WHAT SOILS ARE BEST FOR AGRICULTURE? 243 



the soil or crops will not grow. This is done by flooding 

 and then draining the land, thus washing out some of the 

 alkali. In some parts of the country the soil becomes 

 acid and this prevents the growth of crops. In such cases 

 lime is used to neutralize the acid and thus sweeten the 

 soil. 



SELF-TESTING EXERCISE 



Select from the following list the words which best fill the spaces in the 

 sentences below and arrange the words in proper numerical order. A 

 word may be used more than once. 



gravel black decreases fertilizers 



loam dry increases capillary 



clay wet enrich lime 



humus air ability acid 



sand scarce checked water 



silt evaporates abundant mulch 



red condenses dissolves conserve? 



A good garden soil contains (1) , composed largely of fine 



grains of quartz, (2) , which is extremely fine, and (3) 



which contains organic compounds and gives the (4) color 



to a rich soil. A compact soil neither allows (5) .to pass up 



or down readily nor does it allow space for (6) which is neces- 

 sary for the roots of most plants. Water creeps up through minute 



crevices by (7) action. The movement of water is (8) by 



cultivation. Packing a porous soil (9) the loss of water from 



the surface where it (10) and passes into the (11) Loos- 

 ening the particles and increasing the air spaces within the soil 



(12) the loss of water which (13) if it reaches the surface. 



Cultivation of the surface produces a (14) that (15) mois- 

 ture. Soils long used lose their (16) to produce (17) 



crops unless (18) are added to (19) them. Acid soils are 



sweetened by the addition of (20) 



STORY TEST 



WILL ARCHIE HAVE A GOOD INDOOR GARDEN? 

 Read carefully and critically. List all the errors and suggest corrections. 



I plan to have an indoor garden. I have a large flat pan to 

 hold the soil. It was a problem to know what soil to select. I 

 went to a sand pit where there were all kinds. The sand was 



