SOILS FERTILIZERS. 217 



phorus cari'ied ;i\v;iy in tlit> hones of live stock, in niill<, jind in the grains which 

 are sold off the farm." 



An investigation of the causes of variation in soil fertility as affected by- 

 long continued use of different fertilizers, B. E. Brown and J. J. Skinner 

 (Penusj/lrftititt Sta. Ritt. 190S, pp. 26-68, pis. 3). — This article gives the results 

 of investigations undertaken in 1907 to deterniirie if possible the causes of varia- 

 tion in yield of plats of residual limestone soil which have been used for the 

 past 2;") years in fertilizer experiments on a 4-year rotation consisting of torn, 

 oats, wheat, and clover and timothy. The fertilizer experiments had shown 

 that the soil resi)onds best to api)lications of pliosphoric acid. 



Extraction of the soil of the different i)lats with 1 per cent citric acid gave 

 results showing some agreement between the amounts of phosphoric acid dis- 

 solved and the yields obtained. Tliere were no decided differences in the 

 amounts of lime, magnesia, phosplioric acid, and potash extracted by hydro- 

 chloric acid of 1.115 sp. gr. Plats giving the highest yields were uniformly 

 low in water-soluble nitrogen as compared with plats giving lower yields. 

 Total nitrogen in general harmonized with the yields. Plats which had 

 received muriate of potash alone or in combination were in greater need of lime 

 than plats not so treated. 



" Soil extract studies were carried on, using wheat seedlings as an indicator 

 of soil conditions. High-yielding plats, during season wiieat was on the ground, 

 gave comparatively poor extracts. Low-yielding plats, however, gave good 

 extracts during the same period. 



"After harvesting the wheat these plats approached much nearer the order 

 that obtained in the field. The results may be ascribed to products of i)lant 

 growth." 



A study of certain mutual properties of two adjoining fields which gave 

 widely varying yields, B. E. Brown i rcnnsj/Ivania Sta. Rpt. 1908, pp. 102- 

 lO-'f). — A chemical study of the soils of two adjoining fields, the soils of which 

 were of the same origin but varied widely in productiveness as a result of 

 difference in treatment, showed that the less productive soil was uniformly 

 poorer in fertilizing constituents, less retentive of moisture, and more in need of 

 liming than the productive soil. 



Physical and chemical study of the Milton Grove soils, W. Frear (Pcnii- 

 sylvauia Sl<t. Rpt. l'.)08, pp. ll'l-lTi, fig. /). — Determinations of hygroscopic 

 moisture, carbon dioxid. organic carbon, loss on ignition, chlorin, and nitrogen in 

 soils used in experiments in growing tobacco under shelter are reported and 

 discussed. 



Report on "Wisconsin soil resources and need of a soil survey, S. Weidman 

 and A. K. Whitson {Rpl. Coiiserv. Com. Wis., 1 (1909), pp. 37-53, fig. /).— 

 Data from the State census reports for 1SS5, 181)5, and 1005 are reported which 

 show that there has been a healthy and reasonable increase in the percentage 

 of improved farm lands in Wisconsin since 18S5. It is shown that 32.3 per cent 

 of the total area of the State is improved farm land, and it is estimated that 

 from 70 to 75 per cent of the total area may be ultimately brought under culti- 

 vation. The soil re.sources of the southern half of the State are much better 

 utilized than those of the thinly settled northern half. It is believed that con- 

 servation and development of soil resources of the State depend upon a 

 systematic survey of the soils. 



" Since this work is largely to be used as the foundation of much of the work 

 of the agricultural exi)eriment station, it is important that the work be done 

 through the cooperation of the geological and soil survey with the agricultural 

 college. The soil survey should be carrietl on simultaneously in the northern 

 and southern parts of the State." 



