322 GENERAL SCIENCE 



care than any other kind, especially with respect to 

 moisture at the time of cultivation. 



Sandy soil is composed mostly of sand through which 

 the excess water soon passes by nitration, leaving it 

 dry enough to be plowed in a short time after a rain. 

 Sandy soil will not bake or pack like clay soil and for 

 this reason it is more easily cared for, although it is best 

 not to plow it when too wet. 



Loam soil is composed of a mixture of clay and sand. 

 A sandy loam has a large per cent of sand, and a clay 

 loam has more clay than sand. Loam soils are the best 

 because the clay in them prevents the water from escaping 

 too rapidly and the sand prevents the soil from packing 

 and from being baked by the sun. Loam soils can be 

 plowed when more moist and when dryer than clay soils, 

 but it is best not to plow loam soil if it balls when squeezed 

 in the hand. 



Soil in gardens, flower beds, and flower pots should be 

 stirred when it is moderately moist and will not adhere 

 to a great extent to the tool being used. Plants in flower 

 pots will do better if the soil is loosened occasionally 

 before watering them. 



222. Why Cultivate Plants? In primitive times the 

 soil was plowed or stirred in order to dispose of undesir- 

 able vegetation or weeds so that the desired crop might 

 not be hindered in its growth. Cultivation for this one 

 purpose was practiced for several thousand years and up 

 to very recent times. Some farmers who are not ac- 

 quainted with the nature of the soil still think that they 

 cultivate principally to destroy weeds. The growth of 

 weeds has been a benefit to man because they required 

 the crops to be cultivated and thus the soil was made 

 more favorable for the growth of the desired plants. 



