AQUEOL'S SOLUTIOJf OF TIIK SOIL. 323 



Mode whereby dilute solutions may nourish Crops.— 



There are other considerations Mliicli niay en:il)lc us to 

 reconcile extreme dilution of the nutritive liquid of the 

 soil, with the conveyance by it into the plant of the req- 

 uisite quantity of its appropriate food. It is certain 

 that the amount of matters found in solution at any 

 given moment in the water of the soil by no means repre- 

 sents its power of supplying nourishment to vegetation. 



If the water which has saturated itself with the solu- 

 ble matters of the soil be deprived of a portion or all of 

 these matters, as it might be by the absorptive action of 

 the roots of a plant, the water would immediately act 

 anew upon the soil, and in time would dissolve another 

 similar quantity of the same substance or substances, and 

 these being taken up by plants, it would again dissolve 

 more, and so on as long and to such an extent as the soil 

 itself would admit. In other words, the same water may 

 act over and over again in the soil, to transfer from it to 

 the crop the needful soluble matters. It has been shown 

 that the substances dissolved in water may diffuse through 

 animal and vegetable tissues independently of each other, 

 and independently of the water itself. (11. C. G., p. 340.) 



Deportment of the Soil to renewed portions of Water. 



— ^It remains to satisfy ourselves tliat the soil is capa1)le 

 of yielding soluble matters continuously to renewed por- 

 tions of water. The only observations on this point that 

 the writer is acquainted Avith are those made by Schulze 

 and Ulbricht. Schulze ex[)erimented on a rich soil from 

 Goldberg, in Mecklenburg ( Vs. St., YI., 411). This soil, 

 in a quantity of 1,000 grams (= 2.3 11)S.) Avas slowly 

 leached Avith pure water, so that one liter (— 1.056 quart) 

 of liquid passed it in 24 hours. The extraction was con- 

 tinued during six successive days, and each portion was 

 separately examined for total matters dissolved, and for 

 phosphoric acid, which is, in general, the least soluble of 

 the soil-ingredients. 



