The Relation of Nitrogen. 165 
TABLE VIII. 
Content of Nitrogen, Phosphorus and Acre Yield. 15 to 85% Organic Matter. 
Sample Bushels of Per Cent. Lbs. per Per Cent. Lbs. per Per Cent. Lbs. per 
ontwe Organic : F > : 
No. Onions AIT: 3 Acre Nit Acre Phos Acre 
Matter 
19x Onions 78.16 781, 600* 2.800 28, 000 398 3, 980 
20x Onions 81 18 811, 800 3.010 30, 100 426 4, 260 
796, 700 29, 050 4,120 ave. 
*—Wt. muck soil, 1,000,000 Ibs. per acre 64 ms. 
x—Acid soil. 
DISCUSSION OF RESULTS. 
About 50% of the soils of Elkhart County are of the Miami loam 
and Miami sandy loam types, and about 27% are of the Plainfield sandy 
loam type. These soils are rather low in organic matter and 51% are 
acid. The crop yield as given by the man in charge of the farm and 
corroborated as to the possible yield when the samples were secured 
bears a close relation to the organic matter present, and this in turn is 
closely associated with the amounts of nitrogen and phosphorus present. 
There were only three samples—1, 10 and 51—which were exceptions 
to the general rule that high plant food content equals good corn yield. 
Sample 1 is a greenish ferrous iron soil turning brown when exposed 
to air on plowing. Sample 10 is a sandy soil, low in potassium. There 
may be other causes also for the corn on this soil turning yellow when 
it is about two or three feet high. The reason for the poor yield of 
Sample 51 has not been investigated. Summarizing the data in Tables 
1-6, relating to plant food content and corn yield, it is noted that the 
difference in yield between the 0-2% and the 8-10% organic matter 
averages 25.6 bushels. Using this figure as a standard for organic 
matter increase, it is shown that on average field conditions for every 
increase of 2,672 pounds of organic matter, 71.6 pounds of nitrogen and 
35.7 pounds of phosphorus per acre (2,000,000 pounds) there is an 
increase of one bushel of corn. 
