Vertical Distribution of Plant-Parasitic Nematodes in Sweet Potato

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Soil properties in sweet potato fields at 0–30 cm depth in Central, Manyatta, and Nembure regions in Embu County, Kenya_

Soil property	Central		Manyatta		Nembure		P value
	Mean	SE	Mean	SE	Mean	SE
pH	4.89	0.23	4.70	0.16	4.72	0.14	0.74
Total Nitrogen%	0.36	0.01	0.38	0.02	0.29	0.03	0.02*
Total Organic Carbon%	4.04	0.14	4.25	0.20	3.36	0.31	0.02*
Phosphorus ppm	25.31	4.43	17.33	2.09	14.86	2.76	0.08
Potassium meq%	0.92	0.16	1.10	0.12	0.84	0.14	0.42
Calcium meq%	2.56	0.69	2.55	0.65	1.81	0.62	0.67
Magnesium meq%	3.39	0.34	3.29	0.33	3.29	0.28	0.97
Manganese meq%	0.79	0.04	0.85	0.05	0.66	0.05	0.02*
Copper ppm	4.83	2.09	3.55	1.34	1.26	0.30	0.26
Iron ppm	27.25	4.15	33.38	7.11	26.68	5.00	0.64
Zinc ppm	34.12	3.49	23.01	2.54	16.18	2.47	<0.0001***
Sodium meq%	0.58	0.03	0.44	0.03	0.46	0.04	0.02*
Sand (%)	10.00	3.89	15.87	5.50	13.71	6.24	0.72
Clay (%)	77.63	3.73	72.13	5.28	75.29	6.15	0.74
Silt (%)	12.38	0.33	12.00	0.34	11.00	0.35	0.02*

Two-way analysis of variance (P values) of region, depth, and their interaction on nematode genera, Pielou’s evenness, Shannon–Weaver, and Simpson diversity indices in sweet potato fields in Central, Manyatta, and Nembure regions of Embu County, Kenya_

	Region	Depth	Region × depth
Nematode genera
Coslenchus	0.11	0.64	0.72
Helicotylenchus	0.97	0.97	0.93
Longidorus	0.98	0.08	0.14
Meloidogyne	0.4	0.35	0.71
Pratylenchus	0.1	0.91	0.81
Rotylenchulus	0.83	0.68	0.83
Rotylenchus	0.65	0.36	0.96
Scutellonema	0.08	0.81	0.75
Trichodorus	0.49	0.17	0.3
Tylenchorhynchus	0.06	0.33	0.83
Tylenchus	0.15	0.32	0.01*
Xiphinema	0.78	0.9	0.07
Psilenchus	<0.0001***	0.93	1
Hemicycliophora	0.01*	0.9	0.98
Hoplolaimus	0.05*	0.56	0.71
Malenchus	0.15	0.79	0.93
Diversity indices
Shannon–Weaver diversity	0.04*	0.03*	0.53
Simpson diversity	0.08	0.05*	0.84
Pielou’s evenness	0.89	0.41	0.24

Simpson and Shannon–Weaver diversity indices of nematode communities in sweet potato fields in Central, Manyatta, and Nembure regions in Embu County, Kenya at 0 cm to 30 cm and 30 cm to 60 cm depths_

Region	Shannon–Weaver diversity		Simpson diversity
	Mean	SE	Mean	SE
Central	1.29a,b	0.06	0.64a	0.02
Manyatta	1.36a	0.06	0.67a	0.02
Nembure	1.12b	0.08	0.58a	0.04
Depth
0–30 cm	1.38a	0.05	0.68a	0.02
30–60 cm	1.15b	0.06	0.59b	0.03