628 EXPERIMENT STATION RECORD. 



with water often have some of their leaves visibly affected, indicating that 

 changes are produced in the sap which are largely responsible for the alter- 

 .■itious in the leaves above, and these changes should not be attributed to the 

 cutting off of the water supply, but rather assigned to its contamination. 



The effect of city sm.oke on vegetation, A. L. Bakke {Iowa St a. Bui. 145 

 (1913), pp. 383-409, pi. 1, figs. 22).— K report is given of a study of the smolse 

 problem in Des Moines, Iowa, in which a discussion is given of the sources of 

 smoke, various smoke belts, their characteristics, and the susceptibility of plants 

 to smoke. Some investigations were conducted on the nature of smoke, physio- 

 logical factors in plant injuries, the effect of different smoke constituents, and 

 the relation of smoke to the storage of material in plants. 



It was found that about manufacturing plants the region may be mapped off 

 in concentric belts, each represented by certain forms of plant life, as some 

 species are more susceptible to smoke injury than others. On account of their 

 resistance to smoke, certain plants are recommended for planting about indus- 

 trial centers. 



Toadstools and mushrooms of the countryside, E. Step {London [1913], 

 pp. XVI +143, pis. 136). — Popular descriptions are given of a considerable 

 number of mushrooms, with notes on their distribution, habitat, edible or poison- 

 ous qualities, etc. 



FIELD CROPS. 



The effect of soil moisture, plant food, and age on the ratio of tops to 

 roots in plants, F. S. Harris {Jour. Amcr. Soc. Agron., 6 {1914), No. 2, pp. 

 65-75). — In this paper previous literature on this subject is reviewed and 

 results given of pot experiments conducted at the Utah Station in which wheat, 

 corn, and peas were grown in soil extracts, sand, and clay loams that were of 

 varying concentrations and of different moisture content and differently fer- 

 tilized. 



The results " show with w-heat seedlings growing in soil extracts the green 

 weight, dry weight, and length of roots was proportionately greater in the dilute 

 than in the concentrated soil extract. Corn, wheat, and peas growing a number 

 of weeks in sand containing different amounts of moisture showed a proportion- 

 ately greater root growth in the drier sand. Corn grown in glass tubes 75 days 

 showed a relatively greater root growth where the level of free water was a con- 

 siderable distance below the surface. Different roots of the same corn plant 

 grown in very wet and in moist sand showed a greater root growth with the 

 lower amount of water. 



"Tests with corn and wheat showed that the ratio of tops to roots was 

 affected by soil moisture even during the germination stage. Wheat harvested 

 at different stages showed relatively more roots during early stages of plant 

 growth than later. Wheat grown to maturity showed a greater relative root 

 growth with low than with high soil moisture, and the moisture during the early 

 stages of growth had the greatest influence on that ratio. Fertilizers added to 

 the soil reduced the relative root growth of wheat." 



Fertilization and cultivation of corn, cotton, and tobacco, C. B. Williams 

 {North Carolina Sta. Circ. 18 {1914), pp. 16). — This gives fertilizer formulas 

 for com and cotton on land in fair condition in the coastal plain section and 

 in the Piedmont section, and also for tobacco. 



Annual report, 1913-14, R. E. Blouin and A. H. Rosenfeld {Rev Indus, y 

 Agr. Tucumdn, 4 {1914), No. 9-10, pp. 369-492, pi. 1, figs. 21).— This report 

 summarizes the work at the experiment station at Tucumdn, Argentina, in 

 varietsil, manurial, and cultural tests with sugar cane, maize, cotton, and 

 legumes for the calendar year 1913. 



