DISEASES OF PLANTS. 147 



The estimation of forest revenue, A. Aknould {licr. Eviix ct FovvIh, JS 

 (1909), No. 21, PI). (l'/l-6Jf9). — A discussion of methods of estimating forest 

 revenue for the purpose of taxation. 



Forest mapping and timber estimating as developed in Maryland, F. W. 

 Besley (Proc. Soc. Amcr. Foresters, J, {1909), No. 2, pp. 196-206). — A detailed 

 account of work accomplished along this line in Maryland is given as having 

 suggestive value at least for similar work in other States. 



The standardizing of log measures, E. A. ZnxiLKR {I'roe. ^oe. Amer. Forest- 

 ers, .'i {1909), No. 2, pp. 112-lHJi). — The author discusses the results secured 

 by using several of the various log rules employed in this country, and comes 

 to the conclusion that these measurements could be best standardized by 

 measuring logs by the middle diameter and selling them by the cubic foot or 

 hundred cubic feet, each producer in the various wood-using industries to 

 determine his own factor for converting raw material into quantities of finished 

 products. 



Wood preservation — a determining factor in forest management, H. F. 

 Weiss {I'roe. Soe. Amer. Foresters, .) {1909), No. 2, pp. 18')-t95). — The author 

 states that the preservative treatment of timber may be considered a specialized 

 branch of forestry, and aims in this paper to show the relation of this 

 specialization to forestry and how one is an integral part of the other. 



Shakes and shake-making in a California forest, C. H. Shinn { Proe. Soc. 

 Amer. Foresters, .'/ {1909), No. 2, pp. 151-171). — This is a brief presentation 

 of the claims and limitations of this miuor forest industry relative to its posi- 

 tion in modern forest managcmeut. 



DISEASES OF PLANTS. 



The control of malnutrition diseases of truck crops, L. L. Harteu ( Virgmia 

 Truck 8ta. Bui. 1, pp. Jf-16, figs. 4)- — The practical conclusions derived from 

 experiments made in cooperation with the Bureau of Plant Industry of this 

 Department on the control of diseases of truck crops due to faulty nutrition 

 are given. The technical results of the investigation are to be the subject for 

 another ijublication. 



In the region covered by this investigation commercial fertilizers are used 

 to a great extent in connection with the production of trucking crops, and 

 in some cases diseases have appeared that partially or wholly destroyed the 

 crops. The diseased condition can be recognized by the retardation of growth, 

 changes in color, root injury, etc. The most prominent conditions discovered in 

 the lands subject to this trouble were their acidity, deficiency in humus, and 

 absence of nitrifying bacteria. 



One of the most important factors contributing to malnutrition was found 

 to be the exhaustion of the organic material in the soil, and various methods 

 were investigated to remedy or prevent the prevailing conditions. The means 

 attempted were the limitation of the amount of fertilizer used, the adjust- 

 ment of the composition of the fertilizer to the crop requirements, and the 

 maintenance of organic matter in the soil. It was found that for many crops 

 the amount of commercial fertilizer could be profitably reduced to a considerable 

 extent, and the addition of lime was also of direct benefit with most crops. 

 Stable manure applied at the rate of 10 to 20 tons per acre gave large increases 

 in yield of cabbage and spinach, and experiments with cowpeas showed that 

 good results could be obtained by the cultivation and plowing under of the 

 crop. This, together with a proper rotation, it is thought will correct the 

 troubles complained of. 



