Improving crop yield and storing carbon

Progress report February 201128 February 2011

NGI report no. 20100920-00-2-R

Improving crop yield and storing carbon

Biochar in conservation farming in Zambia:

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Project

Project: Biochar in conservation farming in Zambia Document No.: 20100920-00-2-R Document title: Improving crop yield and storing carbon

Progress report March 2011 Date: 28 February 2011

Client

Client: Conservation Farming Unit (CFU) Client’s contact person: Peter Aagaard Contract reference: CFU-NGI contract 3 November 2010,

Lusaka

For NGI Project manager: Gerard Cornelissen (NGI + UMB) Prepared by: Gerard Cornelissen (NGI) and Victor

Shitumbanuma (UNZA)

Reviewed by: Gijs Breedveld (NGI) Analysis also done by: Eugene Kana (UNZA), Vegard Martinsen

(UMB), Sarah Hale (NGI)

Summary The main aim of the project is to investigate the potential of organic waste bio-char to sequester carbon and improve the quality of weathered and/or acidic Zambian soils. Here biochar amendment is exclusively combined with Conser-vation Farming (CF). In CF only 10-12 % of the land is tilled. Therefore the expectation is that CF and biochar are a favourable combination, since less biochar is needed to obtain the same effectiveness as with conventional tillage. Chemical characterization of the soil-biochar combinations indicated that biochar could significantly improve the cation exchange capacities and decrease acid satu-ration of especially poor soils (Mkushi, Kaoma).Field tests were established at six sites: Mkushi, Kaoma, Shimabala, NRDC, UNZA farm, Kasisi. Halfway through the growth season the main conclusion was that biochar can strongly improve

maize growth, especially for poor, low-nutrient soils (Kaoma, Mkushi) and at low fertilezer rates. In high-quality soils (Shimabala, NRDC), biochar showed less or no effect.

Contents

1 Introduction 61.1 Consortium 61.2 Background 7

2 Study methods 82.1 Initial simple chemical screening of soil-biochar combinations to

identify the potential of biochar for acidic, Zambian soils 82.2 Pot trials 102.3 Field trials 10

3 Results 113.1 Chemical soil characteristics 113.2 Effect of biochar on soil chemical characteristics 153.3 Field observations halfway the field trials 163.4 Pot trial observations after one week 22

4 Tentative conclusions and further plans 245 Time schedule phase 1 256 References 25 Review and reference page

Document No.: 20100920-00-2-R Date: 2011-02-28 Page: 6

1 Introduction

The main aim of the project is to: Investigate the potential of organic waste biochar to sequester carbon and improve the quality of weathered and/or acidic Zambian soils. Sub-aims include:

A. A small but systematic study of successful and non-successful soil-biochar combinations for Zambian acid soils.

B. Field tests on the effect of biochar on soil acidity, aluminium toxicity, and nutrient availability / fertilizer need.

C. Identify optimal feedstocks and optimal concepts for biochar generati-on.

1.1 Consortium

The consortium consists of the following partners: • Conservation Farming Unit, Lusaka, Zambia (CFU- financing and execu-

tive partner), • University of Zambia (UNZA) Department of Soil Sciences (DSS-

executive partner) • Norwegian Agency on Development Cooperation (Norad- financing

partner) • Norwegian Geotechnical Institute, Oslo, Norway (NGI- executive and

(own-)financing partner) • University of Life Sciences, Ås, Norway (UMB), Faculties of Soil Science

and Social Science (executive partner) The following people are involved in the project:

Prof. Gerard Cornelissen, Norwegian Geotechnical Institute (NGI) & Univ of Life Sciences (UMB), Norway

Project manager:

Dr. Elijah Phiri, UNZA Collaborators:

Victor Shitumbanuma, UNZA Peter Aagaard, CFU Jan Erik Studsrød, Norwegian Embassy in Zambia & Norad Odd E. Arnesen, Norad Matthijs van Leur, UU, The Netherlands Prof. Gijs D. Breedveld, NGI & University of Oslo Dr. Sarah Hale, NGI Dr. Vanja Alling, NGI Prof. Jan Mulder, Institute for Plant and Environment, UMB Dr. Vegard Martinsen, Institute for Plant and Environment, UMB


1.2 Background

Biochar is carbon negative and a source of alkalinity in soils: Biochar is the charcoal product obtained when biomass (preferably organic waste) is heated without access to oxygen (pyrolysis). Biochar is stable for thousands of years in soils, and thus represents carbon that is actively removed from the carbon cycle [Lehmann 2007; Renner 2007; Fraser 2010]. Biochar is rich in alkaline compo-nents (Ca, Mg, K), which may contribute to neutralization of soil acidity [e.g. Gruba and Mulder, 2008; Yamato, 2006]. Thus farmers can use their organic waste materials to improve their crop yields and at the same time can sequester carbon. In addition, the need to open new forest to replace degraded farmland is reduced if biochar renders farmland productive for a longer time.

Figure 1 The principle: by “pyrolysis” (heating without air) biochar is

generated that sequesters carbon in the soil [Lehmann 2007]. Sources of biochar: The best biochar source is organic waste that would other-wise be burned (generating CO2). No energy crops should be used, and no forest should be cut to generate biochar. Biochar in weathered, acidic tropical soils: In order to improve such acidic tropical soil, biochar could be added to it. There are a few scattered studies, both in Indonesia, indicating that biochar amendment can double yields for corn, cow-pea and peanuts [Yamato et al 2006] and rice [Masulili et al 2010], attributeable to strong reductions in soil acidity (over a factor 10) and available toxic aluminium (factor 10 to 100).

