Field Crops Research 150 (2013) 115–125
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Field Crops Research
journal homepage: www.elsevier.com/locate/fcr
Nutrient requirements for maize in China based on QUEFTS analysis
Xinpeng Xu a , Ping He a,b,∗ , Mirasol F. Pampolino c , Limin Chuan a , Adrian M. Johnston d ,
Shaojun Qiu a , Shicheng Zhao a , Wei Zhou a
a
Ministry of Agriculture Key Laboratory of Plant Nutrition and Fertilizer, Institute of Agricultural Resources and Regional Planning, Chinese Academy of
Agricultural Sciences, Beijing 100081, PR China
b
International Plant Nutrition Institute(IPNI), China Program, Beijing 100081, PR China
c
International Plant Nutrition Institute (IPNI), Southeast Asia Program, PO Box 500 GPO, Penang 10670, Malaysia
d
International Plant Nutrition Institute (IPNI), 102-411 Downey Road, Saskatoon, SK S7N4L8, Canada
a r t i c l e
i n f o
Article history:
Received 17 January 2013
Received in revised form 7 June 2013
Accepted 7 June 2013
Keywords:
QUEFTS model
Maize
Crop nutrient requirements
Nitrogen
Phosphorus
Potassium
a b s t r a c t
Estimating balanced nutrient requirements for maize (Zea mays L.) in China is essential to manage nutrient
application more effectively for increasing crop yield and reducing the risk of negative environmental
impact. On-farm datasets were collected from 2001 to 2010 from China’s maize-producing regions to
investigate the relationship between grain yield and nutrient accumulation in the above-ground plant dry
matter of commercial hybrid maize. The QUEFTS (quantitative evaluation of the fertility of tropical soils)
model was used to estimate the balanced nitrogen (N), phosphorus (P) and potassium (K) requirements
in China’s maize growing regions. The analysis indicated that there were great differences in the grain
yield and nutrient uptake between spring maize and summer maize: minimum and maximum internal
nutrient efficiencies (IE, kg grain per kg nutrient in the above-ground plant dry matter) were 36 and
89 kg grain per kg N, 135 and 558 kg grain per kg P, 30 and 132 kg grain per kg K for spring maize, 31 and
70 kg grain per kg N, 108 and 435 kg grain per kg P, 32 and 110 kg grain per kg K for summer maize. The
model predicted a linear increase in grain yield if nutrients were taken up in balance until yield reached
about 60–70% of the potential yield. To produce 1000 kg of spring maize grain yield, 16.9 kg N, 3.5 kg P
and 15.3 kg K were required by above-ground dry matter of maize, and the corresponding IE were 59 kg
grain per kg N, 287 kg grain per kg P and 65 kg grain per kg K. For summer maize, 20.3 kg N, 4.4 kg P,
15.9 kg K were needed to produce 1000 kg maize grain in the linear part, and the corresponding IE were
49 kg grain per kg N, 227 kg grain per kg P and 63 kg grain per kg K. Optimal N:P:K ratios in plant biomass
were 4.83:1:4.37 for spring maize and 4.61:1:3.61 for summer maize, respectively. QUEFTS analysis also
indicated that a balanced N, P and K removal by grain to produce 1000 kg grain, when the target yield
reached about 80% of the potential yield, the grain absorption of N, P and K accounted for 54%, 69%
and 23% of above-ground N, P and K uptake for spring maize, and 67%, 85% and 23% for summer maize,
respectively. Two-year field validation experiments indicated that the QUEFTS model could be used for
estimating balanced nutrient requirements and contributed to developing fertilizer recommendations.
© 2013 Elsevier B.V. All rights reserved.
1. Introduction
Maize (Zea mays L.) as one of the most important crops used
as food, forage, and the raw material of industry, which playing an
important role in food security. Ranking as the most widely planted
crop in China, the planting area of maize is about 29.5% of the food
Abbreviations: FP, farmers’ practice; HI, harvest index; IE, internal efficiency;
K, potassium; N, nitrogen; OPT, optimal nutrient treatment; P, phosphorus; RIE,
reciprocal internal efficiency; SSNM, site-specific nutrient management.
∗ Corresponding author at: Ministry of Agriculture Key Laboratory of Plant Nutrition and Fertilizer, Institute of Agricultural Resources and Regional Planning, Chinese
Academy of Agricultural Sciences, Beijing 100081, PR China. Tel.: +86 10 82105638;
fax: +86 10 82106206.
E-mail addresses: [email protected], [email protected] (P. He).
0378-4290/$ – see front matter © 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.fcr.2013.06.006
crops of the country with 32.5 million hectares in 2010 according
to China Agriculture Yearbook (2011). Chemical fertilizer plays an
important role in increasing food production and maintaining food
security in China. However, excessive and unbalanced fertilizer use
has become a common farmer practice, with overuse of nitrogen
(N) and phosphorus (P) fertilizer attracting great concern related
to environment problems (Cui, 2005; Zhao et al., 2006; He et al.,
2009). Therefore, a good fertilizer recommendation method should
focus on not only maintaining high crop yield, but also reducing
environment risk so as to maintain sustainable development of
agriculture.
