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FERTILIZERS FOR VEGETABLES 



duction of starch and sugar in vegetables and fruits. In 

 most of the experiments that have been made, no difference 

 has been found. In relation to potatoes, sulphate has, in 

 some cases, given larger yields, higher starch content, and 

 cleaner tubers of more uniform size, than muriate, but this 

 is far from being the rule. So far as we can now make a gen- 

 eral statement, little or no difference is usually found on lignt 

 soils, but on heavy or moist soils sulphate of potash will more 

 generally produce potatoes of better cooking quality. 



The importance of an abundance of available nitrogen, 

 phosphorus and potassium in the growing of vegetables muse 

 be obvious when we consider the important work which each 

 of these plant-food constituents performs. As we have pre- 

 viously stated, the most successful production of vegetablos 

 calls for early, rapid and continuous growth. To promote 

 such growth requires the use of considerable amounts of 

 soluble nitrogen and phosphorus. Though phosphorus is 

 used in much smaller amounts by plants than either nitrogen 

 or potassium, we must remember that its supply in most soils 

 is much less. Potassium is used in relatively large amounts 

 in the leafy portions of crops. Therefore, when the leaves 

 and stems of a crop form the marketable portion, the amount 

 of potassium taken from the soil is much greater than when 

 some other portion of the plant is sold. Generally speaking, 

 potassium usually needs to be applied rather generously on 

 light, sandy soils and also on soils rich in muck or peat. On 

 soils containing fair amounts of clay, much lighter applica- 

 tions often suffice, especially if the soil is kept well supplied 

 with calcium carbonate, and also when sodium nitrate is ex- 

 tensively used. 



other Soil Amendments. 



Before taking up the question of particular plant-food com- 

 pounds and the amounts to be used, a word should be said 

 about some particular points connected with soil management 

 in growing vegetables, such as organic matter, calcium com- 

 pounds or acidity, and some of the relations of the character 

 of soil to vegetable growing. 



It is desirable to keep in soils used in growing vegetables 

 large amounts of organic matter, especially for the purpose 



