African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6666

Full Length Research Paper

Responses of potted Acacia natalitia and Scutia myrtina saplings to type of nitrogen fertilizer and rate of application

GE Zharare* and PF Scogings
Department of Agriculture, University of Zululand, Private Bag X1001, KwaDlangezwa 3886, South Africa
Email: [email protected]

  •  Accepted: 09 November 2010
  •  Published: 19 October 2011

Abstract

 

Two experiments were conducted to study the responses of two savanna trees species Acacia natalitia(deciduous legume) and Scutia myrtina (evergreen non-legume) to nitrogen (N). Experiment 1 tested the responses of the species to three N- source fertilizers, namely; limestone ammonium nitrate (LAN), a composite fertilizer NPK3:1:5(26) containing slow release nitrate and an “organic” fertilizer (Accelerator).Experiment 2 tested the responses of the species to five LAN rates equivalent to 0, 3.4, 5.7, 23.1 and 34.6 gN m-2A. natalitia formed functional nodules with soil-born rhizobial species, and hence, responded less to applied N compared with the non-legume tree species S. myrtina. The source of applied N was inconsequential to the growth of A. natalita, but in S. myrtina, LAN produced the most positive growth response. The biomass of S. myrtina, responded positively to increasing LAN application over the entire range of rates tested, whereas that of A. natalitia showed an optimum at LAN rates equivalent to between 23.1 and 34.6g m-2 N. The stimulation of S. myrtina growth by N increased the allocation of dry matter (DM) to the shoots at the expense of the roots in an N rate-dependent manner, whereas A. natalitia generally allocated more DM to the roots.

 

Key words: Biomass, browse, growth, herbivore, nitrogen, savanna, tree.