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Plant biomass, soil microbial community structure and nitrogen cycling under different organic amendment regimes; a 15N tracer-based approach

Heijboer, Amber; ten Berge, Hein F M; de Ruiter, Peter C.; Jørgensen, Helene Bracht LU ; Kowalchuk, George A. and Bloem, Jaap (2016) In Applied Soil Ecology 107. p.251-260
Abstract

Sustainable agriculture requires nutrient management options that lead to a profitable crop yield with relatively low nitrogen (N) losses to the environment. We studied whether the addition of contrasting organic amendments together with inorganic fertilizer can promote both requirements simultaneously. In particular we studied how the chemical composition of organic amendments affects the biomass, activity and composition of the soil microbial community and subsequently carbon (C) and N mineralization, microbial N immobilization and plant growth and nutrient uptake. In a pot experiment, Brussels sprouts (Brassica oleracea, cvar. Cyrus) were grown on arable soil, mixed with 15N-labelled mineral fertilizer and different kinds... (More)

Sustainable agriculture requires nutrient management options that lead to a profitable crop yield with relatively low nitrogen (N) losses to the environment. We studied whether the addition of contrasting organic amendments together with inorganic fertilizer can promote both requirements simultaneously. In particular we studied how the chemical composition of organic amendments affects the biomass, activity and composition of the soil microbial community and subsequently carbon (C) and N mineralization, microbial N immobilization and plant growth and nutrient uptake. In a pot experiment, Brussels sprouts (Brassica oleracea, cvar. Cyrus) were grown on arable soil, mixed with 15N-labelled mineral fertilizer and different kinds of organic amendments (cattle manure solid fraction, maize silage, lucerne silage, wheat straw) differing in C:N ratio and lignin content. After 69 and 132 days, destructive sampling took place to assess the effects of the different treatments on soil microbial biomass (microscopic measurements), microbial community composition (phospholipid fatty acid profiles), soil microbial activity (14C-leucine incorporation), C and N mineralization, plant biomass and 15N retrieval in soil pools, microbial biomass and plant biomass. Addition of organic amendments increased soil microbial biomass, activity and fungal/bacterial ratio and created distinct microbial community compositions, whereby high C:N ratio organic amendments had stronger effects compared to low C:N ratio amendments. Structural equation modelling showed that higher values of soil microbial activity were associated with increased N mineralization rates, increased plant biomass and plant 15N uptake, while microbial 15N immobilization was associated with soil microbial community composition. The outcomes of this study highlight the importance of the chemical composition and the amount of the organic amendments for finding a balance between plant N uptake, microbial N immobilization and N retention in labile and stable soil pools through the effects on the composition and activity of the soil microbial community. The results provide insights that can be used in designing combined input (nutrient and organic) nutrient management strategies for a more sustainable agriculture.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Immobilization, Mineral fertilizer, Mineralization, Organic amendments, Phospholipid fatty acids, Soil microbial community
in
Applied Soil Ecology
volume
107
pages
10 pages
publisher
Elsevier
external identifiers
  • scopus:84978136536
ISSN
0929-1393
DOI
10.1016/j.apsoil.2016.06.009
language
English
LU publication?
yes
id
e6fd344c-5af3-495f-8709-4c572e8ac4cd
date added to LUP
2016-10-13 12:57:06
date last changed
2017-01-01 08:36:39
@article{e6fd344c-5af3-495f-8709-4c572e8ac4cd,
  abstract     = {<p>Sustainable agriculture requires nutrient management options that lead to a profitable crop yield with relatively low nitrogen (N) losses to the environment. We studied whether the addition of contrasting organic amendments together with inorganic fertilizer can promote both requirements simultaneously. In particular we studied how the chemical composition of organic amendments affects the biomass, activity and composition of the soil microbial community and subsequently carbon (C) and N mineralization, microbial N immobilization and plant growth and nutrient uptake. In a pot experiment, Brussels sprouts (Brassica oleracea, cvar. Cyrus) were grown on arable soil, mixed with <sup>15</sup>N-labelled mineral fertilizer and different kinds of organic amendments (cattle manure solid fraction, maize silage, lucerne silage, wheat straw) differing in C:N ratio and lignin content. After 69 and 132 days, destructive sampling took place to assess the effects of the different treatments on soil microbial biomass (microscopic measurements), microbial community composition (phospholipid fatty acid profiles), soil microbial activity (<sup>14</sup>C-leucine incorporation), C and N mineralization, plant biomass and <sup>15</sup>N retrieval in soil pools, microbial biomass and plant biomass. Addition of organic amendments increased soil microbial biomass, activity and fungal/bacterial ratio and created distinct microbial community compositions, whereby high C:N ratio organic amendments had stronger effects compared to low C:N ratio amendments. Structural equation modelling showed that higher values of soil microbial activity were associated with increased N mineralization rates, increased plant biomass and plant <sup>15</sup>N uptake, while microbial <sup>15</sup>N immobilization was associated with soil microbial community composition. The outcomes of this study highlight the importance of the chemical composition and the amount of the organic amendments for finding a balance between plant N uptake, microbial N immobilization and N retention in labile and stable soil pools through the effects on the composition and activity of the soil microbial community. The results provide insights that can be used in designing combined input (nutrient and organic) nutrient management strategies for a more sustainable agriculture.</p>},
  author       = {Heijboer, Amber and ten Berge, Hein F M and de Ruiter, Peter C. and Jørgensen, Helene Bracht and Kowalchuk, George A. and Bloem, Jaap},
  issn         = {0929-1393},
  keyword      = {Immobilization,Mineral fertilizer,Mineralization,Organic amendments,Phospholipid fatty acids,Soil microbial community},
  language     = {eng},
  month        = {11},
  pages        = {251--260},
  publisher    = {Elsevier},
  series       = {Applied Soil Ecology},
  title        = {Plant biomass, soil microbial community structure and nitrogen cycling under different organic amendment regimes; a <sup>15</sup>N tracer-based approach},
  url          = {http://dx.doi.org/10.1016/j.apsoil.2016.06.009},
  volume       = {107},
  year         = {2016},
}