Nature and Landscape Biochar additions to soils: expected effects and preliminary results of field experiments in the Netherlands Pleasure Green Biochar Climate Savior or Bluff Package? Environment Berlin, 5 October 2011 Romke Postma & Kor Zwart & others Sustainable Agriculture
Importance of organic matter for soil quality Organic matter (OM) plays a key role in the maintenance of soil quality aspects, such as Soil fertility Nutrient (N, P and S) supply by decomposition of OM Cation Exchange Capacity (CEC), for Ca, Mg, K and.. Physical soil quality Stability of soil aggregates Water holding capacity Biological soil quality Supplying C and energy to (micro)organisms agriculture
Situation in EU and the Netherlands The decline in organic matter is a serious threat for soil quality in most countries (..) This risk seems to be relatively low in the Netherlands, but regional differences occur (see figures) Reijneveld et al. (2009)
Possible contribution of biochar to maintain soil quality Part of strategy that aims to keep organic matter contents at a desired level Important elements: Soil improvers/conditioners (e.g. compost, biochar) Organic matter (OM) content & stability Nutrient content Crop rotation ti (e.g. root crops, cereals, catch crops) Fate of crop residues (straw) Tillage practices (e.g. minimum tillage)
Biochar properties: C and N content Some properties of biochars made from various originating materials. Based on Chan et al. (2007 1), 2008 2) ) and Harris et al. (2007 3) ). green waste 1) poultry manure 2) poultry manure 2) wood chips 3) poultry manure 3) C, g C/kg 360 380 330 720 820 390 460 N, g N/kg 1.8 20 8.5 2.0 2.5 31 35 C/N-ratio 200 19 39 300 400 10 15 CEC 240 - - 50-100 380-600 (mmol+/kg) Large differences, depending on feedstock used Consequences of differences in C/N-ratio for bioavailability?
Biochar properties: CEC CEC of biochar in comparison with organic matter Effect of ph and ageing of biochar Material CEC ph-kcl 4,5 CEC ph-kcl 7-7.5 (mmol+/kg) (mmol+/kg) Organic matter (humus) 500 2750 Fresh biochar (1) 8 8 1 yr old biochar (1) 31 73 130 yr old biochar (1) 390 1160 CEC of OM and Biochar increases with ph, which might be expected CEC of fresh biochar was very low, but it strongly increased with age CEC of aged biochar is somewhat lower than OM/humus
Biochar soil interaction: CEC after the application to soil Effect of biochar type and application rate on CEC of soil Biochar type ecec (mmol+/ kg soil) at increasing biochar doses (Mg/ha) 0 10 25 50 100 A) Biochar from green waste +) 83 80-88 103 B) Biochar from poultry manure 91 109 128-151 B) Activated biochar from poultry manure 111 132 172-195 +) average of 2 treatments, A) Chan et al. (2007), B) Chan et al. (2008) Significant increase in CEC at high application rates Effects of feedstock: Biochar from animal manure/green waste
Experimental research with biochar in the Netherlands agriculture Fate of biochar as a potential by-product of bioenergy production Possibilities for soil amendment? Effects on C sequestration and N 2O emission Incubation experiments in the lab (Cayuela et al., 2010) Biochar production from animal manure as a way to improve the value of surpluses of animal manure fractions (dry fraction of digested pig slurry) Optimization of the pyrolysis process Inventory of the quality of the produced chars (Ehlert & Oenema, 2010) Field experiments with biochar as a soil improver effects on physical soil quality
Bioenergy and its by-products BIODIESEL (1 st generation) PALM OIL CAKE, RAPESEED MEAL BIO-OIL SYNGAS (pyrolysis) BIOCHAR BIODIESEL (from algae) Less available C More BIOMASS recalcitrant C More N, nutrients Toxic compounds? BIOETHANOL (2 nd generation) NON- FERMENTABLES ALGAE RESIDUE BIOGAS (anaerobic digestion) agriculture DIGESTATE BIOETHANOL (1 st generation) DDGS
Tons of by-products generated e ed per ton of fuel Biodiesel (1st generation) rapeseedmeal 1.6 Bioethanol (1st generation) wheat DDGS 1.5 Bioethanol (1st generation) sugarcane meal 0.8 Bioethanol (2nd generation) non-fermentables 74 7.4 Biogas (anaerobic digestion) digestate 3.5 Bio-oil (pyrolysis) biochar 1.0 Biodiesel (algae) algae residue 1.2
NOW Possible uses of BBPs FUTURE Animal Feed? Biorefinery? agriculture EXPANSION OF BIOENERGY SECTOR Marketing of by-products is critical for biofuel industry Agricultural Soil Amendment? Waste Disposal?
