Liqiang Cui lqcui@ycit - International Biochar Initiative Liqiang... · in a contaminated paddy soil: a two-year field experiment Liqiang Cui ... have expanded for the last decade

School of Environmental Science & EngineeringSchool of Environmental Science & EngineeringYanchengYanchengInstitute of TechnologyInstitute of Technology

Biochar amendment reduces crops uptake Cd in a contaminated paddy soil:

a two-year field experiment

Liqiang Cui

[email protected]

Biochar and New Green Agriculture in China

Contents

Background1

Main research3

Approach2

Conclusions4

Yancheng Institute of Technology 3

� A large area of China’s croplands has been reported to

have Cd contamination in a recent soil pollution survey

(Zhang et al. 2000; Teng et al. 2010), which raised

particular concerns for subsistence-diet rice farmers of

South China (Zhang et al., 2009a).

� Rice paddies subject to Cd contamination appear to

have expanded for the last decade due to irrigation with

waste water , factory waste, chemical fertilization and so

on in South China (Du et al. 2009).

1.1 Soil contamination status of heavy metal


� Rice and wheat have been of particular concern as a Cd

health risk through food exposure by subsistence diet

consumers (Chaney et al. 2005)

� Therefore, reducing Cd plant uptake would be an

urgent demand for safe rice production in China.

1.2 Diet exposure risk of heavy metal


1.3 New technologies in controlling heavy metal contamination

� The biochar was a kind of charcoal material and produced by

pyrolysis biomass at 350 to 550°°°°C using a vertical kiln;

� If biochar was used as agriculture material, it could reduce GHGs

emission in rice agriculture, particularly in the acidic Cd-

contaminated fields (Pan et al., 2010；；；；Zhang et al., 2011,

Lehmann et al., 2009 ) .


� The biochar is porous, alkaline or slightly alkaline, large surface area and

rich in highly recalcitrant organic matter, chelated organic functional

groups and have the ability of adsorption organic contaminants and

inorganic contaminants (Hartley et al., 2009)。。。。

� The lab experiment proved that biochar could reduce exchange Cd and

Cu and increase soil pH after biochar amendment (Beesley et al., 2011;

Namgay et al., 2010)。。。。

1.3 New technologies in controlling heavy metal contamination

Yancheng Institute of Technology

2 Approach

Mechanism of biochar reduce crops uptake soil Cd

Soil CdCrops uptake Cd

Crops + contaminated soil

Bichar

10

Yieldtissues Cd concentration

Relation of grain and soil exchangeable Cd

Change of soil exchangeable Cd

Affect of soil pH


3 Main Research

2

1Effects of biochar on rice uptake Cd and soil physical and chemical properties

Effects of biochar on wheat Cd uptake and on soil physical and chemical properties


3.1 Effects of biochar on rice Cd uptake


3.1 Effects of biochar on rice Cd uptake

� A field experiment for alleviation of Cd uptake in rice grain using biochar as

soil amendment was initiated in 2009. The experimental site was located in

Yifeng village (31º24.434'N, 119º41.605'E), Yixing Municipality, Jiangsu,

China and was conducted in a rice farm that had been contaminated with

heavy metals from a metallurgy plant in that vicinity since the 1970s. The

status of multi-metal contaminated and high grain Cd level of the rice grown

in the field was already reported by Liu et al. (2006). The rice farm had been

cultivated traditionally under rotation of rice and winter wheat.

3.1.1 Materials and Methods


Table 1. Basic properties of paddy soil and biochar

0.0321.7011.514.435.90467.210.35Biochar

21.8418.0511.40.823.1920.716.07Topsoil

Total Cd (mg kg-1)

CEC (cmol kg-1)

Total K(g kg-1)

Total P(g kg-1)

Total N (g kg-1)

SOC (g kg-1)pH

(H2O)

3.1.1 Materials and Methods


3.1.2 Experimental design

40C34

20C23

10C12 Serious contaminated

soil

CK

Conventional rice and wheat

C01

SoilBiochar application

amount (t ha-1)Crops cultivarTreatmentNo.

Every treatment is three plots with an area of 4 m ×××× 5 m each were laid out in a randomized complete block design.


3.1.3 Results

3.1.3.1 Effects of biochar on the yield of rice

3.1.3.2 Effects of biochar on rice Cd uptake

3.1.3.3 Effects of biochar on soil pH and the concentration of

exchangeable Cd


3.1.3.1 Effects of biochar on yield of rice

The relation of yield of rice with biochar application in 2009-2010

a aa a

a aa a

0

1

2

3

4

5

6

7

8

9

C0 C1 C2 C3Biochar amendment

Yie

ld o

f ri

ce (

t ha-1

)

2009 2010


3.1.3.2 Effect of biochar on brow rice Cd concentration

Brow rice Cd concentration 2009-2010

bab

ab

a

babab

a

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

C0 C1 C2 C3

Biochar amendment

Bro

wn

rice

Cd

(mg

kg-1

)

