biomass & soil quality patricia bruneau (snh) with contribution from willie towers (mluri) soils...
TRANSCRIPT
Biomass & soil quality Biomass & soil quality Patricia Bruneau (SNH)Patricia Bruneau (SNH)
with contribution from Willie Towers (MLURI)with contribution from Willie Towers (MLURI)
Soils in Scotland / Soil qualityBiomass production impacts on soil
– Direct and indirect impacts– Soil carbon – GHG – Climate change
Soil Classification for Scotland
Podzol (24%)
Gley soil (21%)
Mountain soil
Brown Earth (12%)
Total C-stores in UK soils. Total soil C (x 1012 g) Depth (cm) England and Wales N. Ireland Scotland 0-30 1209
172 1161
30-100 870 124 1025 >100 - - 3248 Total 2079-2890 296 5434-6948
Soil carbonScotland’s soil > 50% of C in UK soilsSOM : key properties for soil function
Properties that differentiate soils
PHYSICAL PROPERTIESDepth of horizons
Soil textureMoisture content
Soil structurePorosity
CHEMICAL PROPERTIESNutrient status
Soil reaction (alkaline, neutral, acidic)Organic matter content
BIOLOGICAL PROPERTIESSoil biodiversity
Above ground biodiversity
Inherent properties of soil soil texture organic matter content the soil reaction - whether the soil is alkaline, neutral or acidic Mineralogy
Transient properties of soil
the nutrient status - how much nitrogen, phosphorus and other nutrients are present in the soil and how available they are to plants
Depth of horizon - whether it is to a hard or contrasting layer or a feature that presents a physical barrier
moisture content - how wet the soils are, how free-draining or impeded, how susceptible to flood or drought
porosity / hydrology– how easy it is for water to move through the soil.
soil fauna – biodiversity
Soil structure
Soil quality or ‘soil health’ “the capacity of a soil to function within the ecosystem boundaries and interact positively with the environment external to this system”
The concept of soil quality was developed to define the capacity within natural or managed ecosystem boundaries of any given soil to deliver one or more of the six function of soil define below:
Food and fibre production Environmental interactions (soil/air/ water)
Ecological habitats, biodiversity
archaeology /cultural heritage (landscape)
Providing platform for construction
Providing raw material
Resilience / resistance of soil function
Scottish soil are generally in good conditions – threats and pressures
Distribution of the modelled inherent erosion susceptibility to overland flowMLURI
Threats to soil associated with biomass productionThreats to soil associated with biomass production..
Energy crops short rotation coppice (SRC) trees Forest residues And others
“Impacts of energy crops can be beneficial, neutral or negative, according to the crops grown and the land-use they replace (in the case of energy crops), and may also depend on the intensity of extraction, in the case of agricultural residues.”
• Energy grass / annual harvest• Liquid biofuel
For Bioethanol from starch/sugar crops eg cereals, potatoes, sugar beetFor Biodiesel from oil crops eg oilseed rape
Energy crops
Change to soil quality• Physical damage to soil – compaction, erosion, drainage• Contamination – sludge/ waste / fertilisation• Loss of biodiversity• Loss of carbon – increase GHG
Organic matter in arable and pasture soils
0 1 2 3 4 5 6 7 8 9 10
Humbie
Kilmarnock
Biel
Stirling
Pow
Ragdale
Forfar
Organic matter %
Pasture
Arable
Chaney and Swift (1984)
Land use change in vegetation and management alter soil biodiversity
0
10
20
30
40
50
60
ferti
liser
ferti
liser
ferti
liser
ferti
liser
ferti
liser
ferti
liser
beetles collembola earthworms enchytraeids nematodes protozoa
farming practice
expe
rimen
tal r
esult
s (n)
higher diversity
no difference
lower diversity
0
2
4
6
8
10
12
14
16
18
20
orga
nic
inpu
t
orga
nic
inpu
t
orga
nic
inpu
t
orga
nic
inpu
t
orga
nic
inpu
t
orga
nic
inpu
t
sewa
geslu
dge
sewa
geslu
dge
sewa
geslu
dge
acari beetles collembola earthwormsenchytraeids protozoa collembola earthworms protozoa
farming practice
expe
rimen
tal r
esul
ts (n
)
higher diversity
no difference
lower diversity
Stockdale et al. 2006 JNCC report 364
• Woody products less than 7cm diameter and are co-products from thinning and clearfell forestry operations.
Forest residues
Change to soil quality• Physical damage to soil – compaction, erosion• Impoverished soil fertility• Acidification• Eutrophication of water course• Degradation of landscape / habitats
• Trees planted primarily as fuel for renewable energy production
• 2-4 yrs rotations.
Short rotation coppice
Table 2: Effects of land-use conversions on losses/gains of carbon in soil
Soil losses or gains (tonnes C per ha per year)
Certainty of Data1
Reference
Losses Gains Arable to Grassland 0.3 - 1.9 * Soussana et al., 2004 Arable to Forestry 0.3 - 1.4 *** Freibauer et al., 2004 Arable to Permanent Pasture 0.27 * Post and Kwon, 2000 Grassland to Arable 0.95 - 1.7 * Soussana et al., 2004; Freibauer
et al., 2004 Grassland to Forestry 0.1 ± 0.02 * Soussana et al., 2004 Forestry to Arable 0.6 ** Freibauer et al., 2004 Forestry to Grassland 0.1 ± 0.1 * Soussana et al., 2004 Agroforestry 0.52 - 0.74 * Sharrow and Ismail, 2004 Peatland Cultivation 2.2 - 5.4 * Freibauer et al., 2004 Wetland to Arable 1.0 - 1.9 * Freibauer et al., 2004 Revegetation on: Abandoned Arable 0.3 - 0.6 ** Wetlands from Arable 2.2 - 4.6 ** Freibauer et al., 2004; Soussana Wetlands from Grasslands 0.8 - 3.9 ** et al., 2004
1* = low certainty / agreement among experts, ** = medium certainty / agreement among experts, *** = high certainty / agreement among experts
Soil as a medium for plant growth
A rab le c rop s Im p roved g rass
F ood p rod u c tion
B ioen erg y F ores try
F ib re p rod u c tion
G raz in g A m en ity
S em i-n a tu ra lveg eta tion
P lan t g row th
Upland ecosystemsDecreasing nutrient inputs
Annual to perennial
Soil biodiversity
Soil In verteb rate D iversity (Sh an n on -W ein er In d ex H ') Mean Mean±SE Mean±1.96*SE
crops/weeds
tall grass/herbs
fertile grass
infertile grass
lowland w
ood
upland wood
moorland/grass
heath/bog
Vegetation Aggregate C lass (C VS)
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
H'