FERTILIZERS IN FRUIT GROWING 123 



the cultivator, and to have the soil above them lightened 

 to let in air, so that, by microbe action, their nitrogen may- 

 take the form of nitrate, and go to feed the trees. 



Sixth : Does it pay to practice green manuring with rye 

 or with crimson clover? Sometimes, and then again, some- 

 times not. Think first what green manuring does — that is 

 book farming ; and then think whether your land needs 

 that thing done — that is practical farming. Either crop 

 gets a start in midsummer or early fall. Now before clover 

 or rye do much of anything above ground, they send out 

 and down a very large root system below ground. While 

 the crop looks as though it were standing still for several 

 weeks, it is growing tremendously below ground, and reach- 

 ing out and laying hold of all the available food that it 

 can get. It takes very little moisture out of the surface 

 soil in the fall of the year, but takes up available plant- 

 food rapidly. If the crop is clover, and if the soil is not 

 rich in available nitrogen, — and it is not likely to be, — con- 

 siderable nitrogen may be taken out of the air and fixed 

 by the clover for its use. When spring comes, assuming 

 that the crop is not winter-killed, a rapid growth begins 

 above ground. The green crop still draws some food from 

 the soil, and as its foliage increases, pumps water also out 

 of the soil at a pretty rapid rate. This goes on until the 

 crop is turned under. Then decay begins, going on much 

 more quickly in clover than in a grain crop, and gradually 

 the plant-food of this green mass is turned over to the 

 growing trees. 



How soon the matter of a green crop becomes available 

 to plants, after plowing under, we cannot tell. It is not, 

 probably, very prompt in its action. By July, we believe 

 our fruit trees have a larger amount of nitrogen and 

 mineral plant-food in their leaves than in any other 

 month. From then on, they are passing it back into this 

 growing wood. Their greatest demand on the plant-food 

 of the soil has been met for the year. It is generally 

 believed, too, that a large supply of soluble plant-food in 

 the soil, later in the season, may stimulate growth too 

 much, and leave too little time for the wood to ripen and 

 harden up before winter. This is a point where careful 



