the solution of this problem. The profitable use of purchased manures must be limited to particular localities and special conditions of production, and they can not be made available to any extent as the staple source of fertility in general farm practice, as the markets of the world could supply the wants of but a very small proportion of the farms of the country.
Improved breeds of animals, and improved plants and seeds, in great variety, especially adapted to particular purposes, can now be obtained on every farm., and the rapid development of the mechanic arts has provided the most perfect implements and machines for economizing labor in every process. These lines of progress furnish important contributions to the means of profitable production, which the farmers of the country can not fail to appreciate. There remains, however, an extended field that is practically unworked, in which original investigations are needed to place our system of agriculture in full harmony with the requirements of the age.
From a practical standpoint, and as offering the most probable means of substantial progress, under present conditions of production, the subject of paramount importance to the farmer, and which should, therefore, receive a prominent place in a course of instruction in practical agriculture, is the utilization of farm residues of all kinds, with their available stores of the elements of fertility. Among these, barn-yard manure, from its obvious direct relations to the economics of production, should receive the share of attention its importance demands; but it must not, by any means, be looked upon as the only residue of the farm of economic interest. In a consistent system of practice, these residues must be made an efficient part of the circulating capital of the farm, and converted as rapidly as practicable, and with the least possible waste, into products of marketable value.
From the complex phenomena presented in the nutrition of plants and soil metabolism, the best methods for utilizing these residues can not be formulated in specific rules of practice that are of universal application. On every farm special conditions will be found which require intelligence and judgment in the application of general principles; and opportunities will be afforded, in each particular case, for the adjustment and balancing of the many contributions of science to meet the practical demands that arise from the varying combination of details presented in a wide range of topics, including the amelioration of soils by drainage and thorough tillage, the judicious arrangement of a succession of crops that will provide for a suitable supply of food for the animals of the farm, and the profitable appropriation of every element of fertility as soon as it is made available for the purposes of plant-growth; together with the economic conversion of
