202 ANNUAL, REPORT O'S' THE Off. Doc. 



large areas it has nearly ceased to grow at all. This is a most 

 serious matter. The legumes are our cheapest dependence for nitro- 

 gen, a costly essential element of plant food when purchased out- 

 right, and one that is very apt to be limiting crop yields by its 

 scarcity. Then, too, the clovers are specially valuable in furnishing 

 organic matter that aids in freeing inert material in the soil and 

 conserving moisture. Good tilth and resultant productiveness are 

 dependent upon organic matter in the soil, and the legumes are in- 

 valuable. These clover failures, excepting the ones in occasional 

 years that are due to insect depredations or disease, are confined 

 chiefly to these very large areas of our country in which the soils 

 contain a low percentage of lime. We find an exception in the case 

 of some soils once fairly rich in lime, whose supply of soluble lime 

 has leaked out and left them distinctly acid. The prevalence of 

 soil acidity in the lands outside of the limestone areas is amazing, 

 and there is reason to believe that these areas increase as land grows 

 older. The litmus paper test, and especially in the hands of the inex- 

 perienced, may rightly be discredited by scientists, but in Ohio, 

 where laboratory tests numbered by hundreds have shown that soil 

 acidity is widespread in the state, it is a fact that an actual lime 

 requirement often is found in a soil that does not show evidence of 

 acidity by the litmus paper test, and I believe reports from farmers 

 would show that this test rarely, if ever, has led to applications of 

 lime where they were not beneficial. Soil acidity, due to a lack of 

 a base to unite with free acids in the soil, is widespread outside of 

 true limestone belts of land, and this acidity is hostile to clover, and 

 limits most crop yields directly and indirectly. 

 Let us restate our four seemingly isolated facts tersely: 



1. A region like the blue grass section of Kentucky, whose soil owes 



its peculiar excellence to a limestone rich in phosphorus, bears 

 evidence of special favors from nature's hand. 



2. Scientists and farmers secure more marked results, as a rule, 



from applications of phosphoric acid than from any other one 

 element. Nature's store of this element in the land usually is 

 limited in amount and often tightly held. 



3. A lim.estone country is a rich country. 



4. Soil acidity Is very prevalent outside of limestone areas, and it 

 is limiting the production of clover and, directly or indirectly, 

 of all other crops. 



Dr. Hilgard, than whom I know no more competent authority upon 

 the subject of "soils,' terms carbonate of lime — pulverized lime- 

 stone — ^'a dominant factor" in soil productiveness. It improves tilth 

 conditions, neutralizes acids, favors clover, renders phosphoric acid 

 and potash available, directly or indirectly, and promotes the con- 

 version of vegetable matter into htimiis. He finds that "lower per- 

 centages of potash, phosphoric acid and nitrogen are adetpiate when 

 a large proportion of lime carbonate is present," Now, if we take 

 this statem.ent in connection with our second fact that phosphoric 

 acid is the limiting element of plant food in immense arens of our 

 eastern land, we may see how peculiarly blessed is that region whose 

 soil comes from a phosphatic limestone. It has the phosphoric acid, 

 it has the lime to favor bacterial action and promote clover growth 