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Biochar in Zambia. It is expected that Zambian soils are particularly sensitive to biochar amendment, since they are mainly acidic sandy or sandy-loam soil [FAO 2006]. These coarse types of soils exhibit modest reserve acidity and can thus relatively easily be neutralized by alkaline biochar. Regions 2b (coarse sandy, degraded soils) and 3 (highly leached acrisols, slash and burn practice) are expect-ed to be most suitable for testing. Conservation Farming and Biochar. In the present field tests, biochar amend-ment is exclusively combined with Conservation Farming (CF-conservation tillage by basin digging and mulch generation by leaving residues on the land, in some cases combined by crop rotation (Conservation Farming). None of the field trials were performed at Conservation Agriculture plots (Faidherbia nitrogen-fixing trees to improve fertility). In CF/CA, only 10-12 % of the land is tilled. Therefore the expectation is that CF and biochar are a favorable combination, since biochar is only inserted into the planting basins, and thus local biochar concentrations at those places where the plants grow are relatively high, and less biochar is needed to obtain the same effectiveness as with conventional tillage. 2 Study methods

Soils/sites were selected from a range of sites in Zambia:

1. Kaoma (region IIb, Western Province): grey, weathered alluvial sand. GPS: S 14°49.571’ E 24°52.970’. Conservation Tillage, newly opened plot.

2. Mkushi (region III): sandy, weathered, acidic loam. Conservation Farming, newly opened plot. GPS: S 13°36.361’ E 29°22.681’

3. NRDC (Lusaka, region IIa): clay loam, neutral. GPS: S 15°22.712’ E 28°22.269’. Conservation Farming, long-used plot.

4. Shimabala (North of Kafue town, region IIa): clay loam, good organic content, good soil after 10 years conservation farming. GPS: S 15°39.278’ E 28°14.503’. Conservation Farming with adjacent Conservation Agriculture, long-used and well-maintained plot.

5. UNZA experimental station, 20 km east of Lusaka, acidic, mode-rately weathered red iron-rich soil. Conservation Tillage, Newly opened plot.

6. Kasisi Organic Farm (outside CFU auspices and funding), 10 km north of Lusaka International Airport. Conservation Tillage, Newly opened plot.

2.1 Initial simple chemical screening of soil-biochar combinations to identify

the potential of biochar for acidic, Zambian soils

Soils. From regions 2b and 3 in Zambia have been sampled and analysed. Soils were characterized for pH Cation Exchange Capacity (CEC), exchangeable


(NH4Cl extractable) Al3+, Ca2+, Mg2+, Na+, K+, Fe2/3+, CaCl2-extractable Al, pyrophosphate-extractable Al, Fe and Organic C. Biochars. Biochars from three different feedstocks have been synthesized using local/traditional kiln technology. The following three biochars have been used: i) corn stover biochar, since this is a organic waste material that serves hardly any purpose than limited use as a stove lighter (generation temperature for the corn stover biochar was measured to be 340 C); ii) charcoal dust, a waste product of charcoal generation that is only used for firing briquettes to a very limited extent; iii) wheat straw biochar. pH. Changes in pH or absence thereof will give valuable and easily-obtained indications on the feasibility of biochar amendment for Zambian acid soils. We hypothesize that especially low-CEC soils will be amenable to pH increase upon biochar amendment. Acid neutralizing ability. As a preliminary study, materials from the three pro-ducts were crushed by hand in a porcelain mortar and then passed through a 2 mm sieve. The material that passed through the sieve was then used to carry out a series of tests used to characterize the materials. There include the pH, the acid neutralizing ability and the acid neutralizing value. To determine the acid neutra-lizing ability of the materials, 125 ml of distilled water was applied to the 25 ml suspensions used to measure the pH of the different biochar materials. The resulting 150 ml suspension was then titrated with 0.05 N H2SO4, which was constantly stirred with a magnetic stirrer, while the pH of the suspension was measured with a digital pH meter. The results obtained were then used to plot the relationship between the pH of the suspension and the amount of acid applied to the suspension. Bulk density of Biochar from maize cobs: The dry bulk density of the non charred maize cobs and charred maize cobs were determined using the paraffin method. Pieces of charred and non charred maize cobs were weighed and dipped in a wax. This resulting wax coated samples were then tried to a stone of known volume and mass and immersed in water in a volumetric cylinder. The volume of water displaced by the stone and wax coated maize cob pieces was measured. The volume of wax was determined from the density of wax and then subtracted the volume of water displaced by the stone and wax coated pieces of maize cob. The bulk volume of the cobs was then determined by subtraction of the volume of the stone from the volume of water displaced by the stone and the cob. The bulk densities of the charred and non charred cobs were then calculated. Triplicate samples of both the charred and non charred pieces were used to determine the bulk densities of the samples.


Polycyclic Aromatic Hydrocarbons, PAH. These are toxic and carcinogenic com-pounds that can be formed during incomplete combustion (pyrolysis). Adding bio-char to soil could introduce these compounds into the soil if they are formed dur-ing biochar generation. Therefore we measured both total PAH, as well as water-soluble “biologically available” PAHs in the biochars. Details of the follow-up parameters are given in Appendix A. 2.2 Pot trials

Pot trials have been started at the end of January 2011 at UNZA, directed by Victor Shitumbanuma and Eugene Kana. In total 132 pots have been started according to the following scheme. Soils used: UNZA, Kaoma, NRDC, Shimabala (all started), Mkushi (planned). Crop: Maize. Biochars:All samples in triplicates or quadruplicates.

Charcoal dust, corn stover.

Table 1 Setup of pot trials 1 Control 2 Control + NPK (basal “D” 0.9 g per kg) 3 Corn stover biochar 20 g per kg soil dry

weight + basal “D” 0.9 g per kg

Charcoal dust 20 g per kg soil dry weight +

basal “D” 0.9 g per kg 4 Corn stover biochar 5 g per kg soil dry




weight + 50%- basal “D” 0.45 g per kg


50%- basal “D” 0.45 g per kg After the first test, at least one additional growth cycle will be studied without amending fresh biochar, to study the prolonged fertility effect of biochar. Details of the approach and follow-up are given in Appendix A. 2.3 Field trials

Field tests were set up in the following manner:

1. CFU-led field demonstrations consisting of five plots at Shimabala, Mkushi, NRDC, Kaoma. Five plots at each site:

a. Control plot. b. 0.8 tons/ha corn stover biochar c. 0.8 tons/ha charcoal dust d. 4 tons/ha corn stover biochar e. 4 tons/ha charcoal dust


2. UNZA experimental farm: block trial consisting of 40 plots of size 5 x 5 m. Setup:

a. Controls, no addition b. Controls, fertilizer only c. CFU (fertilizer + liming + top dressing urea) d. Corn stover biochar 0.5, 1, 2.5, 5, 7.5, 10, 15, 20 tons/ha e. Charcoal dust 0.5, 1, 2.5, 5, 10, 15, 20 tons/ha f. Wheat straw biochar 0.5, 1, 2.5, 5, 10, 15, 20 tons/ha

3. Kasisi Organic Farm (outside CFU auspices and funding): block trial consisting of 24 plots, with all three biochars at several manure: biochar amendment ratios.