Previous studies on fertilizer recommendation mainly focused
on two categories, soil based and plant based fertilizer recommendation. Fertilizer recommendation based on soil testing and yield
targets has been reported to increase yield for the wheat–maize
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X. Xu et al. / Field Crops Research 150 (2013) 115–125
rotation system in North-central China (He et al., 2009). However,
it is expensive and time consuming to take numerous soil samples for small-holder farmers with great variation due to variation
in individual fertilization patterns (Huang et al., 2006). In addition, the great challenge for North Central and South China is the
limited time between the two crops grown each year. The crop
based fertilizer recommendation needs to estimate crop nutrient
uptake to balance crop removal for a certain grain yield target.
Previous studies used for crop nutrient estimation usually used a
single value summarized from few data for large areas, which at
times could make fertilizer recommendations misleading. Most of
the nutrient management in the past usually ignored the interactions of plant nutrients and only address a single nutrient. However,
nutrient balances in agricultural development are important to
develop and sustain modern agricultural systems without incurring human and environmental costs (Vitousek et al., 2009). The
site specific nutrient management (SSNM) has been used to more
closely match nutrient supply and demand within a specific field
in a particular cropping system, and thus proved to obtain high
crop yield and high nutrient use efficiency (Buresh and Witt, 2007;
Witt et al., 2006; Dobermann and Cassman, 2002), and to protect environment (Pampolino et al., 2007). The SSNM approach
advocates that fertilizer requirements should be based on more
generic, quantitative approaches, such as simulation models to estimate the relationships between grain yield and nutrient uptake
(Witt et al., 1999; Maiti et al., 2006). The QUEFTS model originally developed by Janssen et al. (1990), taking into account the
interactions of N, P and K, provides a generic empirical relationship
between grain yield and nutrient accumulation that in plants follow
a linear–parabolic–plateau model (Smaling and Janssen, 1993; Witt
et al., 1999). The model avoids deviation where a single, or a few
data, are used to get nutrient uptake data to guide fertilizer application. It excludes the lower and upper 2.5th, 5.0th or 7.5th percentile
of all the measured internal efficiencies data as the maximum nutrient accumulation (a) and maximum nutrient dilution (d) to define
the envelop function. The data where harvest index (HI) < 0.4 were
excluded because that data was treated as crop suffering stress from
other factors other than nutrient supply, such as water stress, and
other biotic or abiotic stress (Janssen et al., 1990). There are numerous reports that estimate nutrient uptake with the QUEFTS model at
different target yields including rice (Witt et al., 1999; Buresh et al.,
2010; Das et al., 2009), maize (Setiyono et al., 2010; Liu et al., 2006;
Janssen et al., 1990), and wheat (Pathak et al., 2003; Liu et al., 2006;
Maiti et al., 2006). The QUEFTS model considers the interactions
between N, P and K, and the requirements of N, P and K can be estimated, therefore it provides a very practical tool for site-specific
nutrient management concepts for major crops (Dobermann and
Witt, 2004; Khurana et al., 2007; Witt et al., 2004; Setiyono et al.,
2010).
At present, the research on the relationship between grain yield
and nutrient uptake of maize employed by the QUEFTS model in
China were published by Liu et al. (2006) with merely 521 maize
data from 1985 to 1995, and reported by Zhang et al. (2012) with
1065 spring maize data from 2006 to 2009 in North China. These
studies either had insufficient data, or considered small regions,
limiting the representation for the whole maize-producing regions
of China to estimate nutrient requirement. Those past and individual experimental data are insufficient to serve as adequate nutrient
management and fertilizer recommendations for current intensive
maize production systems of China. Therefore, the objectives of this
study were to: (1) determine the envelop functions describing relationships between grain yield and nutrient uptake by maize across
a wide range of yields and environments in China; (2) estimate the
balanced N, P and K uptake requirements in China; (3) conduct onfarm evaluation of nutrient uptake simulated by QUEFTS for both
spring maize and summer maize in China.
2. Materials and methods
2.1. Experimental sites
In China, spring maize and summer maize are both grown.
Spring maize is mainly planted in the Northeast (NE), Northwest
(NW), and Southwest (SW) of China with mono-cropping system,
while summer maize is mainly planted in North-central (NC) China
and some small planting in the Middle and Lower reaches of the
Yangtze River (MLYR). NC China and MLYR have plenty of rainfall
with the opportunity for supplemental irrigation under drought
conditions, while spring maize planting regions are principally
rainfed. Maize production is mainly concentrated in the NC, NE and
NW, with sown area of 10.78, 9.51 and 5.39 million hectares, and
production of 60.19, 54.79 and 29.86 million tons of maize yield,
respectively (China Agriculture Yearbook, 2011). Both the NE and
NW are dominated by cool temperate with a single cropping system of spring maize and grown from late April or early May to midor late September, while the NC is dominated by a temperature climate with a winter wheat–summer maize rotation. SW and MLYR
have a temperate, subtropical humid and sub-humid climate with
winter wheat–summer maize rotation, or spring maize/summer
maize rotated with rape, rice or other crops. Summer maize was
grown from mid-June to late September or early October. Single basal application was very common phenomenon for farmers
whether summer maize or spring maize. Fertilizer was usually
applied about one week before planting and ridge culture for spring
maize, but sowing and fertilizer application at the same time or onetime fertilizer application at seeding stage and no-till for summer
maize. There is the similar plant population for both summer maize
and spring maize with ranging from 55,000 to 65,000 plant ha−1 .
