Rice Production in Southwestern Louisiana 31 
Corn also has been grown in rotation with rice on some of the 
well-drained lands in an attempt to control red rice. The corn is 
usually grown in high ridges, and this practice makes this crop in- 
effective in controlling the red rice. In making the high ridges a 
large proporton of the red-rice seed is covered so deeply that it 
does not germinate or grow during the season that the corn is being 
cultivated. It remains viable, however?, and germinates when later 
the land is prepared for rice. The last cultivation of the corn crop 
also is too early to kill all the weed growth of that same season. For 
this reason alone corn is less useful in a rotation with rice than a 
crop requiring cultivation until a later date. The Biloxi soybean 
meets this requirement effectively, for if weed seeds do germinate 
after the last cultivation is given to this crop the new growth will 
be killed by frost before seed is produced. 
The effectiveness of continued clean cultivation in controlling red 
rice was determined at the Rice Experiment Station during the sea- 
sons of 1911 to 1915, inclusive, as a part of the general experiments 
on weed control. The land was as foul as that in the sod and mow- 
ing experiment already described. One-fourth of an acre of this 
land was plowed in the winter of 1910 and disked the following 
spring. Plowing in winter and disking in spring were repeated each 
year during the period of the experiment. Seed, however, was not 
sown. A perfect stand of red rice was obtained in the spring of 
1911. Each plowing and disking brought a certain part of the red- 
rtce seed to the surface, where it germinated and later was killed by 
disking. Eleven successive germinations of red-rice seed were ob- 
tained during 1911. In each of the three succeeding seasons the num- 
ber of germinations was less. In the spring of 1915, which was the 
last season of the experiment, a stand of only 15 red-rice plants was 
obtained on the entire one- fourth acre plat. This method unques- 
tionably is effective but is expensive in time and labor. The land 
is also unproductive, a loss properly charged to cost. In addition, 
the soil loses in physical condition and fertility. Although effective 
in actually eradicating the red rice, this method is not equal to the 
soybean rotation. Before seeding both the soybeans and the rice, 
thorough tillage must be included as an important part of the weed- 
control program ; but tillage alone can not meet all requirements. 
SUMMARY 
The largest acreage of rice in the United States in one area is 
grown in southwestern Louisiana. Level prairies, clay soils under- 
lain by an impervious subsoil, a large supply of cheap water for 
irrigation, and a subtropical climate have contributed to the success 
of rice culture in this area. 
The rice fields of southwestern Louisiana should be plowed in 
late autumn or early winter to a depth of 5 to 7 inches. The weather 
conditions of November are very favorable for field work, on account 
of the comparatively small amount of precipitation during this 
month. Winter-plowed land must be kept free of surface water. 
Lack of winter drainage may necessitate a second plowing in the 
spring and require much labor to get even an average seed bed. The 
results of an experiment on varying the depth of plowing show that 
