THE FOREST NURSERY 257 



Recent experiments by Guif 1 on sandy soil poor in plant nutri- 

 ents show the great importance of lime even when used alone in 

 stimulating growth in spruce, Scotch pine, and fir, both in the 

 seedbed and in the transplant bed. The experiments appear to 

 show that lime had a better effect on growth than superphosphates, 

 nitrate of potash, or cow manure where the following amounts were 

 used per 100 square feet of seedbed or transplant bed. 



Lbs. 



Nitrate of potash 7.3 



Superphosphates 9.2 



Lime 18.3 



Cow manure 550 



Nitrate of potash, Chilian saltpeter, and other materials rich 

 in available nitrogen should not be applied to the seedbeds or 

 transplant beds until they are needed by the growing plants, 

 because they are leached from the soil and lost by excessive rain- 

 fall. They should be applied sparingly, only in quantity necessary 

 for immediate use. When used in excess, not only is the surplus 

 lost through leaching, but the young nursery stock, particularly conif- 

 erous stock, is likely to be seriously injured. It is best to apply 

 them at the rate of 100 to 200 pounds per acre, one or more times 

 during the growing season as found necessary, or in mixture with 

 other materials. 



Kainit and wood ashes are particularly rich in potash. Either 

 may be used to supply a deficiency in potash due to the repeated 

 removal of nursery crops. Kainit gives good results on soils that 

 are inclined to be overwet. Wood ashes, although chiefly valuable 

 for their potash content, contain considerable phosphoric acid and 

 also serve as an important amendment for sandy soils. Leached 

 ashes have lost a large part of their available plant food, but as a 

 soil amendment are as valuable as in the unleached form. Potash 

 is not readily lost from the soil by leaching. Either kainit or 

 wood ashes can be added to the soil in the autumn and by so 

 doing all danger from applying to the beds immediately before 

 the seed is sown or after the plants are up is removed. A ton of 

 kainit per acre is not too much to apply to overwet soils deficient 

 in potash. One or two tons of hardwood ashes per acre can be 

 used as a top dressing in the autumn, to be worked into the soil 

 the following spring. 



1 Guif, E.: Annales de la Science Agron., 6. 1913. 



