Crop rotation effects on Pratylenchus neglectus populations in the root zone of irrigated potatoes in southern Alberta

Figures & data

Table 1. Characteristics of crop rotations and soil-nutrient management practices preceding potato, and average marketable and total potatoes for the period 2001–2009.

Rotation	Crop sequence	Nutrient inputs kg ha^−1	2001–2009 average marketable yield Mg ha^−1	2001–2009 average total yield Mg ha^−1
3-year Conventional	B-W-P	112N-67P-67K	27.9b	35.8c
3-year Conservation	B-W-P	62N-28P-67K +28 t/ha compost	31.2a	41.1ab
4-year Conventional	W-SB-B-P	112N-67P-67K	31.5a	40.5b
4-year Conservation	W-SB-B-P	37N-0P-67K +42 t/ha compost	30.1ab	39.9b
5-year Conservation	W-SB-W-B-P	37N-0P-67K +42 t/ha compost	31.9a	43.2a
6-year Conservation	O(t)-T-T-SB-B-P	37N-0P-67K +42 t/ha compost	31.5a	40.9ab

W = wheat; P = potatoes; B = beans; SB = sugar beet; O(t) = oats harvested as green feed in July; T = timothy.

Table 2. Effect of rotation length on population densities of Pratylenchus neglectus in soil (nematodes per 100 mL soil) planted to potato, by sample date. Analyses were conducted on log(X + 100) transformed data; data presented are means of raw data.

		Rotation length
Sample date	P^1	3-year^2	4-year^2	5-year	6-year
Autumn 2006	0.025	241a^3	165abc	228ab	106 c
Autumn 2007	0.077	129	99	59	56
Spring 2008	<0.001	262a	23c	72b	74b
Summer 2008	0.22	35	7	14	5
Autumn 2008	0.036	77a	24b	44b	59b
Spring 2009	<0.001	176a	23c	80b	33bc
Summer 2009	0.002	101a	21b	61ab	38b
Autumn 2009	0.075	112	69	61	127
Spring 2010	0.005	70a	7b	15b	6b
Summer 2010	0.66	19	3	11	2

¹ Effect of rotation length on the sample date, from SLICE command of PROC MIXED.

² Data are means of Conservation and Conventional systems.

³ Means within a row labelled with the same letter are not significantly different at P ≤ 0.05.

Fig. 1 Effect of rotation length on population densities of P. neglectus in soil planted to potato (nematodes per 100 mL soil), by season of sampling. Analysis of variance and mean separations were conducted on log(X + 100) transformed data.

Fig. 2 Effect of rotation length on population densities of P. neglectus in roots of potato (nematodes g⁻¹ root). Analysis of variance and mean separations were conducted on log(X + 100) transformed data. N.S. = non-significant effect of rotation in analysis of variance.