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Page:Popular Science Monthly Volume 73.djvu/15

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there is much deleterious crowding and repressive rivalry among the natural mixtures of plants, but at the same time there seem to be associations that are mutually beneficial. No doubt man secures a great temporary advantage by isolating chosen plants and freeing them from competition, but this is clearly at some permanent disadvantage which is partially corrected by rotation, fertilizing and tilth. Can not a greater advantage be secured by a larger use of the combination method? It is clear that legumes and cereals are helpful associates in rotation and in some combinations. May not the principle be pushed much farther by the modern processes of selection and culture, so that legumes and cereals may be made more intimate companions in culture; so that, indeed, such helpful associates may replace weeds as the constant and spontaneous companions of the crops we cultivate? While kept in such subordination as to be servants of the chosen crop, may they not still aid effectively in covering and protecting the soil and thus guard against undue surface loss. Certainly much can be done by such congenial plants, used as fall, winter and spring crops, to cover the soil when specially exposed to wastage.

These and similar devices may be used to reduce the bare surfaces so much developed by present modes of cultivation, and may make it possible to cover permanently by profitable protecting crops the slopes where surface wash is most menacing.

But a critical question remains to be answered: Can such modes of soil-management and crop-selection be made to give reasonable profits? Before we can hope that the millions who till the soils will join effectively in a radical scheme of soil-conservation, it must be made to appear that the scheme will give reasonable returns at every large stage of its progress; must pay, let us say, in the long run of a lifetime. We may fairly assume that intelligent people will be guided by the total returns of a lifetime in lieu of beguilement by the ultra-quick returns of forced and wasteful cropping in total neglect of later results. It may be assumed that he who tills a farm from his twentieth to his sixtieth year will find more satisfaction in the summed profits of forty crops of increasing value, enhanced by the higher value of his land at the end, even though the margin above cost be no greater, than in the sum of forty crops of decreasing values with a debased land at the end. Our practical problem is, therefore, to so improve processes, to so increase intelligent management, and to so exalt the point of view, that every large step in the processes proposed shall give satisfactory returns for the labor involved. How far this is practicable just now, I must leave to those whose technical knowledge in the practical art of tillage fits them to answer; but it is clear that if such protective measures are not profitable now, they must soon become so; for, if the loss of soil proceeds at the present rate and the number of inhabitants