The data sites were widely distributed with covering a wide range of
soil types, climatic conditions and agronomic practices. Normally,
farmers apply more fertilizers for summer maize rotation system
than spring maize. At least one of the three macronutrients was
included for nutrient uptake data, while those only having the data
of grain yield without nutrient uptake were not shown (Fig. 1).
2.2. Data source
The database used for this analysis included field experiments
conducted by the International Plant Nutrition Institute (IPNI)
China Program and various studies conducted by our groups and
others published in journal papers in the past decade (2001–2010).
The experimental sites covered (i) different environments, soils and
cropping systems in China (Table 1); (ii) irrigated maize and rainfed
maize; (iii) treatments including full N, P and K balanced fertilizer
(OPT) and omission plots for N (OPT-N), P (OPT-P) and K (OPT-K),
respectively, and unfertilized (F0), and farmers’ practice (FP) and a
series of nutrient omission treatments consisting of FP-N, FP-P, and
FP-K; (iv) crop parameters, such as grain yield, N, P and K uptake in
both straw and grain.
At each experimental site, weeds, pests and diseases were
controlled, fertilizer applied mainly based on soil testing and targets yield in the field experiments of IPNI (He et al., 2009). Each
experiment used the same hybrid maize variety and a completely
randomized block design, with the plot sizes ranged from 30 to
60 m2 , and the yields of grain and straw and nutrient uptake of
N, P and K were analyzed in the different treatments at maturity after harvest. The moisture of grain is 0.155 g H2 O g−1 fresh
weight, and harvest index (HI) is grain dry matter as a proportion of above-ground plant dry matter (grain and straw after
drying at 70I). Nutrient harvest index is defined as kg nutrient in grain per kg nutrient in total above-ground dry matter at
maturity. Plant N, P and K concentrations were measured using
wet oxidation, and determined by micro-Kjeldahl distillation and
X. Xu et al. / Field Crops Research 150 (2013) 115–125
117
Fig. 1. Distribution of experimental sites for maize in five production regions of China.
titration, vanadomolybdate yellow color method, and flame spectrophotometers method (Chinese Society of Soil Science, 2000),
respectively.
curves of optimal N, P and K uptake at different yield potential
levels.
2.3. Model development
2.4. Field validation
The QUEFTS model was initially developed by Janssen et al.
(1990), which describes the relationship between grain yield and
nutrient supply, and further used to evaluate relationships between
grain yield and nutrient uptake in total above-ground dry matter
with a large data set following a linear–parabolic–plateau model
(Smaling and Janssen, 1993). In this study, we used a solver model
in Microsoft Office Excel that was developed for rice (Witt et al.,
1999) and adapted it to maize (Liu et al., 2006; Setiyono et al.,
2010). A brief description of key steps are provided here: (a) screen
the data set and remove outliers/potential errors; (b) determine
the two boundary lines to describe the maximum and minimum
accumulation of the nutrient in the plant, respectively; (c) simulate
On-farm field validation was conducted in 323 farm fields
located in Jilin, Liaoning, Heilongjiang, Henan, Hebei, Shandong and
Shanxi provinces in 2010–2011 to validate the QUEFTS model. The
sites represented both spring maize and summer maize. The fertilizer recommendation was provided by the Nutrient Expert (NE) for
Hybrid Maize decision support system. The NE is the computer software developed by IPNI based on the SSNM strategy, which includes
QUEFTS predicted nutrient uptake for determining the crop’s optimal nutrient requirements (Pampolino et al., 2012). N fertilizer
recommendation was determined by yield response and agronomic
efficiency, and fertilizer P and K was determined from the target
yield and yield response. Up to now, the NE has been applied in
Table 1
Summary of experimental sites for maize production in five regions in China.
