4 



BULLETIN 1320, U. S. DEPARTMENT OP AGRICULTURE 



200 feet in length and were spaced 4.1 feet apart. The location of 

 this test with relation to other cotton plantings on the experiment 

 farm is shown in Figure 1, and the planting diagram of the test is 

 shown in Figure 2. 



Conditions were favorable for the germination of the seed in the 

 first three plantings, and good stands were obtained. Dry weather, 

 following rains which occurred during the last week in April, dried 

 out the soil to a considerable depth, and a stand of about 30 per cent 

 resulted from the planting of May 12, the remainder of the seed lying 

 in the ground until germinated by a rain on May 30. The seedlings 

 produced from the seed that germinated first grew rapidly and pro- 

 duced vigorous plants. The moisture supply in the surface soil was 

 inadequate to support growth of the seeds that germinated late, and 

 most of the resulting seedlings died or remained stunted throughout 

 the season. 



Fig. 1. — Diagram of part of the United States San Antonio Field Station, showing the location of successive 

 plantings and the separate late-planting test of cotton with relation to other cotton plantings 



The first three plantings were thinned to two plants in a hill with 

 the hills 12 inches apart. Thinning was done by hand in order to 

 obtain as regular spacing as possible. The fourth planting was not 

 thinned, as the poor stand rendered this unnecessary. 



The April 19, April 28, and May 5 plantings were thinned on May 

 25, June 4, and June 8, respectively. At the time of thinning, the 

 plants in the first two plantings had from five to seven true leaves 

 and averaged about 20 centimeters in height. The plants in the 

 third planting were slightly larger when thinning was done, averaging 

 22.5 centimeters in height and having from six to eight true leaves. 



GROWTH RATE OF SEEDLINGS 



In order to compare the rate of development during the seedling 

 stage, the height and number of nodes on 10 representative plants in 

 each planting were recorded when the first floral buds, or squares, 

 appeared. The plants in each planting were examined on June 1 and 