Second generation biofuels outperform first generation in C sequestration and N 2 O emission Chars have high h C-sequestration ti and low N 2 O emission i Cayuela et al., GCB Bioenergy 2009
Amount of C, kg 1000 900 800 700 600 500 400 300 200 100 Dynamics of decomposition and accumulation of SOM and BC in soil 0 0 10 20 30 40 50 60 70 80 90 100 Decomposition of organic products Decomposition of organic C in Dutch soil types Biochar SOM peat compost cattle slurry crop residue time, years C content, % C content, % 5,0 4,5 4,0 3,5 3,0 2,5 2,0 1,5 1,0 0,5 0,0 sandy soil + compost +biochar 8 reclaimed peat 7 old marine clay sand 6 riverine clay loess 5 young marine clay 4 3 2 1 0 0 20 40 60 80 100 agriculture 0 20 40 60 80 100 Time, in years time, in years Effect of repeated application of BC and compost on the course of soil C
Biochar from animal manure: effects of pyrolysis conditions Effect of pyrolysis temperature, duration and O 2 Ehlert & Oenema, 2010 Relative biochar yield decreased with increasing temperature Effects of pyrolysis duration and presence/absence of O 2 were marginal
Biochar from animal manure: extractable C and N-mineralization Hot Water Extractable C (HWC) decreased with increasing pyrolysis temperature Anaerobic N mineralization was the lowest in 400 o C-chars: at lower and higher temperatures N-mineralization was higher Ehlert & Oenema, 2010 Ehlert & Oenema, 2010
agriculture Field experiments: locations L Locations differed in soill type and crop rotation Crop rotations were representative for the region year 2 3 location 1 1 2 3 2010 s.wheat s.beet s.barley 2011 potatoes potatoes s.beet 2012 s.barley s.barley potatoes 2013 s.beet potatoes carrots
Field experiments: soil properties and experimental set up Biochar additions varied between locations (table) Charcoal, activated carbon and torrefied material Control (no soil improver) and reference (compost) ost) Mineral fertilizers applied according to recommendations Location Soil type Soil properties Crop 2010 Type and amount of biochar applied, in Mg per ha ph- KCl clay % OM, % Charcoal Activated carbon Torrefied material 1 KW Light clay 7.0 26 3.5 spring 5 5 wheat 2VM Reclaimed 52 5.2 2 11.6 sugar beets 5 5 15 peat 3 LS Silt clay 6.8 17 2.0 spring barley 2.5 & 5
Field experiments: results 2010 Small and non significant effects of biochar on crop yield and/or quality It is expected that effect will increase after several years Treatment Location 1 grain yield wheat, Mg/ha Location 2 fresh weight sugar beet, Mg/ha Location 3 grain yield barley, Mg/ha 1. Control 8.00 61.7 9.20 2. Charcoal 2.5 Mg/ha 9.02 3. Charcoal 5 Mg/ha 816 8.16 59.55 911 9.11 4. Activated carbon 8.40 58.6 5. Torrefied material 61.4 6. compost, 6 Mg DM/ha 7.84 60.5 9.02 LSD 0.05 0.38 4.2 0.65
Plans for 2011-2013 Continuation of field experiments Additional biochar treatment (loc. 2) Further characterization of biochars applied Monitoring of crop yield and quality Monitoring of chemical, physical and biological soil properties at location 2: Chemical: CEC, OM%, ph, nutrient availability Physical: bulk density, pf-curves, infiltration rate Biological: C and N mineralization, microbial density of bacteria a and fungi, g, N 2 2O emission sso