26 BULLETIN 1094, U. S. DEPARTMENT OF AGRICULTURE. 
in the yield of spring-sown barley as a result of its following kafir, | 
which is very contrary to the effect of kafir on fall-sown wheat, as | 
shown in rotations Nos. 149, 150, 349. and 350, which have been © 
considered. | 
WHEAT IN 3-YEAR ROTATIONS OF KAFIR, FALLOW, AND WHEAT. 
In 1913 two series of ten 3-year rotations were started. These 20 — 
rotations are all fallow, winter wheat, and kafir. The first series, 
numbered from 501 to 510, inclusive, was planned primarily to study 
methods of raising kafir on wheat stubble, but two of the rotations, 
Nos. 501 and 502, vary from the others in the method of fallow. 
The cultivation for fallow in rotation No. 501 is started in the fall 
by plowing to a depth of 12 to 14 inches with a deep-tillage machine. 
The plat to be fallowed in rotation No. 502 is dynamited before listing 
in the fall. A half stick of dynamite is shot at a depth of 3 feet in 
holes 16 feet apart. The first year 20 per cent dynamite was used, 
but since then 40 per cent has been used. This plat and the plats to 
be fallowed in rotations Nos. 503 to 510, inclusive, are listed in late 
fall. During the spring the lister ridges are leveled by such cultiva- 
tion as may be necessary to prevent weed growth. About midsummer 
the plats are all plowed. Enough cultivation is given after plowing 
to prevent weed growth and to prepare a good seed bed for winter 
wheat. The fallows are seeded uniformly to wheat in the usual man- 
ner, with no special treatment. 
These rotations are so arranged that the fallow, wheat, and kafir 
each occupy a solid block of 10 plats side by side, arranged from north 
to south in numerical order. The wheat stubble is prepared for 
kafir in the several rotations as follows: 
Rotation 501: Fall list, cultivate ridges down in early spring, list at planting time 
(deep tilled for fallow). 
Rotation 502: Same as No. 501 except dynamited for fallow ark of deep tilled. 
Rotation 503: Double-disk in July or August, fall list, cultivate ridges down in 
early spring, list at planting dae 
Rotation 504: Fall list, cultivate ridges down in early spring, list at planting time. 
Rotation 505: Fall list, ridges untouched until planting time, then split ridges. 
Rotation 506: Fall list, work with harrow in spring, list in same furrows at planting 
time. ° 
Rotation 507: Fall list, work with harrow in spring, split ridges at planting time. 
Rotation 508: Early spring list, ridges untouched until planting time, plant in same 
furrows. 
Rotation 509: Double-disk in spring, list at planting time. 
Rotation 510: Untouched until planting time, then list. 
The yields of both wheat and kafir in these 10 rotations for the 
7-year period from 1914 to 1920, inclusive, are given in Table 11. 
Careful study of the data from these and the 10 companion rota- 
tions shows the plat variation or experimental error to be so high 
