SOILS FERTILIZEKS. 225 



stated to be a complete monograph on progress in agronomic science and the 

 manufacture of fertilizers and a useful manual for practical agriculturists and 

 for school use. It treats of the subjects of nutrition of plants, the nature and 

 use of farm and green manures and commercial fertilizers, special fertilizers for 

 different kinds of crops, and -fertilizer legislation and trade. See also a previous 

 note (E. S. R., 22, p. 430). 



Tests of sodium nitrate on beets grown for seed gave inconclusive results. 



Nitrog'en content and yield of crops as affected by different nitrogenous 

 manures, B. L. Hartwell, H. J. Wheeler, and F. R. Pember {Rhode Island 

 Sta. Bui. l-'iS, PI). 291-305, pi. 1). — This bulletin records the results of ten years' 

 experiments on barley, Japanese millet, and oats grown in perforated, uncovered 

 ash cans, which were sunk in the ground nearly to their tops, to determine the 

 availability of nitrogen in starfish, bone, hoof meal, tankage, acid fish, horn 

 meal, and hen manure in comparison with dried blood and sodium nitrate. 



" Considering the entire ten-year period, all of the sources of organic nitrogen, 

 including the dried blood, proved to have about the same high degree of avail- 

 ability. Although the crops from nitrate of soda frequently contained larger 

 percentages of nitrogen, they were not much heavier than those from the organic 

 nitrogenous materials. 



" It is probable that the high availability of the organic manures was due in 

 part to the fact that a neutral i-eaction of the soil was practically maintained, 

 so that putrefaction and nitrification were favored. Inattention to this factor 

 has doubtless led to misconceptions regarding the availability of many sources 

 of organic nitrogen. 



" During the ten years, 5.9 gm. of nitrogen per pot were removed in the 

 crops from the soil to which no nitrogen was added in the manures. The sum 

 of the smaller applications per pot, namely, 5.2 gm., nearly equaled this, and 

 resulted in an increase in crops toward the close of the experiment of over 40 

 per cent in comparison with the crops secured where no nitrogen was added. 

 The sum of the larger applications of nitrogen was about 50 per cent greater 

 than that of the smaller ones; yet, even though this amount was apparently 

 insuflicient for the production of maximum crops, it failed to cause an average 

 increase of more than about 9 per cent in excess of that produced with the 

 smaller amount. The crops were, however, more nitrogenous so that the in- 

 crease in the total nitrogen of the crops was a third greater than the increase 

 in the crops themselves. 



" The cost of the niti'ogen alone, required to maintain a higher degree of 

 productivity than that represented by the yields from the check pots, was of 

 such magnitude as to emphasize strongly the desirability of adopting rotations 

 including legumes, grass, and hoed crops." 



The availability of certain unusual nitrogenous manures, B. L. Haetwell 

 and F. R. Pember {Rhode Island Sta. Bui. I ',2, pp. 275-288, pi. 1).—In view of 

 the high price of nitrogen in standard organic fertilizing material and the in- 

 centive thus afforded to use nitrogenous materials whose fertilizing value is 

 not well understood, pot experiments were made with a number of unusual 

 materials, including " nitrogenous manure," an acidulated mixture of hair, 

 felt, wool, and sometimes leather (nitrogen 7.41 per cent) ; " hide and skin 

 meal" (nitrogen 8.09 per cent); "tartar manure," dried residue of tartar 

 yeast (nitrogen 3.68 per cent) ; beet-refuse compound (nitrogen 6.24 per cent) ; 

 and calcium cyanamid (nitrogen 18.08 per cent) ; in comparison with dried 

 blood (13.62 per cent) and nitrate of soda (15.54 per cent). The cyanamid 

 was included in the experiment mainly to ascertain its toxic effect when applied 

 just before planting. Five crops, barley, millet, oats, millet, and oats, were 

 grown successively on the same soil, a stony loam, in the pots. 



