Search

The method of fertilizer nitrogen (N) application can affect N uptake in tall fescue and therefore its yield and quality. Subsurface-banding (knife) of fertilizer maximizes fescue N uptake in the poorly-drained clay-pan soils of southeastern Kansas. This study was conducted to determine if knifed N results in greater N uptake than the conventional top-dress application method in a deep, well-drained soil of east-central Kansas. The experiment, conducted in a Smolan silty clay loam soil, was a split-plot with fertilizer nitrogen rates 0, 140 and 280 kg N ha−1applied as urea-ammonium nitrate (UAN, 28% N), knifed or top-dressed. Soil inorganic N [ammonium (NH4)- and nitrate (NO3–N)] and N in roots and plant tops were measured at various times during the growing season. At final harvest, most of the knifed N (99.7%) was accounted for in plant tissue (roots and tops) and soil, with more than half of the knifed N remaining as soil inorganic N. With the top-dressed method, 27% was unaccounted for and presumed lost in gaseous form. Knifing fertilizer N in fescue fields of east-central Kansas will maximize the availability of N, reduce potential N losses, and increase forage quality. [ABSTRACT FROM PUBLISHER]

Research has shown that measured water-soluble phosphorus (WSP) from poultry litter might have been less than that released in the field. The effects of acidified extractions on soluble P (SP) concentrations were studied, and a buffer was selected to measure SP at pH 6.0, which is a target value for soil management in Georgia. Soluble P concentrations were extracted from poultry wastes at three pHs: 1) at natural pH, using deionized water (DIw); 2) after titrating DIw suspensions with 0.5N hydrochloric acid (HCl) to pH end-points 3.0, 4.0, and 6.0; and 3) at pH 6.0 with buffers of sodium (Na) acetate, potassium hydrogen phthalate (KHP), 2-(N-morpholino) ethanesulphonic acid (MES), Na cacodylate, imidazole, N-(2-acetamido)-2-aminoethansulphonic acid (ACES), N-(carbamoyl-methyl) iminodiacetic acid (ADA), bis-(2-hydroxyethyl) imino]-tris-[(hydroxymethyl) methane (Bistris), and 1,4 piperazine-bis-(ethane sulphonic acid) (PIPES). Total SP increased 60% to 140% in suspensions acidified with HCl to pH 6.0 compared to suspensions at pH≥8. Dissolved unreactive P responded more (2× to 30×) than molybdate reactive P (20-100%). Buffers extracted more soluble minerals than suspensions acidified with HCl, probably because of their complexation ability. The most effective buffer was MES, because its effects seemed mainly due to acidification. [ABSTRACT FROM AUTHOR]

Under laboratory conditions we studied the possibility of decreasing NH3 emissions from broiler litter by applying one of two nitrifier seeds (a material obtained from the top centimeters of the dirt floor of a chicken house, or Houston Black clay soil) at 0, 2.5, 5, and 10% w/w. Ammonia emission rates, total NH3 trapped in 0.1N H2SO4, and NOx--N concentrations decreased at the highest application rate of either amendment, whereas CO2 emissions increased with the amendments' application rates. We hypothesize that the lack of a significant increase in NOx--N concentrations was due to inhibition of nitrifiers by high NH4+-N, salt and Cl- concentrations, and denitrification promoted by high water, availability of easily decomposable carbon sources, and limited O2 supply. [ABSTRACT FROM AUTHOR]

We developed a new method for determination of atmospheric ammonia (NH3) emissions from land‐applied nitrogen (N). The new method is a modification of two proven passive flux methods, and is an improvement over these existing methods via reductions in cost, labor and analytical requirements. This new method involves use of one rotating mast placed in the center of a circular plot (15 m radius). The samplers we use are glass tubes (7 mm by 200 mm) that have been coated on the inside with oxalic acid to trap NH3. This new method was tested against one of the proven methods in a field experiment. A circular plot (15 m radius) was established and urea was applied to supply 200 kg N ha‐1. Measurements of NH3 volatilization were then made for six days after application. A strong linear relationship was evident between our new method and the reference method for both horizontal and vertical NH3 fluxes, as indicated by correlation coefficients of 0.92 and 0.86 for horizontal and vertical fluxes, respectively. The glass tubes that we used consistently absorbed more NH3 and measured more total NH3 volatilization than the samplers of the reference method. However, given that micrometeorological methods have underestimated NH3 volatilization in the past, we feel that our method has improved the accuracy of NH3 volatilization measurement. In essence, we believe we have developed an improved method for field‐scale determination of NH3 volatilization by reducing initial costs as well as labor and analytical requirements, without sacrificing accuracy of the volatilization measurement. [ABSTRACT FROM PUBLISHER]