Skip to Main Content
Inoculating Acacia koa with Bradyrhizobium and applying fertilizer in the nursery: effects on nodule formation and seedling growthAuthor(s): R. Kasten Dumroese; Douglass F. Jacobs; Anthony S. Davis
Source: HortScience. 44(2): 443-446.
Publication Series: Miscellaneous Publication
PDF: View PDF (510 B)
DescriptionRestoration of Acacia koa A. Gray (koa) forests on degraded sites in Hawaii is important for conservation of rare, endemic plants and animals and is often accomplished by planting nursery-grown seedlings. To be successful after outplanting, koa seedlings must access sufficient nutrients from the soil and outcompete other vegetation. Forming symbiotic associations with nitrogen-fixing microorganisms may help alleviate inherent nutrient deficiencies found on volcanic sites, but interactions between inoculation and fertilization during production of koa seedlings are not well studied. Under operational nursery conditions, we fertilized koa seedlings at six controlled-release fertilizer (CRF) rates (ranging from 0 to 11.9 kg m-3 Osmocote Plus 15N-9P-12K), which were also either inoculated with a locally collected source of nitrogen-fixing Bradyrhizobium spp. or not. Fertilized seedlings were significantly larger than the control; on average, fertilized seedlings were 300% taller and had 180%, 700%, and 350% more root-collar diameter, shoot biomass, and root biomass, respectively. Nitrogen (N) concentration was 23% to 119% greater in fertilized seedlings than nonfertilized seedlings. Inoculation with Bradyrhizobium had no significant affect on seedling characteristics except for root N concentration, which was 8% higher for inoculated seedlings. Fertilizer rate and inoculation interacted to significantly affect nodule number and nodule biomass/seedling. With inoculation, we observed an increase in nodule number (16.5 to 25.5) and biomass (5.8 mg to 11.7 mg) with fertilizer rate up to 4.7 kg m-3 but a decline to nearly zero at the highest rates. Without inoculation, nodule formation was scarce (3.2 nodules/seedling or less) and only observed when CRF was 2.3 kg m-3 or less. Our results suggest that high rates of fertilization and successful nodulation are not mutually exclusive nursery practices. Concurrent use of fertilization and inoculation in the nursery may provide opportunity to produce larger seedlings that have high potential to reduce the time needed to achieve canopy closure and thereby help achieve restoration objectives.
- You may send email to firstname.lastname@example.org to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationDumroese, R. Kasten; Jacobs, Douglass F.; Davis, Anthony S. 2009. Inoculating Acacia koa with Bradyrhizobium and applying fertilizer in the nursery: effects on nodule formation and seedling growth. HortScience. 44(2): 443-446.
Keywordscontainer nursery, controlled-release fertilizer, nitrogen use efficiency, nitrogen-fixing bacteria, forest restoration
- Responses of redwood soil microbial community structure and N transformations to climate change
- Soil Invertebrate and Microbial Populations Under Three Tree Species on the Same Soil Type
- Leaf litter decomposition and microbial activity in nutrient-enriched and unaltered reaches of a headwater stream
XML: View XML