Nutrient management in the food chain of China

Fusuo Zhang Lin Ma

China Agricultural University

Feb. 25 ,2014, Beijing, China-UK Workshop on Nutrient Management and Water Resource Protection

Outline

Problems and challenges

Nutrient flow in the food chain

Strategies of nutrient management

Food security issue of China is always a global concern

Lester Brown

It took several hundred years to realize the dream of food sufficiency in China

(Data from the Statistic Bureau of China; Demand was estimated by using average grain demand of 400 kg/capita/yr)

Year

Gra

in d

eman

d a

nd

pro

du

ctio

n (

M t

on

)

Po

pu

lati

on

(M

)

580 600

620 640

214

305

407

505 431

531

0

200

400

600

800

1000

1200

1400

1600

0

100

200

300

400

500

600

700

1961 1969 1977 1985 1993 2001 2009 2017 2025

Gra

in (m

illi

on to

n)

Year

Grain demand

Grain production

Population

Grain yield in China has been merely secured by much higher input of resources including fertilizer, irrigation, plastic film and pesticides. (National bureau of statistics of China, 1961-2010; Zhang et al., 2011)

Grain production and resources input

50

70

90

110

300

200

100

0300 50 100 150 200 250 300 350

Rel

ativ

e yi

eld

(%)

GH

GI(

kg

CO

2 eq

Mg-1

)

N rate (kg N ha-1)

Africa

Developed countries

China

Environment impact by N loss

Yield response curve130

500

Fertilizer Overuse and MisuseFertilizer Overuse and MisuseFertilizer Overuse and MisuseFertilizer Overuse and Misuse

Air pollution

Bulk N deposition has increased from 13 kg N ha-1 in 1980s to 21 kg N ha-1 in 2000s, among which agricultural Nr sources occupied ~2/3.

NATURE (Liu et al., 2013)

Soil pH was decreased by 0.5 units due to overuse of N fertilizers.

-0.5

Soil acidification

China’s eutrophied lake area reached 8700 km2 (2007) over the last 4 decades.

(China State Oceanic Administration, 2009 ）

(Jin, 2009)

Eutrophication

(Science 2009, 1014-1015)

Outline

Food security and fertilizer application

Nutrient flow in the food chain

Strategies of nutrient management

Nutrient management in the food chainMa Lin’s thesis

(Zhang et al., 2012)

0

10

20

30

40

50

1961 1969 1977 1985 1993 2001 2009

N（

Mil

lion

ton）

Crop uptake

N fertilizer input

Total N input

1.7 fold

2.4 fold

N fertilizer input is 1.7 fold of crop uptakeTotal N input is 2.4 fold of crop uptake

（张卫峰等， 2013 ）

N input and crop uptake in Chinese crop land in 1961-2009

Calculated by using NUFE model (Ma et al.,2010) and FAO data base www.fao.org

“Better Life” in China- rapid growth of animal food, fruits and vegetables

91%

9%

Plant protein Animal protein

81%

19%

65%

35%

1961 1989 2010

The percentage of plant protein and animal protein

(Ma et al., 2013, Data source: FAO)

Booming development of animal husbandry in China in the past 30 years

Pig

, m

eat

cow

, sh

eep

and

goat

, m

ilk c

ow n

umbe

rs

Pou

ltry

num

bers

Year (the Statistic Bureau of China)

0

150000

300000

450000

600000

750000

900000

1050000

1200000

0

1000

2000

3000

4000

5000

6000

7000

800019

78

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

Pig（100 Thousand）Meat cow（10 Thousand）Sheep and goat（100 Thousand）Milk cow（10 thousand）Poultry（10 Thousand）

Des-coupling of crop and animal production

( Wang et al., 2010)

Atmosphere N2, NH3, N2O

Exports and losses

Environmental

Sustainability

Surface watersGroundwater

Erosion and runoff

Leaching

N

Crop production（ soil accumulation）

P

Animal production

Food security

imports

Resource

use efficiency

Food processing

Humanconsumption

(Ma et al., 2010)

Quantify nutrient flow in the food chain by a new modelNUFER (NUtrient flows in Food chains, Environment and Resources use)

