The Year's Progress of the Experiment Station Report of the Director H. L. Russell In presenting the customary annual report of the progress of the Agricultural Experiment Station, attention is directed first to the study of the foundation of all agriculture. The soil is the great fundamental asset in our national wealth. Out of it come life and sustenance for the whole world of nature and mankind. Formerly it was customary to look upon it merely as a mass of inert particles, but we know that it is composed of the most complex materials and in place of being dead and inert, it is pulsing with myriad. forms of life. These living organisms act and react, not only on each other, but on the complex soil particles with which they come in contact. The processes of soil-formation are continually in the making. Weathering is slowly but constantly releasing new plant food, while at the same time the processes of depletion, erosion, leaching, and waste are lessening the value of this asset. To conserve this bank account, and to transmit it unimpaired to future generations is a duty which the human race owes to posterity, but as with nearly all of our natural resources, man has wasted more than he has used. In earlier years when knowledge did not exist, or was imperfectly appreciated, wanton practices led to rapid depletion or exhaustion. Every virgin area that has been opened up for settlement by man has had its pioneer generation of soil-miners, but if future human life is to receive adequate support from the soil, sooner or later the soil-tiller must quit robbing the land and feed his soil as he feeds his flocks. The last decade or two has brought the American farmer to a more complete realization than he has ever before *For the year ended June 30, 1914. known, of the duty that lies before him. The lessons that China and Japan learned a thousand years ago or more made their way slowly toward the occidental world. Even the teachings of old England and the plains of continental Europe fell heedless on American ears. To our fathers the so-called inexhaustible fertility of the magnificent Mississippi valley could never be used up, but the declining crop yields of a section, whether it is wheat, corn, or cotton, spell lessening profit and impairment of capital. Science has now shown in no unmistakable terms that as the chain is no stronger than its weakest link, so the soil is no richer than its content of its most indispensable element. FIG. 1.-A SOIL-FERTILITY BARREL The water level can rise no higher than the lowest stave. The fertility of the soil is limited by the lowest amounts of its most indispensable elements. If depleted of its potash or phosphorus, whether by age-long leaching, or more rapid robbery by careless crop-production, matters little. The effect is the same. Therefore, the fundamental problem is to know how to manage our soils so that not only will they bear fruit, but while doing so they will also retain their original fertility. I. EXPERIMENTAL RESULTS OF THE STATION In reviewing the work of the Experiment Station for the year, we therefore present first the results obtained in the study of soils, as embraced in the work of the Soil Survey, the chemical and biological investigations, as well as the more directly practical results obtained in soil management: A NEW SOIL ACIDITY TEST For years the litmus test has been generally employed for the recognition of soil acidity. This test possesses the great advantage that it can be readily employed by any person, but the reaction of soil with litmus does not clearly indicate the degree of acidity in a soil. Mr. Truog of the Soils department has been studying the various methods of determining soil acidity and has finally devised a new method and apparatus by which the soil acidity can be much more accurately determined than by any of the existing methods. The method itself is very simple, the apparatus inexpensive, and the use of the chemicals involved quite free from danger, so that the process will be available to all persons interested in studying this problem. To 10 grams (0.35 ounce) of soil are added 1 gram calcium chloride, 0.1 gram zinc sulfide, and 100 cc. of water. This mixture is thoroughly shaken and heated in a glass flask. After boiling one minute, a strip of filter paper saturated with a solution of lead acetate is placed over the mouth of the flask, and the boiling continued two minutes more. If the soil is acid the paper will be darkened on the under side in proportion to the degree of acidity. Comparison of intensity of color with a standard color chart enables the approximate degree of acidity to be determined. A compact apparatus has been devised, making it possible to carry out the test as accurately on the farm as in the chemist's laboratory. The test is especially well adapted to the use of field observers, as it not only detects soil acidity more positively than litmus paper, but also indicates the degree. A new quantitative method for determining accurately the total acidity has also been devised and is being tested at present. With the aid of these improved qualitative and quantitative methods, the nature and development of soil acidity is being studied, as well as the effects on crops. The use of this method will greatly increase our knowledge of the degree of acidity existing in various types of soils and therefore be a distinct help in further studies of the relation of acidity to fertility. THE AVAILABILITY OF PHOSPHORUS The fact that very marked differences exist among plants in their ability to secure their supplies of phosphorus (from various compounds of this element in the soil is becoming more and more recognized. It seems possible now to state with reasonable certainty that plants having a high lime content, such as legumes, are vigorous feeders on raw rock phosphate. A preliminary examination of the relation of the amount of phosphorus in the plant to the form of phosphate in the soil has been undertaken. In a considerable number of plants it has been found that when grown on magnesium phosphates, they contain relatively high percentages of this element. This fact may throw light on the assimilation of phosphates by plants and explain the rather wide variation in phosphorus content of crops that is sometimes met with. RELATION OF SOIL ACIDITY TO NITROGEN AVAILABILITY IN SOILS The present state of our knowledge of the relation of soil acidity to the accumulation of nitrogen in the soil, by both free-living bacteria and nodule-forming organisms found in the roots of legumes, as well as its relation to the availability of the nitrogen in the soil, is very unsatisfactory. In view of the large areas of acid soils in Wisconsin and the fact that the nitrogen and the organic matter in many of these soils are extremely low, it is of the utmost importance that the methods of increasing both these constituents through the growth of legumes be thoroughly established on a scientific basis. It is well known that common red clover will grow readily in many of these acid soils, but other legumes, as alfalfa, are much less tolerant to such acid conditions. Is this due to a greater tolerance to an acid condition on the part of the clover plant, or is it due to the clover bacteria being more tolerant to acid than the alfalfa organisms? Are the red clover bacteria capable of fixing atmospheric nitrogen in such acid soils as well as in neutral or alkaline soils? A scientific answer to these and other fundamental problems must be forthcoming before the farmers of our state can afford to commit themselves to a policy of attempting to neutralize in any large degree the acid soils which predominate in many portions of the state. As a step in this FIG. 2.-GOOD CROP OF CLOVER AT SPARTA STATION The past season, after the acidity had been corrected by the use of lime, and the fertility built up with peat, phosphorus, and potash, this poor sand produced four tons of mammoth clover hay per acre. direction, a cooperative study of these problems has been begun by Professor Fred of the Agricultural Bacteriology department and Professor Whitson and Mr. Graul of the Soils department. These problems are being studied on four of the most important soil types in the state, viz., Miami silt loam, a neutral soil from the Station farm at Madison, and the following representative types of acid soils: the Plainfield sand from the Sparta experimental field, the Colby silt loam, and acid peat. |