Clump Sorghum - No Real Yield Advantage

Grain sorghum planted in clumps.

 There has been some recent press indicating there might be an advantage to planting grain sorghum in clumps vs. the traditional seed drop method.  David Ocker agreed to evaluate this planting alternative in the Coastal Bend of Texas, so for the last three years a study was implemented on his farm in Nueces County.  The goal was to evaluate planting of grain sorghum in clumps vs. conventional seed drop method, while at the same time keeping the same plant population per acre.

  Traditional sorghum seeding plates were altered by closing holes so that seed would be dropped in clumps rather than traditional even spacing.  In 2012, grain sorghum was planted in clumps (5 to 6 plants per clump, with clumps spaced about 14 inches apart) within rows and conventionally in a randomized complete block design. Seed was planted with a 24-row planter in which half of the planter (12-rows) planted clumps and the other half planted seed the traditional method, with seed spaced uniformly.  Seeding rates in both cases was 61,256 seed per acre.  Row space was 30-inches. 

  Plots were machine harvested on July 10, 2012 and weighed with an electronic weigh-wagon.  Results from each plot are recorded in Table 1.

Table 1, Comparison of plant population, % moisture, and yield per acre between

 treatments, Ocker Farm, Nueces County, 2012.

Treatment	Plant Population/Ac	% Moisture	Yield/Acre1
Clump	50,312.3 a	14.0	3,519 a
Solid/Conventional	54,956.7 a	14.0	3,557 a
LSD (P=.05) CV Grand Mean	4,997.22 2.7 52,634.51		61.01 0.49 3,538.33

¹Yield per acre is reported in pounds per acre and adjusted to 14% moisture.  Means followed by same letter do not significantly differ (P=.05, LSD).

 Results from this study suggest that there was not a real difference between treatments (i.e. clump planting vs. conventional planting) as the clump planting average yield was 3,519 pounds per acre, while the yield for the conventional planting was 3,557 pounds per acre. Rainfall during the growing season was below normal.

 In 2011 a similar study was conducted with the results in Table 2.

Table 2, Comparison of plant population, % moisture, and yield per acre between

 treatments, Ocker Farm, Nueces County, 2011.

Treatment	Plant Population/Ac	% Moisture	Yield/Acre1
Clump	45,765 a	13.2	3,683 a
Solid/Conventional	46,999 a	13.2	3,545 a

¹Yield per acre is reported in pounds per acre and adjusted to 14% moisture.  Means followed by same letter do not significantly differ (P=.05, LSD).  
 

Results from this study suggest that there was not a real difference between treatments (i.e. clump planting vs. conventional planting) as the clump planting average yield was 3,683 pounds per acre, while the yield for the conventional planting was 3,545 pounds per acre. Rainfall during the growing season was below normal.  

 
Results obtained in 2010 were very similar with no significant yield differences as the clump planting average yield was 5,075 pounds per acre, while the average yield for the conventional planting was 5,082 pounds per acre. Rainfall during the growing season was above normal.

So with one above normal rainfall year and two below normal rainfall years there was not a statistical difference between the two different planting methods  on the Ocker Farm in Nueces County.

The cooperation and support of David Ocker for implementing this trial is appreciated and the support of  Dr. Dan Fromme, Extension Agronomist, for statistical analysis, and consultation is also appreciated.