AMERICAN SYLVICULTURE 



results. The best kalium fertilizer seems to be kainit (kalium 

 chloride) ; the best nitrogen fertilizer is saltpeter. 



After Von Schroeder, the following quantities of phosphates, 

 potash and nitrates are needed to raise 4,000,000 plants on an 

 acre of nursery: 



520 lbs kainit. 



60 lbs. superphosphate. 



320 lbs. whale guano. 



III. Humus, the natural forest manure, is the cheapest fer- 

 tilizer obtainable in the woods. Mould of Pines mixed with that 

 of broad-leaved species is best. Mould just one year old is said 

 to be richest in the bacilli favorable to tree growth, and to be 

 devoid of filiform fungi disastrous to plants. 



The weeds removed from nurseries furnish, through their de- 

 composition, a valuable humus. 



A mixture of humus with street sweepings, kitchen refuse, 

 loam, burned lime, etc., is often placed in heaps near the nurseries. 

 The heaps are kept in a rotation so that the heap made in 1913 

 is used in 1916. The heaps are stirred up repeatedly so as to 

 be acted upon by the air. 



I\^. Vegetable matter other than humus. Vegetable fertilizer 

 may be obtained by raising, on the fallow beds, during the fallow 

 year, cowpeas, clover, lupine (the latter on sandy soil) and other 

 leguminous plants, all to be plowed under in fall. 



Leguminous plants increase the nitrogen in the soil. 



V. Wood ashes: Excessive use of wood ashes is disastrous to 

 sprouting plants, especially on sandy soil. Besides kalium, wood 

 ashes contain from 5% to 20% of phosphoric salts. Wood ashes 

 should be used, however, moderately in Yellow Pine nurseries. 



VI. Sod ashes are recommended where other fertilizers are too 

 costly. Sods of grass, of weeds or of huckleberries are dried and the 

 majority of the dirt is removed. From the sods is constructed a 

 kiln resembling a charcoal pit, wherein layers of sod alternate 

 with layers of brushwood, waste, thinnings, etc. The kiln is coated 

 with sods and wet dirt. Kilns burn, according to size, for from 

 two days to two weeks. The sod ashes contain all mineral fertil- 

 izers needed; have great hygroscopicity and are free from insects, 

 fungi and other bearers of plant diseases. 



Sod ashes should be exposed to the atmosphere for a year 

 before use, and should then be well mixed with the top layer of 

 nursery dirt. 



