246 SOILS: PROPERTIES AND MANAGEMENT 



WATER REQUIREMENTS OF PLANTS BY DIFFERENT 

 INVESTIGATORS 



1 Lawes, J. B. Experimental Investigation into the Amount 

 of Water Given off by Plants during their Growth. Jour. 

 Hort. Soc. London, Vol. 5, pp. 38-63. 1850. 



Pots holding 42 pounds of field soil were used. Evaporation 

 from soil was reduced to a very low degree by perforated glass 

 covers cemented on the pots. The figures quoted are from 

 unfertilized soil. 



2 Wollny, E. Der Einfluss der Pflanzendecke und Beschat- 

 lung auf die Physikalischen Eigenschaften und die Frucht- 

 barkeit des Bodens, Seite 125. Berlin, 1877. 



Wollny grew plants in humous sand in amounts ranging from 

 5 to 12 kilograms. Evaporation was reduced to a very low 

 degree by perforated covers. Actual evaporation from un- 

 cropped cans was observed, howerer. 



3 Hellriegel, H. Beitrage zur den Naturwissenschaftlichen 

 Grundlagen des Ackerbaus, Seite 663. Braunschweig, 1883. 



Hellriegel grew plants in 4 kilograms of clean quartz sand 

 and supplied them with nutrient solutions. The loss by evap- 

 oration from uncropped pots was used in determining losses 



