321 



TABLE 5. 



Percent of increase or Decrease in Humus. 



Horse 



Horse 



Horse 



Horse 







7 



8 



9 



10 







CaO, MgO 



CaO 



CaCOs, 

 MgCOs 



CaCOs 







.06 



— .01 



.06 



.06 



XHj OH soluble humus be- 











fore exposure 



Over 











check. 





.09 



.03 



.12 



— .04 



May 30 to Feb. 16. 





.06 



.10 



— .01 



.10 



Feb. 16 to April 13. 





.02 



— .03 



.57 



.04 



April 13 to June 1. 





.18 



.23 



— .30 



.05 



June 1 to Oct. 15. 

 Oct. 15 to Nov, 22. 















123.1 



46.6 



637.6 



386 



Grams of corn and 

 produced 1915 



stalks 



308 



392 



347 



320 



produced 1916 





Check box 













145.4.. . . 









Grams of corn and 

 produced 1915 















151 









produced 1916 















It will be noticed in Table 4 that fresh steer manure is quite soluble in 

 XH 4 0H 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 dolomitic 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 humifieation 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 humifieation 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 