2009 2010


y=173.42*e(-0.071*x) +123.597

R2=0.997

123

143

163

183

203

223

243

263

283

303

323

0 10 20 30 40

Biochar application (t ha-1)

Ric

e to

tal C

d up

take

(g

ha-1

)

3.1.3.3 Model of total Cd rice uptake and biochar application

Model of total Cd uptake and biochar application in 2009

58.4%


y=74.101*e(-0.059*x) +166.236

R2=0.969

160

170

180

190

200

210

220

230

240

250

0 10 20 30 40


Ric

e to

tal C

d up

take

(g

ha-1

)

3.1.3.3 Model of total Cd rice uptake and biochar application

30.8%



3.1.3.4 Cd concentration of rice tissues in Ripening

The Cd concentration of rice tissues in Ripening Stage in 2009(mg kg-1)

39.49±±±±2.63 b8.56±±±±2.871 b1.12±±±±0.67 cC3

48.05±±±±11.90 b10.29±±±±1.51 b1.68±±±±0.63 bcC2

54.29±±±±7.44 b15.17±±±±1.00 b2.61±±±±0.60 bC1

71.53±±±±9.50 a25.25±±±±8.21 a4.18±±±±0.44 aC0

RootStemRice husk

biochar treatments

Ripening


3.1.3.4 Cd concentration of rice tissues in Ripening

52.03±±±±0.85b11.83±±±±0.36b2.03±±±±0.07bC3

48.89±±±±8.28b14.20±±±±3.20ab1.64±±±±0.64bC2

48.63±±±±1.69b15.60±±±±0.91ab1.54±±±±0.68bC1

66.39±±±±4.83a18.13±±±±0.35a2.72±±±±0.03aC0

RootStemRice husk

Ripeningbiochar

treatments

The Cd concentration of rice tissues in Ripening Stage in 2010(mg kg-1)


Change of exchangeable Cd concentration with biochar amendment in rice season

3.1.3.9 Exchangeable Cd with biochar amendment

7.73±±±±0.01c11.78±±±±2.17a0.91±±±±0.05b0.82±±±±0.09cC3

11.78±±±±0.35b13.98±±±±3.65a0.86±±±±0.20b1.05±±±±0.31bC2

11.20±±±±1.46b13.64±±±±2.45a1.44±±±±0.15a1.17±±±±0.24bC1

15.02±±±±2.03a14.00±±±±1.92a1.52±±±±0.21a1.73±±±±0.22aC0

2010200920102009

DTPA-CdCaCl2-CdTreatments


3.1.3.7 Changes of soil pH in rice season with biochar

Changes of soil pH with biochar amendment in 2009-2010

c

b

aba

c

b

aa

5.8

5.9

6.0

6.1

6.2

6.3

6.4

6.5

C0 C1 C2 C3

Biochar amendment

pH2009 2010


Correlation of CaCl2-Cd with pH in 2009 Correlation of DTPA-Cd with pH in 2009

3.1.3.8 Correlation of exchangeable Cd uptake with soil pH

y = -2.7522x + 18.369

R2 = 0.974

P=0.0131

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

6 6.1 6.2 6.3 6.4 6.5Soil pH

CaC

l 2 C

d (m

g kg

-1)

Cd-pH

y = -5.8573x + 49.908

R2 = 0.5822P>0.05

10

11

12

13

14

15

6 6.1 6.2 6.3 6.4 6.5

Soil pH

DT

PA C

d (m

g kg

-1)

Cd-pH


Correlation of CaCl2-Cd with pH in 2010 Correlation of DTPA-Cd with pH in 2010

3.1.3.8 Correlation of exchangeable Cd uptake with soil pH

y = -1.708x + 11.657

R2 = 0.7534

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

5.8 5.9 6 6.1 6.2 6.3Soil pH

CaC

l 2 -

Cd(

mg

kg -1

)

Cd-pH

y = -14.763x + 101.97

R2 = 0.7451

6

7

8

9

10

11

12

13

14

15

16

5.8 5.9 6 6.1 6.2 6.3Soil pH

DT

PA -

Cd

(mg

kg -1

)

Cd-pH


� Rice grain yield was not affected by the application of

biochar in two years;

� The Cd concentration of different rice tissues were

significantly reduced with biochar application.

� Soil pH was significantly increased, and soil exchangeable

Cd was significantly decreased after biochar application at

least two years.

