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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