HOW TO SUPPLY PLANT FOODS 



and dark, and when the new wood each season is less than a 

 foot long. 



Lack of potash and of lime is shown by sappy growth, by 

 many suckers, and by pale, tasteless, unripe fruit. Fruit trees 

 use less of phosphorus than of the other food elements 

 probably only one-fifth of the number of pounds and of the 

 value of it, as of nitrogen, and one-sixth, as of potash. Phos- 

 phorus goes into fruit, leaves and wood. Potash is the most 

 important of the elements. Potash and phosphorus are min- 

 eral materials, and have to be supplied in chemical form. Nitro- 

 gen is supplied best by legumes by the cover crops. 



Cover crops should be called "fertility crops," for, while 

 they are useful in preventing washing and leaching, cement- 

 ing and baking, and in the holding of moisture, their greatest 

 value lies in their power to add directly to the richness of the 

 soil. Some of the plants adapted to the purpose supply nitro- 

 gen, and all supply organic matter supply these materials 

 cheaper than they can be had from any other source. The 

 aim in sowing a cover crop is to plant it long enough before 

 killing frost to enable it to make a good, thick growth in the 

 fall. If the plant is one that winter-kills, this makes little dif- 

 ference; but, if it grows again in the spring, more vegetable 

 matter will be had before time to plow it down. 



The stalks, leaves and roots add several tons of organic 

 matter to the soil. This is placed right where it will do the 

 most good in the upper foot of soil, whether the crop is 

 plowed under or disked in. It does its work, as has been ex- 

 plained before, by improving the texture of the earth, by hold- 

 ing moisture, by making a home for bacteria, and by returning 

 to the soil the plant-foods which it gathered through its roots, 

 together with new nitrogen gathered by the leaves. 



All the legumes gather nitrogen from the air, and store it 

 in every fiber of the plant. One good clover, pea or vetch 

 crop will give your acre as much of this high-priced plant-food 

 as you will get in $20 worth of any commercial fertilizer. Le- 

 gumes use potash and phosphorus, of course, but they do not 

 waste it if they are left on the land they return it whence 

 it came. This is true of all cover-crop plants. The foods which 

 they consume are only loaned to them over winter. In the 

 spring all the materials come back for the use of the trees, 

 with added nitrogen in the case of legumes, and with pro- 

 tection and physical soil improvement from all kinds of cover 

 plants. 



A cover crop is sown in the latter part of the summer, when 

 trees have made their growth for the year, and when both 

 fruit and trees have begun to ripen. Newly sown plants take 

 up water in great amounts take it away from the trees. This 

 is the thing desired at this time, for tree growth needs a 

 check tl:en. But, still better, young plants require a great deal 

 of nitrogen, but comparatively less potash and phosphorus. 

 As the cover crop grows, it feeds largely on the nitrogen, less 

 on the other elements, leaving much potash and phosphorus 

 for the trees, just when they need them most. 



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