Periodical Literature. 309 



about $100. In their place he sets 2 to 3-year-old alder cuttings, 

 which after having performed the service of increasing the root 

 system of the spruce may be cut out in 15 years. In such a plan- 

 tation after six years the result was astounding. While the por- 

 tions left without alder showed up miserably (yellow color, low, 

 hardly larger than when planted 8 years before), the plants 

 among the alders showed a black green color, a height of 4^ feet, 

 a diameter of nearly 2 inches, a crown diameter of 2^ feet, with 

 stout, 3 to 5-foot long, fibrous root system among the alder roots. 

 The whole surface of the soil was permeated with very fine alder 

 roots bearing nodules many of which dead and in connection with 

 fibrils of the spruce — showing that the influence is directly trace- 

 able to this feature of the combination. Especially on abandoned 

 fields it has been observed that height growth soon ceases, caused 

 by the early competition of the too little extended, although much- 

 branched root system, as an investigation seemed to show. 



Green manuring with lupine on farmland proved of excellent 

 influence on the root system, as several experiments showed. A 

 2-year-old plantation in four foot spacing had strips of 12-inch 

 width sowed with lupine. While the 6-year-old untreated plan- 

 tation was about 3 feet high with i^-inch diameter, the part 

 planted with lupine showed 7 to 8 feet in height and over 2-inch 

 diameters ; the roots in the soil not covered with lupine exhibiting 

 few, within the lupine area thousands of fibrils. Occasionally 

 roots would lengthen beyond the lupine strips and then show the 

 same scarcity of fibrils. Unquestionably the nitrogen of the 

 tubercles of dead lupine roots becomes available to the spruce. 

 Very characteristic for the root system within the lupine area is 

 the deep "anchor" rooting, which even after 6 years went down 

 16 inches, otherwise absent; when the tap roots of the lupine, 

 now descending to 27 inches, shall have died, i. e., when the stand 

 closes up, the root system of the spruce is expected to deepen 

 correspondingly. Characteristic also is the absence of side root 

 development, which does not exceed 30 to 50 inches, so that little 

 root competition is experienced. 



A similar experiment made on raw humus or heath soil proved 

 the same beneficial influence of the lupine. 



In this experiment the cost of $12 per acre is also too high, but 

 it is obvious that it can be much reduced by diflFerent procedure. 



One way was to sow the lupine pods without soil preparation 



