TABLE 5. 
PERCENT OF INCREASE OR DECREASE IN HuMuUSs. 
= = === ——— 
Horse Horse Horse Horse 
a 8 9 10 
CaO, MgO CaO CaCO:, CaCO; 
MgCoO; 
06 —.O01 . 06 06 NH: OH soluble humus be- 
fore exposure Over 
check. 
09 AOS sl —.04 May 30 to Feb. 16. 
06 .10 —.01 .10 Feb. 16 to April 13. 
02 —.03 se 04 April 13 to June 1. 
208 -23 —.30 05 June 1 to Oct. 15. 
NS Pee sie, Ne rte ea tac ys (ella cyele cus cle oreo Neto o seneauey sce, © Oct. 15 to Nov. 22. 
ipa 46.6 637 .6 386 Grams of corn and stalks 
produced 1915 
308 392 347 320 produced 1916 
Check box 
A Sy eA meee hl ow oretr Wace te ey ey arc ea | rerents a toa oaanay osc eo' a) [forests Ars eay oh eee ous Grams of corn and stalks 
produced 1915 
WSs s5.c Biola a stays anag coi elieata teases Ger a atey Eieiere ote tehe auc tobe produced 1916 
It will be noticed in Table 4 that fresh steer manure is quite soluble in 
NH,OH and the solubility is not increased appreciably on exposure in the 
soil. The same is true to a large extent of cow manure, but less of pig 
manure while horse manure is only broken down after about 12 to 18 months’ 
exposure, except in the case of Box 9 which was treated with dolomitice lime- 
stone. It will also be noticed in Table 5 that when the acidity was corrected 
with 171 grams of CaO in Box 8 and 101 grams of CaO, MgO in Box 7, the 
rate of humification was retarded—the CaO and CaO, MgO both having an 
antiseptic action when more is added than is needed to correct the soil acid- 
ity. Chemically equivalent amounts of Ca and Mg (in neutralizing power) 
were added to Boxes 7,9 and 10. It would seem that the growth of corn ob- 
tained in Box 9 was due to the early humifying of the manure (June 1). 
While in Boxes 4, 7 and 8 the humification came too late to benefit this year’s 
crop. The yields in Boxes 3 and 5 were the largest of all but it is probable 
that the higher nitrogen content was the main cause. 
5084— 21 