High N fluxes in the food chain of China

3.1

21

House-Hold2.8

AnimalProduction

7.4

CropProduction

17.3

House-Hold3.5

AnimalProduction

11.0

CropProduction

28.9

House-Hold4.1

AnimalProduction

18.1

CropProduction

40.5

House-Hold5.0

AnimalProduction

21.0

CropProduction

46.1

1980 1990 2000 2010

+ 0.7

+ 11.5

+ 3.6

+ 0.6

+ 11.6

+ 8.1

+ 0.9

+ 5.6

+ 3.1

2.0

2.30.5

3.8

2.80.8

5.5

3.30.9

7.5

3.51.5

0.14

1.1 1.3

0.17 0.18

1.3 1.1

0.15

Unit: Million tonne (Mt)

Air14.3

Air22.4

Air24.1

Air8.6 + 5.7 + 8.1 +1.7

Water6.1

Water11.7

Water15.2

Water3.3 + 2.8 + 5.6 +3.5

(Hou et al., 2013)

Total N losses to environment from 1980 to 2010

～ 4 times

To atmosphere To water bodies

Contribution of N losses from different systems

3.1

21

House-Hold0.37

AnimalProduction

1.1

CropProduction

2.3

House-Hold0.46

AnimalProduction

2.1

CropProduction

4.4

House-Hold0.54

AnimalProduction

4.0

CropProduction

6.9

House-Hold0.62

AnimalProduction

4.5

CropProduction

8.3

1980 1990 2000 2010

+ 0.09

+ 2.1

+ 1.0

+ 0.08

+ 2.5

+ 1.9

+ 0.08

+ 1.4

+ 0.5

0.4

0.330.04

0.9

0.400.06

1.2

0.460.08

1.6

0.470.13

0.14

0.020.02 0.02 0.02

0.17 0.18 0.15

Unit: Million tonne (Mt)

Water0.73

Water1.98

Water2.83

Water0.36 + 0.37 +1.25 +0.85

High P fluxes in the food chain of China

Total P losses to environment from 1980 to 2010

～ 8 times

To water bodies

Contribution of P losses from different systems

N and P losses of China in 2005 and EU in 2000(kg N ha-1)

China in 2005

EU in 2000

NH3 118 17

N2O 4 2

N2 68 44

NOx 15 2

N losses via leaching, runoff and erosion 137 16

P losses via leaching, runoff and erosion 22 *

(Velthof et al., 2009; Ma et al., 2010)* No data

NUE and PUE in ChinaChina in

1980China in

2005Global

NUEc 32 26 ~50NUEa 8 16 20-34NUEf 15 9 14

PUEc 63 36 38PUEa 13 17 ~21PUEf 24 7 19

Note: NUE= (O Main product / I Total)*100(Smil, 2002; Howarth et al., 2003; Van der Hoek, 1998; Galloway, 2002; Liu et al., 2009; Schroder et al., 2010)

Three-Step Strategy to increase crop yield and nutrient use efficiency at the same time

- For ensure both food security and environment quality simultaneouslyC

rop

pro

du

ctiv

ity

Water and nutrient input

At present（ saving fertilizer）

The 2nd stepYield increase10%-20% （ High-yield）

The 3rd stepYield increase 30%-50%

Increase soil fertility

The 1st stepSaving N by 30%

without yield penalty

Cut down N fertilizer by 30-50% reduces N loss into environment greatly without diminishing crop yield!

2009

(First step)

Mean maize grain yield and modeled yield potential, N balance (fertilizer inputs-harvest outputs) and N applied per unit of grain produced for different management systems: integrated crop and soil system management approach (ISSM, n=66), farmers’ practice (FP, n=4548), and high-input, high-yielding studies (HY, n=43).

(Chen et al., PNAS, 2011)

----Increase yield and NUE by 30-50%

(Third step)

Three-Step Strategy to increase animal productivity and decrease nutrient losses at the same time

1

2

3

i No discharge of manure

-20%

NU

E

Lo

ss

es

ii Further treatment of manure, low emission application

-20%

iii Low emission animal house and manure storage

-5%

2. High quality feed

+13%

1. Genetic improvement

Productivity improvement

+18%

3. Balance feedHerd management

+15%

Feed N input

Times

Present level

2 Three-Step Strategy in crop production

1 Optimize diets

Environment

Fertilizer industry

Decrease pressure

Decrease demand

Decrease losses

3 Recycle wastes

2 Three-Step Strategy in animal production

Nutrient management in food chain

N and P cost in the food chain in ChinaN

and

P c

ost i

n th

e fo

od c

hain

(kg

/kg)

1980 2005 2030

Changes in diet

Year(Ma et al., 2014)

Thanksfor your attention !

AcknowledgmentsNSFC, MoA , MoE, MOST