4 SOILS AND PLANT LIFE 



sand? Is it not best to have the sand, silt and clay all 

 mixed ? 



Conclusion. — You have seen the largest stones, or 

 pebbles, in the swiftest part of the creek or river, and the 

 soil in layers near the stream ; and you have seen the finest 

 mud on the top of the soil where the water had dried up 

 along the roadside. Explain why these things are so. 



3. Soil Names, or Types. — We have seen how a soil 

 may be made up of sand, silt and clay. If it contains a 

 large amount of sand, we call it a sandy soil ; if of clay, a 

 clay soil. A soil made up of about one half sand, and the 

 other half silt and clay is called a loam soil. If the per- 

 centage of silt is large, it is called a silt loam ; of clay, a 

 clay loam ; of gravel, a, gravelly loam ; of stone, a stony 

 loam. 



EXERCISE 2 



Object. — To find the percentage of sand, clay and silt 

 in the soil of fields at home or near the school building. 



Procedure. — Secure two or more samples of soil, about 

 one half cupful each, from different fields. Place each in a 

 jar, which has first been weighed, and weigh again after 

 the sample has been put into it. From these weights, 

 find the weight of each sample. Now separate the sand, 

 silt and clay just as you did in Exercise 1 . Find the weight 

 of each of these constituents in each sample, taking care 

 that all appear about equally moist when weighed. These 

 weights can be determined more easily if all jars used 

 are first weighed and the weights recorded. After you 

 have found the weight of the sand, the silt and the clay 

 in each sample, find what per cent each of these is of the 

 original sample. 



Conclusion. — Do you find any difference in the per- 

 centage of sand or clay which the different fields contain? 



