1588 Report of Farmers' Institutes 



time a crop is plowed under it produces acid. xVnj soil which is 

 characterized hy the absence of carbonates is in a condition to 

 become acid. As long as we keep in the soil the materials that 

 neutralize acidity, soil acidity is impossible. The most natural 

 neutralizing material is calcium carbonate, but caustic forms of 

 lime are often more economical to use in Xew York State. 



The students of soil chemistry have come to recognize the fact 

 that any chemical compound put on the soil may have a variety of 

 effects. J^itrate of soda put on to supply nitrogen, will undoubt- 

 edly do that, but it has many other effects besides. It will affect 

 the solubility of the insoluble compounds that are in the soil ; it 

 will modify the solubility of other plant materials put in, and it 

 may affect its physical properties. 



If large amounts of nitrate of soda are used for a long time, an 

 accumulation of sodium carbonate is likely to result. This attacks 

 the structure of the soil and the crumb formation is broken down. 

 Potassium carbonate and sodium carbonate will also have this 

 effect. It is possible for a soil to get into a very bad physical con- 

 dition by the excessive use of nitrate of soda. This is not a diffi- 

 cult condition to overcome, however, as it mav be counteracted bv 

 the use of acid phosphate or ammonium sulphate. It is, therefore, 

 good practice to use ammonium sulphate when nitrate of soda is 

 applied in large amounts. Soils have become acid through the con- 

 tinued use of ammonium sulphate. Land plaster will also over- 

 come to some extent the effect of sodium carbonate, changing the 

 sodium carbonate to calcium carbonate. 



The continued use of acid phosphate has made soils acid. This 

 can easily be overcome by the use of lime. Soils are not usuall\ 

 made acid as a result of the use of potash salts, due to the small 

 applications. 



The best method for making the litmus test is as follows: Take 

 an ordinary glass tumbler and into the bottom and next to the glass 

 ])laee a piece of blue litmus paper. Over the litmus paper fit a 

 piece of white blotting paper or filter paper, cut round, so as to 

 fit in comfortably tight. On top of the white blotting paper or 

 filter paper put the soil to be tested. Then pour on enough water 

 to wet the soil thoroughly so that the moisture will go down through 

 to the litmus paper. If the l)hie litmus paper is turned to a pinkish 



