Wednesday, 9 November 2005
5

The Urea-Nitrogen Equivalence of Fresh and Pelleted Poultry Litter for Flood-Irrigated Rice.

Bobby R. Golden, Nathan A. Slaton, Richard J. Norman, Kristofor R. Brye, and Russell E. DeLong. Univ. of Arkansas, 1366 W. Altheimer Dr., Fayetteville, AR 72704

The N-fertilizer value of poultry litter applied preplant to flood-irrigated rice (Oryza sativa L.) is unknown. The research objective was to compare preplant incorporated fresh (FPL) and pelleted (PPL) poultry litter with urea applied preflood across a range of N rates to determine the urea-N equivalence of poultry litter for the production of rice grown in the direct-seed, delayed-flood production system. Five site-years of data were collected on silt loam soils in eastern Arkansas. Fresh and pelleted litter were preplant incorporated at total-N rates ranging from 34 to 269 kg/ha and compared with urea applied preflood (5-lf stage) at rates from 34 to 168 kg N/ha. Experiments were a randomized complete block with a 3 (N source) x 5 (N rate) factorial treatment arrangement plus an unfertilized control. Net N uptake was measured at panicle differentiation (PD) and anthesis and net grain yield at maturity. Regression analyses indicated that the N source x rate interaction was highly significant for net N uptake at PD and anthesis and grain yield for all site-years. Rice grain yield and N uptake increased linearly or non-linearly as N rate increased within each N source. The linear and/or non-linear slope coefficients for FPL and PPL were always similar within and among site-years and significantly lower than the slope coefficients for urea. For rice receiving urea-N, net grain yield increased non-linearly with maximal yields produced with 101 to 135 kg N/ha. For rice receiving FPL and PPL, net grain yield increased linearly with near maximal yields produced occasionally by application of 269 kg total-N/ha. Based on net grain yield, multiplying the total-N content of preplant incorporated FPL and PPL by 0.3 reasonably estimates the preflood urea-N equivalence of FPL and PPL for rice produced with the delayed-flood system in Arkansas.


Handout (.pdf format, 201.0 kb)

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