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

Abstract

Stored soil water and growing season precipitation generally support early season growth of grain sorghum (Sorghum bicolor L. Moench) in dryland areas but are insufficient to prevent water stress during critical latter growth stages. The objective of this study was to determine if growing plants in clumps affected early season growth and subsequent grain yield compared to uniformly spaced plants. We hypothesized that growing grain sorghum plants in clumps would result in fewer tillers and less vegetative growth so that more soil water would be available during the grain-filling period. Results from 3 yr at Bushland, TX, and 1 yr at Tribune, KS, showed that planting grain sorghum in clumps of three to six plants reduced tiller formation to about one per plant compared to about three for uniformly spaced plants. Grain yields were increased by clump planting by as much as 100% when yields were in the 1000 kg ha 21 range and 25 to 50% in the 2000 to 3000 kg ha 21 range, but there was no increase or even a small decrease at yields above 5000 kg ha 21 . Our results suggest that planting grain sorghum in clumps rather than spaced uniformly conserves soil water use until later in the season and may enhance grain yield in semiarid dryland environments.Abbreviations: LAI, leaf area index; PET, potential evapotranspiration.

Soil degradation as a reason for inadequate human nutrition

“…Growing sorghum and millet in clumps can improve early season growth in dry areas, enhance grain yields, and increase use efficiency of scarce rainwater. Bandaru et al (2006) observed that grain yields were improved by clump planting by as much as 100% when yields were in the 1 t ha− 1 range and 25% to 50% when in the 2 to 3 t ha −1 range. Productivity of the Asian rice-wheat Table 1 Expected ratio of crop production and cultivated land area in 2020 relative to those in 1990 (Evenson 1999;Cakmak 2002 system, which has stalled (Timsina and Conner 2001), can also be greatly enhanced through management of nutrients and water, and by improving use efficiency of input.…”

Allometric Method to Estimate Leaf Area Index for Row Crops

“…The same appeared to apply to PP. Previous studies have shown that planting sorghum in clumps reduced tillers and leaves per plant compared with uniform plant spacing (Bandaru et al, 2006;Krishnareddy et al, 2009), which implied that LAPP varied with planting geometry, but could conceivably have had a compensating effect on LAI (i.e., LAI and PP were weakly correlated). Nonetheless, inclusion of either CH or PP did reduce measured vs. calculated LAI discrepancies for sorghum.…”

Genetic Variability and Control of Nodal Root Angle in Sorghum

“…In contrast, a wide root angle might enhance water extraction from the wide interrow spaces in water-limited environments where skip-row confi gurations are used to meter out the available stored soil water through the crop cycle (Whish et al, 2005). As nodal root angle is determined during the seedling stage, when occurrence of drought stress is uncommon provided the crop is sown in wet soil, results on root angle in the current well-watered experiments do have relevance to farming systems in southern United States, eastern Australia, and the monsoonal region of India's central west, where postanthesis drought stress is prevalent (Chapman et al, 2000;Bandaru et al, 2006;DeLacy et al, 2010). As nodal root angle is determined during the seedling stage, when occurrence of drought stress is uncommon provided the crop is sown in wet soil, results on root angle in the current well-watered experiments do have relevance to farming systems in southern United States, eastern Australia, and the monsoonal region of India's central west, where postanthesis drought stress is prevalent (Chapman et al, 2000;Bandaru et al, 2006;DeLacy et al, 2010).…”