SOILS FERTILIZERS. 



319 



Averaijc (iiuiikiI soil Iciiipcratiircs for \oru:<<ji(ni ■shitioiis 



Name of station. 



Aas 



.Umshorf,' 

 Kotvold. 

 Bod...... 



Steiul . . . 



Temperature of soil at — 



Period. 



1896-1904 

 1900-1904 

 1900-1901 

 19U0-1904 

 1900-1904 



I Air tem- 

 i perature. 



One- 

 fourth 

 meter. 



4.28 

 1.54 



3.20 

 5.16 



5.67 

 3.38 

 4.33 

 3.43 

 6.01 



One and 

 one-half 

 meters. 



6.13 



-V. \\ . WOLL. 



The solvent action of roots upon the soil particles, A. D. Hall (Sci. I'roy. 

 Ticeiitieth Cent.. I ( lUoii). \ o. /. /</). .)/-.)7).^Tht' author reviews the literature 

 of this subject, rojicliint,' the coiichision "that il is not necessary to assume tlie 

 existence of an e.xcretion from the roots of the i)lant >)f a permanent acid, or- 

 ganic or inorpinic, to attack the solid mineral ])articles of the soil and to bring 

 them into solution for the nutrition of the plant. The growing j)ortions of a 

 plant root are always giving off carbon dioxid, and carbon dioxid, especially in 

 the concentrated solution which must be momeutarilj^ formed in the cell wall of 

 the root hairs, has an a])preciable solvent effect upon the majority of the min- 

 erals composing the soil. This carbon dioxid alone is capable of giving rise to 

 such solutions as are required for the nutrition of the plant. As the direct 

 evidence is also adverse to the idea of an excretion of acid, the principle of not 

 seeking remote causes would lead us to attribute to carbon dioxid, and to carbon 

 dioxid only, the long-recognized solvent power of the plant upon the soil." 



The fallow in modern agriculture, S. Rhodin {K. Landthr. Alcad. Handl. 

 och Tidskr., JfO (1906). Xo. 1, pp. .57-72, fig. 1). — The evidence and views in re- 

 gard to the value of bare fallow, especially in Swedish agriculture, are 

 brieliy discussed. While bare fallow of loose sandy soils is not to be recom- 

 mended, because the losses of nitrogenous substances occurring, generally speak- 

 ing, exceed the gains through nitrification, this is not the case witli other types 

 of soils. Here an accumulation of nitrates takes place through the fallow, 

 which greatly benefits the following grain crop. 



Field experiments with cabbages in 1903 and with potatoes in 1904 and 1905 

 were conducted for the purpose of determining whether inoculation of sandy 

 soils with fallow soil would prove beneficial on account of the large bacterial 

 content of the latter. The systems of fertilization followed are shown below, 

 the different ijlats receiving as a basal fertilizer 37 per cent potash salt and 

 Thomas phosphate, at the rate of 22.5 and 400 lbs. per acre, respectively. The 

 nitrate gf soda was applied at the rate of 300 lbs. per hectare (267 lbs. per 

 acre) and the inoculated soil at the rate of (i cubic meters per hectare. 



Yields per acre (uid /icrrrnfai/r increase of crops on inoculated and uninoculated 



iirareUy soil. 



