EXERCISE 21 



THE EFFECT OF WORKING A SOIL TOO WET 



Statement. The experienced farmer waits until his soil is dry enough after a rain before he cul- 

 tivates it. He has learned that if he cultivates his soil while it is wet, it will be very hard and cloddy 

 when it is dry. This is because the grains of a soil when cultivated too wet slide over one another like 

 putty until they become a solid mass instead of sticking together in small aggregates or crumbs. Such 

 a soil is said to be puddled, which means that its granular structure has been destroyed. When 

 a mud ball can be made of the soil or when it will not crumble in the hand, the soil is too wet to be 

 worked. The farmer should know how to keep his soil in fine tilth. 



Object. To compare the effect upon different types of soils of working them too wet and to learn 

 how the tendency of soils to puddle may be corrected. 



Materials. Six flowerpots or tin cans ; clay ; loam ; sand ; dry, pulverized barnyard manure ; 

 seeds of wheat. 



Directions. Fill two flowerpots each with clay, loam, and sand respectively. Fill another with a 

 mixture of equal parts of clay and finely pulverized barnyard manure. Saturate soils in each with water 



and stir thoroughly one pot 

 of each kind of soil. Leave 

 the others unstirred. Al- 

 low the soils to dry, and 

 plant ten kernels of wheat 

 or five of corn in each. 

 Water as often as is nec- 

 essary and observe the 

 growth of the plants in 

 each soil. Record the re- 

 sults and explain the rea- 

 sons for the differences. 

 Examine each soil under 



Fig. 25. Showing the effect on the structure of soil of working it too wet as compared with 

 working it when it was in the proper degree of dryness 



the microscope for tilth, granular structure, soil aggregates, etc., according to method described in 

 exercise 14. Make a mud ball of each soil under experiment and allow them to dry. Test them 

 for hardness, and examine their structure. Also make mud balls of some of the type surface soils 

 and subsoils of the neighborhood, including some from cultivated and sod lands, and compare them 

 as above indicated. What lessons in soil handling do these results teach ? 



Questions. Which type of soil puddles the most easily and completely ? Which soil shows the best 

 tilth? Which the poorest? Give reasons for your findings. Which soil may be plowed with the least 

 amount of harm while wet ? What is the effect of the presence of organic matter on the readiness with 

 which a soil will puddle ? What is the effect on soil structure of grazing winter wheat with cattle when 

 the soil is wet ? Does it injure the soil structure to drive a team and wagon over it while the soil is 

 wet ? Ask the farmers of the community whether sod land may be plowed and worked when wet 

 with less injury than can stubble land, and why. Ascertain if land is injured as much by being puddled 

 in the fall as in the spring, and why. Ascertain if the injury is as great from cultivating soil too wet if 

 the weather continues wet as if it becomes dry, and give reasons. 



References. Waters, H. J. Essentials of Agriculture, p. 62. Ginn and Company. King, F. H. Physics 

 of Agriculture, pp. 231-234. Mrs. F. H. King. Mosier and Gtjstafson. Soil Physics and Management, 

 pp. 136-138. J. B. Lippincott Company. Roberts, I. P. The Fertility of the Land, p. 90. The Maanillan 

 Company. 



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