Apr. 15, i9i8 Soil Acidity as Influenced by Green Manures 



173 



Tables II. — Composition of green tnanures and others used in experiments 



Material. 



Legumes: 



Soy bean 



Canada field pea . . 



Sweet clover .... 



Alfalfa 



Red clover 



Hairy vetch 



Nonlegumes : 



Wheat 



Rape 



Oats 



Com 



Rye 



Timothy ........ 



Redtop 



Sorrel 



Other man-arcs: 



Poultry manure . . 



Barnyard manure 



Orig- 

 inal 

 mois- 

 ture 

 con- 

 tent. 



P.cl. 

 76.7 

 80. 7 



72-5 

 65.8 

 61.6 

 66.4 



75-2 

 89. 1 

 83.2 

 87.9 

 56.1 

 60. I 

 60. 2 

 80.5 



64. 7 

 74-7 



In water-free substances. 



Organic 

 matter. 



P.cl. 



78.04 



88.85 



92. 16 



91-37 



92-75 



93-04 



89.36 

 80.33 

 88.46 

 91.29 

 95-40 

 93-76 

 93-99 

 90. 18 



71-38 

 60.83 



Ash. 



P.ct. 



21. 96 



11.15 



7.84 



8.63 



7-25 



6.96 



10. 64 



19.67 



11-54 

 8.71 

 4. 60 

 6. 24 

 6. 01 

 9.82 



28.62 

 39- 17 



Alkalin- 

 ity of 

 ash.a 



P. ct. 

 6. 92 

 7.80 



5-27 

 7.82 



5-63 

 3-27 



6. 00 

 10. 48 



5-35 

 4. 70 

 I. 27 

 2.32 

 I. 60 

 3-67 



9-65 



5-32 



Water- 

 soluble 

 acidity 

 of 

 manures. 



P.ct. 



1. 70 

 4. 02 



2. 90 

 2. 13 



.28 

 I. 91 



.19 



2.88 

 8.15 

 5-92 

 3-07 

 •23 

 .42 

 3.01 



{'') 



Nitro- 

 gen. 



Quantity 

 of fresh 

 material 

 to yield 



10 gm. 



of dry 

 matter. 



3-56 

 4-79 

 3.08 

 2. 72 



1-33 

 I. 29 

 I. 07 



3-35 

 I- 57 



Gm. 

 42.9 

 50-5 

 36.3 

 29. 2 



26. O 



29.8 



40. 

 91. 



59- 

 91. 

 22. 



25- 

 25- 



50- 



28.3 



39-5 



a In terms of the calcium-carbonate equivalent. 



SOIL USED 



b Alkaline. 



With the view of detecting a change iu the degree of acidity or hme 

 requirement after the addition of the green manures, a soil already 

 distinctly acid was chosen. This soil was taken from plot 32. The 

 lime requirement of this soil, as shown by concordant duplicate 

 determinations by the Veitch method, was equivalent to 4,644 pounds 

 of calcium carbonate to the acre 7 inches (2,000,000 pounds). This 

 quantity will hereafter iu this paper be called the "limestone re- 

 quirement." The soil employed had, before this determination, been 

 freed from stones and roots by sifting through a screen with meshes of 

 a diameter of 3 mm. Before use it was thoroughly mixed to make it 

 uniform throughout. 



PREPARATION OF GREEN MANURES AND SOIL MIXTURES 



The fresh green manures were cut fine with scissors and then passed 

 through a sausage mill until thoroughly subdivided. The water re- 

 moved from the green residues during the process was carefully replaced. 

 The fine product was used for the experiment of Series I. Other por- 

 tions of the same materials were carefully air-dried and similarly sub- 

 divided for use in Series 11. 



Of the fresh materials thus prepared, the respective quantities stated in 

 the last column of Table II as equivalent to 10 gm. of dry matter were 



