Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-0789
    Keywords: Chitin ; Heterodera trifolii ; Meloidogyne spp. ; Nematodes ; Nodulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Effects of soil amendment with crabshell chitin on the growth of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.), and on populations of soil bacteria, fungi, and plant-parasitic and free-living nematodes were investigated in a pot trial. Five soil samples were collected from Te Puke (Paengaroa Shallow Sand, a Typic Hapludand) and five from Hamilton (Bruntwood silt loam, an Aquic Hapludand), New Zealand. Subsamples of each soil were either amended with chitin or unamended and planted with white clover and ryegrass. The ryegrass shoot weight in amended soil was greater (P〈0.01), most probably due to N mineralised from chitin. A significantly lower (P〈0.01) root: shoot ratio of ryegrass in the amended soil also suggested improved N availability, and therefore less root mass was needed to support a given shoot mass. A reduction in nodulation was observed in 12-day-old white clover seedlings (P〈0.05) and also in 6-week-old seedlings (P〈0.01). The shoot weight of white clover was significantly lower (P〈0.05) in amended soil, possibly due to phytotoxic effects of chitin. Chitin increased (P〈0.01) the populations of bacteria and fungi by 13-fold and 2.5-fold, respectively. The cyst nematode of white clover, Heterodera trifolii, was significantly reduced in chitin-amended soil, possibly due to increased levels of chitinase produced by rhizosphere microorganisms. Two other plant-parasitic nematodes, Pratylenchus spp. and Tylenchus spp., were also reduced in ryegrass roots and in soil as a result of the chitin amendment. However, the total number of free-living nematodes increased 5.4-fold in amended soil.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-0789
    Keywords: Key words Chitin ; Heterodera trifolii ; Meloidogyne spp. ; Nematodes ; Nodulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Effects of soil amendment with crabshell chitin on the growth of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.), and on populations of soil bacteria, fungi, and plant-parasitic and free-living nematodes were investigated in a pot trial. Five soil samples were collected from Te Puke (Paengaroa Shallow Sand, a Typic Hapludand) and five from Hamilton (Bruntwood silt loam, an Aquic Hapludand), New Zealand. Subsamples of each soil were either amended with chitin or unamended and planted with white clover and ryegrass. The ryegrass shoot weight in amended soil was greater (P〈0.01), most probably due to N mineralised from chitin. A significantly lower (P〈0.01) root: shoot ratio of ryegrass in the amended soil also suggested improved N availability, and therefore less root mass was needed to support a given shoot mass. A reduction in nodulation was observed in 12-day-old white clover seedlings (P〈0.05) and also in 6-week-old seedlings (P〈0.01). The shoot weight of white clover was significantly lower (P〈0.05) in amended soil, possibly due to phytotoxic effects of chitin. Chitin increased (P〈0.01) the populations of bacteria and fungi by 13-fold and 2.5-fold, respectively. The cyst nematode of white clover, Heterodera trifolii, was significantly reduced in chitin-amended soil, possibly due to increased levels of chitinase produced by rhizosphere microorganisms. Two other plant-parasitic nematodes, Pratylenchus spp. and Tylenchus spp., were also reduced in ryegrass roots and in soil as a result of the chitin amendment. However, the total number of free-living nematodes increased 5.4-fold in amended soil.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-5036
    Keywords: agro-ecosystem ; diversity ; food-web ; macrofauna ; nematode ; trophic interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An ongoing study initiated in August 1990 investigated the effects of disturbances (organic mulching, cultivation, herbicides) on the detritus food-web in annual (maize) and perennial (asparagus) cropping systems. In this paper we attempt to simultaneously assess the functional and taxonomic structure of various components of this food-web. Biota in the perennial system was the most responsive to disturbance. The microflora was strongly influenced by mulching, and through tritrophic effects caused increases in top predatory but not most microbe-feeding nematodes. These effects have become increasingly apparent as the study has progressed and, in the asparagus site, have worked their way down the soil profile over time. Cultivation in the asparagus site caused large increases in bacterial-feeding nematodes, probably due to the high weed levels which developed during the winter months under that treatment. Evidence appears to exist for a cascade effect operating due to top down effects of nematodes on lower trophic levels. Ordination analysis of the nematode data demonstrated that nematode populations were more closely related to the state of environmental factors at earlier samplings than at contemporary samplings, and that the linkages between the nematode and environmental data sets strengthened over time. For both the nematode and soil-associated beetle data distinct assemblages of organisms were found in the mulched plots; distinct assemblages of nematode genera also emerged in the cultivated asparagus plots after two years. The soil-associated macrofauna was usually linked to high weed and surface organic residue levels. Species diversity of soil associated nematodes was not particularly responsive to disturbance while that of the soil-associated beetles was strongly enhanced by mulching and (sometimes) high weed levels. Approaches based on either functional group or species composition data emerged in our study as reasonably sensitive indicators for assessing the response of the soil biota to disturbance.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...