Tillage and Irrigation 71 



TILLAGE METHODS 



The frequency of tillage depends on the nature of the 

 soil, the annual rainfall, the time of the year and weather 

 conditions. The necessity of keeping down weeds usually 

 sets the pace, but soil moisture is an equally important 

 guide. Some soils are dry and leachy ; others hold mois- 

 ture tenaciously. Gravelly soils with a clay subsoil 

 hold moisture much better than tight clays, since the 

 gravel acts as a surface mulch. Ten cultivations may 

 be as effective upon this soil as four upon others. The 

 best time to kill weeds is when they are sprouting. Three 

 cultivations then cost no more than one after the weeds 

 have become so large that they slip between the culti- 

 vator teeth and must be chopped off with the hand hoe. 

 Some growers cultivate thirty times a season and give 

 five hand hoeings. The average among good growers is 

 fifteen cultivations and three hand hoeings. 



The loss of water from an uncultivated strawberry 

 field, by evaporation, is much larger than is commonly 

 supposed. Soils that are packed and crusted by a rain 

 lose water very rapidly. The crust should be broken 

 as soon as the soil is dry enough to be worked. On light 

 sandy soils do not begin cultivation until the plants are 

 well established ; early tillage causes the sand to drift 

 over some plants and away from others. 



Depth of tillage. 



The nature of the soil and seasonal conditions deter- 

 mine the depth of tillage. Tight clay soils need deep 

 tillage; sandy soils shallow tillage. In dry weather 

 cultivation should be shallow; in wet w^eather deep. 

 For ten days or two weeks after the plants are set culti- 