pH
OM (%)
Annual precipitation (mm)
Latitude (◦ N)
Longitude (◦ E)
Region
Province
Maize season
NE
Jilin
Liaoning
Heilongjiang
Spring
Spring
Spring
4.9–8.4
4.5−8.3
4.8–8.3
0.8–5.2
0.5–4.5
1.0–6.2
400–1000
450–1000
400–650
40.89–46.28
39.05–43.52
43.45–53.53
121.65–131.29
118.86–125.76
121.22–135.07
664
581
234
NW
Shaanxi
Ningxia
Gansu
Xinjiang
Inner Mongolia
Spring
Spring
Spring
Spring
Spring
7.5–8.6
7.9–8.4
7.3–8.5
7.8–8.5
6.2–8.9
0.2–0.7
0.1–0.7
0.2–1.5
0.1–1.5
0.1–4.5
200–600
200–600
100–300
100–500
350–450
31.76–39.56
35.26–39.37
32.63–42.79
34.35–49.17
37.44–53.35
105.77–111.19
104.35–107.58
92.79–108.70
73.45–97.37
97.19–126.04
78
16
203
29
70
NC
Beijing
Shanxi
Shandong
Henan
Hebei
Summer
Spring and Summer
Summer
Summer
Summer
5.0–8.4
7.8–8.7
4.7–8.6
5.3–8.4
5.2–8.2
0.2–1.4
0.3–1.7
0.2–2.0
0.2–1.7
0.2–1.5
550–650
350–700
550–900
500–900
350–500
39.44–41.05
31.70–34.57
34.42–38.38
31.41–36.37
36.08–42.67
115.43–117.49
105.48–111.02
114.60–112.72
110.39–116.62
113.45–119.83
54
754
568
1089
518
MLYR
Hubei
Hunan
Jiangsu
Anhui
Summer
Spring and Summer
Summer
Summer
5.3–7.9
4.4–7.7
7.2–8.4
4.9–7.6
0.4–2.4
0.4–2.2
0.2–1.7
0.4–1.7
750–1500
900–1700
800–1200
700–1400
29.14–33.26
24.65–30.12
30.76–35.12
29.41–34.65
108.36–116.12
108.78–114.25
116.37–121.89
114.89–119.64
11
17
46
20
SW
Chongqing
Guizhou
Yunnan
Sichuan
Summer
Spring and Summer
Spring and Summer
Summer
4.6–7.7
4.4–7.4
4.4–6.6
5.5–7.9
0.5–1.5
0.4–3.1
0.6–2.5
0.4–2.3
750–1400
1100–1400
600–2000
1000–1300
28.18–32.21
24.64–29.22
21.16–29.23
26.05–34.31
105.29–110.18
103.60–109.45
97.55–106.16
97.37–108.51
39
24
17
12
NE, Northeast; NW, Northwest; NC, North-central China; MLYR, the Middle and Lower reaches of the Yangtze River; SW, Southwest; OM, organic matter.
Case (n)
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X. Xu et al. / Field Crops Research 150 (2013) 115–125
some Asia countries, such as China, Indonesia and Philippines (He
et al., 2012; Pampolino et al., 2012).
Following the NE based fertilizer recommendation,
110–211 kg N ha−1 , 13–31 kg P ha−1 , 21–80 kg K ha−1 were applied.
Other field management was conducted by best management
practices guided by NE. At maturity, crop samples were harvested
for N, P and K nutrient uptake for correlation analysis between
QUEFTS model simulated nutrient uptake and observed nutrient
uptake.
3. Results and discussion
3.1. Characteristics of grain yield and nutrient uptake
The maize data we collected included both spring maize and
summer maize from 2001 to 2010. Average grain yield (15.5% moisture content) was 8.53t ha−1 for all data sets, with ranged from 1.65
to 17.86 t ha−1 (including omission plots). The average grain yield
in this study was less than the 12 t ha−1 of average yield achieved in
the USA and Southeast Asia (Setiyono et al., 2010), but higher than
the national average maize grain yield of 4.97 t ha−1 in all China
(China Agriculture Yearbook, 2011). The reason for these differences was that most of the data were from experiments located
in the plain regions, and the field management was superior to
farmers’ practices. During the 1985–1995 period grain yield ranged
from 0.55 to 10.98 t ha−1 (Liu et al., 2006), lower than our study due
to improved maize varieties and nutrient management in the past
decade. The HI ranged from 0.19 to 0.77 with an average of 0.47
and most of HI within 0.4–0.6 (Fig. 2). If the HI is less than 0.4, it
was supposed that these data suffered from either biotic or abiotic
stress other than nutrients (Hay, 1995).
The average nutrient concentrations in grain were
13.27 g N kg−1 , 3.75 g P kg−1 , 4.08 g K kg−1 , and those in straw were
7.69 g N kg−1 , 1.83 g P kg−1 , 12.97 g K kg−1 . Nutrient concentrations
varied tremendously in both grain (4.00–33.19 g N kg−1 ,
0.81–10.20 g P kg−1 ,
0.93–16.08 g K kg−1 )
and
straw
(1.87–23.09 g N kg−1 ,
0.04–5.93 g P kg−1 ,
2.19–43.20 g K kg−1 )
due to different environmental conditions and the management
practices imposed as treatments (nutrient omission plots, optimal
treatment and farmers’ practice). The average above-ground
nutrient accumulation of N, P and K were 165.56, 40.40 and
136.95 kg ha−1 , and ranged from 38.22 to 520.00, from 5.61 to
156.45 and from 17.25 to 605.55 kg ha−1 , respectively. Nutrient HI
of N, P and K were 0.61, 0.65 and 0.23, and N-HI and P-HI were less
than Setiyono et al.’s study (0.64 for N and 0.84 for P), especially for
P-HI (Table 2). The ratio of P concentration in straw and grain was
close to 1:2, far above the ratio of 1:5 reported by Setiyono et al.
(2010). The average P uptake in straw was 14.61 kg ha−1 in our
study, which was higher than the value of 5.4 kg ha−1 in Setiyono
et al. study. The excess P accumulation in the straw in our study
indicated a sign that P was not used efficiently.
