152 The Principles of Fruit-growing. 



should be slight. Nothing could be better calculated 

 to dry out a potato field or a corn field than throw- 

 ing the ground up in high ridges, leaving a large 

 surface exposed to the action of sun and wind. 

 In fruit plantations which are in a proper state of 

 cultivation, a small -toothed or even spike -toothed 

 cultivator will be found sufficient to maintain the 

 surface mulch. 



The roller, in Us relation to soil moisture, is an 

 implement whose value depends largely upon local 

 conditions. There is no tool which requires more 

 judgment as to its proper use. On light, loose, 

 sandy or gravelly soils, where every effort must be 

 made to solidify and pack the particles closely to- 

 gether, the roller must be used repeatedly. The 

 difficulty with such soils is that the spaces between 

 the grains are so large that the water is permitted 

 to pass through freely, and is lost by percolation. 

 The capillary openings are so large that there is 

 very feeble rise of the water to take the place of 

 that used by plants and lost by evaporation. The 

 roller lessens the size of these pores in solidifying 

 the soil, and the capillary force is then strong 

 enough to draw the water to the surface. If, now, 

 the soil is left in this condition, it has been put 

 in the best possible form for parting with its 

 moisture into the atmosphere, and it will take ad- 

 vantage of the opportunity unless prevented by 

 establishing a surface mulch. In seeding land in a 

 dry time, the soil should be rolled in order to bring 

 sufficient moisture to the seeds to insure germina- 



