Subsurface liming effects on cotton development and root growth: A greenhouse study

Cotton (Gossypium hirutum) yields in the Virginia Coastal Plain are often reduced by restricted root growth due to acid subsoils and hardpans, and sandy soils with low water-holding capacity. The objective of this experiment was to determine if subsoiling or subsoiling and subsoil lime placement affected nutrient element uptake, root growth and penetration, and plant development on selected Coastal Plain soils. Treatments were (i) untreated check, (ii) simulated subsoiled to 61 cm, and (iii) simulated subsoiled to 61 cm and 1 t ha(-1) of lime applied to the subsoiled trench. Cores 30.5 cm in diameter and 81 cm deep were collected in the field and placed in the greenhouse. The cotton cultivar DP50 was grown on these soils cores for 90 days. Rooting depth and taproot length were measured and approximate total root length was determined by the line intersect method. Root dry matter weight increased (p<0.05) by 52 and 35 grams per plant for the subsoiled and limed treatment over the untreated check, respectively. Taproot length was longer and rooting depths were deeper (p<0.05) in the subsoiled and subsoiled and limed treatments. An increase (p<0.05) in copper (Cu), manganese (Mn), and zinc (Zn) uptake in the rootmass of the subsoiled and limed treatment was observed. No difference in either macronutrient or micronutrient uptake, other than Cu, Zn, or Mn was observed. First flower occurred at 70, 69, and 59 days which provided 7, 10, and 13 bells per plant at 90 days for the untreated, simulated subsoiled, and simulated subsoiled and limed treatments, respectively.