EXERCISE 27 



DETERMINING DEFICIENCIES OF A WORN SOIL 



Statement. Any cultivated soil not fertilized naturally by such means as frequent overflows will 

 eventually need to be fertilized artificially, as by the use of green manure, barnyard manure, or com- 

 mercial fertilizers. In some soils one element of plant food will become depleted first and another ele- 

 ment first in another soil. In some soils depletion already has been carried so far that two or more 

 elements must be applied for successful crop growth. To apply to a soil only the elements which 

 growing crops need is scientific practice. To apply the wrong elements or elements in addition to those 

 needed is waste. 



Object. To determine the plant needs of worn soils of the neighborhood. 



Materials. Infertile soil ; dry, finely pulverized barnyard manure; steamed bone meal; sodium 

 nitrate ; wood ashes ; nine flowerpots or tin cans ; labels ; seeds of wheat. 



Directions. Laboratory test. Number the flowerpots and fill each with an infertile soil from the 

 neighborhood. Treat them as follows : 



Pot No. i is to be left untreated as a check with which the others are compared. Pot No. 2 is to receive 

 10 grams of nitrate of soda; No. 3, 10 grams of dry, pulverized barnyard manure; No. 4, 10 grams of 

 steamed bone meal ; No. 5, 10 grams of unleached wood ashes ; No. 6, 10 grams of nitrate of soda and 10 

 grams of steamed bone meal; No. 7, 10 grams of nitrate of soda and 10 grams of wood ashes; No. 9, 10 

 grams of nitrate of soda, 10 grams of steamed bone meal, and 10 grams of wood ashes. 



Plant six wheat grains in each pot and place the pots where plant growth can take place to the best 

 advantage. Be sure that all pots have equal advantages. Water each pot with clean rain water. At the 

 end of six weeks compare the plants as to color, vigor, size, etc. Continue the test until the plants in 

 some of the pots cease to grow. Carefully remove the plants from each pot, wash the soil from the 

 roots, and compare the size of an average plant from each pot. Compare the root, stem, and leaf 

 development of each. Under which system of fertilization was the greatest growth produced? Weigh 

 the green plants produced in each pot. Place them in a labeled envelope, allow them to become [air 

 dry, and weigh. Record and discuss results. Apply the lesson to the farm practice of the community- 



Questions. Under which system of fertilization did the plants have the best color and attain the 

 greatest size? To what do you attribute this result? What did barnyard manure supply that was 

 lacking in the other fertilizers used? What manures and fertilizers are most generally used in your 

 neighborhood ? What amounts are usually applied to the acre and to what crops ? Is all the barn- 

 yard manure made in your locality preserved and applied ? To what crops is it usually applied and 

 at what rate per acre? How is it applied, with a hand fork or a manure spreader? Which method 

 should be used ? 



References. Waters, H. J. Essentials of Agriculture, pp. 79-84. Ginn and Company. Warren, G. F. 

 Farm Management, pp. 183-203. The Macmillan Company. Parker, E. C. Field Management and Crop 

 Rotation, pp. 269-280, 290-305. Webb Publishing Company. Mosier and Gustafson. Soil Physics and 

 Management, pp. 389-407. J. B. Lippincott Company. 



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