Cover crops and organic mulches for nematode, weed and plant health management

Abstract

Traditional cover cropping systems for nematode management seldom consider weed and soil nutrient management concurrently. Integrating cover crops suppressive to plant-parasitic nematodes with a cover crop mulching system could improve traditional approaches. Two field experiments were conducted in 2003 and 2004 to evaluate 'Tropic Sun' sunn hemp (Crotalaria juncea) and 'Iron Clay' cowpea (Vigna unguiculata) as summer cover crops and as organic mulches. Both experiments were in a 3 × 3 split-plot design in which the main plots were summer planting of sunn hemp, cowpea or fallow, and the subplots were organic mulch of sunn hemp, cowpea or no mulch. The summer cover crop was followed by turnip (Brassica rapa) and lima bean (Phaseolus lunatus) in the autumn. Using sunn hemp as organic mulch suppressed root-knot nematodes more effectively than using it as a cover crop, but only on a less susceptible host such as turnip, and not on a very susceptible host such as lima bean. While sunn hemp as a cover crop failed to enhance beneficial free-living nematodes, sunn hemp as an organic mulch enhanced bacterial-feeding nematode population densities. Sunn hemp mulch also suppressed broadleaf weeds but not grasses or nutsedges. Although sunn hemp and cowpea cover crops did not increase lima bean N and K content, their mulches increased N and K content. Similar results were observed for turnip and lima bean yields. Population density of root-knot nematodes was positively related to abundance of omnivorous nematode in 2003. The abundance of plant-parasitic nematodes was negatively related to the infestation levels of Pasteuria penetrans, and the abundance of predatory nematodes in 2004. Factors that might have affected the performance of sunn hemp on nematode communities are discussed.

Comparison of Carbon Sequestration Potential of Winter Cover Crop Cultivation in Rice Paddy Soil

“…The highest biomass productivity was observed in rye. The results of this experiment contradicted with the findings of Wang et al (2008), who proposed that the biomass productivity of legumes were comparatively higher than that of non-leguminous cover crops. This difference might be attributed to the differences in agro-ecosystem of these two studies.…”

Ecology of the dorylaimid omnivore genera Aporcelaimellus, Eudorylaimus and Mesodorylaimus

“…In a glasshouse test, maxima in Eudorylaimus and Aporcelaimellus population levels occurred at about 130 days after addition of organic amendments, with a second peak 6 months later (McSorley & Frederick, 1999). It is not clear whether population peaks of these nematodes observed after 4-6 weeks in a field study (Wang et al, 2004a) were indicative of life cycle length or a result of increased egg deposition and hatch.…”

Potential of Crotalaria juncea as cover crop for cyst nematode suppression under Central Europe conditions

“…while in other studies the leguminous cover crop cowpea [Vigna unguiculata (L.) Walp.] 'Iron Clay' was only resistant to one species [51] . In general, northern Europe (52° 16' N) is out of the range of preferred cultivation of C. juncea [52] but it is grown successfully in the temperate climate of Maryland, US and the Po Valley of Italy [22,23] .…”