No. 1, August, 1920] AGRONOMY 3 



17. Connor, S. D. Agricultural value of Indiana peat and necessary fertilizers. Jour. 

 Amer. Peat Soc. 13: 13-17. 1920. — Indiana contains several hundred thousand acres of peat 

 and muck soils, mostly neutral, but some acid. If properly drained and fcrt ilized t hese soils 

 are capable of producing large and profitable crops. Ordinary crops on neutral peat soils 

 respond to potash fertilization; on acid ones to lime and phosphate. — G. B. Rigg. 



18. Dunbar, B. A., and E. R. Bin nic wins. Proso millet investigations— analysis of 

 the oil— a characteristic alcohol. Jour. Amer. Chem. Soc. 42: 658-666. 1920. 



19. Elayda, I. A preliminary report on the acclimatization of alfalfa. Philippine Agric. 

 8: 70-76. 1 pi. 1919. 



20. Ellis, J. H. The stage of maturity of cutting wheat when affected with black stem 

 rust. Agric. Gaz. Canada 6: 971. 1919. — Experiments conducted at the Manitoba Agricul- 

 tural College show that, contrary to popular notion, wheat attacked by rust should not be 

 cut on the green side. Two fields of badly rusted Marquis wheat were divided into seven plots 

 each. Seven stages of maturity starting with the late milk stage were examined in relation 

 to weight and quality of grain yield. Premature cutting resulted in a brighter color of the 

 grain but decreased yield. Cutting when the grain was firm showed the greatest weight per 

 bushel and greatest yields. Grain cut in the "late" milk stage gave 56 pounds per bushel 

 and that cut in the "firm" stage 59 pounds per bushel. — O. W. Dynes. 



21. Francis, T. C. Tobacco-growing in Cuba. Sci. Amer. Supplem. 88: 304-305. 6 

 fig. 1919. 



22. Garner, W. W., and H. A. Allard. Effect of the relative length of day and night 

 and other factors of the environment on growth and reproduction in plants. Jour. Agric. Res. 

 18: 553-605. PI. 64~79, 35 fig. 1920. — The duration of the daily period of illumination was 

 found to be a factor of the first importance in the growth and development of plants, par- 

 ticularly with respect to sexual reproduction. At Washington, D. C, during the summer 

 months a number of species and varieties were subjected to continuous daily periods of solar 

 illumination of 5, 7 and 12 hours' duration, by placing the different series of test plants in a 

 dark chamber at 3, 4 and 6 o'clock, p.m., respectively, and returning them to the open at 

 10, 9 and 6 a.m., respectively, on the following morning. In certain cases the daily exposure 

 consisted of two periods, daylight at 10 a.m. and 2 p.m. to dark, 4 hours of darkness at mid- 

 day thus intervening. The control plants were fully exposed throughout the entire day. 

 Soja max, Nicotiana tabacum, Aster linariifolius, Mikania scandens, Phaseolus vulgaris, 

 Ambrosia artemisiifolia, Raphanus sativus, Daucus carota, Lactuca saliva, Brassica oleracea, 

 Hibiscus moscheutos, Viola fimbriaiula, Solidago juncea, were used. In all species tested 

 the rate of growth was proportional to the duration of the daily exposure to light. The length 

 of the vegetative period (germination to flowering stage) was shortened, lengthened or not 

 affected, depending on the species and variety. The time required for ripening of fruit was 

 markedly reduced. Under the artificially shortened daily illumination the duration of the 

 vegetative period of early, medium, late, and very late maturing varieties of soy beans was 

 only 21 to 28 days while the respective periods of the controls were 26, 62, 73, 110 days. All 

 varieties thus behaved as early maturing ones. Similarly, the vegetative period of Aster 

 linariifolius was reduced from 122 to 36 days and that of Maryland Mammoth tobacco was 

 reduced from 155 to 60 days while Connecticut Broadleaf tobacco was not materially affected. 

 A variety of Phaseolus vulgaris from the tropics attained the flowering stage in 28 days under 

 the shortened exposures as against 109 days required by the controls, and the corresponding 

 periods for Ambrosia artemisiifolia were 27 and 85 days. Mikania scandens, Raphanus sati- 

 vus and Hibiscus moscheutos, on the other hand, were unable to flower under the reduced light 

 exposures. Two daily exposures with 4 hours' darkness intervening had little effect on time 

 of flowering. By suitably controlling the duration of the daily illumination soy beans, aster 

 and ragweed were induced to complete two vegetative and reproductive cycles in one season. 

 The relation of the seasonal length of day to the natural distribution of plants and to practical 



