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The Cornell Reading-Courses 



A type of shovel cultivator especially suited to cutting off weeds and 

 leaving an efficient thin surface mulch is the duckfoot, wing, or sweep 

 shovel. On stony or hard soil this shovel cannot be recommended. 



Pulverizers 



Something more vigorous than a harrow is sometimes required on lumpy 

 soil; grinding and crushing action is most effective. For pulverizing and 

 leveling the surface, the plank drag is effective. Clod crushers are a type 

 of corrugated roller, the weight of which may be concentrated on any 

 resistant lump. 



Packers 



The most common tool used to pack the soil is the roller, of which the 

 log roller is the pioneer type. The value of the roller depends largely on 

 its weight and diameter. For the same weight the smaller diameter is 

 more efficient than the larger diameter. The roller is often used immedi- 

 ately after plowing to press down the furrow slices so that they will not 

 be torn up by the harrow and so that a more level surface is provided for 

 the team. In countries where the winters are severe and the roots of 

 plants are torn loose from the ground by frost, the roller is used in order 

 to press roots into the soil and to firm the soil around the roots so that they 

 may renew their growth. Rollers usually are made in two or more sections 

 for convenience in turning, and have a basket or some other arrangement 

 for loading in order to increase the weight. As a pulverizer the solid 

 roller is inefficient. (Fig. ioo.) Its weight is distributed over too much 

 surface and it is likely to press the clods into the soft soil rather than to 

 crush them. 



Another type of roller is the subsurface packer, which comes near to 

 being an ordinary clod -crusher. Its surface is broken so that it cuts into 

 the soil and exerts pressure to considerable depth. It is especially useful 

 in the spring of the year and in arid regions, in pressing the furrow 

 slice into close contact with the subsoil and at the same time leaving a 

 loose layer of soil on the surface as a mulch to save water. 



Special soil-working tools 



There are a number of instruments designed for use in special crops 

 or under special conditions. Among these may be mentioned: (a) the 

 lister, which plows and plants at the same time, used mostly under semi- 

 arid and pioneer conditions; (b) the grape and berry hoe for working close 

 to small fruits; (c) the adjustable disk for reaching under trees with low- 

 hanging limbs. It should be said also that many seeding implements 

 cultivate and pulverize the soil in the process of planting the seed. The 

 grain drill, in particular, is of this sort. 