Table 2 Fertilizer amendment and planting date at the various sites

Soil Basal D Top dressing Planting date Kaoma Biochar 1cup/basin No Nov 19

CFU 1cup/basin Yes (1x) Nov 19 Mkushi Biochar 1cup/basin Yes (2x) Nov 26 NRDC Biochar 2 cups/basin No Nov 19

CFU 2 cups/basin Yes (2x) Nov 19 Shimabala Biochar 1cup/basin Yes (2x) Nov 16

CFU 1cup/basin Yes (2x) Nov 16 UNZA Biochar 1cup/basin Yes (2x) Dec 18

CFU 1cup/basin Yes (2x) Dec 18 Kasisi Biochar Manure ”Tea” Nov 29

For a detailed setup, see Appendix A. Follow-up monitoring includes the following:

- CEC, extractable cations, extractable anions: measured by Plant root simulators (PRSs), infinite-sink samplers for nutrients that are left in the soil from Feb-March 2011.

- pH - Crop total biomass, corn grain yield

3 Results

3.1 Chemical soil characteristics

A short overview over the key chemical characteristics of the soils is given here. A complete table of soil and biochar chemical characteristics can be found in Appendix B.


pH. All soils except the NRDC one were acidic, UNZA farm soil showing strongest acidity at pH 3.8 (Table 3). The biochars were alkaline (pH > 7), but not so strongly so, probably because of the moderate generation temperatures. For pH in water and 1 M KCl, see appendix B. CEC. The Cation Exchange Capacity (CEC) of the soils was low for Mkushi and Kaoma soil (< 5 cmol/kg), moderately low for UNZA soil (9 cmol/kg), and normal for NRDC and Shimabala soils (> 15 cmol/kg). The biochars exhibited much higher CECs (40 and 85 cmol/kg for the corn stover biochar and the char-coal dust, respectively). The CEC of biochar is expected to rise even further over time, as has been observed before at Cornell University. OC and N. The Organic Carbon (OC) contents of the soils were below 1%, except for the Shimabala soil (1.8%). This is likely due to the log history of CA at this site, as well as the relative fertile character of the site in a low-lying area close to the Kafue river. OC/N ratios were high for soils and biochar alike, with the exception of the relatively “good” soils at NRDC and Shimabala (OC/N for these soils < 20). Table 3 pH, Cation Exchange Capacity (CEC), Organic Carbon (OC),

Organic Nitrogen (N) and C/N ratios of soils and biochars

Soil/char pH (0.01 M CaCl2)

CEC (cmol/kg)

Org C (%)

N (%) C/N

Mkushi 4.9 3 0.4 b.d. n.d.

Kaoma 5.4 4 0.5 0.01 50

Shimabala 5.2 29 1.8 0.09 20

NRDC 6.9 17 0.9 0.05 18

UNZA 3.8 9 0.8 0.02 40

Charcoal dust 7.9 85 65 0.8 80

Corn stover char 7.6 40 74 0.8 90

Overall, Mkushi and Kaoma soils are both acidic and the most weathered lowest-CEC soils, whereas UNZA soil is still low in CEC and the most strongly acidic. Shimabala and NRDC are better soils, with much better nutrient holding capacity and limited acidity. On the basis of the limited set of chemical soil characteristics, biochar could be expected to be most effective in Kaoma and Mkushi, thereafter UNZA, and least effective in Shimabala and NRDC. The charcoal dust biochar exhibits better characteristics than the corn stover biochar (higher CEC and pH).


On the basis of the overall observations, charcoal dust could be expected to be somewhat more effective than corn stover biochar. Acid neutralizing ability. The titration curves of the biochar suspensions are presented in Figures 2a and 2b. Figure 2a shows the titration curve of the wood charcoal from its initial pH to about pH 5.0, the typical pH value of most Zambia soils. The titration curves shows that about pH 6.7 the charcoal has a strong buffering capacity, indicating the probable presence of some functional group with a dissociation constant of pKa of about 6.7. There seems to be a substantial amount of compounds with this functional group or groups in the charcoal which strongly buffer the solution. In the charcoal sample this functional group consumes about 30 % of the acid required to drop the pH of the suspension from pH 8.03 to pH 5.0.Figure 2b shows a combined plot of the titration curves for suspensions of charcoal, wheat straw biochar and maize cob biochar used in the crop trials. All three biochar materials indicate the ability to neutralize acid. The highest capacity is associated with charcoal followed by maize cob biochar and the least is the wheat straw biochar. The wheat straw and maize cob biochars also show some buffering around pH 6.7, but not the same extent as in the wood charcoal, indicating that these biochar materials all contain some functional group that dissociates at pH of about 6.7, though the quantities of these compounds vary with material.

