AGEICULTURAL BOTANY. 429 



" The beaker metliod, with dried blood or cottonseed meal for ammonification, 

 with ammouium sulphate or dried blood for nitrification, and with mannite for 

 nitrogen fixation, is eminently satisfactory. 



" The ammonification of dried blood or of cottonseed meal runs parallel with 

 the numbers of bacteria while there is very little relation between the ammonifi- 

 cation of peptone solutions and numbers. 



" Increased nitrification leads to slight accumulations of nitrates in the soil. 



" Natural accumulations of nitrates in the soil tend to obscure the differences 

 due to the lime treatment. 



" The solution method for nitrogen fixation is quite unreliable. 



"Applications of lime increase the yield of oats; 2 and 1 ton per acre very 

 slightly, but 2 and 3 tons to quite a large extent. 



"Applications of lime up to 3 tons per acre increase the nitrogen content of 

 the oats crop more rapidly than the yield itself." 



The use of street sweepings from Montevideo as a fertilizer, J. Schroder 

 (Agros, 2 {1911), No. 11, pp. 315-317). — Analyses of this material are reported, 

 and its fertilizing value is briefly discussed. The dried material contained 

 9 per cent of water, 0.3 per cent of nitrogen, 0.35 per cent of phosphoric acid, 

 and 0.6 per cent of potash. The material is considered a valuable fertilizer 

 when not too coarse and freed from stones and other inert matter. 



Fertilizers, 1911 (Lab. Inland Rev. Dcpt. Canada Bui. 227, pp. 23). — 

 Analyses of 161 samples of fertilizers collected for inspection during May, 1911, 

 in the Dominion of Canada are reported. 



AGRICULTURAL BOTANY. 



A study on periodicity in plant growth as related to climatic variations, 

 E. Vanderlinden {Sejjarate from Rcc. Inst. Bot. L60 Errera Bruxelles, 8 

 (1910), pp. 2J,7-323, pis. 16; abs. in Met. Ztschr., 28 (1911), No. 7, pp. 33-',, 335; 

 Quart. Jour. Roy. Met. Soc. [London], 37 (1911), No. 160, pp. 364, 365).— 

 Phenological observations covering a period of 14 years on 39 species of plants 

 are recorded, and an attempt has been made to correlate these data with 

 climatological data, experimental evidence, etc. 



The greatest differences between actual and normal dates of flowering were 

 noticed in those plants which flower early in the spring. For plants flowering 

 normally in May less difference was noticed, but beginning with June they 

 gradually increased. Heat and radiation are said to be the only climatological 

 factors that sensibly affect the flowering of plants, the other factors being 

 practically negligible except occasionally with summer-flowering plants. The 

 factors that hasten flowering in dormant plants are temperature and radiation 

 above normal for several days. A low percentage of moisture in the air also 

 stimulates flowering, while cold, cloudy weather, with considerable rain, retards 

 it. Favorable or unfavorable conditions retain their effect for some time and 

 they are not entirely counterbalanced by changed conditions. 



In general, plants flower at certain times, which are determined to a large 

 extent by heredity, but when blooming is delayed flowers may be brought forth 

 by stimulating effects much lower than would be required for precocious 

 blooming. Autumn and winter climates are said to be without visible effect 

 on spring and summer flowering. Species of plants that normally flower about 

 the same time will, in most cases, be equally retarded or advanced in their 

 actual dates of blooming. Second blooming, as sometimes occurs in late summer 

 or autumn, is not due to earlier climatic conditions. An equal departure from 

 normal temperature lias less effect on plants in summer than in spring. 



