WOEK OF THE DELTA EXPERIMENT FAEM IN 1912. 7 



In October and November a sample digging was made of four rows 

 equidistant across each plat. In tliis digging aU the potatoes in 

 each liill were gathered, regardless of size or condition, and a sorting 

 was made in wliich all potatoes of marketable size and in marketable 

 condition were segregated, weighed, and classed as marketable. The 

 cuUs were then sorted and weighed, being classed as undersized or 

 scabby. The undersized scabby potatoes were classed as undersized, 

 and only the potatoes wliich but for the scab would have been mar- 

 ketable were classed as scabby. In computing the results of the 

 sample digging, the percentage of scab and unmarketable sizes was 

 determined in terms of the marketable potatoes obtained in tliis 

 digging, and the results were taken as being representative of the 

 plat as a whole. 



In December and January the final digging of marketable potatoes 

 was made, and this yield when added to the marketable potatoes 

 obtained during the sample digging and computed to an acreage 

 yield is carried in the tables as the market yield. 



TESTS OF TILLAGE METHODS WITH GREEN MANURE AND COMMERCIAL 



FERTILIZERS. 



Alternate lands in field F were plowed 6 inches and 12 inches deep, 

 respectively, m February. The north half of the alternate pans was 

 sown to vetch early in March, and the south half of the same pair was 

 sown to barley. Certain blocks of these lands were treated with 

 commercial fertilizers. The vetch made very little growth, but the 

 barley reached a height of 15 to 18 inches by the middle of May, when 

 the lands were replowed. 



In addition to the fertilizers applied in March on certain of the 

 green-manured and bare plats, fertilizer was applied in the rows of 

 potatoes on certain other of the green-manured and bare plats at 

 planting time, early in June. The fertilizers used in both cases were 

 K2SO4 (potassium sulphate), KCl (potassium chlorid), and CaHP20e 

 (superphosphate). All were very high grade. All planting on field 

 F was at a depth of 6 inches. The results of this test are given in 

 Table I, together with comparisons of the results obtained with the 

 same green manures and tillage methods but without the use of com- 

 mercial fertilizers. 



For convenience in comparing averages, the data are given in con- 

 densed form at the close of the table where the averages of aU the 

 results obtained with commercial fertilizers are compared with the 

 results secured on the unfertilized plats. 



[Cir. 127] 



