Uthei' Pa'pers. 261 



out, whicli strictly speaking, is not true. It is only the exhaustion 

 of the accumulated jjlant food in the soil. It is not available, it 

 lies dormant and inert in the soil beneath. It, therefore, needs 

 deeper plowing and subsoiling, thorough cultivation and pulver- 

 izing. Then the plant food becomes available. The roots of the 

 plants come in contact with this food and a strong, vigorous growth 

 IS tlie result. It is a fact that a soil may contain enough plant 

 food to produce a thousand large crops, and yet the crops we obtain 

 from it will hardly pay for cultivation. The plant food is there, 

 but the plants cannot get at it. It is not in an available condition, 

 it is not soluble. A case is quoted by Professor Johnson, where a 

 soil contained, when analyzed to the deiDth of one foot, 46.52 per 

 cent, of nitrogen to the acre, but only sixty-three per cent, of 

 this was in an available condition. And this is equally true of 

 phosphoric acid potash and the other elements of plant food. No 

 matter how much plant food there may be in the soil the only 

 portion that is of any immediate value is the small amount that is 

 annually available for the growing crops. There are two kinds of 

 fertilizers, natural or artificial. Now anything that will furnish 

 this food, anything that will cause the soil to produce what the 

 climate of season is capable of producing, is a good fertilizer. 

 Nitrogen, phosphoric acid and potash are the most valuable in- 

 gredients in manure. 



How to keep up the fertility of our apple and peach orchards 

 is now becoming an important question and is attracting consider- 

 able attention. There are two methods generally recommended, 

 I dare not say generally practiced. The one is to keep the orchard 

 in bare fallow, the other to keep it in grass and top dress with 

 manure, and either eat the grass off with sheep and pigs, or else 

 mow it frequently and let the grass rot on the surface for mulch 

 and manure. This, of course, applies only to bearing orcliards. 

 When we apply manure to our orchards the ammonia phosphoric 

 acid potash are largely retained in the first few inches of surface 

 soil and the deeper roots get hold of only those portions which 

 leach through the upper layer of earth. Nitric acid, however, is 

 easily washed down into the subsoil and would soon reach all the 

 roots of the trees. I therefore recommend for orchards plenty of 

 barnyard manure, leached ashes and lime. My personal exper- 

 ience with fertilizers is rather limited but from the results I am en- 

 couraged to give them a still further trial. In the spring of 1882 

 I used two hundred pounds of dried blood from the packing house 

 iit the rate of about three hundred pounds per acre sowed broad- 



