FIELD EXPERIMENTS IN I915. 



15 



Sample 3404 was also from Fort Fairfield from a potato field that 

 had 1,200 pounds of commercial fertilizer the year that it was sampled. 

 It had been in grass for the two preceding years. 



Sample 3405 was from Caribou from a field that had been in grass 

 for two years and was in grass the season the sample was taken. 



Sample 3406 was also from Caribou from a field that had been 

 cultivated for 13 years and was in oats the year that the samples were 

 taken, potatoes the year before and had been in grass for the two 

 preceding years. 



Sample 3407 was from a field in Houlton that had been cultivated 

 for more than 30 years. It was in potatoes for the second consecutive 

 year the season the sample was taken. Fertilizer had been used at the 

 rate of 1,500 pounds to the acre. 



Sample 3408 was from a newly cleared field at Houlton, and was 

 unusually light soil for Aroostook County, one part of the field being 

 almost a loam. 



Analyses of Aroostook soils by conventional methods showing 

 total nitrogen and potash, and the potash, lime and phos- 

 phoric acid that is dissolved out by hot strong hydrochloric 

 acid. 









Soluble in Strong 



Acid. 



Station 



Total 

 nitrogen 



Total 



pot \ sh 









number 















Potash 



Lime 



Phosphoric 

 acid 



549 



.217 



1.45 



.310 



.176 



.211 



550 



.135 



1.70 



.354 



.198 



.151 



551 



.113 



1.46 



.313 



.190 



.172 



552 



.257 



1.57 



.369 



.308 



.262 



3403 



.281 



_ 



.34 



.31 



.25 



3404 



.259 



- 



.36 



.21 



.26 



3405 



.239 





.28 



.11 



.26 



3406 



.238 





.27 



.22 



.26 



340 7 



.226 



- 



.33 



.12 



.32 



3408 



.176 





.35 



- 



.22 



Small as these percentages are, they mean large totals of 

 the constituents in the surface soil of an acre. For instance, 

 the soil to the depth of a foot from which sample 549 was 

 taken would carry about 8,700 pounds of nitrogen, 8,400 

 pounds acid soluble phosphoric acid and 12,000 pounds acid 

 soluble potash. The amount of these constituents carried off 

 in a single crop of potatoes is insignificant. A crop of 300 

 bushels of potatoes would remove about 55 pounds of nitrogen, 

 25 pounds of phosphoric acid and 85 pounds of potash. Added 

 to the top foot of soil these amounts would make only the 

 slightest differences in the percentage composition. Eighty-five 

 pounds of potash in an acre of soil means only .0021 per 



