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Individual study: Effects of cover crop quality and quantity on nematode-based soil food webs and nutrient cycling

Published source details

DuPont S.T., Ferris H. & Van H.M. (2009) Effects of cover crop quality and quantity on nematode-based soil food webs and nutrient cycling. Applied Soil Ecology, 41, 157-167


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Crop production: Grow cover crops in arable fields Mediterranean Farmland

A replicated, randomized, controlled study in 2005–2007 in an irrigated tomato-maize field in Davis, California, USA, found lower tomato yields, but higher maize yields, in plots with winter cover crops, compared to bare fallows in winter. Crop yield: Lower tomato yields were found in plots with cover crops, compared to fallows (27–47 vs 68 Mg/ha). Higher maize yields were found in plots with cover crops, compared to fallows, for two of three mixtures of cover crops (mixtures with legumes: 30–31 vs 16 Mg/ha). Implementation options: Higher maize yields were found in plots that were cover cropped with legumes, compared to plots that were cover cropped with grains only (30–31 vs 16 Mg/ha). Similar tomato yields were found in plots with different mixtures of cover crops (27–47 Mg/ha). Methods: Three mixtures of winter cover crops (legumes only, legumes and grains, or grains only) were grown on five plots each, and five control plots were bare fallows on which weeds were controlled by burning (111 m2 plots; six raised beds/plot). Tomatoes were grown in 2006, and maize was grown in 2007, without fertilizer.

 

Soil: Grow cover crops in arable fields Mediterranean Farmland

A replicated, randomized, controlled study in 2005–2007 in an irrigated tomato-maize field in Davis, California, USA, found more carbon, ammonium, and nematodes in soils with winter cover crops, compared to bare fallows. Organic matter: More carbon was found in soils with cover crops, compared to bare fallows (1.04% vs 0.94% total carbon). Nutrients: Similar amounts of nitrate and total nitrogen were found in soils with cover crops or bare fallows (7 vs 5–8 NO3-N ppm; 0.11% vs 0.10% total nitrogen), but more ammonium was found in soils with cover crops, for one of three mixtures of cover crops (legumes: 6 vs 5 NH4-N ppm). Soil organisms: More nematodes were found in soils with cover crops, compared to bare fallows, for two of three mixtures of cover crops (mixtures with legumes: 588–617 vs 435 nematodes/100 g soil). Implementation options: Similar amounts of carbon, total nitrogen, and nitrate, and similar numbers of nematodes, were found in soils with different mixtures of cover crops (0.99–1.04% total carbon; 0.11% total nitrogen; 5–8 NO3-N ppm; 512–617 nematodes/100 g soil), but more ammonium was found in soils that were cover cropped with legumes, compared to grains or a mixture of legumes and grains (6 vs 5 NH4-N ppm). Methods: Three mixtures of winter cover crops (legumes only, legumes and grains, or grains only) were grown on five plots each, and five control plots were bare fallows on which weeds were controlled by burning (111 m2 plots; six raised beds/plot). Tomatoes were grown in 2006, and maize was grown in 2007, without fertilizer. Soil samples were collected in May and September 2006–2007 (four times in the spring of 2007), with soil cores (12 cores/plot, 15 cm depth, 2.5 cm width).