Water for dryland grain production in the Texas panhandle is limited. Agronomic practices such as reduction in plant population or change in sowing time may help increase maize ( Zea mays L.) yield potential. Tiller formation under dryland conditions leads to more vegetative growth and reduced yield. We hypothesized that clump planting dryland maize would reduce environmental stress, tillering, and vegetative growth, and increase harvest index by having more soil water available during grain filling. Clump planting was studied during 2008 at Bushland, Texas. Two plant populations - 30,000 and 40,000 plants ha -1 - and three plant geometries - clumps of three or four plants (3 PPC or 4 PPC) and equally spaced single plants (ESP) - were grown in 75 cm rows. Growing season precipitation was 209 mm. Harvest index (HI) 200-seed mass and harvested ears were higher in 3 PPC and 4 PPC compared with ESP. Three PPC planted at 40,000 plants ha -1 had the highest harvest index of 0.46. The ESP produced 27% more unproductive ears compared with 3 PPC and 4 PPC. Leaf area index (LAI) was 14% more in ESP than in 4 PPC. The lower population produced higher HI and seed mass than the higher population, regardless of geometry. Grain yields were not significantly higher for clumps, yet increased number of productive ears, seed mass, and HI values, suggesting clump geometry may be a good strategy for dryland maize production.