Figure 2. Titration curves for suspensions of the three biocharmaterials with acid

Millimoles of H+ applied per 100 g of biochar

0 5 10 15 20 25 30 35 40 45 50

pH of

bioc

har s

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4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

CharcoalWheat Straw Biochar Maize cob biochar

Figure 1. Titration curve of charcoal suspension with 0.05N H2SO4

millimoles of H+ added per 100g of charcoal

0 10 20 30 40 50 60 70 80 90 100 110

pH of

charc

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4.5

5.0

5.5

6.0

6.5

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7.5

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8.5


Bulk density of the maize biochar The bulk densities of the charred and non charred maize cobs are presented in Table 4. Table 4 Bulk densities of the charred and non-charred maize cobs

Sample Bulk density ( kg.m-3) Standard error Sample size

Non Charred Maize cobs

Charred maize Cobs

98.6 216.5

35.5 57.0

3 3

The average bulk density of the charred maize cobs was found to be about 99 kg .m-3 while that of the non charred cobs was 217 kg.m-3. The results show that the density of the maize cob biochar is relatively low. Therefore large volumes of the material are required to supply a given mass of biochar. Based on calculations of the densities of non-charred maize cobs and charred maize cobs we were able to calculate the average recovery rate of the maize cob biochar productions that was used at UNZA Farm. Results indicate that efficiency or recovery rate of the maize cob biochar produced at UNZA Farm was about 45.6 % or that on average one can expect to obtain about 45.6 % of mass of the fresh maize cobs used as maize cob biochar. Polycyclic Aromatic Hydrocarbons, PAH. Total PAH concentrations in the pure biochar were in the order of 2 µg/g (Figure 3), which is very close to the soil level where 95% of organism species are considered protected. Since biochar will only be mixed into the soil in 2-5% amounts, PAHs in the currently tested biochars are probably not a problem. This is confirmed by the freely available concentrations (below 2 ng/L for all PAH compounds). This is a factor of 10-100 below the “maximum tolerable risk” where 95% of species is protected. Figure 3 Total and available concentrations of the toxic and carcinogenic

PAHs in the used biochars.


3.2 Effect of biochar on soil chemical characteristics

The pH of the three acidic low-CEC soils was substantially increased by addition of both biochars (Table 5). With the addition of 5% charcoal dust, the soil acidity was almost completely neutralized, due to the combination of an alkaline pH and high CEC of the biochar generating a lot of neutralizing capacity. As expected, charcoal dust was more effective than corn stover biochar in pH neutralization. Table 5 Changes in pH upon amendment with 5% biochar and shaking

overnight

Soil/ Char

pH (0.01 M CaCl2) pH + 5% corn stover BC pH + 5% char dust

Mkushi 4.9 5.9 6.8

Kaoma 5.4 6.3 7.0

UNZA 3.8 4.8 6.2

The soil CECs were significantly increased, and for the poorest Mkushi soil even more than doubled, by the addition of 5% biochar (Table 6). Table 6 Changes in CEC upon amendment with 5% biochar

Soil/ char

CEC (cmol/kg)

CEC + 5% corn stover BC

CEC + 5% charcoal dust

Mkushi 3 7 8

Kaoma 4 6 7

UNZA 9 11 11

An important parameter for soil fertility is the number of cation exchange sites that are occupied by acid protons H+ (instead of beneficial nutrients). The acidic soils had a high acid saturation (> 50%) that was slightly reduced by the addition of corn stover BC (Table 7), and strongly reduced by charcoal dust, even to zero for Mkushi and Kaoma soils, being the lowest-CEC soils that had the least “amount” of acidity to compensate (lower CEC and higher pH than UNZA soil). The OC contents of biochar-amended soils increased to over 3%, a very good value for agriculture (Table 7).


Table 7 Acid saturation of the cation exchange sites (with and without 5% biochar. Also OC of the soils with 5% charcoal dust.

Soil/ char

Acid saturation

(%)

Acid saturation + 5% corn stover BC

Acid saturation

+ 5% charcoal dust

OC + 5% charcoal dust

(%)

Mkushi 61 62 0 3.5

Kaoma 55 36 0 3.3

UNZA 83 72 32 3.3

3.3 Field observations halfway the field trials

Kaoma Kaoma soil is a poor, weathered, acidic alluvial sand, and no top dressing was applied (only basal D- 1 cup, half the usual amount).Here biochar was observed to be a strong fertility booster, even at the low application rate of 0.8 ton/ha. At the high application rate (4 ton/ha) the effect was strong, with 2-3 times better growth in the biochar-amended soils than in the control ones (Figure 4a,b).

Figure 4a Kaoma maize after 2 months, at low biochar application rates. No top dressing applied.


Figure 4b Kaoma maize after 2 months, at high biochar application rates. No

top dressing applied. Mkushi Kaoma soil also is a poor, weathered, acidic soil, but top dressing was applied, as well as basal D (only 1 cup, half the usual rate). Biochar was observed to be fertility booster, but much less strongly so than in Kaoma, probably because the top dressing application could have masked the effect of the biochar (Figure 5). Only for the 4 t/ha charcoal dust application, a significant improvement over the controls was observed. We expect that a new growth season with limited or no top dressing will result in much better growth in the biochar fields than in the control ones, since this first year the biochar has probably been “loaded” with nutrients, as a sponge that prevents them from leaching out to the groundwater.

charcoalhigh

maize charhigh

control


Figure 5 Mkushi field trial after 2 months, at high biochar application rates. Top dressing applied 2x; basal D one cup.

Shimabala Shimabala is a much better soil than Mkushi or Kaoma and therefore a lower effectiveness of biochar was expected. This was confirmed by the halfway obser-vations: no differences were observed between amended and nonamended plots- all were in excellent state, as could be expected after all those years of conser-vation farming!

Figure 6 Shimbala field trial after 2 months. Top dressing applied 2x; basal

D one cup.


NRDC NRDC soils were also good with regard to nutrient holding capacity and pH (neutral). Also under these conditions the effectiveness of biochar was observed to be limited in this stage of growth (Figure 7).

Figure 7 NRDC field trial after 2 months. Top dressing applied 2x; basal D one cup.

UNZA farm Planting here was relatively late, but a good block trial was established.

