66 The Colorado Experiment Station 
the climatic conlitions are sufficiently different to constitute a factor 
in the results. Second: differences in soils. Third: differences 
in varieties of beets, or strains of seed used, and there are still others. 
While it is beyond my power to eliminate these factors, we can, I 
think, avoid attaching too much importance or too little importance 
to them, and also desist from making an excuse of them to explain 
things which we do not understand. We know that the climatic 
conditions of the Poudre Valley are very different from those of the 
Eastern part of the state, which lies in the Arkansas Valley, but we 
have already seen that this latter section of the state does produce 
excellent beets, not only in regard to high sugar content, but also in 
regard to their content of injurious ash and nitrogen. It has been 
proved that droughty conditions increase bpth the total and the in¬ 
jurious nitrogen in beets, but we have scarcely any better beets than 
have been grown in this section of the state and it follows that in 
considering our results, especially of 1910, we cannot justly appeal 
to climatic conditions as affording the explanation for adverse re¬ 
sults which we cannot otherwise explain. 
The chemical composition of the soil on which these experi¬ 
ments were made is given in full in connection with Analysis XV, 
which is a sample from one of the check plots in this series which 
received no fertilizer in either 1909 or 1910. The statements rela¬ 
tive to the composition of this soil are based upon a series of fifteen 
analyses. I may state that this soil yields a solution with hydro¬ 
chloric acid which shows the presence of ferrous salts, but not a trace 
when treated with water. On panning a portion of the soil no iron 
sulfids could be detected, only a black sand. No sulfuretted hydro¬ 
gen could be detected on treatment with hydrochloric acid and lead 
paper. The coarse sand is composed of quartz and felspar. It 
seems probable that the ferrous compound present is a carbonate, 
siderite, possibly in combination with the calcic or magnesic car¬ 
bonate, ankerite or mesitite. There is lime carbonate enough pres¬ 
ent to give a rather lively effervescence. 
The available potash in 4,000,000 pounds of the surface foot of 
this soil was 400 pounds, of the second foot from 120 to 320 and 
of the third foot from 160 to 640 pounds. The phosphoric acid 
available in this amount - of soil from the surface foot was 120, 280 
and 400 pounds. The humus nitrogen calculated in like manner 
gives us from 1,000 to 2,000 pounds for the first foot, 1,600 pounds 
for the second foot and from 320 to 2,000 pounds for the third foot. 
Taking the average of available potash and phosphoric acid in the 
three sets of samples taken to a depth of three feet we obtain a sup¬ 
ply, soluble in citric acid solution, of 773 pounds of potash and 796 
pounds of phosphoric acid per acre. If we assume one-quarter of 
the humus nitrogen to be or to become available during the season, 
