1917.] PUBLIC DOCUMENT — No. 31. 25 a 



previous season. This material is composed principally of sug- 

 ars synthesized in the tops, and both synthesis and transloca- 

 tion to the roots appear to continue until the tops are killed 

 by frost. The destruction of the tops by rust, or their prema- 

 ture removal, must lessen the amount of sugars stored in the 

 roots, and therefore the crop of the following season. 



The absence of either nitrogen, phosphoric acid or potash 

 from the annual top-dressing limits the growth of the roots. 

 A complete fertilizer rich in nitrogen is required in generous 

 amounts. The percentage of nitrogen in all parts of the plant is 

 proportional to the amounts applied. The fertilizing constitu- 

 ents stored in the roots over winter appear to be nearly or quite 

 sufficient for the full development of the succeeding spring crop, 

 although nitrogen appears to be taken in small, and lime and 

 sulfuric acid in larger, quantities during the cropping season. 

 Sulfuric acid appears to equal or exceed phosphoric acid in im- 

 portance in the asparagus plant, but the sulfate of lime con- 

 tained in acid phosphate appears to meet fully the needs of the 

 crop for the former acid. 



THE CRANBERRY SUBSTATION, WAREHAM. 



Work in the cranberry substation during the past year has 

 related as usual to a wide variety of subjects. Some of the 

 more important results and conclusions based upon the work of 

 the previous year have been presented in Bulletin No. 168, 

 which will be found in later pages of this report and which can 

 be obtained also as a separate if desired. 



Experiments designed to determine the conditions under 

 which the fruit in storage, both before and after screening, will 

 keep best received a large share of attention. Experiments in 

 holding the unscreened fruit under varying conditions affecting 

 ventilation, temperature and the admixture of leaves and vines 

 with the fruit were carried out with results which in general 

 might have been anticipated from the known facts concerning 

 other fruits. Among the most significant of the results of the 

 year described in the bulletin is the demonstration of the im- 

 pairment in keeping quality resulting from the ordinary methods 

 of screening and handling. Although the berries do not show 



