Laboratory experiments were conducted in 2010, 2011, and 2012 in Stoneville, MS, utilizing urea fertilizer to quantify the nitri cation potential of southern soils, and to evaluate a nitri cation inhibitor aimed to reduce nitri cation rates on clay soils. Field research was conducted from 2011 to 2013 evaluating the e ectiveness of dicyandiamide (DCD) and sulfur-polymer coated urea at reducing N loss compared to urea alone on clay soil. e number of days when half the total recovered inorganic N was in the NH 4 + -N form (half-life for ammonium) for each soil and stabilizer for the nitri cation potential and N stabilizer experiments was determined. Nitrogen was applied to the soil at 0.115 g kg -1 for both laboratory experiments while DCD was applied at three di erent rates for the N stabilizer experiment. ese studies con rmed that the Sharkey clay soil (very-ne, smectitic, thermic Chromic Epiaquerts) at Stoneville, MS, had signi cantly higher nitri cation potential compared to three other soil types studied and DCD increased half-life for ammonium by approximately threefold when compared to non-amended urea. Field experiment data indicated that increasing DCD rate to 17 kg ha -1 increased rice (Oryza sativa L.) grain yield response and resulted in yields comparable to the standard treatment, which was urea applied 1 day before ood establishment (dbf). e sulfur-polymer coated urea applied 12 dbf reduced nitri cation; however, it yielded less than the standard treatment. Products that limit nitri cation and subsequent denitri cation can optimize N e ciency, resulting in greater potential for increased yields and decreased production costs.

‘CL162’ (CV‐135, PI 661110), a Clearfield long‐grain rice (Oryza sativa L.) cultivar was developed by Mississippi State University Delta Research and Extension Center in Stoneville, MS, and jointly approved for release by Mississippi State University and BASF in 2011. The population from which CL162 was derived began as a single cross of CFX‐18 (‘CL161’)/‘Priscilla’ (PVP 9800212) made in 2001. CFX‐18, later named CL161, contains the gene for resistance to imazethapyr and imazamox, which are used in the Clearfield rice production system. CL162 was tested at 14 locations in Mississippi in 2008–2010 and in the Uniform Regional Rice Nursery conducted in 2010 Louisiana, Texas, Missouri, and Mississippi, where it had an average grain yield of 9.9 t ha−1 compared with 10.0, 8.9, and 10.7 t ha−1for the comparison cultivars ‘Cocodrie’, ‘CL131’, and ‘CL151’, respectively. Its consistency in grain yield across production sites and years can be attributed, in part, to its excellent straw strength, as shown by a lodging incidence of 3% over the same number of test locations and years, compared with 17% for CL151 and 4% for CL131. CL162 averaged 84 d to 50% heading and 120 d to maturity over all tests from 2008 to 2010 compared with Cocodrie, which averaged 85 d to 50% heading and 119 d to maturity. CL162 is rated as susceptible to sheath blight (caused by Rhizoctonia solani J.G. Kühn); moderately susceptible to bacterial panicle blight (caused by Burkholderia glumae), rotten neck blast (caused by Pyricularia grisea Sacc.), and straighthead disorder; and moderately resistant to leaf blast (caused by Pyricularia grisea Sacc.).