LII'-IIHG ORCHARD SOILS 



To offset the acidifying effect of repeated applications of sulfur in an 

 orchard, about 3 pounds of high magnesium lime aro needed for each pound of sulfur 

 applied as sulfur dust or wettable sulfur spray. In other v;ords , an orchard 

 receiving 500 pounds of sulfur per acre per year will need about 1^ tons of lime 

 every other year just to neutralize the sulfur. No wonder many of our orchard 



soils are extremely acid, 



(-' 



How does a fruit grower go about getting the high magnesium lime needed for 

 his orchard? ¥[e put this question up to L, C. Kimball, Worcester County 

 Assistant in Conservation. Here are his comments; "First contact your local 

 community committeeman or the County Agricultural Conservation office, A farmer 

 requests as much lime as he thinks he needs. The community committee then 

 considers the request. It may recommend more or less than the farmer, although 

 the county committee usually approves the smaller of these tv;o amounts. Bulk 

 spreading is the common practice in larger orchards, the lime coming to the farm 

 in trucks. Smaller orcnards still get delivery in bags. At least three lime 

 concerns have a product testing 21^0 magnesium oxide (MgO), One of these concerns 

 (Les) also has a product from another quarry testing 7;o. Others deal in high 

 calcium lime, some testing as low in HgO as ,5;^o". 



There is seldom enough of the 21% product to supply the demand among fruit 

 growers. But every fruit gro-wer should specify this high magnesium type of lime. 

 No cheaper form of magnesium, to prevent a deficiency in future years is available. 

 By all means get a 21^o luigO lime if you can, and in no case apply a lime with less 

 than 7% MgO. Conservation v/orkers \/ill be very cooperative in conforming so far 

 as possible to the needs of the fruit grower. Tell him what you want. As in 

 some other fields, it may be a case of "the v;heel that does the squeaking gets 

 the grease". The 3 to 1 ratio between lime and sulfur is well worth remembering, 



THB MAG::BSIU1>1 deficiency SITUATION 



(V\fe quote here part of a letter on this subject written by 1(7. G, Colby of the 



Agronomy Department) 



"Many if not most of the soils of our state are potentially deficient in 

 magnesium. The easiest and cheapest way to supply magnesium, unless serious sym- 

 ptoms of deficiency are present, is to use magnesium limestone. Since many of the 

 orchard soils need lime, the use of dolomitic limestone serves a double purpose, 

 viz,, correcting a soil acidity and supplying the nutrients magnesium and calcium. 

 The use of high calcium lime mijjht even accentuate the need for magnesium. 



In the mineral nutrition of plants, the plant tends to take in a fairly 

 constant quantity of bases, calcium, magnesium, potassium and sodium. If the 

 available supply of any one of these elements greatly overbalances the supply of 

 any of the other three, deficiency symptoms of any one of these three may eevrlop^ 

 In other v^ords, an over-supply of calciiom makes it more difficult for the plant to 

 obtain both magnesium and potassium and an over-supply of potassium in turn makes 

 it more difficult for the plant to obtain magnesium and calcium, etc. This helps to 

 explain, for example, why plots treated with potash frequently develop magnesium 

 deficiency symptoms whereas plots receiving no potash show no magnesium deficiency. 



It seems to me that the A.CP. has some-^ing very worthv;hile to offer to the 

 orchardists of Massachusetts and that if the conservation program can give magnesium 

 limestone rather than high calcium limestone, they will be accomplishing two objec- 

 tives, viz,, neutralizing excess soil acidity and supplying the nutrients, calcium 

 and magnesium," 