3.1.4 Summary


3.2 Effects of biochar on wheat Cd uptake


3.2.1 Effects of biochar on yield of wheat

Change of the wheat yield during with biochar amendment 2010-2011

a

a

aa

a

a a a

0

1

2

3

4

5

6

7

C0 C1 C2 C3

Biochar amendment

Whe

at y

ield

(t

ha-1

)

2010 2011


3.2.2 Effects of biochar on grain Cd of wheat

Change of the grain Cd of wheat concentration with biochar amendment during 2010-2011

b

b

aba

aa a

b

0

2

4

6

8

10

12

14

C0 C1 C2 C3

Biochar amendment

Whe

at g

rain

Cd

(mg

kg-1

) 2010 2011


y=68.317*e(-0.049*x) +88.841

R2=0.999

88

98

108

118

128

138

148

158

168

0 10 20 30 40


Tot

al C

d up

take

(g

ha-1

)

3.2.3 Model of total Cd wheat uptake and biochar application

43.5%



y=165.091*e(-0.02*x) +148.346

R2=0.976

148

168

188

208

228

248

268

288

308

328

0 10 20 30 40Biochar amendment (t ha-1)

Tot

al C

d up

take

(g

ha-1

)

3.2.3 Model of total Cd wheat uptake and biochar application


53%


3.2.4 Cd concentration of wheat tissues in Ripening

43.62±±±±9.08 b15.03±±±±3.19 c55.94±±±±5.31 b11.45±±±±3.99 bC3

43.36±±±±4.35 b18.89±±±±1.11 b64.25±±±±8.06 ab13.89±±±±2.29 bC2

59.51±±±±4.20 a20.49±±±±1.42 b70.05±±±±1.03 a16.12±±±±1.50 abC1

56.77±±±±1.69 a25.53±±±±1.33 a73.40±±±±1.43 a22.68±±±±3.04 aC0

RootStemRootStem

20112010Biochar

treatments

The Cd concentration of wheat tissues in Ripening Stage (mg kg-1)


Change in Cd mobility in soil with biochar amendment in wheat season

3.2.3 Effects of biochar on soil exchangeable Cd

12.50±±±±0.07 b 13.13±±±±0.43 b2.77±±±±0.24 a 3.60±±±±0.71 cC3

14.90±±±±1.59 ab13.00±±±±0.55 b2.74±±±±0.69 a 4.60±±±±0.30 bC2

14.32±±±±1.38 ab14.29±±±±0.42 a3.50±±±±0.53 a 5.40±±±±0.36 abC1

16.98±±±±2.07 a 14.77±±±±0.82 a3.56±±±±0.48 a 6.01±±±±0.34 aC0

2011201020112010

DTPA-CdCaCl2-CdBiochar

treatment


3.2.4 Effects of biochar on soil pH

Change of soil pH with biochar application in 2010-2011

a

ab

ab

bb

ab

aa

5.2

5.3

5.4

5.5

5.6

5.7

5.8

5.9

6.0

C0 C1 C2 C3

Biochar amendment

Soil

pH

2010 2011


Correlation of CaCl2-Cd with pH in wheat season in2010

Correlation of DTPA-Cd with pH in wheat season in2010

3.2.6 Correlation of soil exchangeable Cd uptake with soil pH

y = -9.8565x + 60.498

R2 = 0.9718

P=0.0141

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

5.5 5.55 5.6 5.65 5.7 5.75 5.8

pH

CaC

l 2 C

d (m

g kg

-1)

Cd-pH

y = -7.7521x + 57.523

R2 = 0.863

P=0.0713

12.5

13.0

13.5

14.0

14.5

15.0

5.5 5.55 5.6 5.65 5.7 5.75 5.8

pH

DT

PA-C

d (m

g kg

-1)

Cd-pH


3.2.6 Correlation of soil exchangeable Cd uptake with soil pH

Correlation of CaCl2-Cd with pH in wheat season in2011

Correlation of DTPA-Cd with pH in wheat season in2011

y = -3.358x + 22.402

R2 = 0.851P=0.08

2.5

2.7

2.9

3.1

3.3

3.5

3.7

5.5 5.6 5.7 5.8 5.9Soil pH

CaC

l 2 C

d (m

g kg

-1)

CaCl2-Cd

y = -13.117x + 89.91

R2 = 0.7583P=0.1290

12

13

14

15

16

17

18

5.5 5.6 5.7 5.8 5.9

Soil pHD

TP

A C

d (m

g kg

-1)

DTPA-Cd


� The yield of wheat was not affected with biochar application

in two years;

� The Cd concentration of different wheat tissues were

significantly reduced with biochar application.

� Soil pH was significantly increased, and soil exchangeable

Cd was significantly decreased after biochar application at

least two years.

3.2.7 Summary


4 conclusions

� The yield of the rice and wheat is stable with biochar application

in two years.

� The rice and wheat tissues Cd concentration were significantly

decreased nearly by 50%.

� Soil pH was significantly increased amended biochar.

� Soil exchangeable Cd concentration was decreased and 3.5-5.4

times higher in wheat season than rice season.

� There was a significant negative correlation between the soil

exchangeable Cd and soil pH.


4 conclusions

� The results prove that the biochar is a very environment

safe soil conditioner for inhibition the Cd crops uptake at

least two years.

� From the results, it is a safe soil conditioner to reduce the

Cd crop uptake by stabilizing, strongly adsorbing the

exchangeable Cd and improve the soil pH.


Biochar application Seedling stage Jointing stage

Ripening stage Rice harvest Wheat Ripening stage

Documents

Liqiang Cui lqcui@ycit - International Biochar Initiative Liqiang... · in a contaminated paddy soil: a two-year field experiment Liqiang Cui ... have expanded for the last decade