Figure 8a Preparing for basin digging at the UNZA farm


Figure 8b Planting basins at UNZA farm The soil at UNZA farm was the most strongly acidic one. Here no top dressing was applied, however, two cups of basal D were administered. This trial started later (Dec 23) so differences were probably less pronounced after only slightly more than one month. The main differences between the biochar fields and control plots were i) stronger growth in the biochar fields (Figure 9); ii) less water stress in the biochar fields (greener and flatter leaves). This indicates that the biochar also can increase the water holding capacity of the soil, something that will be investigated in the later stages of phase 1.


UNZA Feb. 2011

Control Fertilizer only

Figur 9a UNZA field trial after 1 month (control/NPK only). Top dressing applied 2x; basal D one cup. NPK boosts growth in a significant way.

Figure 9b UNZA field trial after 1 month (charcoal dust). Top dressing

applied 2x; basal D one cup. Charcoal dust boosts growth in a significant way

UNZA Feb. 2011

Charcoal 10 t/ha Charcoal 20 t/ha


Kasisi: biochar + organic farming

Only manure Only biochar

Kasisi Organic Farm This soil was not yet tested but is suspected to be low in CEC and pH. Tentative first observations include (Figure 10): i) charcoal dust biochar is more effective than corn stover biochar; ii) biochar is a bit more effective than composted manure only (and will sequester carbon); iii) the combination manure + biochar is most effective.

Figure 10 Kasisi field trial after 2 months (manure only and charcoal dust only, both 8 t/ha). Charcoal dust seems more effective than only manure.

3.4 Pot trial observations after one week

Although the pot trials have only been running for one week. Some tentative observations can be made:

i) The low-CEC soils seem to suffer from fertilizer stress ii) Biochar is effective, and biochar + half the amount of fertilizer leads to

better growth than biochar-only or fertilizer-only (Figure 11).


Figure 11a UNZA pot trial with Kaoma soil after 1 week. Fertilizer stress and

good effect of corn stover biochar are observed.

Figure 11b UNZA pot trial with UNZA farm soil after 1 week. Slight fertilizer

stress and good effect of especially charcoal dust are observed.

Kaoma

Control NPK Maize C Maize C+½NPK

UNZA Farm

Control NPK Maize C Char C+½NPK

Maize C+½NPK


4 Tentative conclusions and further plans

The combination UNZA, CFU and NGI/UMB proved effective in setting up field trials at only 4 weeks notice.

1. Biochar is probably most effective in weathered, low-CEC and/or acidic soils, i.e. mainly in the west and north of Zambia, but also at some places in the south.

Tentative halfway conclusions comprise the following;

2. Chemical characterizations of soils, charcoals and combinations thereof give indications for the biochar effectiveness in the field.

3. The corn stover biochar production process should be optimized (mainly w.r.t. temperature) to produce a better-quality biochar with regard to soil fertility.

1. Measure crop yield for the field trials Further plans for phase 1 include the following (for details see appendix A):

2. Measure water holding capacity with and without biochar 3. Complete the chemical testing for all soils with different amounts of bio-

char 4. Complete two growth cycles in the pot trials 5. Complete characterization of the soils and biochars 6. Measure toxic organic contaminants (combustion products, Polycyclic

Aromatic Hydrocarbons) in the biochars 7. Carry out column leaching tests with the soils with and without biochars,

to improve mechanistic process understanding 8. Complete inventory of socio-economic questions, and interest a master

student to investigate the agronomic aspects of biochar application under Zambian conditions (Appendix C).

1. Repeat the field trials without novel biochar amendment, to look at the long-term effectiveness of biochar amendment

Tentative plans for phase 2 include the following

2. Establish field trials in more locations, especially in the north (acidic and weathered soils)

3. Establish tests with other crops than maize 4. Carry out in-depth research on socio-economic and agronomic issues (see

Appendix C). 5. Investigate optimal ways to generate biochar in Zambia (household stoves,

mobile modern pyrolysis units, optimized kilns- possible involvement UNDP).

6. Support CFU in the quantitative monitoring of the effect of prolonged CFU on the soil quality.

7. Disseminate the concept of biochar through the CFU extension infrastruc-ture and the UNZA university curriculum at School of Agricultural Scien-ces (possible involvement AGRA).


5 Time schedule phase 1

6 References

• FAO (2006). Aregheore, E.M. County Pasture/Forage Resource Profiles, Zambia.

• Fraser, B. (2010) High-tech charcoal fights climate change. Environ. Sci. Technol. 2010, 548.

• Gruba P, Mulder J (2008). Relationship between aluminum in soils and soil water in mineral horizons of a range of acid forest soils. Soil Science Soc. Amer. J. 72, 1150-1157.

• Lehmann, J. (2007) A handful of carbon. Nature, Vol. 447(7141), pp. 143-144.

• Masulili, A.; Utomo, W.H.; Syechfani, M.S. Rice Husk Biochar for Rice Based Cropping System in Acid Soil. J. Agricult. Sci. 2010, 2, 39-47.

• Renner, R. (2007) Rethinking biochar. Environ. Sci. Technol. 2007, 5933. • Rutherford, D.; Rostad, C.; Wershaw, R.L. Effects of formation conditions

on the pH of biochars. Poster International Biochar Initiative Conference, Denver 2009.

• Yamato et al, 2006. Effects of the application of charred bark of Acacia mangium on the yield of maize, cowpea and peanut, and soil chemical properties in South Sumatra, IndonesiaSoil Sci Plant Nutrition 2006, 52, 489.

