Free-living nematode assemblages associated with maize residues and their ecological significance

Month	Minimum temperature (°C)	Average rainfall (mm)
March	14.6	245
April	14.7	619.2
May	14.8	299.6
June	13.3	78
July	12.7	51.5
August	12.3	18.8
September	13.0	38.5
October	14.6	51.5
November	15.5	100.1
December	14.7	109.2
January	13.6	46.5
February	21.6	21.6

Table 2.

Soil physicochemical characteristics at Nyangati study site in Mwea Sub-county, Kenya.

Soil property	Mean	Standard error
Calcium me %	6.07	0.788
Clay %	44.00	4.000
Copper ppm	2.95	0.090
Iron ppm	23.50	3.239
Magnesium me %	3.63	0.135
Manganese me %	0.97	0.114
Phosphorus ppm	16.67	1.667
Potassium me %	0.75	0.096
Sand %	46.67	3.712
Silt %	9.33	0.667
Sodium me %	0.16	0.074
Soil pH	5.85	0.057
Total Nitrogen %	0.18	0.003
Total Organic Carbon %	2.03	0.050
Zinc ppm	0.20	0.029

1 Note: me = milliequivalent.

Table 3.

Average number of nematodes in 250 g soil collected from control and decomposition plots during season one.

Taxa	Cp-class	Control Mean ± SE	Decomposition Mean ± SE	F-value	P-value
Bacterivores
Acrobeles	2	42 ± 9.5	58 ± 8.0	37.039	<0.001***
Acrobeloides	2	16 ± 4.4	8 ± 3.5	9.153	0.005**
Alaimus	4	31 ± 8.8	30 ± 5.7	2.331	0.137
Aphanolaimus	1	5 ± 2.4	2 ± 1.1	1.327	0.258
Cephalobus	2	107 ± 6.4	109 ± 9.9	0.106	0.747
Cervidellus	2	52 ± 11.3	23 ± 3.8	0.082	0.777
Drilocephalobus	2	0 ± 0.0	3 ± 2.0	1.946	0.173
Eucephalobus	2	91 ± 12.9	118 ± 21.1	2.92	0.098
Geomonhystera	2	10 ± 4.8	7 ± 3.6	0	0.996
Heterocephalobus	2	120 ± 20.9	86 ± 13.4	1.927	0.175
Plectus	2	26 ± 9.0	37 ± 7.6	7.016	0.013*
Prismatolaimus	3	18 ± 4.0	40 ± 11.0	2.586	0.118
Rhabditis	1	39 ± 8.0	41 ± 12.6	0.223	0.64
Stegelleta	2	0 ± 0.0	1 ± 1.3	0.272	0.325
Wilsonema	2	31 ± 10.1	17 ± 4.2	0.679	0.417
Fungivores
Aphelenchoides	2	16 ± 5.8	9 ± 3.2	1.088	0.305
Aphelenchus	2	143 ± 1.0	181 ± 19.0	2.479	0.126
Ditylenchus	2	13 ± 4.6	1 ± 1.3	49.301	<0.001***
Filenchus	2	16 ± 2.2	9 ± 2.7	9.997	0.004**
Omnivores
Aporcelaimellus	5	0 ± 0.0	4 ± 1.9	4.719	0.038*
Eudorylaimus	4	8 ± 2.4	3 ± 1.3	3.684	0.064
Labronema	4	62 ± 4.0	65 ± 8.0	1.196	0.283
Predators
Discolaimus	5	8 ± 2.4	10 ± 3.3	0.076	0.784
Nygolaimus	5	36 ± 6.9	42 ± 6.4	9.345	0.005**
Seinura	2	0 ± 0.0	6 ± 2.4	22.167	<0.001***

1 Notes: Cp = colonizer-persister value. *P < 0.05; **P < 0.01; ***P < 0.001.

Table 4.

Average number of nematodes in 250 g soil collected from control and decomposition plots during season two.

Taxa	Cp-class	Control Mean ± SE	Decomposition Mean ± SE	F-value	P-value
Bacterivores
Acrobeles	2	39 ± 7.5	58 ± 12.8	6.604	0.015*
Acrobeloides	2	42 ± 8.0	27 ± 6.0	1.434	0.241
Alaimus	4	8 ± 2.4	10 ± 3.9	0.059	0.81
Cephalobus	2	151 ± 10.4	280 ± 26.9	25.737	<0.001***
Cervidellus	2	42 ± 13.5	34 ± 12.1	0.466	0.5
Drilocephalobus	2	5 ± 2.4	9 ± 3.2	4.225	0.049*
Eucephalobus	2	101 ± 19.1	164 ± 23.8	48.172	<0.001***
Geomonhystera	2	16 ± 3.5	8 ± 3.0	7.391	0.0108*
Heterocephalobus	2	57 ± 10.8	129 ± 14.8	68.576	<0.001***
Mesorhabditis	1	0 ± 0.0	14 ± 4.9	37.891	<0.001***
Panagrolaimus	1	3 ± 1.2	5 ± 2.0	0.486	0.491
Plectus	2	10 ± 3.5	27 ± 4.7	96.111	<0.001***
Prismatolaimus	3	16 ± 3.5	24 ± 4.2	3.989	0.055
Rhabditis	1	21 ± 7.0	73 ± 34.4	2.592	0.118
Wilsonema	2	3 ± 1.2	3 ± 1.5	0.207	0.652
Fungivores
Aphelenchoides	2	29 ± 6.1	98 ± 29.5	13.911	<0.001***
Aphelenchus	2	164 ± 20.9	320 ± 47.2	18.84	<0.001***
Filenchus	2	21 ± 4.8	16 ± 6.0	2.041	0.163
Omnivores
Aporcelaimellus	5	0 ± 0.0	1 ± 1.3	1	0.325
Eudorylaimus	4	26 ± 4.2	22 ± 5.2	1.34	0.256
Dorylaimellus	5	0 ± 0.0	1 ± 0.7	1	0.325
Labronema	4	39 ± 7.1	47 ± 7.1	2.561	0.12
Mesodorylaimus	4	23 ± 3.5	10 ± 2.9	13.006	0.001**
Prodorylaimus	4	0 ± 0.0	3 ± 1.5	3.649	0.066
Predators
Discolaimus	5	8 ± 1.5	8 ± 2.0	0.051	0.823
Mononchus	4	5 ± 1.5	4 ± 2.7	4.741	0.037*
Nygolaimus	5	78 ± 10.3	54 ± 9.9	5.483	0.026*

