Effect of fertiliser treatment and stocking rate on pasture nematode populations in a yellow-grey earth

Abstract

Soil was sampled in 1973 from 32 plots of a pasture of ryegrass, cocksfoot, and white clover that had been sown in autumn 1967. The trial had a factorial layout. Treatments were grazing by 14.8 or 22.2 ewes per ha, and topdressing with 125 or 500 kg superphosnhatc/ha annually and with 0 or 5.50 tonne lime/ha in 1968. Populations of Pratylenchus, Paratylenchus, Heterodera triiolii larvae, Mononchidae, and total nematodes changed significantly in response to at least one of the treatments; no change was found in Helicotylenchus, H. trijolii cysts, or Dorylaimida. The most marked effect was a fourfold increase in the Pratylenchus population in response to both liming and superphosphate. Stepwise multiple regression of nematode populations with dry matter production and five soil chemical factors gave only eight significant coefficients, three with soil P, four with soil pH, and one with soil Ca. Increase in Pratylenchus in the heavily fertilised plots may have been partly responsible for the low increase (3%) in dry matter production. The role of nematodes such as Heterodera, Pratylenchus. Paratylenchus. and Helicotylenchus, which are widespread in New Zealand pastures, is worth further investigation.

Invasion of white clover roots by fungi and other soil micro-organisms IV. Survey of root-invading fungi and nematodes in some New Zealand pastures

“…Codinaea fertilis and root knot nematode were not found in samples from the east and south of the South Island, however, which is consistent with suggestions that these micro-organisms may be restricted in pasture to moist and lor warm regions of New Zealand (Menzies 1973a;Yeates, 1975).…”

“…Stem nematode (Ditylenchus dipsaci (KUhn) Filipjev) and free-living ectoparasitic nematode species, which are common in New Zealand (Yeates 1975) and which can also damage white clover (McGlohon et al 1961;Williams & Barclay 1972), would not have been detected in our survey.…”

“…Most of the root damage observed in our survey could be attributed to endoparasitic nematodes (H. trifolii and species of Meloidogyne and Pratylenchusi, These nematodes are known to be pathogenic to white clover (Chapman 1964;Colman 1964;Minton 1965;Willis & Thompson 1969) and are reported to depress clover growth in New Zealand pastures (Yeates 1976(Yeates , 1977. Stem nematode (Ditylenchus dipsaci (KUhn) Filipjev) and free-living ectoparasitic nematode species, which are common in New Zealand (Yeates 1975) and which can also damage white clover (McGlohon et al 1961;Williams & Barclay 1972), would not have been detected in our survey.…”

Identification of soil factors that relate to plant parasitic nematode communities on tomato and yam in the French West Indies

“…However, they are also influenced, to a greater or lesser extent, by most of the biological, chemical and physical components of the soil envi-Ž ronment Upadhyay et al, 1972;Jacq and Fortuner, . 1979;Yeates, 1976Yeates, , 1981Cuc and Prot, 1992 . As a result, there are soils or regions within soils that are unsuitable for particular nematode species and which, thus, contain fewer individuals or different nematode communities than more favourable environments.…”

Invasion of white clover roots by fungi and other soil microorganisms

“…Infection by Rhizobium trifolii Dangeard, 1926, and vesicular arbuscular (V A) mycorrhizal fungi is generally considered beneficial (Brown 1974;Crush 1974;Powell 1976), whereas invasion by the endoparasitic nematodes Heterodera trifolii Goffart, Meloidogyne spp., and Pratylenchus spp. can severely depress clover growth (Minton 1965;Yeates 1976Yeates , 1977. Root-invading fungi known to be pathogenic to white clover include several Fusarium species (Leath et al 1971;Menzies 1973b) and, in New Zealand, Codinaea fertilis Hughes & Kendrick, which is considered to be a major cause of the disappearance of clover from pastures in some localities (Menzies 1973a).…”