|Authors: ||T. Forge, D. Neilsen, G. Neilsen, T. Watson|
|Keywords: ||replant disease, Pratylenchus penetrans, raspberry, cherry, nematode suppression, fumigation alternatives|
Young fruit trees or berry crops replanted into soil previously used for the same crops are often stunted.
This replant disease syndrome is usually associated with root-lesion nematodes (genus Pratylenchus) and infection by opportunistic soil-borne fungi.
Poor soil physical and chemical properties also contribute to poor replant establishment and may interact with the biotic agents.
Commercial growers have relied primarily on chemical fumigants to reduce pathogen populations prior to replanting.
In order to develop more sustainable alternatives to fumigation, we studied the effects of manure-based compost amendments on nematode populations, soil nitrogen (N) and replant establishment of sweet cherry in British Columbia.
The principal field experiment involved comparing pre-plant amendments of compost, fumigation or an untreated control, with or without post-plant application of bark mulch, under micro-sprinkler or drip irrigation.
The compost amendment suppressed root-lesion nematode populations and increased first-year shoot growth, but not trunk diameters, relative to the untreated control; first-year shoot growth in compost-amended plots was similar to that in fumigated plots.
Soil mineral N was initially greater in fumigated plots than in other treatments.
Later in the growing season, soil mineral N was reduced in mulched plots relative to non-mulched plots.
Correspondingly, leaf N was lower in mulched plots, but only under micro-sprinkler irrigation.
These results indicate that bark mulch can induce moderate N immobilization during the first year after establishment, particularly under micro-sprinkler irrigation.
We conclude that pre-plant incorporation of compost can be an important component of an integrated approach to optimizing replant establishment without fumigation.
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