|Popham, T - USDA-ARS|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 3, 1996
Publication Date: N/A
Technical Abstract: Reduced nitrogen availability in no-till due to leaching and denitrification prompted the need to evaluate nitrification inhibitors (NIs) that offer reduced N losses from soils. Field studies were conducted on Renfrow silt loam from 1990 through 1994 near El Reno, OK, to evaluate the ability of Nitrapyrin [2-chloro-6(trichloromethyl) pyridine] (NP) and Dicyandiamide (DCD) amended urea applied in the fall on dry matter accumulation, N-uptake and N redistribution in no-till winter wheat. Fertilizer (60 kg N ha-1) treatments were urea treated with or without NIs, were surface broadcast (BR) or placed 3 to 4 cm below the seed row (BL), and no N. Amending urea with or without NIs had no significant effect on total dry matter accumulation, but were significantly greater that no N. Total accumulation of N in whole plant in 1993 was 1.5 gNm-2 greater for all BL treatments than BR treatments. In 1993 and 1994 DCD-N treatment (both BR and BL) accumulated 1.7 and 1.4 gNm-2 more than NP treatment. Total precipitation received during the active growth period (April and May) was -10, -17, +46 and +52% more than 27 yr. average in 1991, 1992, 1993 and 1994, respectively. These results suggest that NI response was greatest when climatic and soil conditions were favorable for N losses and improved N-uptake. N-uptake and redistribution of N in various plant parts will be discussed.