LIMING ORCHARD SOILS 



^C J. 



VtTiy should an orchardist be interested in liming his soils, anyway? .-iftc 

 all, a fruit tree is just a tree and who ever seriously considered applying lir-ie 

 to tracts of timber? Yes, a fruit tree is just a tree but we are asking it to 

 produce a crop every year, not once in thirty or forty years. Consequently, we 

 must give that tree the best soil environment that we can, to keep it at a high 

 level of production. For that matter, we may someday lime and fertilize timber 

 trees if the demand for forest products becomes sufficiently acute. About eightee; 

 years ago, the writer visited some fertiliser trials with pine trees near Berlin, 

 Germany and saw some very marked responses of timber trees to the use of fertilizers 



If we are interested in creating the best possible soil environment for the 

 tree to grow in, what is the role of Lime? Lime plays many roles in the soil, both 

 simple and complex. Following is a short discussion of some of them. 



First, we say that we want to correct the soil acidity. Soil acidity is a 

 bad thing and we want to get rid of it. Therefore, we vi^ant to add lime. ilThile in 

 a sense this statement may be correct, it does not explain all that is involved. 

 Soils are acid because of an abundance of active hydrogen ions. V/e could also say 

 that they are acid because of the absence of calcium, magnesiimi and some of the 

 other basic elements. Actually, we are more concerned with the latter statement 

 than the first. iVe are much more concerned about the absence of calcium and 

 magnesium than we are about the presence of hydrogen. If the soil is well supplied 

 udth the basic elements, calcium and raarnesium, the acidity as represented by 

 active hydrogen will take care of itself. In fact, the hydrogen ion plays a very 

 important and vital role in the nutrition of a plant. It has been sho;vn that the 

 hydrogen ion is not necessarily a villain and that some "acidity" is actually a 

 good thing. 



If liming is an essential operation in the treatment of acid orchard soils, 

 hovr much lime should one apply? The conventional procedure is to take a repre- 

 sentative sample of soil and have it tested for "pH". Recommendations are then 

 based on the pH test. This procedure is satisfactory as far as it goes but there 

 may be other points to consider besides pH when applying lime to orchard soils. 

 The terrain of an orchard may be steep and it may be about as easy to apply two 

 or even three tons to the acre as it is to apply one ton. Hence infrequent hea^.^ 

 applications of lime would be more practical than frequent light applications. 

 Another factor for orchardists to consider is the acidifying materials used in 

 carrjang out the spray program. The most important acidifying element is sulfur. 

 It takes about three pounds of limestone to neutralize one pound of sulfur. 



Some orchardists using sulfur ddst may use as much as five or six hundred 

 pounds of this material per acre per year. To neutralize this quantity of sulfur 

 1500 to I8OG pounds of limestone would be required. Hence, an orchardist using 

 large quantities of sulfur should make heavier 'applications of lime than one using 

 much smaller quantities of such acidifying substances. 



In any discussion of the liberal use of limestone on Massachusetts soils, the 

 role of boron should be mentioned. For most plants to grow normally, a fairly 

 definite balance of calciijm and boron must exist in the soil. Since the natural 

 supply of boron is fairly lov; in most Massachusetts soils, heavj' applications of 



