1917] Fories: Irrigation Effects of Copper Compounds Upon Crops 411 



The prevalence of small amounts of copper in vegetation 

 throughout this locality is shown by the figures in table VI. 

 Samples of corn and alfalfa contained comparable quantities of 

 copper, which, however, were exceeded by the amount found in a 

 sample of mistletoe growing on a willow fully twenty-five feet 

 above the ground. This is due chiefly to the perennial character 

 of mistletoe which, therefore, has more time to accumulate cop- 

 per. It is interesting to note also that seeds of alfalfa and 

 corn contain less copper than corresponding foliage. Corn leaves 

 were observed to contain 6.1 parts of copper per million parts of 

 air-dry substance, while grain from the same locality contained 

 from 0.73 to 0.43 parts. Alfalfa seed contained about one-half 

 as much copper as the stalks and leaves, while w^heat hay carry- 

 ing a large proportion of grain showed a low proportion of cop- 

 per. These facts are probably connected with transpiration, 



TABLE VII 



Copper in Vegetation from Other Localities 



Sample No. 

 and date Description of sample 



3508 Alfalfa hay, station farm near 

 Aug. 25, '05 Phoenix (tAvo samples) 



3516 Alfalfa, before blooming, station 

 Oct. 25, '05 farm near Phoenix 



3515 Alfalfa hay, Colorado bottom, 



Oct. 4, '05 Yuma date orchard 



3517 Barley hay, station farm near 

 May, 1905 Phoenix 



3518 Corn, leaves only, station farm near 

 Oct. 25, '05 Phoenix 



3519 Corn, leaves only, grown on Killito 

 Oct. 14, '05 near old Fort Lowell 



3529 Corn, leaves and bloom, same field 

 Dec. 27, '05 as No. 3519 



3520 Mistletoe from eottonwood 30 ft. 

 Oct. 14, '05 above ground, old Fort Lowell, 



near Tucson 



3989 Young (5 mos. old) alfalfa roots 

 Dee. 31, '08 from C. & A. ranch irrigated 



with mine waters containing cop- 

 per, from Bisbee 



3990 Corn roots from C. & A. ranch irri- 



gated with mine waters contain- 

 ing copper, from Bisbee 



Condition and 



weight taken, 



grams 



2109 

 air-dry 



1408 

 air-dry 



1106 

 air-dry 

 1262 

 air-dry 



1304 

 air-dry 



595 

 air-dry 



284 

 air-dry 



1132 

 air-dry 



1160 

 air-dry 



2.12 

 air-dry 



16.7 

 air-dry 



Cu 

 found, 

 grams 



.0021 



.0031 



.0011 



none 



.0002 

 .0005 

 .0018 

 .0015 



.001 

 .0001 



Cu 

 p.p.m. 



1.00 



2.20 



1.00 



none 



.15 



.84 



6.30 



1.32 



.85 

 47.00 



.00025 15.00 



