408 ANNUAL REPORT OF TH(E Off. Doc. 



jnents upon the subject at the Pennsylvania Experiment Station 

 might well be presented at this time. 



Permit me at the outstart to present a brief statement of the 

 present practice in Pennsylvania and to note some of the claims 

 made by advocates of the two agents to be compared. 



Pennsylvania is richly supplied with limestone, in strata readily 

 accessible in the eastern counties, less easily reached in the western 

 and northwestern counties and entirely lacking in the exposed 

 strata of the northern and the extreme western parts of the Com- 

 monwealth. The use of lime, as shown by a careful inquiry made 

 several years ago, is extensively practiced by the majority of Penn- 

 sylvania farmers, es^pecially by those whose lands are clays or 

 heavy loams. Even in communities where, for a time, the intro 

 duction of commercial fertilizers led to the abandonment of liming, 

 the occasional use of lime has again come into vogue as a valuable 

 means of controlling the conditions of crop production. The use 

 of carbonate of lime, except as it has been applied in the form of 

 w^ood ashes to the orchards and gardens on the stony hillsides of 

 our northern counties, has on the other hand, been very limited. 



The general consensus of opinion, based upon the extensive local 

 experience in the practice of liming, is, that lime is an excellent agent 

 for the maintenance of good tilth on heavy lands; that, when prop- 

 erly used, it greatly increases the crops produced, and leads to no ob- 

 servable deterioration of lands of strong character; and that it is a 

 specific for the treatment of our soils. There are many communities, 

 however, where the old saying, 'Lime enriches the father, but im- 

 poverishes the son,' is frequently heard, especially with reference to 

 farms on which care has not been taken to maintain the humus and 

 nitrogen supplies by careful husbanding of the straw and manure, 

 and by the skillful use of green manuring. The need for the exer- 

 cise of caution in liming light lauds, lest they become OA'er alkaline 

 or be injured in texture, is quite generally recognized. 



The advocates of the use of crushed limestone and other carbon- 

 ates of lime, in place of lime (caustic or slacked lime), claim that the 

 carbonate performs practically all of the functions of lime in the 

 soil and should be preferred laecause it is the compound in which 

 nature furnishes this valuable alkaline earth. Lime is said, by 

 them, to work too rapidly and therefore wastefully, especially in the 

 destruction of humus and the conversion of the insoluble stores of 

 nitrogen into soluble forms that, because present in excess, produce 

 stem and leaf out of proportion to grain, and that leach away in 

 drainage waters before the crops can utilize them. Lime is further 

 said on the basis of many laboratory observations, to retard the de- 

 velopment of certain valuable soil bacteria, especially those that 

 gradually convert the slightly available humus nitrogen into highly 

 available nitrates; whereas, carbonate of lime is declared to be 

 always helpful, rather than prejudicial to the best development 0/ 

 these little friends of the tiller of the soil. 



The results to be considered shed some light upon a number of 

 points in the controversy. The field experiments included from a 

 part of the general fertilizer experiments begun at State College in 

 1880 and still in progress — the longest continued series of fertilizer 

 experiments in America. 



