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United States Department of Agriculture

Agricultural Research Service

Title: Growing Dryland Grain Sorghum in Clumps to Reduce Vegetative Growth and Increase Yield

Authors
item Bandaru, Varaprassad - WTAMU
item Stewart, B - WTAMU
item Baumhardt, Roland
item Ambati, Satish - WTAMU
item Robinson, C - WTAMU
item Schlegel, Alan - KANSAS STATE UNIVERSITY

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 3, 2005
Publication Date: June 1, 2006
Citation: Bandaru, V., Stewart, B.A., Baumhardt, R.L., Ambati, S., Robinson, C.A., Schlegel, A. 2006. Growing dryland grain sorghum in clumps to reduce vegetative growth and increase yield. Agronomy Journal. 98:1109-1120.

Interpretive Summary: Grain sorghum (sorghum bicolor L. Moench) grown in dryland areas is often seeded in soil containing 4 to 8 in. of plant available soil water. This stored water supplements growing season precipitation so early vegetative growth is usually good even in low rainfall years. However, water normally becomes limiting as the season progresses and grain yields are severely reduced because of water stress during the critical reproduction and grain filling growth stages. We hypothesized that growing grain sorghum plants in clumps, as compared to uniformly spaced plants, would result in fewer tillers and less vegetative growth so that a larger portion of the soil water would be available during the grain filling period. Our objective was to compare clumps of plants to the same number of evenly spaced plants and determine number of tillers, biomass and leaf area production during different growth stages, water use during vegetative and reproduction stages, grain yields, and harvest index values. Results from three years of study at Bushland, TX, and one year at Tribune, KS, showed that planting dryland grain sorghum in clumps of three to six plants significantly reduced the formation of tillers compared with uniformly spaced sorghum. Reduced tillering decreased water use during the early part of the growing season so that more water was available later, which increased grain yields and harvest index values. Clumps increased grain yields compared with uniformly spaced plants by as much as 100% when yields were about 1000 lbs/acre. The increase was 25 to 50% in the 2000 to 3000 lbs/acre range, but there was no increased yield above 5000 lbs/acre.

Technical Abstract: Grain sorghum (sorghum bicolor L. Moench) grown in dryland areas is often seeded in soil containing 100 to 200 mm of plant available soil water in the soil profile. This stored water supplements growing season precipitation so early vegetative growth is usually good even in low rainfall years. However, water normally becomes limiting as the season progresses and grain yields are severely reduced because of water stress during the critical reproduction and grain filling growth stages. We hypothesized that growing grain sorghum plants in clumps, as compared to uniformly spaced plants, would result in fewer tillers and less vegetative growth so that a larger portion of the soil water would be available during the grain filling period. The objective was to compare clumps of plants to the same number of evenly spaced plants and determine number of tillers, biomass and leaf area production during different growth stages, water use during vegetative and reproduction stages, grain yields, and harvest index values. Results from three years of study at Bushland, TX, and one year at Tribune, KS, showed that planting dryland grain sorghum in clumps of three to six plants significantly reduced the formation of tillers compared with uniformly spaced sorghum. Reduced tillering decreased water use during the early part of the growing season so that more water was available later, which increased grain yields and harvest index values. Clumps increased grain yields compared with uniformly spaced plants by as much as 100% when yields were about 1000 kg/ha range. The increase was 25 to 50% in the 2000 to 3000 kg/ha range, and there was no increase or a small decrease above 5000 kg/ha.

Last Modified: 9/20/2014
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