1905.] 



Manuring of Forest Trees. 



i73 



Society, for the purpose of ascertaining what form of manuring 

 is likely to give the best results ; one set of these proposed 

 experiments provides for planting on soil which is (1) unculti- 

 vated ; (2) cultivated, but unmanured ; (3) green manured 

 without artificials ; (4) green manured, with the addition of lime ; 

 and (5) green manured, with the addition of 8od kg. basic slag 

 and 400 kg. kainit. Another set provides for the application of 

 various combinations of artificial manures, but without green 

 manuring. 



Several experiments have already been made in Germany, 

 but sufficient time has not yet elapsed for any definite con- 

 clusion to be arrived at, though in one case at Eberswalde, where 

 a trial was begun in 1901, the trees on the manured plots show a 

 marked advantage over the unmanured plots. 



In this connection it may be of interest to record some obser- 

 vations on the subject of forest manuring recently made by 

 Dr. Schwappach, of Eberswalde. Dr. Schwappach considered 

 that nitrogen was the most important requirement for forest 

 plants. Lime, however, is regarded as important, as it helps to 

 make the stores of humus available for plant food. In many 

 cases, indeed, the favourable effect of basic slag seems due to 

 the lime which it contains. As only the cheapest manures can 

 be profitably employed in forestry, leguminous plants are of 

 the first importance as sources of nitrogen, while in other cases 

 slow and long-acting manures should be employed. Careful 

 management of the humus is a point which is considered deserv- 

 ing of special attention, as it is the only source of plant food in 

 the later stages of the trees. 



On poor soils, German experience shows that a preliminary 

 cultivation by green manuring, with the application of basic 

 slag, is a most successful method of securing a good growth from 

 young plants. The cultivation of leguminous plants offers 

 also the best means of deepening the soil. It is pointed out, 

 however, that guidance as to proper manuring should be 

 obtained from an analysis of the soil. The cost of manuring 

 will be well repaid by the rapid growth of the young trees and 

 by their successfully resisting the diseases and dangers attending 

 the early stages of growth. 



