Nutrient Cycling in Agroecosystems

, Volume 75, Issue 1, pp 271–284

Nitrogen dynamics in maize-based agroforestry systems as affected by landscape position in southern Malawi

  • Rebbie Harawa
  • Johannes Lehmann
  • Festus Akinnifesi
  • Erick Fernandes
  • George Kanyama-Phiri
Original Paper

DOI: 10.1007/s10705-006-9033-y

Cite this article as:
Harawa, R., Lehmann, J., Akinnifesi, F. et al. Nutr Cycl Agroecosyst (2006) 75: 271. doi:10.1007/s10705-006-9033-y

Abstract

In Malawi, agroforestry is very promising for N replenishment; however, there are still large variations in the performance of these agroforestry technologies on farmers’ fields. A study was conducted on-farm to determine the influence of three landscape positions on N dynamics in maize (Zea mays L.)-based agroforestry systems. The agroforestry systems were relay fallow using Sesbania sesban (L.) Merr or Tephrosia vogelii (Hook F.), simultaneous fallow using Gliricidia sepium(Jacq.) Walp., and maize without trees as a control. Sesbania was superior to other systems in the bottom slope, producing the highest tree biomass (1,861 kg ha−1), whereas, gliricidia gave the highest tree biomass production in the mid-slope (2,147 kg ha−1) and upper slope (1,690 kg ha−1). Preseason inorganic N, maize flag leaf N concentration, maize total N uptake and maize yields followed a similar trend to tree biomass production with tree-based cropping systems exhibiting higher productivity (P < 0.05) than the cropping systems without trees. Nitrogen leaching from gliricidia agroforestry systems was lower than in the other agroforestry systems across all landscape positions as evidenced by 17% lower amounts (P < 0.05) of inorganic N adsorbed to ionic exchange resin membranes at 60 cm soil depth most likely due to the permanent root system of gliricidia. The difference between δ15N values of the trees and the soil did not change between landscape positions suggesting that if the leguminous trees fixed atmospheric N2, the proportion of total N uptake was identical at all locations. We concluded that landscape positions have a significant effect on tree performance with sesbania remarkably adapted to the bottom slope, gliricidia to the mid-slopes and tephrosia fairing similar in both the bottom slope and mid-slopes.

Keywords

Tree biomassN uptakeN2 fixationLeachingFallow

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • Rebbie Harawa
    • 1
  • Johannes Lehmann
    • 1
  • Festus Akinnifesi
    • 2
  • Erick Fernandes
    • 3
  • George Kanyama-Phiri
    • 4
  1. 1.Department of Crop and Soil SciencesCornell UniversityIthacaUSA
  2. 2.SADC-ICRAF Agroforestry ProgrammeChitedze Agricultural Research StationLilongweMalawi
  3. 3.The World BankWashingtonUSA
  4. 4.Bunda College of AgricultureUniversity of MalawiLilongweMalawi