2010 2011

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov

Visits NGI/UMB X X X X X

Chemical screening soils

X X X

Pot trials 1st cycle

X X

Pot trials 2nd cycle

X X

Field trials X X X X X X X

Follow-up pot and field trails (chem and biol)

X X X X X X X

Interpretation X X X X

Reporting X X

Evaluation X

Possible start phase 2

(X) (X)

Document No.: 20100920-00-2-R Date: 2011-02-28 Page: 1 Appendix: A

Appendix A A1. Screening of feasibility biochar amendment for

acidic Zambian soils

- 25 soil

- Mixed samples (0-20 cm?)

samples from all over Zambia, preferably acidic and/or sandy samples (pH < 6,0-6,2)

- (Approximate) GPS coordinates - Description of location - Measure pH, CEC, Extractable metals: Al3+, Ca2+, Mg2+, Na+, K+ - Add 0%, 0.3%, 1%, 3%, 10%, 30% (dry weight basis) of three

different biochars to soils: o Grass biochar, corn stover biochar, charcoal dust o Measure pH, CEC, Extractable metals: Al3+, Ca2+, Mg2+, Na+,

K+ for the biochars o Per biochar needed 100 g o 0, 0.03, 0.1, 0.3, 1, 3 g biochar per 10 g soil (6 x 2 x 25 = 450

samples) o Mix 1 week o Measure pH after 1 week, for three biochars, in water 1:5 (450

samples) o Measure CEC, Extractable metals: Fe2+, Al3+, Ca2+, Mg2+, Na+,

K+ (450 samples o Soil particle size distribution o Water holding capacity at some biochar concentrations?


A2. Pot experiments UNZA

5 Soils: - 1 soil from region III Mkushi (acidic, sandy, weathered) - 1 soil from region IIb Kaoma, “Kaoma 3” (nonacidic, sandy, weathered-

pH 6.5, GPS: S 14°49.910’ E 24°55.342’, NOT “Kaoma 4” (where field trials are going to take place) since some burning has taken place there

- UNZA farm - NRDC - Shimabala

- 5-kg pots in round 1, 3-kg pots in round 2 - Homogenize all soil well before starting the experiment - 3 biochars: Corn stover biochar, grass biochar, charcoal dust - Measure pH of soils and biochar - Mix biochar in soil, and let it rest for 3 days - Measure pH and CEC - Plant maize - Dig in 1 pieces of 0.3 m POM plastic into soils (only POM in reference

plots and biochar high (40 g/kg) - Four replicates per treatment - Three soils - Three treatments and two controls (Control, Control + fertilizer, Biochar

4% + fertilizer, Biochar 0.5% + fertilizer, Biochar 4% + half of fertilizer) - 108 biochar pots (3 soils x 3 biochars x 3 treatments x 4 replicates = 108

pots) - 24 control pots (3 soils x 2 treatments x 4 replicates = 24 pots) - Total 132 pots - 250 kg of each soil needed - Randomized placement of pots in greenhouse (clear labeling) - Treatment 2, 3 and 4 include the recommended amount of fertilizer;

treatment 1 no fertilizer, treatment 5 half the amount of fertilizer - Repeat experiment with 2 complete growth cycles to assess prolonged

effect of biochar on soil quality and crop growth 1 Control 2 Control + NPK (basal “D” 0.9 g per kg) 3 Corn stover biochar 20 g per kg soil dry







weight + 50%- basal “D” 0.45 g per kg


50%- basal “D” 0.45 g per kg


Follow up parameters - Measure pH of soils at end of experiment

o pH in water, 1:5 v/v, shake 1 hour, measure in slurry o pH in KCl 1 mol/L, 1:5 v/v, shake 1 hour, measure in slurry

- CEC at end of experiment - Soil particle size distribution - Water holding capacity - Extractable nutrients of soils at end of experiment

o K, Na, Ca, Mg o Phosphate, Nitrate, Sulphate

- TOC at end of experiment (quantification of amount of biochar remain-ing)- to be done by NGI

Chemical parameters: organic pollutants

- Available PAHs in soil: POM sampled, frozen, and sent to NGI. Only in reference plots and Biochar-high 1.5 kg/m2, 48 samples

- Total PAHs in biochar and soil: triplicate soil and char samples, 18 sam-ples

- PAH uptake in plants: sample above-ground parts for treatments 2 and 4, freeze non-dried, 18 samples

Experiment 1: Parameters to be measured for each treatment

- Start in February - 3 kg pots

Measurement T=0 (start) T=end (2 months for maize?)

pH X X Nutrients, CEC X X

Shoot length X Above ground biomass X

Root biomass X Experiment 2 (complete growth cycles with soils from experiment 1- no new biochar or NPK additions): Parameters to be measured for each treatment

- Start in April after evaluation - 3 kg pots with all soil that can be retained from round 1 - Finish in June

Measurement T=0 (start) T=end (6 weeks) pH X X Nutrients, CEC X X Shoot length X Above ground biomass

X

Root biomass X


A3. CFU Field demonstrations at farmer fields - 2 biochars: Corn stover biochar and charcoal dust - 2 plots per biochar (0.8 and 4 tons per ha) - No replicates but large fields (10 x 10 m or 3 x 50 m) - Plot size 100-150 m2 (10 x 10 m) - Minimally 1 m between plots - 5 plots per farmer - Moderate amount of fertilizer (280 kg/ha, 18 g per basin, two cup 8 basal

D per basin) - Biochar put into planting holes CF - NO LIMING! - Some mixing of biochar and soil in planting basin

Kaoma, Mkushi, NRDC, Shimawala Maize Plot nr Biochars: charcoal dust, corn stover Biochar Basal “D” 1 Control Basins - 16 g/basin 2 Corn stover 0.8 tonn/ha Basins 50 g/basin 16 g/basin 3 Corn stover 4 tonn/ha Basins 250 g/basin 16 g/basin 4 Charcoal dust 0.8 tonn/ha Basins 50 g/basin 16 g/basin 5 Charcoal dust 4 tonn/ha Basins 250 g/basin 16 g/basin Follow-up monitoring

- Measure pH of soils at start and end of experiment (triplicates!o pH in water, 1:5 v/v, shake 1 hour, measure in slurry

)

o pH in CaCl2 0.01 mol/L, 1:5 v/v, shake 1 hour, measure in slurry o pH in KCl 1 mol/L, 1:5 v/v, shake 1 hour, measure in slurry

- CEC at start and end of experiment - Water holding capacity - Soil particle size distribution - Extractable nutrients of soils at end of experiment (triplicates!

o K, Na, Ca, Mg (cations) )

o Phosphate, Sulfate, Nitrate (anions) - Repeat experiment with another complete growth cycle to assess pro-

longed effect of biochar on soil quality and crop growth (phase 2) Farmer observations

- crop development - crop growth: dryweight yield per m2 - general ecosystem observations


REVISED BIOCHAR EXPERIMENTS TO BE CONDUCTED BY CFU -MAIZE

Maize Biochar has half the bulk density of Charcoal. Biochar at high rate reduced by 50% as it is impossible to apply 20 x 100ml jars in 1 CF basin.

