484 ANNUAL REPORT OF THE Off. Doc. 



methods he can greatly assist the soil in absorbing the maximum 

 amount of that which does fall and at the same time reduce the loss 

 from surface washing; and further, by the establishment of a dust 

 mulch he can in a large measure succeed in holding this moisture 

 in the subsoil for the use of the crop in case of drought. 



LIMING 



As a means of correcting soil acidity, and as an aid in improving 

 the physical condition of many soils, we have yet to find a substance 

 that is more eiflcient or economical than ordinary builders' lime. 

 When lime in this form is applied to a rather heavy clay soil it tends 

 to flocculate the fine clay particles by cementing them together into 

 small granules thus making the soil more easily tilled and less liable 

 to bake and crack. In the case of a clay soil, this treatment serves 

 to render the soil more open and porous, thus permitting a freer 

 admission of air and allowing the water to percolate through it 

 more readily. In this sense we can readily see that on such soils lime 

 becomes an important adjunct to thorough drainage. On sandy 

 soils, however, lime has an opposite eflect. Such soils are frequently 

 benefited by being rendered more compact, and hence have a ten- 

 dency to become less leachy in character and to be more retentive 

 of moisture. It should be the aim to increase the organic matter in 

 such soils by the use of stable manure or by the occasional plowing 

 under of green crops. 



When viewed in the light of present experimental evidence, by 

 far the more important reason for applying lime to the soil is for 

 the purpose of counteracting the evil effects of free acids which may 

 be present. When the remains of plants undergo decay upon soils 

 deficient in carbonate of lime and magnesia, acid or sour humus is 

 liable to be produced which is a condition particularly obnoxious to 

 most agricultural plants. Such a condition is especially likely to 

 occur when heavy crops of green manure are plowed down, particu 

 larly in hot weather. In such cases liming is an effectual and prob 

 ably the most economical remedy. 



Our experiments on Ohio soils have been shown conclusively that 

 where an application of plant food is required some form of available 

 phosphorous must receive first consideration; but where soluble 

 phosphates are applied to soils deficient in lime and magnesia the 

 phosphoric acid combines with the iron and alumina of the soil to 

 form compounds that are not readily utilized by plants. If, however, 

 the soil be fairly well supplied with lime and magnesia this transfor- 

 mation is retarded so that the plant is afforded an opportunity to 

 utilize much of the phosphoric acid before it becomes unassimilable, 

 the effect of the lime in this case being to assist in maintaining fresh 

 applications of phosphoric acid for a considerable time in a more 

 available form. 



In many parts of Ohio, and especially throughout the entire eastern 

 half of the state, it is becoming increasingly difficult to get a good 

 stand of clover where no lime has been applied. On soils which have 

 received a dressing of lime, however, clover will grow luxuriantly 

 even though it refused to grow before the lime was applied. I 

 would say, therefore, especially to those who have trouble in secur- 

 ing satisfactory crops of clover, that they might do well to investigate 

 this question of applying lime to the soil as I should expect much 

 benefit from its use in cases similar to those which I have indicated. 



