Abstract
Short rotation coppices (SRC) with poplar on arable soils constitute no-till management in combination with a changed litter quality compared to annual crops. Both tillage and litter quality impact soil organic matter (SOM) composition, but little is known on the sustainability of this impact at the molecular level. We compared the microbial colonization and SOM quantity and quality of a young (4 years), old (17 years) and a former SRC with hybrid poplar (Populus maximoviczii × Populus nigra cv. Max) to adjacent arable sites with annual crops or grass. Total fungal and arbsucular mycorrhizal fungal phospholipid fatty acid (PLFA) markers were increased under no-till treatments with permanent crops (SRC and grass) compared to tilled cereals. Enrichments in fungal biomass coincided with C accumulation close to the soil surface (0–5 cm) but was abolished under former SRC after return to annual tillage. This management change altered the spatial distribution but not the accumulation of SOM within the topsoil (0–30 cm). However, lasting qualitative changes in SOM with increased proportions of lignin, lipids and sterols were found under current and former SRC. Increased colonization by arbuscular mycorrhizal fungi was correlated with increased invertase activity (R = 0.64; p < 0.05), carbohydrate consumption and a corresponding accumulation of lignins and lipids in the SOM. This link indicates a regulatory impact of mycorrhizal fungi on soil C dynamics by changing the quality of SOM. Increased stability of SOM to microbial degradation by higher portions of lipids and sterols in the SOM were assumed to be a sustainable effect of poplar growth at Eutric Cambisols.
Highlights
Perennial woody biomass crops are of increasing economic relevance [1], leading to an expansion of poplars (Populus spp.) in short rotation coppice (SRC) on arable soil
SRC on arable soils leads to various soil ecological impacts such as changes in the microbial community and an increased litter quantity caused by winter harvest in the leafless state and woody litter with a
The Corg and Nt concentrations in the upper 0–5 cm of soil under current SRCs at CAH and GUL exceeded those of the reference sites with cereals or grasses (REF) (Table 1)
Summary
Perennial woody biomass crops are of increasing economic relevance [1], leading to an expansion of poplars (Populus spp.) in short rotation coppice (SRC) on arable soil. SRC on arable soils leads to various soil ecological impacts such as changes in the microbial community and an increased litter quantity caused by winter harvest in the leafless state and woody litter with a. The elevated litter input from poplars in combination with the no-till management in SRC increased the C storage in soil organic matter (SOM) in former arable soils in Northern. There are reports on initial C losses under SRC [7] and increased portions of less-stable C fractions under poplar, which suggest an accelerated organic matter decomposition in the following land use [8]. The effects of poplars in SRC on the soil C stocks differ site- [9]
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