756 FIELD-CROPS IN COMBINATION WITH FORESTRY. 



slight, for the expenses are considerable; only where the 

 peasant pays for the cultivation of the ground, the demands 

 on the forest cash -box for simultaneous or subsequent stocking 

 with forest plants are reduced considerably. Every day 

 experience proves that by agricultural cultivation, sowing and 

 planting of forest plants is facilitated, and that, owing to the 

 working of the soil, the young plants grow quickly. The 

 protection afforded by the corn to young sowings of spruce, 

 against lifting by frost, drought and enemies of all kinds is 

 specially beneficial. 



The principal danger caused by field-crops to the forest is 

 the consequent reduction in fertility of the soil. The crops 

 take from the soil those very substances, which are generally 

 deficient (potash, nitrates and phosphates), and these materials 

 are required just as much by woody plants as by those grown 

 by the farmer, the latter requiring them merely in larger 

 quantities than the former. The agricultural plants, however, 

 grow only in the surface soil, which owing to the decom- 

 position of the weeds forming the soil-covering and of the humus 

 from dead leaves, etc., and to the cultivation it has received, is 

 more or less richly supplied with assimilable nutritive salts. 



The field-crop robs the surf ace- soil undoubtedly of a con- 

 siderable amount of nutritive matter, and the more so the longer 

 the land is under crops ; the forest plants can satisfy their 

 wants less fully in the soil, the poorer the latter, and the more 

 exacting the species of tree grown, and the less provision has 

 been made for its roots to penetrate deeply in the soil. Bat 

 when coppice is grown associated with field-crops (Had-wcdd], 

 the greater or less reduction in fertility of the soil occurs every 

 15 to 20 years only ; or when high forest is so grown (Roder- 

 wald and Waldfeldbau) , only every 80 to 100 years : if then, 

 the soil-covering is carefully protected on areas so treated, no 

 litter removed and the soil by nature sufficiently rich and moist, 

 the results of the deprivation of nutriment will be felt very 

 little. In the case, however, of poor soil exhausted by the 

 fieldcrops, bad consequences will result for the forest growth ; 

 if this is not visible at once during its youth the wood must 

 undoubtedly suffer in its subsequent development. 



Whenever temporary field-crops are to be grown on a 



