SORGHUM EXPERIMENTS ON THE GREAT PLAIN-. 67 
EXPERIMENTS AT BIG SPRIXG, TEX. 
Date-of-seeding experiments at Big Spring, Tex., were conducted 
with Sumac and Red Amber during the three years. 1919 to 1921. 
The limited data thus obtained are supplemented by rather definite 
experience acquired incidentally to the sorghum-variety tests of the 
four preceding years. 
The sorghums were surface planted in 44-inch rows on winter- 
plowed land in single tenth-acre plats. The preceding crop was 
usually cowpeas. In 1919 moisture conditions were favorable, and 
excellent yields were obtained from all dates of seeding. The sea- 
sons of 1920 and 1921 were fairly satisfactory for forage production, 
but the soil was considered too dry to attempt seeding until June 1 
except for the April 15 tests of 1921. 
The yields of forage obtained from the date-of-seeding tests at 
Big Spring, Tex., together with the average heights and the average 
lengths of season are shown in Table 17. The yields of seed were 
not obtained. 
The experimental data here presented must be considered in con- 
nection with the known seeding conditions of the years 1915 to 1918 
in order to justify any conclusions. Decision as to the best date of 
seeding at Big Spring is based almost entirely on the question of 
available soil moisture. The frost-free period is long enough to 
permit the maturity of a crop sown at any date within the limits of 
those tested, if there is sufficient moisture, as in 1919. The rainfall 
is extremely irregular and is often distributed in small showers which, 
on account of the excessive rate of evaporation, are of little if any 
value. In 1915 there was plenty of rain for seeding in April and any 
time up to the middle of May, after which it was too dry again 
until the last of June. Again in 1916 there was moisture in April, 
but this evaporated rapidly, and May and June were droughty. 
Throughout 1917 the soil was never wet down more than 4 to 6 
inches, and crops were an entire failure. The only opportunity for 
getting a stand was following a 0.98-inch rain on June 24. In 1918 
the only opportunity for seeding was immediately after 3.53 inches 
of rainfall during the first week of June. 
These observations, covering the period from 1915 to 1918 supple- 
mented by the records of 1919 to 1921, indicate that seeding should 
be attempted the latter part of April or early in May if there is 
sufficient moisture in the soil. When conditions are not favorable 
at that time, seeding should be deferred until a rain of 1 inch or 
more has provided suitable soil conditions. 
EXPERIMENTS AT TUCUMCARI, X. MEX. 
The date-of-seeding experiments at Tucumcari, X. Mex., were 
conducted from 1917 to 1921 with Sumac and from 19J7 to 1920 
with Red Amber. These varieties were seeded at 15-day intervals 
from April 15 to July 1 as regularly as soil conditions would permit. 
As at Big Spring, Tex., the data are necessarily rather irregular: 
still they afford a basis for certain recommendations when considered 
in connection with the known soil and climatic factors of the experi- 
mental period and of preceding years. 
All seedings made before June 1 in 1917 and before May 15 in 1919 
were ruined bv soil blowing. In 1918, 1920, and 1921 no seedings 
