EVAPOTRANSPIRATION ETC., WITH IRRIGATED GRAIN SORGHUM 



13 



Heads per Acre and Weight per Head 



The number of heads per acre and weight per 

 head were primary components of large variations 

 in yields in 1959. The lower yield on the low 

 moisture levels was a result of fewer and smaller 

 heads as compared to the higher moisture levels 

 (tables 7 and 8). Nitrogen fertilizer increased the 



weight per head over the 0-nitrogen plot on the 

 medium and optimum moisture levels (table 8). 

 However, there was only a small difference in head 

 weights between the 60-, 120-, and 240-lb./acre 

 nitrogen application rates. Therefore, large dif- 

 ferences in yield between these treatments were 

 due primarily to the number of heads per acre. 



Table 6. — Average height of irrigated grain sorghum in 1957, 1958, and 1959, Bushland, Tex. 





Fertilizer No. 1 



Height at moisture level 2 of — 



Average 

 for all 





M, 



M 2 



M 3 



M 4 



M 5 



M„ 



moisture 

 levels 



F, 



Ft. 

 3. 14 

 3.38 

 3.34 

 3. 22 

 3. 24 

 3. 18 



Ft. 

 3.85 

 3.93 

 3.95 

 3.94 

 3. 75 

 3.74 



Ft. 

 3.67 

 3. 76 

 3. 89 

 3. 84 

 3.61 

 3. 74 



Ft. 

 4. 15 

 3.98 

 4. 22 

 4. 12 

 4. 12 

 4. 15 



Ft. 

 4. 29 

 4. 10 

 4.24 

 4.35 

 4.23 

 4. 15 



Ft. 

 3.89 

 3.76 

 3.95 

 3.90 

 3.80 

 3.86 



Ft. 

 3. 83 



F 2 



3. 81 



F 3 



3. 93 



F 4 



3. 89 



F 6 



3. 79 



F„ 



3.80 





Average - __ _- 







3.25 



3. 86 



3. 75 



4. 12 



4.23 



3.86 



3. 84 









1 See p. 5 for fertilizer applications. 



2 See p. 5 for irrigation schedules. 



Table 7. — Number of heads per acre of irrigated grain sorghum (RS-610) as affected by moisture and fertilizer 



treatments, Bushland, Tex., 1959 



Production Data 



Fertilizer treatment 



No. 



N 



P 2 5 



Heads at moisture levt . * of — 



M, 



M 2 



M, 



M 4 



M., 



M B 



Average 

 for all 



moisture 

 levels 



F,. 



F 2 . 

 F 3 - 

 F 4 - 

 F 6 - 

 F,- 



Lb. /acre 

 240 

 

 60 

 120 

 240 

 240 



Lb. /acre 

 

 30 

 30 

 30 

 30 

 60 



Thousands 



43. 5 



44. 8 

 46.5 

 41.8 

 42. 

 47.8 



Thousands 

 57.3 

 52. 8 

 56. 

 58. 

 58. 5 

 63.3 



Thousands 

 67.3 

 56. 

 58.8 

 72.3 

 71. 5 

 72.5 



Thousands 

 69. 

 58.3 

 65. 

 71. 

 75.3 

 75.5 



Thousands 

 76. 

 61. 5 

 61.0 

 74.3 

 77.5 

 76. 8 



Thousands 

 59.5 

 50. 5 

 58.8 

 62.3 

 59.8 

 69.5 



Thousands 

 62. 1 

 54.0 

 57. 7 

 63.3 

 64. 1 

 67.5 



Average. 



44.4 



57.6 



66.4 



69. 



71. 2 



60.0 



61.4 



Analysis of Variance 



Component 



Degrees of 

 freedom 



Mean 



square 



2 



Moisture (M)__ ... .. . . . _ _._ 



5 

 15 



5 



25 



90 



143 







2 322 43** 



Error (a) - . 



29 19 



Fertilizer (F) 



566 98** 



MXF 



55 97** 



Error (b) 



14. 81 



Total 















1 See p. 5 for irrigation schedule. 



2 **= Significant at the 1-percent level. 



