78 CROP GROWING AND CROP FEEDING. 



had a letter from an old and observant farmer in one of th most prosperous 

 agricultural sections of the State of Maryland, who deplored the fact that his 

 neighbors had used lime to such an extent that their lands were less pro- 

 ductive than formerly. He said that for over thirty years he had used noth- 

 ing on his farm but acid phosphate and clover, with an occasional dressing 

 of a moderate amount of lime to preserve the sweetness of the soil and to 

 enable it to grow large crops of clover. The result was that he made 40 

 bushels of wheat per acre where his neighbors grew less than formerly. Now, 

 in his application of acid phosphate every third year he applied in it 40 per 

 cent, of the sulphate of lime, and adding a small dressing of freshly slaked 

 lime every sixth year, he kept releasing the potash in his soil, and hence 

 needed only the phosphoric acid in his fertilizer. His red clay soil contains 

 an almost inexhaustible deposit of potash as an insoluble silicate, and the lime 

 gradually gives him the use of some of this. How long he can keep up 

 the productiveness of his land without adding potash will, of course, 

 depend on the amount his soil contains. The wise farmer will, however, 

 watch closely and stand ready to supply the deficiency as it occurs, but will 

 not waste money in the purchase of what he does not at present need. 



Limestone, from which lime is made, is an impure carbonate of lime, in 

 many instances being mixed with a large percentage of magnesia, making 

 what is called dolomite, or magnesian, limestone. As the magnesia is a use- 

 ful plant food this is not a bad mixture for most soils. Where pure lime is 

 wanted the purer the stone, even till it becomes marble, the better. Oyster 

 shells are used as a source of lime in the coast region, and they are a pure car- 

 bonate of lime, and when free from earthy impurities, make a very pure 

 lime. In some parts of the South lime is burned from the fossil shell rock 

 and contains a small percentage of phosphoric acid. One of the greatest of 

 the values of lime to the farmer is in enabling his soil to grow clover. It is 

 found that the constant growing of clover and the accumulation of organic 

 matter in the soil tends to create an acid condition. Under this condition, 

 the microbes that enable the clover plant to collect nitrogen do not thrive, 

 and the soil microbes that carry on the work of transforming the organic 

 nitrogen into nitrate will not exist. The farmer finds that he can no longer 

 grow clover with any success, for the land is "clover sick." This is generally 

 the result of an acid condition of the soil. Lime will correct this condition and 

 will usually cause the clover to grow luxuriantly. Most of the legumes are 

 lime-loving plants. The great success of alfalfa in the arid regions of the West 

 is largely due to the fact that the lime has not been washed out of the soil. In 

 the Eastern States no great success with alfalfa has ever been had except from 

 liming it. We visited a year or so ago the grass experiment farm of Peter 