There were great differences in grain yield and nutrient uptake
between spring maize and summer maize (Table 3). Although
both average HIs were the same, there were big gaps for grain
yields between spring and summer maize. The average grain yield
of spring maize was significantly higher than summer maize,
by 1.6 t ha−1 . Concentrations of N, P and K in grain and straw
in summer maize (14.55 g N kg−1 , 4.48 g P kg−1 , 4.15 g K kg−1 in
grain and 8.25 g N kg−1 , 2.32 g P kg−1 , 13.70 g K kg−1 in straw) were
higher than those in spring maize (11.60 g N kg−1 , 2.71 g P kg−1 ,
4.00 g K kg−1 in grain and 6.96 g N kg−1 , 1.13 g P kg−1 , 11.96 g K kg−1
in straw). There were the similar N accumulation in the aboveground for both spring maize (165.38 kg ha−1 ) and summer maize
(165.71 kg N ha−1 ), the average P accumulation in the aboveground was 34.63 kg ha−1 for spring maize less than 44.95 kg P ha−1
for summer maize, while K accumulation in the above-ground for
spring maize (148.70 kg K ha−1 ) was higher than summer maize
(127.45 kg K ha−1 ). The reason may be that two or more crops are
planted in one year and the higher N and P fertilizer application
led to high soil indigenous N and P supply for summer maize than
Fig. 2. Distribution of grain yield and harvest index of maize. The box plots of grain yield for spring and summer maize in this study, solid and dashed lines indicate median
and mean, respectively. The box boundaries indicate the upper and lower quartiles, the whisker caps indicate 90th and 10th percentiles, and the circles indicate the 95th
and 5th percentiles.
X. Xu et al. / Field Crops Research 150 (2013) 115–125
119
Table 2
Descriptive characteristics statistics of all maize data, including grain yield (15.5% moisture), harvest index (HI), N, P and K accumulation in grain, straw and total above-ground
dry matter, concentrations of N [N], P [P]and K [K] in grain and straw, and nutrient HI.
Parameter
Unit
n
Mean
SD
Minimum
25%Q
Median
75%Q
Maximum
Grain yield
Harvest index
N uptake grain
P uptake grain
K uptake grain
N uptake straw
P uptake straw
K uptake straw
[N] in grain
[P] in grain
[K] in grain
[N] in straw
[P] in straw
[K] in straw
Plant N
Plant P
Plant K
N-HI
P-HI
K-HI
t ha−1
kg kg−1
kg ha−1
kg ha−1
kg ha−1
kg ha−1
kg ha−1
kg ha−1
g kg−1
g kg−1
g kg−1
g kg−1
g kg−1
g kg−1
kg ha−1
kg ha−1
kg ha−1
kg kg−1
kg kg−1
kg kg−1
5044
4252
3771
2917
2954
3698
2917
2952
3648
2926
2964
3622
2897
2933
4806
3442
3484
3698
2917
2948
8.53
0.47
95.14
25.91
29.28
63.11
14.61
105.77
13.27
3.75
4.08
7.69
1.83
12.97
165.56
40.40
136.95
0.61
0.65
0.23
2.32
0.06
30.75
14.34
18.61
28.57
11.02
61.63
3.50
1.96
1.93
2.55
1.23
6.00
55.15
19.95
70.30
0.09
0.17
0.10
1.65
0.19
10.50
2.77
2.95
10.63
0.23
8.79
4.00
0.81
0.93
1.87
0.04
2.19
38.22
5.61
17.25
0.25
0.21
0.03
6.98
0.43
75.41
15.50
18.38
46.36
6.06
66.41
11.30
2.37
2.90
6.06
0.79
8.56
131.61
25.04
92.96
0.55
0.54
0.16
8.38
0.47
93.09
20.75
25.83
58.41
12.00
93.53
12.70
2.98
3.64
7.22
1.50
11.31
158.65
36.33
122.63
0.62
0.69
0.23
9.96
0.52
111.09
33.50
33.43
75.26
19.96
128.36
14.44
5.09
4.72
9.00
2.60
16.30
190.81
52.46
160.67
0.66
0.78
0.28
17.86
0.77
269.93
83.25
166.40
348.53
88.21
561.19
33.19
10.20
16.08
23.09
5.93
43.20
520.00
156.45
605.55
0.88
0.98
0.79
n, number of observations; SD, standard deviation; Q, quartile.
spring maize, and high K uptake for spring maize resulted from high
soil K contents in spring maize production areas. The nutrient harvest index of N, P and K were 0.60, 0.68, and 0.24 for spring maize,
and 0.61, 0.63 and 0.22 for summer maize, respectively. It is likely
that fertilizer recommendations based on nutrient uptake should
be distinguished for spring and summer maize.
