438 



Trials of New Varieties of Cereals. 



[Aug., 



The effect is that after each " turn " of the drill, two half- 

 drill-strips of the same race are seeded alongside, so that when 

 the drill has made 21 " turns " there are 10 drill-wide-strips 

 (20 half-drill-strips) of each race and two half-drill-strips — one 

 at each end of the series. The produce of the two half -drill- 

 strips first drilled at the edge of the field is excluded from the 

 experiment and therefore the weighed produce will be that of 

 20 half-drill-strips or half an acre of each race. If the series 

 consists of only one race and a control, it will be best to drill 

 22 drill-strips and exclude one full drill-strip (two half-drill- 

 strips) at each end of the series. 



It is necessary that the coulters of the drill should be at 

 precisely equal distances apart, except the two on either side 

 of the centre, where, in the case of a drill with an odd number, 

 one has been put out of action. It is necessary, therefore, to 

 use a drill in which the distances apart of the coulters are 

 adjustable. It is convenient to have something more than a 

 row-space along the lines separating the two races, i.e., in the 

 centre of the drill, but it is imperative that the " over-all " 

 width of the two half-drill-strips should be precisely equal, so 

 that each race pets an equal area. It is also very necessary 

 that all the coulters should deliver the seed at equal depths. 

 The two halves of the drill should in fact be alike in all 

 respects. 



The drill should be fitted with a good steerage and the first 

 turn " should be driven on a marked out line. At eacih 

 successive turn it should be so driven as to give a uniform 

 space in the line of the wheel-tracks which will be the centre 

 line of each variety strip, dividing each such strip into two 

 equal half-drill-strips. This space should be equal to that in 

 the centre of the drill separating the two races. The effect 

 will be to give each half-drill-strip an equal area with some- 

 thing- more than a row-space in the centre of each variety 

 strip, and a similar space between each variety strip: all the 

 spaces being uniform in width. This arrangement is necessary 

 in order to facilitate separation of the races at harvest. 



The diagram below shows that with a 13-coulter drill using 

 12 coulters 7 in. apart, and with 12-in. spaces between 

 the half-drill-strips, the width actually seeded including spaces 

 is 47 in. for each half-drill-strip. The length required to 

 give 1/40 acre per half-drill-strip is therefore in this case 

 278 ft. If less or more coulters are used the length will be 

 correspondingly altered. 



