126 EXPEEIMENT STATION RECOKD. 



acid aiul potash over that originally present in the soil. Digestion with citric 

 acid showed very little alteration in the amounts of soluble constituents during 

 the experiment, the effect of liming being much less marked in this case than in 

 case of the water-soluble constituents. 



The examination of the soils after S mouths with reference to changes in the 

 nitrogen showed a larg(» increase in the proportion of nitrite nitrogen in the 

 limed soil. The total nitrogen as nitrite and nitrate increaseJ in all cases, 

 although the nitrate nitrogen remained almost stationary except in the clay 

 soil. The fact that there was no loss of the very soluble nitrites and nitrates 

 is taken to indicate that the decrease of water-soluble potash and phosi)horic 

 acid was not due to percolation through the walls of the pots so much as to 

 conversiou into less soluble forms. 



Experiments with lime and crushed limestone on a Pennsylvania clay loam 

 soil, W. Frear (Pen II. Dcpt. Ayr. Bid. l.j.'i, pp. 7'.9-.S'.j). — This article summarizes 

 briefly the results obtained in a series of experiments at the Pennsylvania Ex- 

 Ijeriment Station which have been continued since 1880. The results show in 

 brief that the use of burnt lime imder the conditions of these experiments, 

 namely, in excessive amounts on a soil in no particular need of lime, caused a 

 net decrease rather than a gain in production, whereas with carbonate of lime 

 there was a slight increase in yield, but entirely insufficient to pay the cost of 

 application. 



The relation between the effects of liming', and of nutrient solutions con- 

 taining different amounts of acid, upon the growth of certain cereals, B. li. 

 Hartwell and F. R. Pember {Rhode Island »S7o. Rpt. li)01, pp. 358-.iS0. pis-. 

 2). — Field experiments having shown that rye and barley are very differently 

 affected by liming, the water cultures with these crops here reported wei-e un- 

 dertaken to determine " whether varieties of plants which were most benefited 

 by liming were likewise most susceptible to injury by certain acids, when their 

 seedlings were grown in nutrient solutions possessing definite degrees of 

 acidity. . . . 



" The water-culture experiments showed that barley seedlings were not more 

 susceptible than rye seedlings to injury from acidified nutrient solutions, even 

 though the field results proved that barley I'eceived very much more benefit 

 than rye, from liming. 



" While recognizing the caution which should be exercised in drawing con- 

 clusions concerning growth in the soil, from results secured by solution cul- 

 tures, it seems certain, in searching for an explanation of the great differences 

 exhibited by different kinds of plants in respect to liming, that other chemical 

 properties of lime should be prominently studied along with its function as a 

 corrector of acidity, even when attention has been given to the plant-food 

 ingredients. 



"According to the method of experimentation employed, the growth of wheat, 

 rye, barley, and oat seedlings was not materially influenced by any degree of 

 alkalinity which is insufficient to cause precipitation from an ordinary nutrient 

 solution. 



*' The growth of these same seedlings, in nutrient solutions, was likewise 

 scarcely affected by an acidity e(pial to about -g^o^o" "i" '^'^'*- -^ depression in 

 green weight of about 20 per cent resulted when the acidity equalled ^^o"' ^"^^ 

 an increase in the acidity to about y/oo and j-r^-o, decreased the production of 

 green weight around 40 and 60 per cent, respectively. 



" The very marked property of the seedlings of rendering the nutrient solu- 

 tions alkaline was measured by titrations against standard acid at the end of 

 the final periods of growth. 