A

2m B

2m C

2m D

2m E

Charcoal Dust

Maize Stover

Control

Charcoal Dust

Maize Stover

Biochar

Biochar

Biochar

Biochar

10m 14 basins

x

11 rows

154 basins

10m

50 gms BC/Basin

50 gms BC/Basin

NIL

250 gms BC/Basin

250 gms BC/Basin

7.7kgs

7.7kgs

38.5kgs

38.5kgs

793 kgs/ha

793 kgs/ha

3965 kgs/h

a

3965 kgs/ha

1 jar

2 jars

5 jars

10 jars

2 cups D/basin

2 cups D/basin

2 cups D/basin

2 cups D/basin

2 cups D/basin


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19Row

Basin 1

Basin 55

CharC low Maize C low CharC high Maize C lowControl

Basin 10

Basin 40

C C C C

Corn stover biochar

50 g per basinCorn stoverbiochar

250 g per basin

Corn stover biochar

50 g per basin

Corn stover biochar

50 g per basin

Control plot

Charcoal dust

250 g per basin

Charcoal dust

50 g per basin

10 m

10 m

1 m


Field plot experiments Experimental Station UNZA - ONLY conservation tillage - Only planting basins - Basins: 16 000 basins per ha, this means 25 basins per 4 x 4 m plot,

according to CF - No rip lines (to be done in phase 2) - Basal “D” fertilizer in modest amounts: 280 kg/ha, i.e. 16 g per basin - Plot size 16 m2 (4 x 4 m) -

Wheat Maize Charcoal

Strip 3 Strip 2 Strip 1

600 CONTROL 0 150 300 1200 CONTROL CONTROL CONTROL

150 CFU CONTROL 600 0 300 CFU CFU CFU

300 0 600 CFU 150 CONTROL 0 0 0

CONTROL 150 300 0 600 CFU 30 30 30

600 300 150 CONTROL CFU 0 60 60 60

150 CONTROL CFU 300 0 600 150 150 150

300 300 300

600 450 600

900 600 900

1200

1200 900

1200

Treatment Biochar Biochar Fert Lime

Label mt/ha gram/basin cups/basin cups/basin

Corn 1 0,0 0 0 0 Absolute Control

Biochar

2 0,0 0 2 2 CFU Recommendation

3 0,0 0 2 0 Biochar Control

Wheat 4 0,5 30 2 0

Biochar

5 1,0 60 2 0

CFU

6 2,5 150 2 0

Charcoal 7 5,0 300 2 0

8 10,0 600 2 0

CFU

9 15,0 900 2 0

No lime

Absolute

10 20,0 1200 2 0

Control


Follow-up monitoring - Measure pH of soils at beginning and end of experiment

o pH in water, 1:5 v/v, shake 1 hour, measure in slurry o pH in KCl 1 mol/L, 1:5 v/v, shake 1 hour, measure in slurry

- CEC at end of experiment - Soil particle size distribution - Water holding capacity - Extractable nutrients of soils at end of experiment

o K, Na, Ca, Mg (cations) o Phosphate, Sulfate, Nitrate (anions)

- Repeat experiment with another complete growth cycle to assess prolong-ed effect of biochar on soil quality and crop growth

- N2O emissions, CH4 emissions: if possible measured with UMB equipment during field visit in May, samples analyzed in Norway

Field observations

- crop development - crop growth: dryweight yield per m2 - Analyze 15 plants per plots: plans size with standard deviation - general ecosystem observations


Field plot experimental station Kasisi Key: first number in bracket is the amount of biochar in tons per hectare, and the second number represents the amount of compost in tons per hectare.

6 5 4 3 2 1

control wheat straw charcoal dust manure only charcoal dust g/nut

(0,0) (0.8,4) (8,4) (0,12) (4,8) (0.8, 8)

12 11 10 9 8 7 wheat straw charcoal dust g/nut wheat straw charcoal dust wheat straw

(4,8) (0.8,4) (4,8) (4,4) (0.8,8) (4,0)

18 17 16 15 14 13 charcoal dust charcoal dust g/nut charcoal dust wheat straw charcoal dust

(4,0) (0.8,12) (4,4) (8,8) (0.8,12) (0.8,0)

22 21

20 19

wheat straw wheat straw SMALL ANTHILL charcoal dust charcoal dust

(4,12) (0.8,0)

(4,12) (4,4)

28 27 26 25 24 23

charcoal manure only wheat straw charcoal dust control 2 manure only

(8,12) (0,8) (0.8,8) (8,0) (0,0) (0,4)

31

manure only (0,2)


Table Fertilizer amendment and planting date at the various sites Soil Basal D Top dressing Planting date

Mkushi Biochar 1 Yes (2x) Nov 26

Kaoma Biochar 1 No Nov 19

CFU 1 Yes (1x) Nov 19

Shimabala Biochar 1 Yes (2x) Nov 16


UNZA Biochar 1 Yes (2x) Dec 18

CFU 1 Yes (2x) Dec 18

NRDC Biochar 2 No Nov 19


Kasisi Biochar Manure ”Tea” Nov 29

Document No.: 20100920-00-2-R Date: 2011-02-28 Page: 1 Appendix: B

Appendix B Soil and Biochar characteristics

Sam

ple

pH_H

2OpH

_CaC

l 2

pH_K

ClH

+N

a+M

g2+

Ca2+

K+M

n2+

CEC

Acid

sa

tura

tion

Base

sa

tura

tion

Org

. C

%To

t. C

%To

t. H

%

Tot.

N

%C/

N

ratio

UN

ZA fa

rm4.

