SUMMARY

All the tests here cited indicate a marked improvement in the growth of alfalfa from applications of acid phosphate. As between the 16 per cent and the 44 per cent acid phosphate there seems to be little preference, so far as benefit to the alfalfa is concerned, provided equivalent quantities of phosphoric acid are applied. This being the case, it would appear that the farmer should use whichever form is the cheaper, based upon the relative proportions of this element.

Barnyard manure showed some benefit but not enough to justify paying much for it, as the cost of hauling and applying is considerable.

Neither gypsum nor sulphur had an appreciable effect on the yields of alfalfa.

In preliminary tests plats receiving applications of acid phosphate have yielded appreciably more seed than the accompanying checks.

This bulletin is a contribution from

Office of Western Irrigation Agriculture. C. S. SCOFIELD, Senior Agriculturist

ADDITIONAL COPIES

OF THIS PUBLICATION MAY BE PROCURED FROM
THE SUPERINTENDENT OF DOCUMENTS
GOVERNMENT PRINTING OFFICE
WASHINGTON, D. C.
AT

5 CENTS PER COPY

UNITED STATES DEPARTMENT OF AGRICULTURE

DEPARTMENT BULLETIN No. 1419

Washington, D. C.

October, 1926

FACTORS AND PROBLEMS IN THE SELECTION OF PEAT LANDS FOR

DIFFERENT USES

By ALFRED P. DACHNOWSKI, Associate Physiologist, Office of Soil Bacteriology, Bureau of Plant Industry

It is estimated that approximately 79,000,000 of the 113,537,000 acres of wet land in the United States are of potential economic importance. The question whether the utilization of these peat lands is economically practicable is of special interest in the States bordering the Great Lakes and those on the Gulf Coastal Plain, and the rest of the country, concerned with the growing needs of a growing population, is showing an increasing interest in the problem.

For an economically sound solution of the problem, agriculture and other industry must have a fuller knowledge of the nature of the peat lands and must deal with them according to that knowledge. It is essential that the problem be seen as a whole, or at least broadly, sothat the relationship among the various conditions and factors which must be coordinated and controlled in the future utilization of the peat lands may be understood.

Just what type of peat area shall be used is often more important than the choice of the surface material. It is equally clear that in: any particular case the selection depends upon several factors, among which the general economic considerations taken int. ccount are frequently only the more obvious ones. On the oth hand, the profile features of the peat area, the stage of disintegration of the

The acreage of peat land was much larger at an earlier time, but with the settlement of the States many extensive areas of shallow peat that were long under cultivation have now disappeared. Only blackcolored mineral soils with a high humus content remain to-day to suggest the former locations of such

areas.

95731-26-1

different layers, and the condition of the water supply and of the mineral substratum are seldom examined. For this reason there has always been a certain element of hazard and doubt in the economic development of peat resources.

Experience in the United States appears on the whole to be in accord with that reported for Europe. From many peat lands under cultivation the returns in vegetables, forage crops, or small grains have been disappointing, although for unknown reasons on occasional fields excellent crops have been raised. Some peat lands are easily tilled, increase the quality of timber produced, supply a material which yields a satisfactory artificial manure upon composting, or carry a roadbed designed for heavy traffic, while other peat areas are not giving promising results. To remove the element of doubt, or at least to reduce it, is the purpose of this bulletin. Briefly, the object is to formulate a basis for a more definite selection and also for safer and more economic procedure in the work of improving, for different uses, peat lands which have been abandoned in various sections of the country.

EXAMINATION OF PEAT LANDS

In order to determine the class to which any peat-land unit belongs a systematic examination of the fundamental factors is required. Undue stress has often been laid on the color of the peat material, the acid reaction, or the native surface vegetation, as the factors which indicate the type of land to be chosen for development. In many instances, farmers have failed because the peat area did not produce according to expectations based on surface conditions. The observed failures are now well understood to be due to inexperience as to the widely varying essential differences between peat lands, each case requiring more or less special examination; and, in consequence, efforts are now being directed toward working out a more dynamic and geographic basis for correlating the possibilities and limitations of peat lands. The aim is to prevent the difficulties at their source, rather than to adopt doubtful corrective measures. It is therefore of considerable importance to supplement in various ways the general observations upon peat and muck, with more detailed descriptions of the whole profile and of certain outstanding factors, such as the sources of ground water and mineral subsoil. Upon information concerning these factors an intelligent estimate of peat areas may be based.

A field method to establish a natural classification of peat lands has now been used over a section of this country large enough to lead to wide general views. Directions for a uniform method to be followed have been published under the title "The Stratigraphic Study of Peat Deposits" (11). As a supplementary aid to this subject a series of investigations limited to restricted regional areas has been made (9, 14, 15), and others are in progress. These studies are not without interest to those who are working on the nomenclature and mapping of peat lands, on comparative researches in general soils science, and in geology and ecology.

'Serial numbers (italic) in parentheses refer to "Literature cited," at the end of this bulletin.