HORTICULTURE 47 



gous diseases. In truth, they and lime have just the opposite tendency. 



Special care, then, need only be exercised in the application of 

 nitrogen. The wood and leaf growth, as has already been pointed 

 out, will show whether sufficient nitrogen is being supplied or not, 

 and any excessive growth of leaf or twig will be conclusive evidence 

 that too large a quantity has been used. Such a mistake in a young 

 orchard may be readily remedied by planting to corn and removing 

 both the corn and fodder, and in the case of large trees that seem to 

 have been overfed with nitrogen, seed to timothy, removing as hay 

 the crops, and by one or the other of these means the danger is 

 quickly removed. The utmost care, however, should be taken not to 

 carry this depleting process too far. It is like bleeding a patient for 

 some malady a most excellent thing to do when the patient really 

 requires to be bled, but not a good thing if the bleeding process is 

 carried too far. 



This cropping under all circumstances is a great temptation, as 

 it is reducing the expenses of handling and giving an additional re- 

 turn from the land, but if carried to the extent of depleting the soil 

 and no effort be made to restore the fertility thus removed, the small 

 return obtained from the farm crop will be much more than lost in 

 the reduced vigor of the orchard and the diminishing crops of fruit. 

 As has already been pointed out, it is especially bad policy to have 

 the land alternately rich and poor. Better trees and better "fruit will 

 be obtained by a consistent policy of one side of the proposition or 

 the other, and rather a somewhat underfed tree, existing under uni- 

 form conditions, than one that is this year underfed and next year 

 overfed, or that is alternately rich and poor. 



Application of Commercial Fertilizers. On mature bearing 

 orchards that are occupying the entire ground, it is quite as well to 

 make the application broadcast and in the spring, immediately 

 before the first cultivation, letting the tillage given mix the fertilizer 

 with the soil. In the case of barnyard manure, it is possible and 

 advisable to make the application in the autumn, after the ground 

 is firm, say, from the first of November on, unless the land be very 

 steep so that there will be serious loss from surface washing. The 

 material would then be incorporated with the soil by the early cul- 

 tivation, just as in the case of the commercial fertilizer. (Mo. E. S. 

 Cir. 22.) 



HUMUS. 



While always nitrogen, potash, and phosphorus are the ele- 

 ments most needed in the soil, a compound known commonly as 

 humus, although not in itself a plant food, is so useful in improving 

 the physical condition of the soil that it should be mentioned among 

 the fertilizers. This material is the result of the decay of vegetable 

 matter. It is nearly analogous to charcoal in its qualities of absorb- 

 ing and holding gases and moisture. In the soil humus prevents 

 washing and keeps it open and porous, and by its own decay sets 

 free acids and perhaps other compounds that assist in making avail- 

 able plant food in the soil. It is the presence of this material ^ in 

 stable manure that probably largely accounts for its superior action 



