8 The Bulletin 



objection HAS BEEN GREATLY EXAGGERATED, AS EXPERI- 

 MENTS HAVE SHOWN. It has been demonstrated that in the pres- 

 ence of an abundance of calcium carbonate smaller percentages of nitro- 

 gen, phosphorus, and potassium compounds are generally required for 

 crop production than when calcium is deficient. The presence of cal- 

 cium carbonate is of especial value in preventing the formation of the 

 insoluble iron and aluminum phosphates." The above may help to 

 explain why very heavy applications of acid phosphate have been made 

 to certain North Carolina soils with relatively indifferent results. 



EFFECT OF CALCIUM CAKBONATE ON ACID PHOSPHATE IN THE SOIL 



WHEN THE PRESENCE OF IRON AND ALU.UINITM OXIDES 



ARE NOT TAKEN INTO THE CONSIDERATION 



A large number of our most eminent authorities on agricultural 

 science have found, by observation and experiment, that the presence 

 of lime carbonate in the soil exerts a most favorable action not only 

 on the natural phosphates, but also on those applied artificially in the 

 form of commercial fertilizers. Should lime carbonate produce a nega- 

 tive effect on the phosphates of the soil, rendering them insoluble and 

 unavailable to the plant, then a "lime country," instead of being a "rich 

 country," would be the poorest country imaginable. 



In E. S. R., Vol. 20, No. 2, Messrs. Guthrie and Cohen, in reporting 

 an experiment on the effect of lime on the various soil constituents, 

 state: "The amount of water soluble plant food, however, was larger 

 in .the limed than in the unlimed soil, but only in the sandy soil did 

 the liming increase the proportion of water soluble pliosj)horic acid 

 and potash over that originally present in the soil." 



In E. S. R., Vol. 26, No. 4, H. K. Vippond reports an experiment 

 testing the availability of phosphoric acid in the soil as follows : "The 

 general conclusion reached was that a fair amount of lime in the soil 

 assured a fair availability of phosphoric acid." 



In Bulletin No. 90 of the Tennessee Experiment Station, Dr. C. A. 

 Moores reports the results of a series of tests in the use of acid phos- 

 phate with and without lime, and in all cases and under varying condi- 

 tions there was a greater crop production from acid phosphate on limed 

 land than on land that was not limed. 



In E. S. R., Vol. 18, No. 7, Messrs. Wheeler and Adams, of the Rhode 

 Lsland Experiment Station, in reporting the tests of nine phosphates, 

 found, as a rule, that soluble phosphates were more I'lTcctivc on limed 

 than on unlimed soils. Lime, INSTEAD OF PROVING INJURI- 

 OUS IN CONNECTION WITH SOLUPLE PHOSPHATES, AS 

 IS OFTEN ALLEGED, PROVED DEC^JDFDLY HELPFUL IN 

 THE MAJORITY OF CASES, and even in many inshiiu'es .to plants 

 which were not particularly in need of liming." 



In 1900 the Rliodo Island Experiment Station concluded a series of 

 experiments in the u.sc of acid j)hosplKite i>n limed and unlimed soils 



