-8- 



should be applied. Unless the soil is obviously very acid we ought not to 

 apply lime vfithout first making a soil test. In grandfather's day, folks 

 took sulfur and molasses in the spring on the assuraption that it would do 

 no ham and it might do some good. Some folks lime the soil on the same 

 basis, a little now and then as a matter of insurance. 



In the absence of a soil test, much can be learned about the need for 

 lime by studying the natural growth of weeds, grasses, etc. If orchard grass 

 grows waist high, we needn't worry about soil acidity. And if clovers thrive, 

 there is reason to believe that conditions are reasonably favorable for the 

 trees. But if the cover crop consists of a discouraged grovith of cinquefoil, 

 sorrel, dewberries, poverty grass, and certain sedges, there is ev^ry reason 

 to believe that the soil is very acid. Ordinary grasses fail to grov/ before 

 these miscellaneous acid tolerant plants occupy the soil. An occasional ap- 

 plication of lime is of great benefit in maintaining a good cover- crop which 

 exerts an indirect effect upon the troo. The continued use of sulfur in the • 

 control of apple scab has more or less completely changed the type of cover 

 crop in many of our orchards. Tliis is to be expected since 500 pounds of sul- 

 fur mixed with the surface six inches on an acre of fine, sandy ioam tends to 

 lov/er the acidity rating by about one-half a pH unit. In other words, a soil 

 rating pH 6 might actually become pH 5.5 after applying a quarter of a ton of 

 sulfur per acre. It is interesting to note that many of our best orchards 

 are on soils ranging betv/een 5.5 and 6.5, 



One other factor in connection with soil acidity should also be con- 

 sidered. Magnesium deficiency is becoming a serious problem, particularly in 

 eastern Massachusetts. Many such orchards are on Gloucester or Merrimac soils 

 which are naturally low in magnesium. Such soils are also inclined t'l be 

 strongly acid. As a matter of good orchard management, soils of this kind 

 should be limed, using a high magnesium or dol :)mitic limestone. This will 

 aoc mplish two purposes. It will tend t'l c 'nditi on the s 'il by reducing 

 acidity, and it may ultimat^ily supply s me of the magnesium nw lacking in 

 the soil. But if the deficiency is severe, a more readily available form 

 of magnesium, such as magnesiuiii sulphate -tr epsom salts, should als'i be ap- 

 plied. An application of high magnesium limestone seems to be long overdue 

 on the average fruit farm. In view of the fact that 50 gears may have elapsed 

 since some of our fields received an application of lime, the 50th Anniversary 

 of the Massachusetts Fruit Qrowers ' Association is an appropriate time to satis- 

 fy a long felt need. 



To clear up any misunderstanding concerning the relation of the pH num- 

 bers to actual soil acidity the following figures are presented: 7 represents 

 a neutral soil; 6,5 slightly acid; 6.0 moderately acid; 5.5 medium acid; 

 5,0 strongly acid; 4«5 very strongly acid; and 4.0 extremely acid. A soil 

 which rates pH 4 is ten times as acid as one v;hich rates 5, and one hundred 

 times as acid as one vihich rates 6. Practically all of our Massachusetts 

 soils fall within the range of pH 4.5 to pH 6.5. 



Evolution of the apple box: Bin - Barrel - Basket - Box, 

 Perhaps the Bag deserves a place in this scheme of things. 



