20 BULLETIN 453, U. S. DEPARTMENT OF AGRICULTURE. 



Sugar, at first glance an excessively expensive amendment for use 

 on soil, is not so much more expensive than formaldehyde in the 

 quantities which appear of value in preventing damping-off at three 

 of the nurseries. If some unrefined sugar-bearing substance could 

 be substituted for the table product used in the experiments, it is 

 entirely possible that for certain soils sugar would become an eco- 

 nomically satisfactory treatment for coniferous seed beds. Zinc 

 chlorid also, while probably somewhat more expensive than formal- 

 dehyde, is not so costly as to be economically impossible on soils 

 where it may prove to be the most effective disinfectant. Both of 

 these substances are, however, decidedly more expensive than sul- 

 phuric acid or copper sulphate. 



The most troublesome thing about the treatment with acid is that 

 at some nurseries it is necessary to give treated beds frequent water- 

 ings during the germinating period for the protection of the roots of 

 the seedlings against chemical injury. This has been found to be 

 the case in acid plats at three nurseries, and with copper and zinc 

 salts at one nursery, respectively, where these disinfectants have 

 given evidence of greatest commercial value. At one of these 

 nurseries (Halsey, Nebr.) figures are available which indicate the 

 cost of the treatment with acid and subsequent watering. The 

 additional labor cost of the seed sowing, due to the use with it of the 

 acid application, was furnished by the forest officers. The figures 

 follow. 



Additional cost of seed beds at Halsey, Nebr. , due to acid treatment, per 1,000 square feet 

 (space occupied by paths excluded). 



Cost of acid (allowing for freight, drayage, and waste) SI. 00 



Additional labor in seed sowing, due to application of acid 80 



Labor cost of extra waterings required by acid beds during germinating period . 2. 70 

 Depreciation of containers for applying acid solution, and increased supervisory 

 cost (estimated), not to exceed 50 



Total charge against treatment 5. 00 



The above figures were obtained in 1912. Subsequent changes in 

 nursery practice have probably changed the costs, but no later fig- 

 ures are available. 



This cost of $5 per 1,000 square feet, or one-half cent per square 

 foot of seed bed, would seem very high if put on an acreage basis. 

 For extensive farming operations it would, of course, be excessive. 

 But because of the very high cost of coniferous seed and the very small 

 area on which the seed-bed operations of even a large nursery are 

 usually concentrated, this cost is easily offset by even a slight increase 

 in the stand of seedlings secured. The actual cost of production of 

 seedlings is seldom less than 50 cents per thousand by the end of the 

 first growing season. The prices commonly quoted by commercial 

 nurseries for seedlings of most species which have remained in the 





