442 



STATE BOARD OF AGRICULTURE. 



Plot 3 was cultivated twice after the beginning of the experiment. On the 

 22nd of July the weeds were cut with a hoe from all of the plots, without 

 stirring the soil. 



To determine the amount of moisture in the soil, samples were taken 

 with a section of one and one-fourth inch gsis pipe fitted at one end with 

 a tool steel edge, in the inside of which there was a rim which reduced the 

 diameter at that point to one and one-eighth inches. This cutting edge was 

 attached to the gas pipe by means of a piece of brass tubing one end of 

 which fits into the cutting edge of the gas pipe while the other is inserted 

 into the end of the section of gas pipe which has been bored out for the 

 purpose. The core of soil, being.sinaller in diameter than the bore of the 

 gas pipe, is readily emptied from the opposite end of the tube into the 

 tin dish used for carrying the sample to the laboratory. These dishes are 

 six inches in diameter, two inches deep and fitted with screw covers which 

 make them practically air tight. At the laboratory the dishes containing 

 the samples of soil are weighed and placed, after the covers are removed, 

 in a drying closet, heated by steam. Here the moisture is rapidly driven 

 off. As soon as thoroughly dried and cool the dishes, still containing the 

 dried soil, are weighed. The difference between the first and second 

 weight is the amount of water in the original sample. By placing the 

 sample of soil, at the moment of taking it in the field, into an air-tight 

 dish from which it is not removed until after its weight is determined, all 

 opportunity for a loss of moisture is removed. 



The soil samples were taken from the center row of each plot, the sam- 

 ples for the given day being taken on the same cross row, in order that 

 they might be as near together as possible and hence more comparable. 

 The sampling was begun at the east end of the plot and progressed regu- 

 larly westward. The samples were taken in foot sections and in duplicate, 

 the average of the duplicates being reported as the per cent of moisture 

 for the given determination. The variation between these duplicates was 

 usually very small. The samples were taken three times a week as a rule. 

 Twice a week the samples were taken to a depth of one foot only and 

 once per week to a depth of three feet, keeping separate the samples for 

 each foot in depth. The table given below shows the average per cent and 

 the average weight of water per cubic foot in the three different plots, and 

 for intervals of one foot in depth up to three feet. In the first column 

 under each plot is given the average per cent of moisture in the first, 

 second and third foot for the season, in the second column the weight of 

 water per cubic foot on the average, for the entire time covered by xho ex- 

 periment. 



Water content of three corn plots. 