84.

13.

87.

50.

00.

31.

10.

20.

29.

182

.517

.50.

80.

80.

20.

048

NRD

C8.

07.

06.

90.

40.

12.

812

.70.

70.

116

.62.

597

.50.

90.

90.

50.

117

SHIM

ABAL

A 6.

55.

65.

25.

40.

010

.012

.11.

00.

228

.519

.081

.01.

81.

80.

90.

119

MKU

SHI

6.5

5.2

4.9

1.9

0.0

0.2

0.8

0.1

0.1

3.1

61.1

38.9

0.4

0.4

0.1

0.0

>100

GAR

T CH

ISAM

BA6.

74.

74.

28.

80.

04.

46.

80.

30.

020

.243

.356

.71.

61.

60.

90.

128

KAO

MA

3- p

ot tr

ial

6.9

4.5

4.4

3.1

0.0

0.1

0.5

0.1

0.0

3.8

82.5

17.5

0.2

0.3

0.0

0.0

>100

KAO

MA

4 Av

erag

e6.

55.

35.

42.

40.

00.

31.

50.

10.

04.

355

.045

.00.

60.

60.

10.

033

4

KAO

MA

4 St

d de

v0.

00.

00.

00.

10.

00.

00.

00.

00.

00.

198

.21.

80.

00.

10.

00.

011

CHAR

COAL

DU

ST

from

CFU

8.3

7.9

7.9

2.2

11.1

60.3

12.4

0.1

86.0

0.0

100.

064

.564

.52.

00.

883

CORN

STO

VER

BIO

CHAR

8.0

7.1

7.6

4.8

0.0

0.6

1.0

33.4

0.0

39.9

12.0

88.0

74.3

74.5

3.2

0.9

87

Document No.: 20100920-00-2-R Date: 2011-02-28 Page: 1 Appendix: C

Appendix C The socio-economic dimensions of biochar Resource management is as much about social processes as physical ones Introduction Environment problems in countries like Zambia are daily development problems. Resource degradation, in countries where so many depend on their local resources for survival, is not just an environmental problem with global implication. It is also a social problem which hits at the local level and affects the poor and vulnerable first and hardest. Therefore, for biochar evaluation to be relevant to real problems, it must address the problems as the villagers perceive them. Socio-economic challenges and chances specific to Zambia Phase 1 : Tentative exploration socio-economic dimensions, formulating

investigations for phase 2 Phase 2 : Actual field research of the social economic dimension, to be

carried out mainly by 2-3 master students in social science at UMB, to be stationed in the communities.

Research on the socio-economic dimensions should include questions concerning: Phase 1 : Tentative exploration socio-economic dimensions

– Socio economic analysis, e.g o Poverty o Means of income o Social organisation

– Allocation of resources

o Labour: w.r.t. biochar the promising feedstock of corn stover pro-bably involves relatively little extra labour. The stovers are assem-bled anyway during harvest, and they serve no purpose and are considered worthless by many farmers.

o Biomass: especially corn stover and charcoal dust are considered excellent feedstocks, since they are essentially a waste that is turn-ed into a resource when turned into biochar.

o Finance: formulate questions and hypotheses on how charcoal making is best organized and financed.

o Time o Competition of resources (e.g. competition charcoal for cooking

and charcoal for soil improvement): charcoal dust is unsuitable for cooking, so a promising source of biochar.

o Biochar

– Market mechanisms o markets charcoal: commercial wood charcoal currently costs

around USD 120 per ton, which would be too much for use as soil fertilizer. Optimal concepts need to be identified to reduce the price of biochar.

Document No.: 20100920-00-2-R Date: 2011-02-28 Page: 2 Appendix: C

o markets biochar

– Dissemination of CF and biochar o Failure factors: an analysis of success and failure factors wrt

practises of dissemination. To be more specific: how can we explain that an obvious proven method like CF is not taken over by many farmers while they can see the success of it at the neigh-bouring fields. One explanation could be the seemingly difficult nature of a novel technique, but this needs to be further explored.

o Analysis of successful ways of dissemination: CFU managed a textbook dissemination of the CF/CA concept. It is expected that biochar can be disseminated in Zambia and probably neighbouring countries via the CFU infrastructure.

– to be carried out by the University of Life Science, Ås, Norway Phase 2: Actual field research of the social economic dimension.

– making use of field research Master students, in collaboration with NorAgric (Jens Aune, Lars Olav Eik)

– Further details mentioned in phase 2 working plan (below).

Kontroll- og referanseside/ Review and reference page

Skj.nr. 043

Dokumentinformasjon/Document information Dokumenttittel/Document title Biochar in conservation farming in Zambia. Improving crop yield and storing carbon. Progress report February 2011

Dokument nr/Document No. 20100920-00-2-R

Dokumenttype/Type of document Rapport/Report Teknisk notat/Technical Note

Distribusjon/Distribution Fri/Unlimited Begrenset/Limited Ingen/None

Dato/Date 28 February 2011 Rev.nr./Rev.No.

Oppdragsgiver/Client Conservation Farming Unit (CFU) Emneord/Keywords

Stedfesting/Geographical information Land, fylke/Country, County Zambia

Havområde/Offshore area Kommune/Municipality

Feltnavn/Field name Sted/Location

Sted/Location Kartblad/Map

Felt, blokknr./Field, Block No. UTM-koordinater/UTM-coordinates

Dokumentkontroll/Document control Kvalitetssikring i henhold til/Quality assurance according to NS-EN ISO9001

Rev./ Rev. Revisjonsgrunnlag/Reason for revision

Egen-kontroll/

Self review av/by:

Sidemanns- kontroll/

Colleague review av/by:

Uavhengig kontroll/

Independent review av/by:

Tverrfaglig kontroll/

Inter-disciplinary

review av/by:

0 Original document GCo GBR

Dokument godkjent for utsendelse/ Document approved for release

Dato/Date

Sign. Prosjektleder/Project Manager Gerard Cornelissen

Improving crop yield and storing carbon

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