3.2. Internal efficiencies and reciprocal internal efficiency
Our measurements of IEs (Internal efficiency, kg yield per kg
nutrient uptake) and RIEs (Reciprocal internal efficiency, nutrient
uptake requirement per ton of grain yield) were based on analysis of
several treatments including optimal fertilizer treatment, omission
plots and farmer’s practices (Table 4). Average IEs of N, P and K were
53.81, 248.01 and 68.33 kg grain per kg for all maize data, ranging
from 22.74 to 140.95 kg kg−1 for N, 74.22 to 945.52 kg kg−1 for P, and
14.53 to 183.08 kg kg−1 for K, respectively. To produce 1000 kg grain
yield, the average N, P and K needed were 19.70, 5.04 and 16.67 kg,
ranging from 7.09 to 43.98 kg for N, 1.06 to 13.47 kg for P, and 5.46
to 68.84 kg for K, respectively. Compared to previous research, the
IEs of N and P were less than those achieved by Setiyono et al. (IEs of
56 kg kg−1 N, 400 kg kg−1 P and 56 kg kg−1 K), while IE-K was higher
than the latter. As compared to the research conducted by Liu et al.
(2006) (IEs of 42.3 kg kg−1 N, 254.9 kg kg−1 P and 50.6 kg kg−1 K), our
study had higher IEs for N and K, but with similar IE-P value.
There were great differences in IEs and RIEs between spring
maize and summer maize. For spring maize, the IEs of N, P and K
were 60.21, 315.45 and 73.88 kg kg−1 , and the corresponding RIEs
were 17.50 kg N, 3.67 kg P and 15.72 kg K. Compared with average
RIEs of 16.8 kg N, 3.3 kg P and 9.5 kg K for spring maize in North
China during 2006–2009 (Zhang et al., 2012), values of RIEs of
N and P in the current study were a little bit higher, while the
RIE-K in the current study was lower than Setiyono et al. (2010)
observation and much higher than reported by Zhang et al. (2012).
For summer maize, the IEs of N, P and K were 48.83, 194.80
and 63.83 kg kg−1 , and the corresponding RIEs were 21.41 kg N,
Table 3
Descriptive characteristics statistics of spring and summer maize data, including grain yield (15.5% moisture), harvest index (HI), N, P and K accumulation in grain, straw and
total above-ground dry matter, concentrations of N [N], P [P] and K [K] in grain and straw, and nutrient HI.
Parameter
Grain yield
Harvest index
N uptake grain
P uptake grain
K uptake grain
N uptake straw
P uptake straw
K uptake straw
[N] in grain
[P] in grain
[K] in grain
[N] in straw
[P] in straw
[K] in straw
Plant N
Plant P
Plant K
N-HI
P-HI
K-HI
Unit
t ha−1
kg kg−1
kg ha−1
kg ha−1
kg ha−1
kg ha−1
kg ha−1
kg ha−1
g kg−1
g kg−1
g kg−1
g kg−1
g kg−1
g kg−1
kg ha−1
kg ha−1
kg ha−1
kg kg−1
kg kg−1
kg kg−1
n, number of observations; SD, standard deviation.
Spring maize
Summer maize
n
Mean
SD
n
Mean
SD
2256
1890
1665
1222
1255
1615
1222
1253
1589
1203
1239
1589
1200
1231
2104
1518
1558
1615
1222
1249
9.42
0.47
93.69
21.95
31.84
64.52
10.93
113.91
11.60
2.71
4.00
6.96
1.13
11.96
165.38
34.63
148.70
0.60
0.68
0.24
2.34
0.06
28.13
12.64
20.92
34.76
9.23
80.02
2.06
1.34
2.10
2.59
0.67
6.31
60.52
20.44
89.06
0.09
0.14
0.10
2788
2362
2106
1695
1699
2083
1695
1699
2059
1723
1725
2033
1697
1702
2702
1924
1926
2083
1695
1699
7.80
0.47
96.29
28.76
27.39
62.02
17.26
99.78
14.55
4.48
4.15
8.25
2.32
13.70
165.71
44.95
127.45
0.61
0.63
0.22
2.03
0.07
32.64
14.80
16.45
22.59
11.44
42.37
3.82
2.00
1.78
2.36
1.30
5.65
50.58
18.33
48.20
0.09
0.18
0.10
120
X. Xu et al. / Field Crops Research 150 (2013) 115–125
Table 4
Descriptive statistics of the internal efficiency of N, P and K (IE, kg grain per kg nutrient) and its reciprocal internal efficiency (RIE, kg nutrient per 1000 kg grain yield) for all
maize, spring maize and summer maize in China.
Data set
Parameter
Unit
n
Mean
SD
25%Q
Median
75%Q
All maize
IE-N
IE-P
IE-K
RIE-N
RIE-P
RIE-K
kg kg−1
kg kg−1
kg kg−1
kg t−1
kg t−1
kg t−1
4806
3442
3484
4806
3442
3484
53.81
248.01
68.33
19.70
5.04
16.67
13.14
123.76
23.68
4.89
2.26
6.60
45.09
144.18
51.05
16.33
3.04
12.27
52.71
222.44
67.86
18.97
4.50
14.74
61.25
329.36
81.48
22.18
6.94
19.59
Spring maize
IE-N
IE-P
IE-K
RIE-N
RIE-P
RIE-K
kg kg−1
kg kg−1
kg kg−1
kg t−1
kg t−1
kg t−1
2104
1518
1558
2104
1518
1558
60.21
315.45
73.88
17.50
3.67
15.72
13.78
112.01
25.91
4.24
1.62
7.25
51.52
234.39
57.18
14.90
2.54
11.27
59.47
303.32
72.79
16.82
3.30
13.74
67.11
393.49
88.73
19.41
4.27
17.49
Summer maize
IE-N
IE-P
IE-K
RIE-N
RIE-P
RIE-K
kg kg−1
kg kg−1
kg kg−1
kg t−1
kg t−1
kg t−1
2702
1924
1926
2702
1924
1926
48.83
194.80
63.83
21.41
6.13
17.43
10.11
105.29
20.65
4.67
2.10
5.91
41.38
131.57
47.92
18.14
4.16
13.08
48.67
149.79
62.07
20.55
6.68
16.11
55.13
240.66
76.46
24.17
7.60
20.87
n, number of observations; SD, standard deviation; Q, quartile.
