Soil-Solution N Under Conservation Tillage: A Tension Lysimeter (ceramic cup) Study On Conventional and Sod-Based Crop Rotations.

Leaching of nutrients through the soil profile is of public concern due to potential risks of groundwater contamination. Fertilizer and irrigation management are important to improve nitrogen/water-use efficiency and reduce N losses, especially on sandy soils. Research is in its 10^th year at the University of Florida’s North Florida Research and Education Center in Quincy studying the impact of sod-based rotation under conservation tillage on cotton (Gossypium hirsutum L.) and peanut (Arachis hypogaea L.) yield and quality. Oats (Avena sativa L.) were grown as winter-cover crop between major crops. Perennial grass such as Bahia (Paspalum notatum Flugge) in rotation with cotton and peanut has improved crop yields and economic gains. It also has a positive effect on pest/disease reduction in a comparison with conventional rotations. In this study we assessed N concentrations in soil solution obtained by tension lysimetry (TL) technique; the TL-samplers were randomly assigned to conventional and sod-based rotations at the depth of 0.6 and 1.2 m (2 and 4 ft). Soil-solution samples were taken monthly and analyzed for pH, electrical conductivity (EC), and nitrate-N. The results are discussed in relation to the water quality protection and an attempt is made to offer possible managerial responses.