title: Sunn hemp cover cropping and organic fertilizer effects on the nematode community under temperate growing conditions.
abstract: Field experiments were conducted in Maryland to investigate the influence of sunn hemp cover cropping in conjunction with organic and synthetic fertilizers on the nematode community in a zucchini cropping system. Two field treatments, zucchini planted into a sunn hemp living and surface mulch (SH) and zucchini planted into bare-ground (BG) were established during three field seasons from 2009 to 2011. In 2009, although SH slightly increased nematode richness compared with BG by the first harvest (P < 0.10), it reduced nematode diversity and enrichment indices (P < 0.01 and P < 0.10, respectively) and increased the channel index (P < 0.01) compared to BG at the final harvest. This suggests a negative impact of SH on nematode community structure. The experiment was modified in 2010 and 2011 where the SH and BG main plots were further split into two subplots to investigate the added influence of an organic vs. synthetic fertilizer. In 2010, when used as a living and surface mulch in a no-till system, SH increased bacterivorous, fungivorous, and total nematodes (P < 0.05) by the final zucchini harvest, but fertilizer type did not influence nematode community structure. In 2011, when incorporated into the soil before zucchini planting, SH increased the abundance of bacterivorous and fungivorous nematodes early in the cropping season. SH increased species richness also at the end of the season (P < 0.05). Fertilizer application did not appear to influence nematodes early in the season. However, in late season, organic fertilizers increased enrichment and structure indices and decreased channel index by the end of the zucchini cropping cycle.
authors.affiliation: Department of Entomology, University of Maryland, 4112 Plant Sciences Bldg., College Park, MD 20742.
authors.forename: Jermaine
authors.initials: J
authors.lastname: Hinds
authors.affiliation: Department of Plant and Environmental Protection Sciences, University of Hawai'i, 3050 Maile Way, Room 310, Honolulu, HI 96822.
authors.forename: Koon-Hui
authors.initials: KH
authors.lastname: Wang
authors.affiliation: Science and Math Division, Kaua'i Community College, 3-1901 Kaumuali'i Highway, Lihu'e, HI 96766.
authors.forename: Sharadchandra P
authors.initials: SP
authors.lastname: Marahatta
authors.affiliation: USDA, ARS, Nematology Laboratory, Henry A. Wallace Beltsville Agricultural Research Center (BARC)-West, Bldg. 010A, Rm. 112, 10300 Baltimore Ave., Beltsville, MD 20705.
authors.forename: Susan L F
authors.initials: SL
authors.lastname: Meyer
authors.affiliation: Department of Entomology, University of Maryland, 4112 Plant Sciences Bldg., College Park, MD 20742.
authors.forename: Cerruti R R
authors.initials: CR
authors.lastname: Hooks
keywords: Crotalaria juncea; free-living nematode; living mulch; no-till; strip-till; surface mulch