rornjyloc^LC od Poxama^phs 



NITROGEN IN PE.ACH TREES . A 17-year-old unfertilized peach orchard in Davis, 

 California, v;as. fertilized in September with ammonium sulfate, calcium nitrate, 

 and urea. The soil and trees were studied during the vdnter and early spring 

 to learn hov/ the nitrogen from these three sources behaved in the soil and in 

 the trees, itamonium sulfate was fixed in the soil more than the other forms 

 of nitrogen, but nitrates had gone down as far as the third foot by February 

 27. Analysis of the shoot bark on March 7 showed the nitrogen content in- 

 creased over that of unfertilized trees. The source of the nitrogen made lit- 

 tle difference. This was also true of the nitrogen content of the leaves which 

 were first examined on April 10. This is in harmony with the usual belief that 

 under most conditions fruit trees will maJce about equally good use of nitrogen 

 from various sources. (Proc. Amer. Soc. for Hort. Sci., Vol. 45, page 5). 



— J. K. Shaiv 



VfARMING THINGS UP . You have doubtless noticed that snow melts more quickly 

 on a black tar road than on a lighter colored cement road. This is because 

 a dark surface absorbs more heat from the S'lm. Observations in New Hampshire 

 show that the inner bark on the south side of a fruit tree may rise to 60° F. 

 or more on a cold winter day, while that of the north side may be 30° to 50° F. 

 lower. Painting the trunks white resulted in much lower temperatures, at no 

 tine more than 10° above that of the air. At night or on cloudy days, there 

 was little difference in bark temperature. If we have sunny weather during 

 a January thaw, peach buds vdll swell much more than \vhen the v;eather is 

 cloudy. (Proo. Amer. Soc. Hort. Sci., Vol. 45, page 33) — J. K. Shaw 



WAX SPR AYS FOR BLOSSOM THINNING . There is considerable interest in the use of 

 sprays for blossom thinning. Hand thinning is laborious and, with prospects 

 of labor shortage, anything that will save labor is of interest. The Michigan 

 Experiment Station proposed to use an oil-wax emulsion for this purpose. It 

 was first used to reduce transpiration and thus economize water in dry periods. 

 A 1/0 concentration used in the regular sprays gave a marked increase in the 

 size and yield of Montmorency cherries. Used as a blossom thinning spray, 

 it seemed to be somewhat effective but more work is needed to determine whether 

 it is entirely satisfactory. It does not injure the foliage as does Elgetol 

 or a Dormant DN spray. We hope to try the oil-wax emulsion this season and be 

 able to report on its effectiveness under our conditions. (Proc, Amer. Soc. 

 Hort. Sci., Vol. 45, page 42). — J. K. Shaw 



ELGETOL KILLS POLLEN GRAIIJS Elgetol used for blossom thinning kills the pis- 

 tils and other parts of the flower; also, it burns the young leaves to some 

 extent. Of course, killing the pistil before fertilization of the egg cell 

 prevents setting of the fruit. V/ork at the Cornell Station shows that Elgetol 

 also kills pollen grains before or after germination even in very dilmtte con- 

 centrations. Therefore, they say that Elgetol should be called a "pollenicide" 

 not a "caustic spray." However, bees may sometimes bring viable pollen from 



