SOIL IMPROVEMENT 73 



will suffer less from drought than if the soil were not plowed 

 until late spring. 



There is one strong argument against late fall plowing: 

 It prevents the growth of a winter cover crop on the field. 

 The very light soils are greatly benefited by winter cover 

 crops. In regions where the climate is drj^, winter cover 

 crops are used to prevent the blowing of soils. In hilly 

 regions where heavy winter rains are common, cover crops 

 are necessary to prevent washing or erosion. 



Depth of Plowing. — For most crops deep plowing gives 

 better results than shallow plowing. A very good general 

 rule for humid climates would be to always plow the soil 

 as deep as the dark surface soil, being careful to not bring 

 too much of the subsoil to the surface. When vegetable 

 matter is plowed under each year, the plowing can extend 

 to a greater depth each time. 



Shallow tillage includes the cultivating and harrowing of 

 soils. There are several objects in view — the preparation 

 of a seed bed, the killing of weeds, and the saving of moisture. 

 (Figs. 36a and b, 37 and 42.) 



Preventing Weeds. — Before crops are planted in the 

 spring, the soil should be so frequently tilled as to prevent 

 the starting of weeds; that is, to kill the little sprouts before 

 they show above ground. On fields of com, potatoes, cotton, 

 and other crops in rows, the tillage should also be very 

 frequent and shallow — thus killing the little sprouts of weeds 

 and checking the loss of soil moisture. If weeds are allowed 

 to grow they take from the soil quite as much plant-food and 

 moisture as the cultivated plants. 



Green Crops as Manures. — ;Crops are frequently grown 

 with the intention of turning them under before they become 

 mature. Such are called green manures. They add vegetable 

 matter to the soil in a form to decay quickly. This produces 

 humus and liberates considerable plant-food in a form ready 

 for crops to use. Both physical and chemical benefits thus 



