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Individual study: Soil microbial biomass, functional microbial diversity, and nematode community structure as affected by cover crops and compost in an organic vegetable production system

Published source details

Nair A. & Ngouajio M. (2012) Soil microbial biomass, functional microbial diversity, and nematode community structure as affected by cover crops and compost in an organic vegetable production system. Applied Soil Ecology, 58, 45-55


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Grow cover crops when the field is empty Soil Fertility

A controlled, replicated experiment in 2005-2009 on loam in Michigan, USA (Nair & Ngouajio 2012) found higher microbial biomass under perennial ryegrass Lolium perenne and compost (195-210 μg/g dry soil) than under ryegrass without compost, or ryegrass/vetch Vicia sativa with and without compost (145-160 μg/g dry soil). Microbial respiration was highest in soil under the ryegrass-compost combination (282 μg carbon dioxide/g dry soil), compared to ryegrass/vetch with no compost (126 μg carbon dioxide). Tomato Lycopersicon esculentum yield was higher in soils after the ryegrass-compost treatment (44 kg/ha) than in ryegrass/vetch with no compost (22 kg/ha). It was not clear whether these effects were due to the cover crop or compost treatments. Two cover crop treatments were sown into soil between crops: ryegrass and ryegrass with vetch. Within these were two compost treatments: compost (25 t/ha dairy compost, but reduced to 12.5 t/ha in 2009) and no compost. There were four replications. Cover crops were mowed and incorporated into the soil before tomato seedlings were transplanted into 7.6 x 0.6 m beds. Four soil samples were taken to 15 cm depth from each treatment during the growing season.

 

Amend the soil with manures and agricultural composts Soil Fertility

A controlled, replicated experiment in 2005-2009 on loam in Michigan, USA (Nair & Ngouajio 2012) found higher microbial biomass under perennial ryegrass Lolium perenne and compost (195-210 μg/g dry soil) than under ryegrass without compost, or ryegrass/vetch Vicia sativa with and without compost (145-160 μg/g dry soil). Microbial respiration was highest in soil under the ryegrass-compost combination (282 μg carbon dioxide/g dry soil), compared to ryegrass/vetch with no compost (126 μg carbon dioxide). Tomato Lycopersicon esculentum yield was higher in soils after the ryegrass-compost treatment (44 kg/ha) than in ryegrass/vetch with no compost (22 kg/ha). It was not clear whether these effects were due to the cover crop or compost treatments. Two cover crop treatments were sown into soil between crops: ryegrass and ryegrass with vetch. Within these were two compost treatments: compost (25 t/ha dairy compost, but reduced to 12.5 t/ha in 2009) and no compost. There were four replications. Cover crops were mowed and incorporated into the soil before tomato seedlings were transplanted into 7.6 x 0.6 m beds. Four soil samples were taken to 15 cm depth from each treatment during the growing season.