6.13 kg P and 17.43 kg K, exceeding those of spring maize. It is difficult to estimate nutrient uptake requirements for empirical studies
from both spring and summer maize due to vast variations in IE and
RIE. Therefore, the data set was divided into two parts, spring maize
and summer maize, according to their respective data to estimate
nutrient requirements.
3.3. Estimating the optimum nutrient uptake
Relationship between grain yield and nutrient uptake was calibrated with the QUEFTS model to determine the borderlines of
maximum accumulation (a) and maximum dilution (d) under the
condition that data with a HI lower than 0.4 were excluded. We
used the constant a and d for running the QUEFTS model calculated by excluding the upper and lower 2.5 (set I), 5.0 (set II), and
7.5 (set III) percentiles of all nutrient internal efficiency data of the
combined data set (all maize data including both spring maize and
summer maize) (Table 5). The nutrient requirements calculated by
the QUEFTS model were similar for all three sets (Figure not shown),
except at the yield target approaching the yield potential. Since set
I included a larger range of variability, it was then used to estimate
balanced nutrient uptake and the relationship between grain yield
and nutrient accumulation, which were similar to previous reports
(Witt et al., 1999; Liu et al., 2006).
The constant a and d of N, P and K were 32 and 83, 111 and 525,
and 31 and 123 kg kg−1 for all maize; 36 and 89, 135 and 558, and
30 and 132 kg kg−1 for spring maize; and 31 and 70, 108 and 435,
and 32 and 110 kg kg−1 for summer maize, respectively. The a and
d of our study were higher than Liu et al.’s (2006) research (21 and
64 kg grain per kg N, 126 and 384 kg grain per kg P, 20 and 90 kg
grain per kg K) except a of P for summer maize, but less than Zhang
et al.’s study (2012) (40 and 87 kg grain per kg N, 166 and 605 kg
grain per kg P, 59 and 210 kg grain per kg K) for spring maize. There
were also some differences compared with the values reported by
Setiyono et al. (2010) (the constant a and d of N, P and K were 40
and 83 kg grain per kg N, 225 and 726 kg grain per kg P, 29 and
125 kg grain per kg K) and Janssen et al. (1990) (the constant a and
d of N, P and K were 30 and 70 kg grain per kg N, 200 and 600 kg
grain per kg P, 30 and 120 kg grain per kg K).
The relationship was estimated using the QUEFTS model
between grain yield and nutrient accumulation in plant dry matter
at maturity under different potential yields (10–20 t ha−1 ) (Fig. 3).
The highest yield potential of 20 t ha−1 was used to run the QUEFTS
model to estimate balanced nutrient requirement because grain
yield is hardly exceeding this potential yield in China (Bai et al.,
2010). Differences were greatest for the balanced N, P and K uptake
requirements (YU) for targeted grain yields depending on the
potential yields as calculated by QUEFTS. However, the model
predicted a linear increase in grain yield if nutrient were taken up
in balance until yield reached about 60–70% of the yield potential.
The QUEFTS model predicted the balanced nutrient accumulation of 18.6 kg N, 4.0 kg P and 15.5 kg K per ton of grain when
the grain yield reached about 60–70% of the potential yield and
IEs of 54 kg grain kg−1 N, 247 kg grain kg−1 P and 64 kg grain kg−1 K
Table 5
Envelope coefficients relating grain yield to the maximum accumulation (a) and maximum dilution (d) of N, P and K in the above-ground dry matter of all maize, spring
maize and summer maize at maturity. Constants a and d were calculated by excluding the upper and lower 2.5 (set I), 5.0 (set II), and 7.5 (set III) percentiles of all nutrient
efficiency data of the combined data set (all maize, spring maize and summer maize).
