Influences of nitrogen inputs on nematode populations under highbush blueberry

Forge, Thomas; Ehret, David; Messiga, Aime; Dorais, Martine

Influences of nitrogen inputs on nematode populations under highbush blueberry

Journal of Nematology

Volume 52 (2020): Issue 1 (January 2020)

By:

Thomas Forge, David Ehret, Aime Messiga and Martine Dorais

Open Access

|Jul 2020

Figures & Tables

Changes through time in the percentage of samples with Pratylenchus crenatus, Rotylenchus robustus, and Paratrichodorus renifer in the experimental area. At each sample date, a single 100 cm3 sample from each of 24 plots (six replicates of four N fertilization treatments) in the experimental area was analyzed. Blueberry bushes were planted in fall of 2008.

Effects of fertilizer nitrogen application rates on population densities of Rotylenchus robustus, from September, 2009 through June, 2019. Error bars are one standard error projecting above the 0N control (pooled standard error from overall ANOVA of non-transformed data). Within a date, points labeled with the same letter are not significantly different (p < 0.05) based on Diff procedure in mixed model repeated measures analysis of log-transformed data. NS, no significant differences.

Effects of fertilizer nitrogen application rates on population densities of Pratylenchus crenatus, from September, 2009 through June, 2019. Error bars are one standard error projecting above the 0N control (pooled standard error from overall ANOVA of non-transformed data). Within a date, points labeled with the same letter are not significantly different (p < 0.05) based on Diff procedure in mixed model repeated measures analysis of log-transformed data. NS, no significant differences.

Effects of fertilizer nitrogen rates on the abundance of root fragments extracted from soil cores (g roots per kg dry soil), from April, 2016 through June, 2019. Error bars are one standard error projecting above the 0N control. Within a date, points labeled with the same letter are not significantly different (p < 0.05) based on Diff procedure in mixed model repeated measures analysis of log-transformed data. NS, no significant differences.

Relationships between Rotylenchus robustus population densities and root biomass. Nematode population data and root biomass data for each plot were averages of six sample dates in 2016 and 2017.

Actual nitrogen application rates by year for the three fertilizer treatments sampled in this study, in relation to rates recommended for blueberry production in British Columbia (BCMAL, 2020)_

		Nitrogen application rates (kg N ha^–1)
	2009	2010	2011	2012	2013	2014	2015-2019
1N	11	14	25	39	100	111	144
1.5N	22	29	50	79	151	167	215
2N	32	43	75	118	201	222	287
Recommended	22	29	50	79	100	111	144

Mean (n=6 replicate plots) population densities (nematodes/100 cm3 soil) of free-living nematodes across dates and N fertilization treatments in 2017_

