FERTILIZERS 137 



is available; plots containing one tenth of an acre may be found 

 more convenient for making rapid calculations. Some experi- 

 menters prefer to lay off plots containing just one square rod and 

 apply the fertilizer at the rate of one pound per square rod or 

 multiple thereof. The fertilizers should be mixed with fine earth 

 and drilled in the rows or else should be sown broadcast just before 

 the planting time of the crop. Each plot should be separated 

 from the adjoining one by not less than four feet to prevent mixing 

 of the fertilizing agents. Note carefully the yields made on each 

 plot, the quality, quantity, weight, and time of maturity being 

 made the basis of the comparison. Lay off your ground and apply 

 your fertilizers according to the diagram on the preceding page. 



If the space available for experimental purposes is small, onl} r 

 four or five plots need be used; and if the fertilizers mentioned 

 above cannot be obtained, useful experiments may be made by 

 using lime, wood ashes, cotton-seed meal, barnyard manure, 

 stable manure, rotten straw, and chicken manure. When no 

 ground suitable for a school garden or testing fields can be obtained, 

 the experiments may be conducted with soil placed in tomato cans. 

 If this plan is used, test the same fertilizer with soil from a number of 

 fields and note the results. Repeat each experiment and thoroughly 

 test your conclusions before announcing your results. 



EXERCISES 



1. Test the soil you are experimenting with and ascertain whether it 

 is acid. To do this take a little soil from three to four inches below the 

 surface and moisten it with a little water. Dip a piece of blue litmus 

 paper in water and then put the paper in the soil. If the paper turns red, 

 the soil is acid. What common element should be added to correct this 

 condition ? Before beginning the experiment test the water used and see 

 that it is neutral. Note the kind of vegetation found growing on the soil. 



2. Secure another portion of soil and test it for alkalinity by substituting 

 red litmus paper for blue litmus paper in the experiments suggested in 

 exercise 1. If the litmus paper turns blue, the soil is alkaline. When this 

 condition exists how may the matter be remedied? Take soil containing 

 stable manure for this experiment. 



3. Test a small portion of lime with both blue and red litmus papers and 

 note the results. 



4. Test common wood ashes with litmus paper and compare the results 

 with those obtained in experimenting with lime. 



