248 



SCIENCE 



[N. S. Vol. XXXIV. No. ! 



Cisco, tells of efforts to protect California 

 fruits from frosts. It is a matter of credit to 

 the Weather Bureau and its California fore- 

 casters that during the winter of 1909-10 in 

 that state there was not a single forecast of 

 injurious frost that was not fully verified, 

 and, what is more satisfactory, there was not 

 a single frost injurious to fruit occurring dur- 

 ing that period which was not forecast from 

 twelve to thirty-six hours in advance. Efforts 

 are being made to select hardy plants which 

 will resist low temperatures, to render the 

 plant dormant and not sensitive during the 

 cold periods, and also to fight the cold and 

 minimize exposure thereto by producing heat 

 artificially. In the April number Mr. E. M. 

 Gruss, of Houston Heights, Texas, tells of the 

 beneficial effects of smudge fires to protect the 

 fruit and garden crops in the southern part 

 of that state by means of checking the noc- 

 turnal radiation. He points out the necessity 

 of rapid action the moment frost is predicted, 

 and also recommends the use of temporary 

 coverings of hay, straw, soil, slatted roofs or 

 mats, or by means of flooding or spraying. 

 At Grand Junction, Col., in the vicinity of 

 which temperatures as low as 15° were ob- 

 served on the night of April 12 last, ample 

 forecasts were widely disseminated by tele- 

 phone, and orchard temperatures were kept 

 above the danger point by means of artificial 

 heating. In the same number of the Review 

 Dr. P. F. Homer, of Pleasant Grove, Utah, 

 tells of work being done there to determine 

 the resistance of fruit buds to frost and the 

 factors which bring about the remarkable dif- 

 ferences noted whereby a freeze will kill one 

 bud on a twig and leave unharmed another 

 one adjacent to it, or will destroy the blos- 

 soms on one tree and not affect another of 

 the same species near by. Mr. W. E. Bonnett, 

 local forecaster at Presno, Cal., also tells of 

 successful efforts in fighting frost in the Cali- 

 fornia vineyards. On April 13, when the most 

 damaging frost in many years occurred near 

 Fresno, and reliable instruments recorded 

 temperatures of 27°, vineyards were protected 

 by means of fire pots in which was burned a 

 specially prepared fuel of sawdust and shav- 



ings. He points out the fact that danger 

 from frosts lies within very narrow limits, 

 and states that growers in his vicinity are 

 awakening to the fact that complete protec- 

 tion is easy and sure. In another note Pro- 

 fessor McAdie describes a new device called 

 an " antifrost candle," a cartridge which con- 

 sists of a cylindrical tube containing slow- 

 burning material. These cartridges are sus- 

 pended in an orchard just beneath the fruit, 

 the ends are lighted, and the heat produced is 

 distributed at the particular level where it i» 

 most needed. 



Andrew H. Palmer 

 Blue Hill Obseevatokt, 

 August 1, 1911 



SPECIAL ABTICLES 



THE NITROGEN AND HUMUS PROBLEM IN 

 DKY-FARMING 



The Utah Experiment Station has been eon- 

 ducting investigations for several years re- 

 garding the effect of crop production, under 

 strictly dry-farming methods, upon the nitro- 

 gen and humus content of the soil. A pre- 

 liminary report' of this work was issued last 

 year. The writer found, contrary to the 

 teachings of modem agriculture, that crop 

 production had not caused a decrease in the 

 nitrogen and humus content of the cultivated 

 soil when compared with that of the adjacent 

 virgin soil. 



Recently a criticism of this report ap- 

 peared in Science^ written by Mr. C. S. 

 Scofield, of the United States Department of 

 Agriculture. There are two main points in 

 Mr. Scofield's criticism: first, the character- 

 istic cultural methods in vogue in the Cache 

 Valley, Utah, were not emphasized so as to 

 bring out the differences between these and 

 the methods in vogue in the Great Plains 

 area of the United States; second, the noted 

 increase in nitrogen and humus content was 

 not correlated with the yields on the cropped 

 land. 



^ Utah Experiment Station, Bulletin No. 109. 

 ^Science, Vol. XXXIII., No. 855, May 19, 

 1911, p. 780. 