Date	April 2017				June 2017				September 2017
Treatment	0N	1N	1.5N	2N	0N	1N	1.5N	2N	0N	1N	1.5N	2N
Ditylenchus	91 (48)	154 (58)	109 (33)	135 (61)	50 (37)	147 (240)	81 (51)	150 (225)	96 (38)	124 (73)	65 (25)	73 (37)
Acrobeloides	43 (43)	104 (77)	69 (31)	98 (80)	41 (28)	166 (286)	117 (54)	109 (97)	31 (10)	77 (51)	81 (24)	68 (68)
Rhabditidae	23 (18)	62 (78)	52 (52)	39 (42)	46 (23)	62 (100)	26 (23)	26 (20)	35 (39)	16 (13)	17 (11)	17 (21)
Aphelenchoides	59 (37)	66 (68)	51 (21)	42 (8)	22 (16)	26 (25)	14 (14)	19 (21)	34 (23)	25 (12)	15 (13)	10 (7)
Filenchus	26 (11)	43 (35)	22 (17)	15 (21)	22 (24)	8 (5)	5 (4)	3 (3)	27 (26)	51 (34)	12 (13)	4 (6)
Cervidellus	23 (23)	51 (47)	28 (39)	14 (17)	13 (25)	42 (72)	5 (8)	4 (7)	16 (13)	23 (16)	8 (4)	5 (6)
Alaimus	9 (10)	7 (7)	3 (6)	1 (2)	21 (18)	7 (7)	13 (10)	5 (6)	24 (16)	15 (19)	5 (5)	4 (7)
Plectus	14 (11)	17 (20)	19 (13)	7 (12)	4 (7)	1 (2)	3 (7)	0	9 (9)	2 (3)	0	2 (5)
Clarkus	4 (10)	7 (12)	2 (3)	0	5 (6)	9 (14)	1 (3)	0	10 (8)	12 (24)	1 (2)	1 (2)
Prismatolaimus	11 (6)	9 (12)	1 (3)	0	3 (5)	0 (1)	0	4 (8)	9 (13))	1 (3)	1 (2)	1 (1)
Aphelenchus	3 (10)	0	1 (3)	1 (2)	1 (1)	6 (15)	0	0	1 (2)	1 (2)	2 (3)	1 (2)
Teratocephalus	6 (9)	1 (2)	1 (3)	3 (5)	0 (1)	1 (2)	0	0	0 (1)	0	0	0
Seinura	1 (1)	0	3 (4)	0	0 (1)	1 (2)	1 (3)	3 (8)	0 (1)	2 (4)	1 (2)	0
Panagrolaimidae	1 (2)	5 (13)	2 (3)	2 (5)	0	0	0	0	0	0	0	1 (2)
Thonus	3 (5)	0	0	0	1 (1)	0	3 (8)	0	1 (3)	2 (4)	0	0
Heterocephalobus	1 (3)	0	0	0	1 (3)	1 (2)	1 (2)	0	1 (2)	0	1 (1)	0
Tylencholaimus	1 (2)	0	0	0	1 (2)	0	0	0	4 (6)	0	0	0
Achromadora	3 (8)	0	1 (3)	0	0 (1)	1 (1)	0	0	0	0	0	0
Cephalobus	0	0	0	0 (1)	1 (3)	0	0	0	1 (3)	2 (4)	0	1 (1)
Monhysteridae	2 (3)	0	0	0	1 (2)	0	0	0	1 (3)	0 (1)	0	0
Diphtherophora	0	0	0	0	0	0	0	0	0	4 (10)	0	0
Diplogasteridae	1 (2)	1 (3)	0	1 (2)	0 (1)	0	0	0	0	0	0	0
Tylenchus	0	0	1 (3)	0	2 (3)	0	0	0	0 (1)	0	0	0
Pungentus	0 (1)	0	0	0	1 (2)	0	2 (5)	0	0	0	0	0
Nygolaimus	0	0	0	0	0	0	0	0	0 (1)	2 (5)	0	0
Acrobeles	0	2 (4)	0	0	1 (2)	0	0	0	0	0	0	0
Rhabdolaimus	0	0	1 (3)	0	0	0	0	0	0 (1)	0	0	0
Aporcelaimellus	0	0	0	0	0	0	0	0	0	1 (2)	0	0
Cylindrolaimus	0 (1)	0	0	0	0	0	0	0	0	0	0	0
Leptonchidae	0 (1)	0	0	0	0	0	0	0	0	0	0	0
Eucephalobus	0 (1)	0	0	0	0	0	0	0	0	0	0	0
Chiloplacus	0 (1)	0	0	0	0	0	0	0	0	0	0	0
Ecumenicus	0	0	0	0	0	0	0	0	0 (1)	0	0	0
Anguinidae	0	0	0	0	0	0	0	0	0 (1)	0	0	0
Trophic groups (nematodes/100 cm ³ soil) and community structure indices
Bacterivorous	138 (98)	259 (214)	179 (45)	165 (123)	133 (78)	282 (452)	165 (56)	148 (94)	128 (72)	137 (69)	112 (29)	98 (47)
Fungivorous	180 (60)	262 (106)	185 (43)	193 (68)	96 (61)	186 (276)	99 (48)	171 (242)	162 (66)	204 (96)	94 (37)	89 (44)
Omni+Preds^a	8 (11)	7 (12)	5 (4)	0	6 (6)	10 (15)	8 (9)	3 (8)	12 (8)	17 (28)	2 (2)	1 (2)
Enrichment Index	51 (9)	51 (10)	55 (12)	53 (10)	67 (12)	52 (11)	46 (15)	53 (8)	56 (10)	46 (4)	45 (12)	46 (11)
Structure Index	41 (10)	25 (15)	23 (12)	12 (11)	54 (19)	32 (14)	29 (11)	17 (13)	52 (13)	46 (10)	21 (14)	13 (13)
Channel Index	66 (19)	61 (27)	50 (21)	60 (24)	30 (17)	50 (21)	54 (21)	51 (31)	56 (19)	70 (18)	58 (12)	64 (25)
Shannon Diversity	7.30 (1.11)	5.66 (1.65)	5.97 (0.88)	4.66 (1.15)	6.79 (1.15)	6.46 (1.22)	4.94 (1.25)	3.99 (0.80)	7.51 (1.92)	7.33 (2.48)	5.37 (1.09)	4.67 (1.01)
Simpson Diversity	5.51 (1.04)	4.60 (1.58)	4.72 (0.70)	3.82 (0.98)	5.42 (1.00)	5.12 (1.10)	3.91 (1.07)	3.17 (0.73)	5.78 (1.79)	4.69 (1.80)	4.24 (1.02)	3.69 (0.84)

Effects of nitrogen fertilizer treatments on the Shannon–Weiner (S–W) and Simpson (Simpson) indices of genus-level diversity, the nematode Structure Index (SI) and Enrichment Index (EI), and population densities (nematodes/100 cm3) of omnivorous+predacious (O + P), bacterivorous (Bact) and fungivorous (Fung) trophic groups_

Treatment	S–W	Simpson	SI	EI	CI	O + P	Bact	Fung
0N	7.02a^a	5.57a	49a	58a	51	9ab	133	146
1N	6.48a	4.90ab	35b	49b	60	11a	226	218
1.5N	5.43b	4.36b	24c	49b	54	5bc	152	126
2N	4.44c	3.51c	14d	50b	58	1c	137	151
ANOVA summary (p-values) ^b
Treatment	< 0.001	< 0.001	< 0.001	0.004	0.39	0.004	0.18	0.09
Date	0.21	0.57	0.05	0.07	0.002	0.47	0.19	0.04
T × D	0.57	0.80	0.29	0.05	0.18	0.67	0.91	0.70

DOI: https://doi.org/10.21307/jofnem-2020-056 | Journal eISSN: 2640-396X | Journal ISSN: 0022-300X

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Language: English

Page range: 1 - 14

Submitted on: Sep 27, 2019

Published on: Jul 6, 2020

Published by: Society of Nematologists, Inc.

In partnership with: Paradigm Publishing Services

Publication frequency: 1 issue per year

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© 2020 Thomas Forge, David Ehret, Aime Messiga, Martine Dorais, published by Society of Nematologists, Inc.
This work is licensed under the Creative Commons Attribution 4.0 License.

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Influences of nitrogen inputs on nematode populations under highbush blueberry

Figures & Tables

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Figure 5:

Actual nitrogen application rates by year for the three fertilizer treatments sampled in this study, in relation to rates recommended for blueberry production in British Columbia (BCMAL, 2020)_

Mean (n=6 replicate plots) population densities (nematodes/100 cm3 soil) of free-living nematodes across dates and N fertilization treatments in 2017_

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