228 EXPERIMENT STATION RECORD. 



matter from city dump, and green manures), lime, and chemical fertilizers (sodiu 

 nitrate, potassium sulphate, and tricalcium phosphate). Wheat plants were grown 

 on the soils by the wire-basket method as follows: 



"Five small wire baskets 3 in. in diameter by 3 J in. in depth are used for each 

 treatment. After the soil has been treated with its respective fertilizer and brought 

 up to the optimum water content with distilled water, the equivalent of about 325 

 gm. of dry soil is placed in each basket. The soil is firmly packed, and 6 germinated 

 kernels of wheat are planted in each basket. During the process of packing a small 

 portion of the soil presses out through the wire mesh, but this is brushed off and 

 returned to the interior of the basket, after which the basket is at once dipped into 

 melted paraffin, which not only forms an intimate contact with the soil, but also 

 produces a water-tight covering. 



"An eighth to a quarter of an inch of washed quartz sand is now placed over the 

 soil of each basket, and its contents at once weighed and the weight recorded. In 

 from 3 to 5 days the wheat plants will have emerged from the soil and have a height 

 of approximately 1 in., at which time the surface of the basket is sealed— that is, it is 

 covered with a piece of paper having a small opening in the center sufficiently large 

 to permit the plants to pass through. The paper is dipped in melted paraffin just 

 before placing it over the soil, and then a small amount of paraffin is run around the 

 outer edge of the paper, thus forming contact with the side of the basket. 



"In this way all evaporation from the soil is prevented, excepting the minute 

 amount which may pass through the small opening immediately around the plants. 

 The loss from this source is so slight in comparison to that which is transpired by 

 the plants that no account is taken of it, but even if the loss were considerable it 

 should be practically the same from all baskets. The weight of the basket is taken 

 immediately before sealing and immediately afterwards, in order to ascertain the 

 weight which has been added to it in the process of sealing. This increase is now 

 added to the original weight of the basket, and the result is what is known as the 

 'optimum weight,' or that weight at which the contents of the basket contain the 

 most favorable amount of moisture for the growth of plants. 



"During the growing of the plants, which usually continues from 18 to 21 days from 

 the date of sealing, the baskets are w r eighed at intervals of 2 or 3 days and watered 

 with distilled water, in order to retain a favorable moisture content for plant growth. 

 By this method the loss of water or the amount transpired by the plants is ascer- 

 tained periodically, and at the end of the experiment the total amount of water given 

 off through the plants of each basket is obtained for comparison with the growth and 

 green weight of the plants, which is ascertained by cutting and weighing the plants 

 at the time the experiment is concluded. All conditions of the experiment are so 

 carefully controlled that the average result of 5 baskets rarely differs more than 5 per 

 cent from the average result of any other 5 baskets that have been treated through- 

 out in precisely the same manner. Differences which occur beyond this amount 

 may therefore safely be attributed to the different manurial treatments which have 

 been given." 



From the results obtained by this method the conclusion is drawn that "both 

 barnyard manure and green manure are beneficial to this soil when in a run-down 

 condition, but that the effects from applications of green manure are decidedly more 

 beneficial in that they are more lasting than for equal amounts of barnyard manure. 

 The benefits from liming are so obvious that they need no comment, while potash 

 and nitrogen in combination with manure are sufficiently beneficial to justify their 

 application, at least in amounts not to exceed 250 lbs. per acre, but the results do not 

 seem to indicate that when applied alone they are of enough effect to warrant their 

 use." 



These results "appear to be in harmony with the actual field experience of suc- 

 cessful farmers in the locality." 



. 



