ANNUAL REPORT, 1933 11 



Magnesium Requirement of Crops. (A. B. Beaumont and M. E. Snell.) 

 The soil on which this experiment is being conducted is only moderately deficient 

 in magnesium, judging from reports of experiments on magnesium-deficient 

 soils in other sections. Within recent years 14 common crop plants have been 

 grown in this experiment, but only 5 — corn, tobacco, oats, buckwheat, and 

 turnips — have shown definite symptoms of magnesium deficiency, and the yield 

 of some of these was not seriously reduced. Buckwheat is one of the most 

 sensitive to magnesium deficiency of the plants studied in this experiment. 

 Certain weeds have shown marked symptoms of magnesium deficiency. The 

 crops grown in 1933 were barley, oats, Sudan grass, Japanese millet, buckwheat, 

 turnips, and corn. With the hope of accentuating soil differences of the field 

 under experiment, an acid-producing fertilizer was used this year, and another 

 application of lime was given the portion previously limed. 



Methods for Determining Magnesium Deficiency in Soils. (J. L. Haddock.) 

 Various laboratory' methods for the determination of mineral deficiencies in soils 

 were studied during 1931-32. Two of these methods showed fair agreement 

 with pot and field tests. The Newbauer method may be used on soils very 

 deficient or well supplied in magnesium. The exchangeable magnesium as 

 obtained by soil extraction with normal KCl solution gave close agreement with 

 magnesium-deficient soils, as shown by chlorosis of corn and tobacco. 



An interesting observation was made in the summer of 1932 on the magnesium 

 plots. It was noted that the common weed, lamb's quarters {Chenopodiiim 

 album L.), was growing on all plots along with buckwheat:. On the plots treated 

 with magnesium the weeds grew to an average height of 3 feet, while on the 

 deficient plots there were fewer weeds and the plants had an average height of 

 only 15 inches. 



Chemical analysis of corn and lamb's quarters grown on the magnesium plots 

 gave some interesting results which suggest that this weed may be useful as a 

 magnesium indicator plant. 



Chemical Content of Corn and Lamb's Quarters as Influenced by Soil Treatment 



Content of Content of 



Treatment Corn Stover Lamb's Quarters 



J Per Cent Per Cent 



Ca Mg Ca Mg 



Calcium alone 0.49 0.12 2.39 0.16 



Calcium -f magnesium 0.39 0.15 1.98 0.44 



Magnesium alone 0.38 0.18 1.40 0.48 



No calcium; no magnesium. 0.41 0.08 1.67 0.12 



Onion Field Experiments. (M. E. Snell.) 



Onion Set Production. The past season's work on this project has but con- 

 firmed the statements made in the last annual report regarding fertilization 

 for onion set production. The yields of sets were somewhat lower in 1933, and 

 there was a tendency for the smaller sizes to be slightly more numerous. Since 

 the use of 500 pounds of the 2-12-8 fertilizer was so successful last year, 1000 

 pounds were tried this year, but no improvement was seen. In previous tests 

 all rows have been 13.8 inches apart, but the past season they were tried 8 and 11 

 inches apart. It was rather difficult to operate between rows only 8 inches 

 apart, and the yield was not increased with the 500 pounds of 2-12-8 fertilizer 

 used. Perhaps 1000 pounds of this fertilizer would have been better in this case. 



