618 EXPERIMENT STATION RECORD. 



The bulletin also contains the results of a study of the influence of chlorids 

 upon the accuracy of the determination of nitric nitrogen by the King method 

 and a study of the composition of the irrigation water used on the various 

 plats. Some of the plats were uncropped, others were planted to alfalfa, sugar 

 beets, potatoes, corn, and oats. No attempt is made to draw definite conclu- 

 sions from the data, but some facts of importance are brought out. 



It was found that nitric nitrogen tends to accumulate in the lower sections 

 of the soil during winter and spring and that the application of irrigation water 

 carries the nitric nitrogen to a large extent below the reach of the roots of the 

 plants. There was an especially low concentration of nitric nitrogen in land 

 bearing alfalfa. Cultivated fallow soil contained more nitric nitrogen at the 

 end of the irrigation season than uncultivated fallow, but in the fall there was 

 little difference in the nitric nitrogen content in the cultivated and unculti- 

 vated plats. The average amount of nitric nitrogen at the close of the spring 

 Iieriod during three years was 142 lbs. per acre in soil on which corn was 

 grown, 98 lbs. per acre on potato land, 27 lbs. per acre on alfalfa land, and 365 

 lbs. on fallow land. 



" In the corn land the average before irrigation was 144 lbs. per acre, while 

 after irrigation it was 104 lbs. per acre ; in potato land the average before 

 irrigation was 110 lbs. per acre, while after irrigation it was 94 lbs. In the 

 alfalfa laud before irrigation the average was 34 lbs., while after irrigation it 

 was 38 lbs.; in the fallow plats the average was 174 lbs. before irrigation, and 

 130 lbs. after irrigation. During the fall period we have the same result; in 

 the corn land there were 63 lbs. per acre; in the alfalfa land there were 32 

 lbs. per acre; while in the fallow land there were 151 lbs. per acre," 



The figures show that the different plants make very different demands upon 

 the nitric nitrogen of the soil. There was a steady decrease in the nitric 

 nitrogen content of potato and corn land from period to period, but that of 

 alfalfa and fallow land remained nearly constant. The nitric nitrogen dis- 

 appeared rapidly from oat land during the last few weeks of the growth of the 

 plant. 



"The nature of the season apparently has a marked effect on the results 

 obtained. In 1905 the application of irrigating water caused a decrease in the 

 nitric nitrogen content of soil on which potatoes were growing, while in 1906 

 exactly the opposite was true, there being an increase in every case." 



Org'anic nitrog'enous compounds in peat soils, S. L. JoDipi {Michigan Sta. 

 Tech. Bui. -'/, in). 2S, fig. 1). — The nitrogenous decomposition products which 

 have been discovered and identified by earlier investigators are enumerated 

 and the details of a study by the author of different samples of Michigan peat 

 by methods essentially the same as those ordinarily employed in the chemical 

 study of protein compounds are reported and form the basis of the following 

 conclusions : 



" There are no nitrates in the types of Michigan peat soil examined. 



" The amount of ammonia is small, ranging from a few thousandths to a 

 few hundredths of one per cent, this representing the nitrogen available im- 

 mediately as plant food. In the case of the brown peat, the amount of 

 ammonia is sufficient to meet the needs of one or two crops, as is evident from 

 the following: There are in an acre-foot in round numbers 170 tons of oven- 

 dried peat, with 0.041 per cent ammoniacal nitrogen, making 0.0697 ton or 

 139.4 lbs. nitrogen as ammonia. 



" Practically all the nitrogen in the peat is of organic nature. 



" The bulk of the organic nitrogen, namely, from two-thirds to three-quarters 

 calculated upon the nitrogen in solution, by boiling with acids, is present in 



