Killing of Plant Tissue by Low Temperature 281 



tends to improve the quality of the fruit by increasing its size. Fer- 

 tiHzing with nitrogen should be as light as it is possible to give and 

 yet keep up proper vigor and size of the tree by combining nitrogen 

 fertilizing with pruning and good cultivation. This may be said, 

 however, that since it has become the regular practice to spray 

 peaches, this injury to color is not so serious as it formerly was be- 

 cause the spraying burns into the peach generally a rather brilliant 

 color. If in addition to spraying the fruit is thinned and the trees 

 kept well open, the injury to color and diminished resistance to rot 

 from the use of nitrogen is not so great. 



Probably under average conditions a good system to follow 

 would be to fertilize with the equivalent of one or one and one-half 

 pounds of sodium nitrate to the tree and to prune as much as possible 

 without reducing the crop of high-grade fruit in any year. The ni- 

 trogen should be applied not every year but only often enough to 

 maintain the desired size of the tree, since the pruning has a dwarf- 

 ing effect. It may be observed that inducing vigorous growth will 

 cause a late growth in autumn; and that therefore the fruit buds 

 and wood will not be in a desirably mature condition for winter. 

 This is certainly true in some northern sections and in case of buds has 

 in several years since 1901 been true in Columbia. Since 1901 there 

 has probably been only one winter when a larger percentage of buds 

 were killed on late growing than on early maturing trees in extreme 

 southern Missouri, and even in that year-1911-12 the wood of the 

 vigorous trees best recovered from the effects of the winter. It 

 should be remembered that in southern Missouri the soil is so light 

 and the season so long that it is not easy to prolong the growth of a 

 peach tree more than two years from planting enough to prevent its 

 going into winter in the best condition for that section. 



It may be said that before recommending a method like this 

 for increasing the hardiness of buds, it probably should be tested 

 out during a period of ten or twelve years so that observations will 

 extend through enough seasons that one may be sure he has struck an 

 average. However, this may be said, that the methods here rec- 

 ommended are certainly the best for the orchard, regardless of the 

 effect on the hardiness of the tree. Fertilizing with nitrogen has 

 caused the tree to resist certain diseases like shothole fungus, as well 

 as to recover from the effects of winter freezes, heavy crops, 

 etc., and has, of course, given a larger tree that could bear a much 

 heavier crop. Heavy pruning has had similar effects except that 



