SORGHUM EXPERIMENTS OX THE GREAT PLAINS. 11 
All of the sorghums are. utilized to some extent for forage. Even 
broomcorn is sometimes pastured, or the stalks are harvested and fed 
to livestock after the brush has been removed. The grain sorghums 
are important as producers of fodder and stover as well as grain. 
The sorgos, or sweet sorghums, are grown primarily for hay and fod- 
der, although a small part of the acreage is used in the manufacture 
of table sirup. Grass sorghums are grown almost exclusively for 
hay and pasture. 
EXPERIMENTAL METHODS. 
The methods of experimentation employed with different crops 
necessarily vary according to the nature of the crop. There are, 
however, certain recognized safeguards against errors, such as plat 
replication, which are common to all properly conducted field ex- 
periments. The methods followed in these sorghum experiments are 
briefly outlined below. 
PRESERVATION OF SOIL UNIFORMITY. 
At Hays, Kans., the sorghums on the experimental plats have 
usually alternated with small grains. At Chillicothe, Tex., since 1915 
the sorghum plats have been included in a 4-year rotation of sorghum, 
cotton, annual legumes, and small grains. At the other stations the 
procedure has not been uniform from year to year. Usually the 
sorghums have followed small grains or cowpeas, although in some 
cases they were grown on summer fallow or following sorghum. 
PLAT TECHNIQUE. 
At Hays, Kans., Amanita, Tex., and Woodward, Okla., the tests 
were usually conducted on duplicate twentieth-acre plats. This plan 
was followed also at Chillicothe, Tex., from 1913 to 1917, since which 
time smaller plats in triplicate have been used. At the other stations 
single tenth-acre plats were most common. 
At all the stations the plats are seeded without dividing alleys, 
except the roadways between the plat series. Along these roads two 
guard rows are grown to prevent marginal influence, which is very 
noticeable in dry years. Within the plat series the influence of the 
adjoining plat is obviated by making the plat two rows wider than 
necessary and discarding one row from each side at harvest time. 
In seeding the plats they are made somewhat longer than necessary 
and trimmed to the required length. At Chillicothe, Tex., it has 
been found better to defer trimming the plats until the sorghums 
are practically mature, for if the trimming is done when the plants 
are small there remains an opportunity for the plants at the ends of 
the plat to benefit by additional moisture late in the season. 
SEEDING METHODS. 
With certain exceptions, the data for comparison of varieties and 
rates of seeding (row space per plant) were taken from plats seeded 
at the most favorable dates, as determined by the date-of -seeding 
experiments and by experience. At Chillicothe, Tex., the three plats 
are seeded at different dates — one early, one medium, and one late— 
and the three yields are averaged. The relation between yields of 
different varieties varies with the date of seeding, and reliable com- 
parison is possible only when each variety is sown on its most favora- 
ble date. 
