298 



THE MANAGEMENT OF MARSH LANDS 



crops such as corn, even the first year, without manure or fertilizers. 

 Potash fertilizers give the greatest returns on most marshes, 

 paticularly those not strongly acid (Fig. 198). Soils showing 

 an apparent need of potash fertilizers only, eventually need phos- 

 phates, particularly those on which no manure is used. Acid 

 marshes usually require both potash and phosphate fertilizers, the 

 potash being often a secondary need. Frequently a phosphate 



FIG. 192. 





1 



N 



FIG. 193. 



FIG. 198. This peat soil responds particularly to potash treatment. O, no treatment; 

 N, nitrogen; P, phosphate; K, potash; KP, potash and phosphate. 



FIG. 199. This peat soil responded readily to phosphate fertilizer, but best to phos- 

 phate and potash. O, no treatment; N, nitrogen; P, phosphate; K, potash; PK, mixture of 

 phosphate and potash fertilizers. 



fertilizer, when used alone, gives no increase in yield, but when 

 used in conjunction with a potash fertilizer it increases the yield 

 as compared to that secured from the use of potash alone (Fig. 199). 

 Frequently muck or peat underlaid by silty clay, or clay at a 

 depth of about twelve or fifteen inches, shows a marked need of 

 potash fertilizer for a few years, but after that this need of potash 

 partially or entirely disappears. This is because the settling of the 



