98 SCHOOL AND HOME GARDENING 



rials. The addition of filler usually reduces the price a little, 

 but often the reduetiou is not'in proportion to the amount of 

 filler used. It is not good practice to pay freight and cost of 

 hauling fertilizers containing filler. For these reasons low- 

 grade fertilizers should seldom be used (Pig. 58). 



9. Which Fertilizer to Use. — Prepare five cans of growing 

 plants, as in the preceding exercise, and leave No. 1 as a check can. 

 No. 2 is to be fertilized with one teaspoonful of nitrate of soda; 

 No. 3 with acid phosphate solution made by mixing two teaspoonfuls 

 with one gallon of water. No. 4 is to receive muriate of potash made 

 by mixing one teaspoonful with one gallon of water. Xo. 5 is to 

 receive all three kinds of fertilizer made by mixing the three in a 

 gallon of water together. Note the comparative growth for several 

 weeks and determine which fertilizer is most needed by that kind of 

 soil for the plants grown 



The same trials may be made with all the kinds of garden 

 soil available. Each may be tried with a few different kinds 

 of garden plants. 1 1 the school garden, fertilizer trials of 

 a similar nature may be carried on. Small plots for each fertil- 

 izer may be staked off, five feet wide and twenty feet long, or 

 any other size desired. It is not difficult to determine suitable 

 amounts of the different fertilizers t(»'use in the trial. If such 

 a plot (5 feet X 30 feet) were to receive one pound of any one 

 kind of fertilizer, it would be approximately at the rate of 

 four hundred pounds per acre. 



Improvement by Tillage. — Implements have been so 

 much improved that tillage is one of the commonest ways to 

 put soil in proper physical condition to yield good crops. 

 Tillage is of two main types: (1) Shallow, as with harrows 

 and cultivators. (2) Deep tillage, as with a plow and disking 

 machines. 



The main objects of plowing are : (1) To turn under green 

 manures and other vegetable matter, such as stubble, stalks, 

 vines and weeds, to get them out of the way and to place them 

 where they will rot to improve the soil. (2) To unlock plant- 



