Evening Republican, Volume 18, Number 133, Rensselaer, Jasper County, 6 June 1914 — LIMING OF THE SOIL [ARTICLE]

LIMING OF THE SOIL

By JOHN B. ABBOTT,

Department of

Soils and Crops, Purdue University Experiment Station. Purdue University Agricultural Extension.

The kind of- lime to use and the amount are matters of distinctly secondary importance. Essentially the same effect will be produced by 100 pounds of marl, ground shells, ground limestone or air slacked lime as by 75 pounds of hydrated lime or 56 pounds of fresh burned lime, and It makes very little difference which Is used. Choice should be based mainly on relative cost and purity, but may be influenced to a certain extent by the facts that burned lime and hydrated lime are more disagreeable to handle than the other forms and probably somewhat more exhaustive of the organic matter In the soil.

The question of real importance is whether to use lime at all er not The answer depends absolutely upon the chemical reaction of the soli- If the soil is basic or alkaline in reaction lime need not be used, but if the soil is acid lime Is needed badly. Acids and bases are exact opposites chemically, and when brought together as they are in the soil they combine and form chemically neutral, and generally harmless, compounds. This chemical combination goes on until all of the acid or all of the base is used up. Of course it is only seldom that the~ amounts of acid and base are just equal, so after the reaction Is complete there is some of one or the other left over. Whichever one is thus left unconibinert governs the character of the soil. If acid compounds are left over the soil is said to be "sour" or acid in reaction.

Investigation and experience have shown that the acid condition is very unfavorable to crop production. This Is particularly true of clover and alfalfa, which fall to develop root nodules in add soils, and in consequence soon sicken and die. In the case of rich soils these crops may survive in spite of acidity, but in such cases they draw their nitrogen from the soil just as other crops do instead of .taking a large part of it from the air, as they are capable of doing under more favorable conditions. Maintenance of a supply of nitrogen in the soil for the grain crops is dependent upon fixation of atmospheric nitrogen by legumes, so the failure of legumes to fix nitrogen is a serious matter. It means soil exhaustion. To correct this very unfavorable, condition the reaction of the soil must be changed from add to alkaline, and lime is the bafelc or alkaline material to use for that purpose. No other treatment whatever-Is practicable. The laws of chemistry are just as immutable as the law of gravity. Add soils contain an excess of acid compounds, and can be rendered alkaline only by adding basic or alkaline material enough to combine with all the acid compounds and have some left over. It makes little difference whether the amount left over be large or small — within reasonable limits—hence it makes little difference whether the application of lime be two tons to the acre or four, except that the smaller the application the sooner it will have to be repeated. Consistent success with Clover or alfalfa is proof that the soil does not need lime. Persistent failure of these crops is a good indication that it does. A simple confirmatory test may be made with blue litmus paper, which can'be purchased at any drug store. Break open a moist clod, Insert a strip of the blue litmus paper, press the soil firmly together again, and leave for ten to fifteen minutes. Pm nounced roddening Indicates aoiditv.