330 EXPERIMENT STATION RECORD. 



of the liureuu of Soiln. Doctor Hilganl (HK-stioned the reliabihty of the water- 

 extrat-t method as a means of determining tht* fertiUty of soils, and strongly dissented 

 from many of the conclusions and generalizations contained in the bulletin. The 

 pa})er cited numerous illustrations of the value of chendcal methods for determining 

 the productiveness of soils, and laid especial stress on the importance of the relative 

 proportion of soil constituents as distinguished from their total amounts. 



Three papers were read on Methods of Conducting Investigations Relating to the 

 Maintenance or Increase of Soil Fertility. In the first of these G. E. Thorne dwelt 

 upon the relation of laboratory and field experiments, and laid stress ujjon the value 

 of the latter when continued for long ])eriods on the same plats. Compared with 

 sucli work laboratory work was declared to ])e comparatively simple. The require- 

 ments of plat experiments were pointed out and the necessity of great care in exe- 

 cution was emphasized, illustrations being drawn from the experience at the Ohio 

 Station. The speaker was unable to see how the results of the i)ast 10 years at that 

 station could have been forecasted in the laboratory by a chemical or physical exam- 

 ination of the soil or otherwise, or how any time could have been saved. In conclu- 

 sion, he laid down the general proposition that deductions relating to soil fertility 

 must be confirmed in the field; that field work should be as scientific in its methods 

 as laboratory work; and that when this is the case, the results are as reliable as any 

 scientific laboratory work. 



The second paper on this subject, presented by E. B. Voorhees, took up the dif- 

 ferent methods practiced to maintain and increase tlie fertility of the soil, considered 

 the relation of income and outgo of plant food to crop production, and compared the 

 availability of nitrogen from different sources for leguminous and nonleguminous 

 crops. The discussion of these topics was based on the results of experiments con- 

 ducted at the New Jersey Station. The methods of Investigations pursued in this 

 connection were described in detail in the course of the paper. 



H. W. Wiley, the third speaker, outlined the reasons for the depreciation of soil 

 fertility, and discussed at some length the results obtained by the Bureau of Chem- 

 istry of this Department, in pot culture experiments with soils from different parts 

 of the United States. The speaker presented a comparison of the amount of phos- 

 phoric acid and potash removed by oats grown in these pot experiments, and the 

 mount of these elements which were found soluble in two-hundredth normal hydro- 

 chloric acid under definite conditions. Attention was also called to the nitrifying 

 power of the different soils used. 



In a paper on Differences between four Southern and four Northern Soils, and 

 Improvements in Soil Management which these Differences Suggest, F. H. King, of 

 the Bureau of Soils, gave an account of cooperative jilat exijeriments with different 

 amounts of manure and guano on corn and potatoes, on typical soils in North Caro- 

 lina, Maryland, Pennsylvania, and Wisconsin. In connection with these experi- 

 ments observations were made on temj^erature, evaporation, rate of nitrification, 

 soluble salts, and other physical and chemical conditions. The southern soils studied 

 were more compact, i. e., less granular, had more defective aeration and drainage, 

 but carried less water, showed a slower rate of nitrification, contained less soluble 

 salts, and gave smaller yields than the northern soils. The means suggested for 

 improving the productive capacity of the southern soils included deeper plowing, 

 the turning under of more organic matter, the raising of more live stock, and the 

 growth of smaller varieties of corn. 



R. H. Forbes, of Arizona, discussed the Methods for the Extension and Practical 

 Application of Soil Surveys, pointing out the great value of soil surveys for selecting 

 lands adapted to new crops and industries under pioneer conditions, and especially 

 of alkali surveys and quick and easy methods of determining the location and amounts 

 of alkali in soils. 



L. G. Carpenter, of Colorado, presented a paper on Methods and Value of Securing 

 Irrigation Supplemental to Rainfall for Humid and Semi-arid Districts, in which he 



