-2- 



Further Evidence on Internal Cork 



Papers dealing with internal cork and relpted troubles continue 

 to appeaj. The raost recent one is from Ca,np.da ajid reports that they are 

 associated with: 



1. High csxhona.te lime soils with a high pH value. Apparently this condi- 

 tion favors nitrification, decreases "boron ava.ilability and interferes 

 with free passage of water in the soil, 



2. A high percentp^e of nitrogen and organic matter especially when asso- 

 ciated with shallow soils. 



3. Soil moisture fluctuations especially in association with high nitrogen. 

 h. Low available potash and high phosphorus-pota.ssium ratio. 



Internp.1 cork was produced experimentally "by water logging the 

 soil in pots, thus killing the lo^er half of the root system. Applications 

 of "boron, either applied in solution to the soil or injected into the trees 

 in solid form controlled the disease. 



Many of these observations agree with those made in Massa.chusetts. 

 We should experiment with boron next summer but it should be remembered that 

 this material is toxic to plants and should not be used except under super- 

 visition of some one v;ho understands its use. ( J« K. Shaw) 



Boron and Root Development 



The prevalance of internal cork in certain varieties of apples in 

 1936 is a cause of much concern with many growers. This has been ascribed 

 to a lack of the minor element, boron, in the tree ajid to the severe drought 

 in mid-summer. There ha.s come to my n.ttention a. German publication which 

 brings out considera.ble evidence showing that when the boron supply is too 

 low root hairs fp.il to develop. This must interfere with water absorption 

 into the roots. Perhaps here is the explanation of the apparent connec- 

 tion bet\teen dry weather and boron deficiency as a cause of internal cork. 



(J, K. Shaw) 



The Descent of Potash 



A recent paper in the Jo-ornpl of Agricultural Research gives some 

 information as to the do\TiV7ard movement of potash in a clay loajti soil. Three 

 layers were considered, 0-7 inches, 7~21 inches, and 21-53 inches. Almost 

 one-thtrd of the applied potassium remplning in the soil ha,d moved from 

 the first to the second layer with no definite evidence that any had moved 

 into the third layer. This was during a period of Gk years. Probably 

 the downwajrd movement would be greater in our lighter soils in New England. 

 The author arrives a.t a, theoretical fertilizer rr-tio of nitrogen, phos- 

 ihoric acid and potash for apple trees in this soil of approximately 

 .558:3.25. What value this ratio mpy have as a guide for orchard ferti- 

 liza.tion is a little uncertain, (J. K. Shaw) 



t 



"Vitamin C in Apples 



At the Wpshington Experiment Station studies have been made as to 

 the effect of the ratio of leaf a,rea to fruit, the size of the fruit, aJid 

 the effect of storage on the vitamin C content of apples. The ratio of 

 leaf area to fruit was effective only indirectly as it affected fruit size. 

 A low leaf area resulted in sraa.ller ppples and a higher vitamin C content 

 p.s most of the vitamin is in or near the skin. The vitamin C loss was 

 greater when a.pples were stored at ^0° than at 32*^ , Delicious aJid Winesap 

 apples were studied. Studies made at oior own Stption show the vitpmin 

 C content of Winesap to be greater than that of Delicious, (J. K. Sha.w) 



