SOILS FERTILIZERS. 119 



effect. Salts which hydrolyze with the formation of acid or allvaliue solutions 

 increase the amount of phosphoric acid yielded to the solution by the phosphates 

 vt iron and alumina. The phosphates of the soil, whether solid solutions or 

 definite chemical compounds, are of such a nature as to yield a solution con- 

 taining very small quantities of phosphoric acid. Inasmuch as all soils con- 

 tain far more basic matter than is sufficient to combine with the phosphoric 

 acid, the least soluble phosphates are the ones which will be formed and will 

 control the concentration of the soil moisture. This fact, together with the 

 well-known phenomena of absorption, gives a satisfactory explanation of the 

 observation that the concentration of the soil moisture is low and varies but 

 little for different soils and with the total amount of phosphoric acid in the 

 soils. For the same reason, the addition of phosphatic fertilizers can not be 

 expected to influence materially the concentration of phosphoric acid in the soil 

 moisture. 



" The action of phosphatic fertilizers is, therefore, on the soil and not pri- 

 marily on the plant ; for the concentration in plant food constituents of the 

 solution on which the plant feeds is not materially altered by the addition of 

 jihosphatii' fertilizers in the amounts used in oi'dinary field practice. 



" The changes in both solution and solid which take place during the progress 

 of leaching su[ierphosi)hates have been descrliied." 



The action of straw manure on the fertility of soils, L. IIiltner and L. 

 Tetkes {Aril. K. Biol. A list. Land ii. Forstic. 5 {IHIIG), Xo. 3. p}). 99-12^: abs. 

 ill ./our. Cliciii. .S'oc. [London]. U.! {1907), No. 53-'i, 11, p. 296). — Pot experi- 

 ments with lupines and oats grown on lupine and potato soils and fertilized with 

 lupine straw, alone or with the addition of potasshmi nitrate, and m all cases 

 with a basal ration of potash and phosphoric acid, are reported. 



The growth of the oats was retarded by the application of lupine straw. 

 The lupines were not affected. The second year the growth of oats Avas greater 

 after lupines than after oats. The after-effect of lupine straw on oats follow- 

 ing lupines was very favorable, incrinising the yield about .^0 per cent, so that 

 the net effect of the lupine straw for the first and second years was good. The 

 addition of nitrate increased the effect of the straw. In case of oats following 

 oats the average gain from the use of lupine straw was only about 19 per cent, 

 making a net loss for the 2 years. 



Field experiments with lupines, seradella, robinia. peas, and beans gave simi- 

 lar results. Alfalfa was injured l)y the application of the straw. The favorable 

 action of the robinia straw, which is very woody, was particularly marked. 

 Straw extract greatly increased the yield of mustard, indicating that it is the 

 insoluble matter of the straw which produces the injurious effects. 



Recent progress in investigations on nitrification, P. Ehrenbekg (Mitt. 

 Deut. Landic. Gesell., 22 {1901), 'No. 13, pp. 134-137).— This is a brief review of 

 recent investigations by Winogradski, Schloesing, Kellner, Godlewski, Boul- 

 langer, and Massol, the author, and others. 



On changes of availability of nitrogen in soils, I, O. Loew and K. Aso 

 (Bui. Col. Ai/i:. Toh-ifo Imp. I'niv., 7 {1907). No. 3, pp. -'/43-^.)S).— From a study 

 of the character of the nitrogenous excretions from living and dying yeast 

 cells and from investigations on the effect of sterilizing soil by carbon bisulphid 

 and heat, the authors conclude that "on the death of cells all soluble matters 

 can pass throughdhe cytoplasm to the outside. Peptones and mineral nutrients 

 are excreted largely by dying yeast cells and very probably also by the microbes 

 of the soil. This phenomenon throws some light on the beneficial action on 

 crops of bisulphid of carbon when applied to soils." 



