Analyses of the effects of potato cyst nematodes (Globodera pallida) on growth, physiology and yield of potato cultivars in field plots at three levels of soil compaction

Abstract

SummaryField experiments were carried out in 1991 and 1992 on sandy soil highly infested with the potato cyst nematode Globodera pallida. Half the trial area was fumigated with nematicide to establish two levels of nematode density. Three levels of soil compaction were made by different combinations of artificial compaction and rotary cultivation. Two potato cultivars were used in 1991 and four in 1992.Both high nematode density and soil compaction caused severe yield losses, of all cultivars except cv. Elles which was tolerant of nematode attack. The effects of the two stress factors were generally additive. Analysis of the yield loss showed that nematodes mainly reduced cumulative interception of light while compaction mainly reduced the efficiency with which intercepted light was used to produce biomass. This indicates that nematodes and compaction affect growth via different damage mechanisms.Nematodes reduced light interception by accelerating leaf senescence, by decreasing the specific leaf area and indirectly by reducing overall crop growth rate. Partitioning of biomass between leaves, stems and tubers was not affected by nematode infestation but compaction decreased partitioning to leaves early in the growing season while increasi~g it during later growth stages.The effects of nematodes and compaction on root length dynamics and nutrient uptake were also additive. This suggests that the commonly observed variation in yield loss caused by nematodes on different soil types is not related to differences in root system expansion between soils of various strength.Cv. Elles, which showed tolerance of nematodes by relatively low yield losses in both experiments, was characterised by high root length density and thick roots. These characteristics did not confer tolerance of soil compaction, since compaction affected root lengths and tuber yields equally in all cultivars.In the first experiment only, high nematode density led to decreased root lengths and lower plant nutrient concentrations. The yield loss which occurred in the second experiment was attributed to the effects of nematodes on other aspects of plant physiology.

The response of potato crop to the spatiotemporal variability of soil compaction under centre pivot irrigation system

“…The status of the Moran's I measured between soil compaction and yield has agreed with many researches that quantified and assured the influence of the spatial variability of soil compaction on potato yield quantification and distribution (Allen & Scott, ; Van loon & Bouma, ; Van Oijen, de Ruijter, & van Haren, ). Statistics of null hypothesis of no spatial correlation between the applied variables (compaction, NDVI and yield) have shown significant testing results, producing pseudo significance p‐value of (0.001) with 999 permutations, for all measured bivariate Moran's I plots.…”

Agronomic and physiological responses of potato subjected to soil compaction and/or drying

“…Soil compaction restricts horizontal and vertical root growth of potatoes in the field, ultimately reducing tuber number and yield (Stalham et al, 2007; Van Oijen et al, 1995). Smaller root systems access less soil volume thereby limiting water and nutrient uptake, which results in smaller plants with less leaf area (Nawaz et al, 2013; Stalham et al, 2007).…”

Assessment of the nematicidal potential of vermicompost, vermicompost tea, and urea application on the potato-cyst nematodes Globodera rostochiensis and Globodera pallida

“…An estimated 2 t • ha -1 of potatoes are lost for every 20 eggs and juveniles per gram of soil (Brown 1969). The loss of yield, however, varies depending on nematode species, genotype (pathotype), and population density at sowing, and also on the potato cultivar, climatic conditions, soil type (Evans and Haydock 1990;Oijen et al 1995), and management (the control) methods were used (Sharma 1998).…”