Nitrification and Yield for Delayed‐Flood Rice as Affected by a Nitrification Inhibitor and Coated Urea

Abstract

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.

Effect of low‐use‐rate zinc fertilization on rice growth and grain yield

“…Second, MESZ was the only Zn-fertilizer treatment that included preplant N (20 kg N ha −1 ), which could have influenced canopy development. The nitrification rate in alkaline soils used for rice production is known to be very rapid (Fitts et al, 2014) and the nitrification rate in soil is known to decline as soil pH declines (Sahrawat, 2008). The soil pH values <7.0 may have limited nitrification and allowed for greater uptake of the T A B L E 3 Rice canopy coverage as affected by the main effects of Zn-fertilization method and Zn-seed treatment, for each of the six locations averaged across sample times (n = 3-5)…”

Assessing nitrogen uptake and the impact of fertilizer amounts and sources on strawberry production in California

“…Regarding the preference of crops for NO 3 – ‐ or ammonium (NH 4 + )‐based fertilizers, results reported in the literature are inconsistent. In general, plants have evolved with a preference for NO 3 – as a primary N source since NH 4 + rapidly converts to NO 3 – in moist, well‐aerated soils (Fitts et al., 2014). Therefore, it is difficult to maintain significant amounts of NH 4 + in soils, except for constant application of NH 4 + –based fertilizers and use of nitrification inhibitors.…”

Influence of soybean management decisions on the subsequent rice crop's response to nitrogen

“…This increased FNUE in the delayed-flood system results in an increased TNU of the rice crop from both the N applied and the PAN in the soil. The elevated TNU of the rice plant supplies sufficient N to achieve higher grain yields (Fitts et al, 2014).…”

“…This increased FNUE in the delayed‐flood system results in an increased total N uptake (TNU) of the rice crop from both the N applied and the PAN in the soil. The elevated TNU of the rice plant supplies sufficient N to achieve higher grain yields (Fitts et al., 2014). The absorption of N during the vegetative growth stage contributes to rice development during reproductive and grain filling stages through translocation, resulting in an increase in grain yield and quality (Bufogle et al., 1997).…”