Influence of brassicaceous soil amendments on potentially beneficial and pathogenic soil microorganisms and seedling growth in Douglas-fir nurseries

•Brassica green manure and seed meals were applied to soil in Douglas-fir nurseries.•Tree growth, soil quality, and potentially pathogenic and beneficial soil-borne microorganisms were analyzed.•B. juncea green manure produced marginal control of Fusarium; seed meals did not.•B. juncea green manure...

Full description

Saved in:
Bibliographic Details
Published in:Applied soil ecology : a section of Agriculture, ecosystems & environment ecosystems & environment, 2016-09, Vol.105, p.91-100
Main Authors: Paudel, Bodh R., Carpenter-Boggs, Lynne, Higgins, Stewart
Format: Article
Language:English
Subjects:
Actinobacteria
antagonists
autumn
beneficial microorganisms
Biofumigation
Brassica green manure
Brassica juncea
Brassica seed meals
chloropicrin
conifers
cropping systems
Cylindrocarpon
enzyme activity
field experimentation
fumigants
Fusarium
Fusarium root rot
green manures
industry
Methyl bromide
microbial activity
Neonectria
nitrogen
pathogens
population density
Pseudotsuga menziesii
Pythium
quarantine
seedling growth
seedlings
Sinapis alba
soil amendments
soil density
soil fumigation
Soil health
soil microorganisms
soil quality
spring
Trichoderma
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•Brassica green manure and seed meals were applied to soil in Douglas-fir nurseries.•Tree growth, soil quality, and potentially pathogenic and beneficial soil-borne microorganisms were analyzed.•B. juncea green manure produced marginal control of Fusarium; seed meals did not.•B. juncea green manure provided similar tree growth as methyl bromide fumigation.•Green manure increased soil dehydrogenase activity and nitrogen mineralization. Fusarium, Cylindrocarpon and Pythium spp. are the major soil-borne pathogens of conifer seedlings. Soil fumigation with methyl bromide and chloropicrin has been the most effective method for reducing the population density and disease pressure of these organisms. Due to safety and environmental concerns, use of methyl bromide as a pre-plant soil fumigant has been abolished in the majority of cropping systems. However, the conifer seedling industry continues to use methyl bromide under a quarantine pre-shipment exemption due to a lack of effective alternatives. Toward identifying alternatives to methyl bromide for management of soil microbial populations, a three-year field study was conducted in northwest USA. The objective of this study was to examine the effects of brassica seed meals and green manures on potentially pathogenic and beneficial microorganisms, soil health, and seedling growth in conifer nursery fields. The study treatments were Brassica juncea seed meal, B. carinata seed meal, Sinapis alba seed meal, B. juncea green manure, methyl bromide/chloropicrin fumigation, and a non-treated control, with four replications in a randomized complete block design. The treatments were incorporated into soil in autumn or early spring, and Douglas-fir (Pseudotsuga menziesii) seedlings were transplanted into plots in late spring. Population densities of Fusarium, Cylindrocarpon, Pythium, actinomycetes, and Trichoderma; mineralizable nitrogen; and dehydrogenase enzyme activity in soil were assessed at pre-transplant, post-transplant, and seedling harvest. The pre-treatment soil pathogen count was similar among study plots. At transplant time, Fusarium spp. densities in soil were generally similar among most brassica treatments but fumigated plots generally had less Fusarium. Treatment with S. alba, however, increased soil densities of Fusarium spp. In 2012, Fusarium spp. density was significantly lower after B. juncea green manure incorporation [1.8 log CFU (colony forming units)] than after chemical fumigation (2.4 log CFU) or
ISSN:0929-1393
1873-0272
DOI:10.1016/j.apsoil.2016.04.007