254 Bureau of Farmers' Institutes. 



surface shall be quite level and uniform. The more worn-out the 

 soil is, the more definite results may be expected. 



(b) Size of Experimental Plots. — A convenient size of plot to 

 use for a field test is one-twentieth of an acre, containing an area 

 of 2,176 square feet. The length and breadth of the plots can 

 be such as suits one's convenience, but it is recommended that 

 each plot measure 204 feet in length by 10 feet 8 inches in width. 

 Between the plots, leave a strip unused three or four feet wide 

 so as to avoid any possible mixing of the different plots. 



(c) Preparation of Land. — Select a portion of the field that 

 represents a fair average, and that has been cropped and manured 

 alike previously; prepare the soil as carefully as possible for the 

 crop and then measure accurately and stake out into plots 204 feet 

 long, and 10 feet 8 inches wide, leaving between the plots a strip 

 three or four feet wide. Mark each plot by a number corre- 

 sponding to the kind of fertilizer used, following a diagram pre- 

 viously laid out on paper. 



(d) Application of Fertilizer. — Distribute each fertilizer over 

 its own plot, mixing it thoroughly with the soil and keeping the 

 fertilizer from going outside the plot. It is better to apply the 

 fertilizer broadcast and before planting, if the crop is not a culti- 

 vable one. For cultivable crops the fertilizer may be applied 

 after planting and harrowed in. On the basis of the amounts of 

 fertilizer given below, there will be one pound of fertilizer or an 

 even multiple of it for each square rod of surface. 



(e) System in Conducting Fertilizer Experiments. — The work 

 must be done from beginning to end, systematically and accu- 

 rately, if best results are to be obtained. The harvested crop 

 must be carefully measured and a record kept of all results. 



(f) Plan of Experiment. — The following diagram represents an 

 arrangement of plots, together with the kinds and amounts of 

 plant-food materials to use. The particular crop with which to 

 experiment may be left to the choice of the farmer. For first 

 trials, corn, or potatoes, or oats may be used, to be followed by 

 such others as are usually raised by the farmer. The work should 

 be carried on for more than one season. It must be kept in mind 

 that weather conditions may seriously interfere to destroy the 

 value of the results. An excessively dry season works against 

 satisfactory results. Therefore, the work should be repeated. 

 All the plots should receive the same amount and kind of cultiva- 

 tion. The same amount of seed should be used. In a word, 



