Agroforestry Systems

, Volume 39, Issue 1, pp 31–44

Soil nitrogen dynamics in alley cropping and no-till systems on ultisols of the Georgia Piedmont, USA

  • C. C. Rhoades
  • T. M. Nissen
  • J. S. Kettler
Article

DOI: 10.1023/A:1005995201216

Cite this article as:
Rhoades, C.C., Nissen, T.M. & Kettler, J.S. Agroforestry Systems (1997) 39: 31. doi:10.1023/A:1005995201216

Abstract

On highly-weathered Ultisols of the Georgia (USA) Piedmont, a combination of no-till agriculture and alley cropping presents an option for rapidly increasing soil nitrogen availability while restoring long-term soil fertility. Three years after the establishment of Albizia julibrissin hedgerows and no-till agriculture trials, we measured inorganic soil nitrogen (NO3-–N and NH4-–N) and net nitrogen mineralization during a 4-month field study and a 14-day laboratory study . We also measured the influence of tree leaf amendments on grain sorghum production and N uptake. Soil nitrate increased four-fold within two weeks of adding Albizia leaf mulch. Soil ammonium did not increase as rapidly nor to the same extent after tree mulch addition. Averaged over the 4-month study, soil nitrate and ammonium were 2.8 and 1.4 times higher in the alley-cropped than in the treeless no-till plots. Net nitrification and mineralization were no higher in the alley cropping plots, during either field or laboratory incubations. Tree mulch additions enhanced crop biomass production and N uptake 2 to 3.5 times under both high and low soil moisture conditions. Our study demonstrates the dramatic short-term impacts of Albizia mulch addition on plant available nitrogen. Combined with no-till practices, alley cropping with Albizia hedges offers Piedmont farmers an option for reducing reliance upon chemical N fertilizer while improving soil organic matter levels.

Albizia julibrissin conservation tillage hedgerow intercropping nitrogen mineralization 

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • C. C. Rhoades
    • 1
  • T. M. Nissen
    • 2
  • J. S. Kettler
    • 1
  1. 1.Institute of EcologyUniversity of GeorgiaAthens GeorgiaUSA
  2. 2.Department of Crop and Soil SciencesUniversity of GeorgiaAthens GeorgiaUSA

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