Evaluation of added nitrogen interaction effects on recovery efficiency in irrigated cotton

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Abstract

Studies were conducted in 1997 and 1999 at the University of Arizona Maricopa Agricultural Center to evaluate the added nitrogen (N) interaction or 'priming effect' on the determination of N recovery efficiencies (NRE) in Upland cotton (Gossypium hirsutum L.). Overall growth patterns of the crop were significantly different between the two years. In 1997, the crop experienced a favorable balance between reproductive and vegetative growth. The NRE estimates were 34.7% and 34.7% for Treatment 1 (recommended fertilizer N rate, 168 kg N ha (RecN)) and 25.2% and 26.0% for Treatment 2 (twice recommended fertilizer N rate, 336 kg N ha (RecN 2×)) for the difference and isotopic dilution technique, respectively. In 1999, however, the crop experienced very poor fruit load and vigorous vegetative growth. This resulted in a crop that produced much more vegetative dry matter at the expense of reproductive dry matter (yield). Higher NRE estimates were observed using the difference technique (50.8% and 40.5% for RecN and RecN 2×, respectively) when compared with the isotopic dilution technique (32.3% and 35.2% for RecN and RecN 2×, respectively). Higher amounts of soil N taken up by the plant were also observed in 1999 when compared with those in 1997. The results presented from these studies indicate that plant uptake of indigenous soil N was much higher in 1999 than in 1997, which is evidence of an added N interaction. However, this increase does not seem to have been stimulated by the addition of fertilizer N but rather the increased vegetative growth and root exploration that occurred in 1999.

Original languageEnglish (US)
Pages (from-to)983-991
Number of pages9
JournalSoil Science
Volume172
Issue number12
DOIs
StatePublished - Dec 1 2007

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Keywords

  • Cotton soil fertility
  • Irrigated agriculture
  • Nitrogen recovery efficiency
  • Soil nitrogen dynamics

ASJC Scopus subject areas

  • Soil Science

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