222 SOILS AND FERTILIZERS 



259. Use of Potash Fertilizers. - - Wood ashes or 

 Stassfurt salts should not be used in excessive amounts. 

 Not more than 300 pounds per acre should be applied 

 unless the soil is known to be markedly deficient in 

 potash, and previous tests indicate that larger amounts 

 are safe and advisable. Potash fertilizers should be 

 evenly spread and not allowed to come in direct con- 

 tact with plant roots, and should be used early in the 

 spring before seeding or before the crop has made 

 much growth. Wood ashes make an excellent top 

 dressing for grass lands, particularly where it is de- 

 sired to encourage the growth of clover. There are 

 but few crops or soils that are not greatly benefited 

 by a light application of wood ashes, and none should 

 ever be allowed to leach or waste about a farm. 



260. Joint Use of Lime and Potash. When a potash 

 fertilizer is used, a dressing of lime will frequently be 

 found beneficial. The potash undergoes fixation, and 

 when it is liberated there should be some basic material 

 as lime to take its place. Goessmann observed that 

 land manured for several years with potassium chlo- 

 ride finally produced sickly crops, but an application 

 of slaked lime restored a healthy appearance to suc- 

 ceeding crops. 67 If the soil is well stocked with lime, 

 its joint use with potash fertilizers is not necessary. 

 If it is acid, lime should be used to correct the acidity 

 before the potash is applied. The use of potash fer- 

 tilizers for special crops is discussed in Chapter X. 



