Rice Production in Southwestern Louisiana 
13 
Weather conditions in southwestern Louisiana are too unsettled 
for the sowing of rice until the latter part of April. Prior to April 
15 the mean temperature is too low to give the proper warmth to the 
soil for quick germination. Cold rains and winds, which are fre- 
quent at this time of the year, also make it difficult and often im- 
possible to prepare a good seed bed. In addition, seed sown at too 
early a date may rot before germination. These conditions do not 
prevail after the last week in April or occur too seldom to cause 
serious loss. 
The relation of mean temperature to date during the seeding 
season is shown in Table 10. The mean temperature for the week 
ended April 28 for the 14-year period from 1910 to 1923, inclusive, 
was 70° F. This temperature is several degrees higher than the 
mean temperature for each of the first two weeks of April. The 
weeks ended May 5 and 12 had mean temperatures of 71° and 
72° F., respectively. The mean temperature for the last week of 
April and for each of the first two weeks of May is sufficiently high 
to insure good germination and stands, so far as the temperature 
factor is concerned. In addition, the weeks ended May 5 and 12, as 
shown in Table 10, have a relatively light precipitation, which, com- 
bined with favorable temperature, makes ideal weather conditions 
for the sowing of rice. 
Table 10. — General cUmatological data at the Rice Experiment Station, Crow- 
ley, La., for each week from April 1 to June 16, inclusive, during the 14-year 
period from 1910 to 1923, inclusive 
Weather conditions 
Apr. 
lto7 
Apr. 
8 to 14 
Apr. 
15 to 21 
Apr. 
22 to 28 
Apr. 
29 to 
May 5 
May 
6 to 12 
May 
13 to 19 
May 
20 to 26 
May 
27 to 
June 2 
June 
3 to 9 
June 
10 to 16 
Temperature (° F.): 
87 
32 
88 
34 
88 
39 
90 
34 
90 
41 
92 
43 
93 
50 
94 
50 
98 
57 
100 
57 
102 
Minimum 
56 
Weekly mean 
66 
66 
69 
70 
71 
72 
73 
75 
79 
80 
80 
Precipitation (inches) : 
Average 
Average number of 
days with 0.01 
inch or more 
0.75 
2.1 
0.90 
1.5 
1.08 
2.1 
1.05 
1.7 
0.88 
1.7 
0.78 
1.8 
0.89 
1.7 
1.41 
1.7 
0.74 
1.9 
1.37 
2.6 
0.81 
2.3 
Wind velocity (miles 
per hour) : 
10.1 
.3 
9.5 
1.8 
9.8 
.8 
10.0 
1.0 
8.1 
.9 
6.8 
. -6 
8.4 
.4 
7.9 
.8 
9.1 
.3 
8.6 
.2 
10.9 
Minimum. - • 
.7 
4.2 
4.6 
4.1 
3.8 
3.5 
3.2 
3.2 
3.3 
2.7 
2.6 
2.7 
Earlier seeding than the best approximate date (May 14), espe- 
cially on land that is foul with weeds, often results in a weedy crop. 
Seeds of many rice-field weeds germinate before or with the rice 
when the crop is sown in April. This foreign growth always 
affects the stand, and the competition reduces the yield. 
The tillage that is required in the preparation of the land for 
seeding in early May has a tendency to control those weeds which 
germinate at a lower temperature than rice. Weedy fields should 
be lightly disked repeatedly until May 10, and later if necessary. 
Such fields should never be sown without this tillage nor at an 
earlier date than May 15. 
