NURSERY PRACTICE FOR PRAIR1E-PLALXS PLANTING 97 



Since small deciduous seedlings with little top are likely to slip out, 

 each inner face of the transplant board is lined with a thin strip of 

 sponge rubber one-half inch wide and one-eighth to three-sixteenths 

 inch thick, to provide a firmer hold on the stems of the seedlings. 

 Details on construction of transplant boards have been given by 

 Olsen {27). The threaded transplant boards are placed in the trench 

 to the proper depth and the trench is filled by dragging in loose soil 

 and caving in the side walls. 



In some nurseries the transplant trench is hand-made with trencher 

 of a commercial type, consisting of two sheets of steel from 24 to 30 



Figure 33. — Trencher used in nursery transplanting in operation. Trencher 

 blade is constructed of 2 pieces of % 6-inch plow steel welded together in front 

 and attached to tool bar of tractor by means of curved cultivator shank. Di- 

 mensions of one side of blade are as follows: Bottom length, 30 inches, top 

 length, 20 inches, depth below flare, 10 inches, reinforcement bar at bottom is z /% 

 by 3 inches. Trench is 1 inch wide at bottom and 2 inches wide at top. A series 

 of small knobs may be welded along the rear edge of the trencher blade, if the 

 trencher has too great a smoothing effect. A, Trencher in action; B, close-up 

 of trenching tool. 



inches long and 10 to 12 inches high, welded together to form a long 

 wedge-shaped tool. A sturdy handle of galvanized iron pipe is 

 attached, and, in use, the instrument is jabbed into the ground by 

 stepping on it. On withdrawal, a wedge-shaped trench is left about 

 10 inches deep and 1.5 to 2 inches wide at the top. The trencher is 

 operated by one man, and where the soil is quite sandy, good produc- 

 tion is attained. 



In heavy soils, the hand trencher is not favored because of low- 

 efficiency, and because it leaves smooth, shiny side walls which may 

 open up in very dry weather or through frost action. In the heavier 

 soils the tractor-drawn trencher of the type shown in figure 33 is 

 preferred because of higher production, and because of the fact that 

 the wider trench leaves room to pack in loose soil between the tree 

 roots and the opposite side wall. By doing this, the cracking open 

 of the trench by drying or frost action is largely avoided. 



Spacing between rows is either 21 or 27 inches in nurseries where 

 furrow irrigation is used. In nurseries equipped with an overhead 

 irrigation system, however, and where a Smith tree lifter is available, 

 a row spacing as close as 10 to 14 inches has been sufficient. 



297878° — 41 7 



