FIELD CROPS. 835 



hui boyond this point no strcniitlKMiiiii;; nction was obsorvod. Rni)eriiliosi)ii!it(>s 

 had the greater iiitluenc-o on tlie rednclion of the cell Jnnien and Thomas slat; on 

 the thicl-:enin;:r of the cell wall, but no ;:,i('at difference in the densily of th(> 

 stems as resnltinf? from the nse of these snl)stances was noticeable. 



The application of nitrogen, on the other hand, reduced the thickness of the 

 cell wall and enlarged the cell lumen. This effect was most apparent in the 

 pith cells, to a lesser extent in the bast cells, and only to a small degree in the 

 epidermal cells. 



The nse of potash as a fertilizer seemed to have no definite effect on oats, 

 but in the case of the grasses, esiiecially the French rye grass, its effect was 

 weakening, as shown by the reduced thickness of the cell wall and the in- 

 creased size of the lumen. Xo difference in effect was observed when kainit 

 or 40 per cent potash salt was used. 



The influence of lime was the same as that of nitrogen but not so marked. 

 No weakened condition of the stem could be determined, because the stems 

 of the plants heavily supplied with lime did not attain the proper size. 



The influence of the different fertiliziiig substances varied between the 

 wider limits in the case of thick cell walls and wide Inmina than in the ease 

 of thin cell walls and narrow lumina. The complete normal api)lication of ferti- 

 lizers was of greater advantage to the cell structure in the plants than the com- 

 plete heavy applications. 



The influence of nitrogenous, phosphatic, and potassic fertilizers upon 

 the percentage of nitrogen and mineral constituents of the oat plant, M. H. 

 PiNGREE {Pcniifiylvama Sta. Rpt. 1906, pi). 7/3-53).— The composition of oat 

 crops grown in 1!M>4 was studied to determine the influence of fertilizer con- 

 stituents on the composition of the plants, the nitrogenous and ash constituents 

 of the crops being i>articularly considered. The fertilizer applications consisted 

 of dried blood, dissolved boneblack, and muriate of potash and were in quanti- 

 ties supplying 24 or 48 lbs. of nitrogen, 48 lbs. of phosphoric acid, and 100 lbs. 

 of potash per acre. Nitrogen and potash alone applied to the preceding corn 

 crop produced but trifling gains by their residual effects upon the oats, while 

 phosphoric acid alone and a complete application produced gains of approxi- 

 mately 2.5 and GO per cent, resjiectively, over the yields given by the unfertilized 

 land. 



It was found that when the mineral fertilizers were associated with nitrogen 

 a larger absorption of ash materials from the soil per unit weight of crop pro- 

 duced took place than where the land had been cropjied for years without any 

 manurial treatment, and that where dried blood was used alone there was a 

 lai'ger production of crop \)vv unit of ash taken up than widi any other treat- 

 ment. Where nitrogen was aiM'lied alone more was taken up per unit of dry 

 matter formed than in any other case. The jiroportion was distinctly less from 

 the crop on the unfertilized i)lat, and still lower where potash alone was used. 

 Where phosphoric acid was used even in a comi)lete fertilizer the proportion of 

 nitrogen was greatly dejtressed, so that in this soil the phosi)horic acid promoted 

 the highest economy in the use of nitrogen for tlie production of the organic sub- 

 stances in the oat plant. There was a smaller proi)ortion of nonalbuminoid 

 nitrogen where nitrogen was ai)plied as a fertilizer with or without phosphoric 

 acid than where no nitrogen was applied, except in the case of the potash 

 manuring. The differences in composition are not regarded as sufiicientl.v pro- 

 nounced to suggest important differences in physiological activity under tlie 

 several systems of fertilization. 



In studying the composition of ash it was fonnd that wher(> nun-iate of potash 

 was used alone there was a large increase in the proi)ortion of potash in the ash 

 of tire straw and a very distinct increase in that of the grain. Where muriate 



