Depths at Which Plants Absorb Water and Nutrients. Ill 



the potatoes, the tops of which were ripening rapidly. At this time the 

 soil in container 9, which bore no crop, was also examined. The results 

 obtained from this examination are given in table 41. 



Table 41. — Loss of water and nitrates, April 1 to July 9. 



vUU wcUUd ctllvJ. tiup 

 H av a i n ~n TYi p n t 



Depth. 



Water-content. 



Nitrates, parts per million. 



Apr. 1. 



July 9. 



Loss. 



Apr. 1. 



Gain by 

 nitrifi- 

 cation. 



July 9. 



Loss. 





feet. 



p. ct. 



p. ct. 



p. ct. 











No. 9. Control. No plants. 



to 0.5 



24.7 



22.9 



1.8 



0.0 



210.0 



210.0 



+210.0 



0.5 to 1 



24.5 



23.8 



0.7 



0.0 



251.0 



251.0 



+251.0 





1 to 1.5 



25.0 



24.8 



0.2 



11.4 



252.6 



264.0 



+252.6 





1.5 to 2 



22.9 



22.5 



0.4 



11 .4 



204.6 



216.0 



+204 . 6 





2 to 2.5 



24.1 



23.2 



0.9 



51.3 



140.7 



192.0 



+ 140.7 



No. 10. Potatoes, 3 stalks 



to 0.5 



28.5 



23.8 



4.7 











1 5 to 2 ft tall* 4 tubers 



0.5 to 1 



24.3 



22.3 



i2.0 











1 to 2 in. in diameter, sev- 



1 to 1.5 



24.4 



20.3 



4.1 











eral rtti ft Hpr nnps T?.ootfl 



1.5 to 2 



23.1 



20.8 



2.3 



364.4 



204.6 



341.0 



228.0 



abundant to 2 ft., fairly- 



2 to 2.5 



23.1 



21.0 



2.1 



358.7 



140.7 



423.0 



76.4 



abundant to 2.5 ft. 



















No. 11. Potatoes, 2 stalks 



to 0.5 



27.8 



19.7 



8.1 











2 ft. tall, 2, 1.7 ft. ; 6 tubers 



0.5 to 1 



23.4 



21.5 



»r.9 











about 1.5 in. in diameter, 



1 to 1.5 



24.6 



21.3 



3.3 











several smaller ones * roots 



1.5 to 2 



23.3 



20.4 



2.9 











flbiinHnnf'. t,n 1 R ft, nnlv 



2 to 2.5 



22.7 



21.7 



1.0 



358.3 



140.7 



334.0 



165.0 



a few penetrated deeper. 



2.5 to 3 



24.5 



23.9 



0.6 













3 to 3.5 



19.3 



20.4 



+1.1 











No. 12. Barley, 154 stalks 



to 0.5 



24.8 



23.5 



«1.3 











with 101 large well-filled 



0.5 to 1 



24.6 



14.8 



9.8 











heads, ave. ht. 2.5 ft.; 



1 to 1.6 



25.9 



19.8 



*6.1 











roots abundant to 2.5 ft., 



1.5 to 2 



24.8 



17.4 



7.4 











beyond which few pene- 



2 to 2.5 



27.4 



21.1 



6.3 



412.2 



140.7 



413.0 



139.9 



trated. 



2.5 to 3 



23.6 



24.1 



+0.5 













3 to 3.5 



22.7 



21.8 



0.9 











No. 13. Barley, 135 stalks 



to 0.5 



27.3 



19.0 



8.3 











with 112 large, well-filled 



0.5 to 1 



26.3 



14.3 



»12.0 











heads, av. ht. 2.5 ft. ; roots 



1 to 1.5 



24.2 



17.2 



7.0 











abundant to 2.5 ft., fairly 



1.5 to 2 



25.2 



17.9 



«7.3 











abundant to 3 ft., beyond 



2 to 2.5 



25.4 



22.8 



2.6 











which a few penetrated 3 



2.5 to 3 



24.7 



23.0 



1.7 



415.3 



140.7 



370.0 



186.0 



to 5 inches. 



3 to 3.5 



24.1 



24.9 



+0.8 













3 to 3.5 



23.0 



23.6 



+0.6 











1 Eight liters of water were added to the soil at this depth during the growth of the plants. 

 « Five liters of water added. 

 3 Six liters of water added. 



In table 41, the control container shows marked gains by nitrification at 

 all depths. The water-losses from this container, except for evaporation 

 through the slit in the roof from the surface 6 inches, fall well within the 

 experimental error of sampling. The potatoes had reduced the water- 

 content to the depth of root penetration, while the absorption of nitrates 

 was also in close agreement with root distribution. So few roots penetrated 

 beyond 2.5 feet that nitrate-losses at this depth were not determined. 