1 .

Table 5.

Nematode ecological and functional indices in control and decomposition plots during season 1 and 2.

	Control	Decomposition
Index name	Mean ± SE	Mean ± SE	F-values	P-value
Season 1
Maturity Index (MI)	2.41a ± 0.038	2.43a ± 0.040	0.38	0.542
Maturity Index (MI2-5)	2.47a ± 0.044	2.49a ± 0.036	0.409	0.528
Channel Index (CI)	60.35a ± 5.95	65.66a ± 5.948	0.985	0.329
Basal Index (BI)	37.82a ± 2.016	35.72a ± 1.652	1.452	0.238
Enrichment Index (EI)	34.52a ± 1.455	33.03a ± 2.472	0.511	0.481
Structure Index (SI)	53.19a ± 2.537	55.73a ± 2.224	1.435	0.24
Season 2
Maturity Index (MI)	2.54a ± 0.033	2.26b ± 0.036	64.715	<0.001***
Maturity Index (MI2-5)	2.57a ± 0.031	2.33b ± 0.029	68.996	<0.001***
Channel Index (CI)	81.01a ± 4.923	68.37b ± 5.864	12.359	<0.001***
Basal Index (BI)	34.44b ± 1.267	42.47a ± 1.495	65.944	<0.001***
Enrichment Index (EI)	28.14b ± 2.519	35.06a ± 2.941	15.409	<0.001***
Structure Index (SI)	59.91a ± 1.535	42.21b ± 2.689	41.205	<0.001***

Table 6.

Metabolic footprints in control and decomposition plots during season 1 and 2.

	Control	Decomposition
Metabolic footprints	Mean ± SE	Mean ± SE	F-values	P-value
Season 1
Composite footprint	5.67a ± 3.444	5.77a ± 3.421	2.482	0.126
Omnivore footprint	4.55a ± 1.750	4.35a ± 2.558	0.825	0.371
Structure footprint	4.99a ± 2.345	5.07a ± 2.702	1.272	0.268
Predator footprint	3.15b ± 2.127	3.82a ± 2.110	19.678	<0.001***
Fungivore footprint	2.91a ± 1.243	2.94a ± 1.101	0.126	0.725
Enrichment footprint	4.326a ± 2.797	4.196a ± 3.262	0.556	0.462
Bacterivore footprint	4.734a ± 3.267	4.918a ± 3.303	2.441	0.129
Season 2
Composite footprint	5.68b ± 3.242	5.95a ± 4.301	11.018	0.002**
Omnivore footprint	4.23a ± 2.479	4.33a ± 2.657	0.679	0.417
Structure footprint	5.22a ± 2.314	5.05b ± 2.870	4.500	0.042*
Predator footprint	4.48a ± 2.485	3.87b ± 2.515	5.894	0.021*
Fungivore footprint	2.89b ± 1.260	3.52a ± 1.972	21.683	<0.001***
Enrichment footprint	3.51b ± 2.755	4.43a ± 4.249	27.425	<0.001***
Bacterivore footprint	4.39b ± 2.945	5.10a ± 4.269	30.782	<0.001***

Functional metabolic footprint of nematodes in control and decomposition plots during the first season. The point at the middle of the rhomboid represents the intersection of the enrichment and structure index. The length of the vertical axis and horizontal axis of the rhombus represents the enrichment and structure footprints, respectively. The functional nematode metabolic footprint is represented by the total area of the functional enrichment and structure footprints.

Functional metabolic footprint of nematodes in control and decomposition plots during the second season. The point at the middle of the rhomboid represents the intersection of the enrichment and structure index. The length of the vertical axis and horizontal axis of the rhombus represents the enrichment and structure footprints, respectively. The functional nematode metabolic footprint is represented by the total area of functional enrichment and structure footprints.

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DOI: https://doi.org/10.21307/jofnem-2021-038 | Journal eISSN: 2640-396X | Journal ISSN: 0022-300X

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Language: English

Page range: 1 - 12

Published on: Jan 1, 2021

Published by: Society of Nematologists, Inc.

In partnership with: Paradigm Publishing Services

Publication frequency: 1 issue per year

Keywords:

Decomposition,

Ecological significance,

Free-living nematodes,

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© 2021 Samuel Maina, Hannah Karuri, Rossa Nyoike Ng’endo, published by Society of Nematologists, Inc.
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 53 (2021): Issue 1 (January 2021)

Free-living nematode assemblages associated with maize residues and their ecological significance

Figures & Tables

Table 1.

Table 2.

Table 3.

Table 4.

Table 5.

Table 6.

Figure 1:

Figure 2:

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