil, to which were added chemical fertili- 

 zers. In one series nitrogen in the form of calcium nitrate was added. 

 Series of sterilized and nonsterilized, inoculated and noninoculated 

 pots were arranged, and the results obtained with each of the three 

 successive crops are shown in tabular form. 



Photographic representations are made of average plants of the third 

 crop, from which it appears that only the leguminous plants were able 

 to utilize the free nitrogen of the air. An increase in the dry weight 

 and the nitrogen was noticeable in each succeeding crop of peas, while 

 with the nouleguminous plants there was a loss of each in proportion to 

 the decrease in assimilable nitrogen. There was an increase noticed in 

 the nitrogen in the soil in some cases where nouleguminous plants were 

 grown, which the author does not seem to explain. This increase was 

 slight for the first crop and increased with successive seedings. The 

 plants did not seem able to utilize the nitrogen so stored. Where com- 

 bined nitrogen in the form of calcium nitrate was added to the pots, in 

 every case a loss was noted in the nitrogen balance at the end of the 

 experiment. 



The accuracy of the experiments which showed a loss of nitrogen, 

 where that substance was given the plants in an assimilable form, was 

 further tested the succeeding season in experiments with oats and 

 similar results obtained. Pots containing no other plants were allowed 

 to become covered with various alg;e, and the nitrogen balance showed 

 gains whether the experiment was conducted in light or darkness. 

 Check pots without plants showed losses in every case. 



On the assimilation of nitric nitrogen and ammoniacal nitrogen 

 by higher plants, Maze (Compt. Bend. Acad. Sci. Paris, 127 (1808), Xo. 

 24, pp. 1031-1033).— The author conducted a series of experiments on 

 the germination of peas, maize, and vetches grown in nutritive solu- 

 tions to which were added various amounts of nitrate of soda or sul- 

 phate of ammonia, to ascertain whether these plants possess the ability 

 of assimilating ammoniacal nitrogen. A tabular report is given of the 

 experiments with maize in which it is shown that ammonia can be 

 absorbed and assimilated by the higher plants. 

 20776— No. 11 2 