Data sets
Nutrients
Set I
All maize
N
P
K
32
111
31
83
525
123
35
117
34
76
474
111
37
122
37
73
441
105
Spring maize
N
P
K
36
135
30
89
558
132
41
155
33
84
519
121
43
172
36
79
494
114
Summer maize
N
P
K
31
108
32
70
435
110
34
113
35
67
387
103
35
117
37
64
353
96
a (2.5th)
Set II
d (97.5th)
a (5th)
Set III
d (95th)
a (7.5th)
d (92.5th)
X. Xu et al. / Field Crops Research 150 (2013) 115–125
121
Fig. 3. Relationship between grain yield and accumulation of N, P and K in total above-ground plant dry matter at maturity under different yield potential simulated by the
QUEFTS model for all maize (a–c), spring maize (d–f) and summer maize (g–i). The boundary lines correspond to the lines of maximum accumulation (YA) and maximum
dilution (YD), YU represent balanced N, P and K uptake in the above ground plant dry matter to achieve a certain maize grain yield target for the given boundaries as predicted
by QUEFTS model from excluding the upper and lower 2.5 percentiles of all internal efficiency data (HI ≥ 0.40). The yield potential ranged from 10 to 20 t ha−1 .
for all maize. An amount of 16.9 kg N, 3.5 kg P and 15.3 kg K accumulated by aboveground parts were required to produce 1000 kg
of spring maize grain yield, and the corresponding IEs were
59 kg grain kg−1 N, 287 kg grain kg−1 P and 65 kg grain kg−1 K. The
requirement of 20.3 kg N, 4.4 kg P and 15.9 kg K to produce 1000 kg
summer maize grain in the linear part of the QUEFTS function, and
the corresponding IEs were 49 kg grain kg−1 N, 227 kg grain kg−1 P
and 63 kg grain kg−1 K (Table 6). Optimal N:P:K ratios in plant matter were 4.65:1:3.88 for all maize, 4.83:1:4.37 for spring maize and
4.61:1:3.61 for summer maize. These ratios were also similar to
the average of measured nutrient uptake (4.10:1:3.39 for all maize,
4.78:1:4.29 for spring maize), the exception being summer maize
(N:P:K ratios was 3.69:1:2.84 derived from average of the measured nutrient uptake). There was a great difference between P
uptake predicted by QUEFTS and the average of measured nutrient uptake. This difference was because the nutrient estimated
from the QUEFTS model was optimal (balanced) nutrient requirements (Janssen et al., 1990; Smaling and Janssen, 1993; Setiyono
et al., 2010), while P uptake in this study was luxury calculated
from the average of measured nutrient uptake, reflecting the high
soil P and excessive P fertilizer application. It was reported that
excessive P fertilizer application in the arable farming system has
led to the accumulation of soil P with an average P surplus of
14.7 kg ha−1 year−1 in China (Chen et al., 2008). A large number of
data points were concentrated in the vicinity of the lower boundary
which reflected an excess or luxuriant uptake of P nutrient in most
summer maize experiments (Fig. 3h). Many studies have shown
that P fertilizer application rates surpassed plant requirement in
North-central China (Li et al., 2010; Zhang et al., 2007). More points
were allocated in the areas close to the nutrient dilution borderline to K uptake for spring maize, indicating the possibilities of K
deficiency for spring maize (Fig. 3f).
122
X. Xu et al. / Field Crops Research 150 (2013) 115–125
Table 6
Descriptive statistics of the reciprocal internal efficiencies of N, P and K simulated by the QUEFTS model to achieve certain grain yield targets and yield potential at 16 kg ha−1
for all maize, spring maize and summer maize.
Yield (kg ha−1 )
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10,000
11,000
12,000
13,000
14,000
15,000
16,000
All maize RIE (kg nutrient/t grain)
Spring maize RIE (kg grain/kg nutrient)
Summer maize RIE (kg nutrient/t grain)
N
P
K
N
P
K
N
P
K
0
18.6
18.6
18.6
18.6
18.6
18.6
18.6
18.6
18.7
18.9
19.6
20.4
21.5
23.0
25.3
30.5
0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.1
4.1
4.2
4.4
4.7
5.0
5.5
6.6
0
15.5
15.5
15.5
15.5
15.5
15.5
15.5
15.5
15.6
15.8
16.3
17.1
18.0
19.2
21.1
25.4
0
16.9
16.9
16.9
16.9
16.9
16.9
16.9
16.9
17.0
17.2
17.7
18.5
19.5
20.8
22.9
30.5
0
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.6
3.6
3.8
4.0
4.3
4.7
6.3
0
15.3
15.3
15.3
15.3
15.3
15.3
15.3
15.3
15.4
15.6
16.0
16.7
17.6
18.8
20.7
27.5
0
20.3
20.3
20.3
20.3
20.3
20.3
20.3
20.3
20.3
20.5
20.7
21.5
22.6
24.1
26.4
30.4
0
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.5
4.7
4.9
5.2
5.7
6.6
0
15.9
15.9
15.9
15.9
15.9
15.9
15.9
15.9
15.9
16.1
16.2
16.9
17.8
18.9
20.8
23.9
Setiyono et al. (2010) estimated balanced nutrient uptakes of
14.7 kg N, 2.6 kg P and 15.9 kg K per ton of grain for maize in the USA
and Southeast Asia, and 25.8 kg N, 4.3 kg P and 23.1 kg K per ton of
grain reported by Liu et al. (2006) for maize in China, and 16.0 kg N,
3.0 kg P and 8.5 kg K per ton of grain reported by Zhang et al. (2012)
for spring maize across Jilin, Heilongjiang, Liaoning provinces and
Beijing city in North China. Balanced N and K uptake required per
ton grain yield in our study did not support that reported by Liu
et al. (2006) and Zhang et al. (2012), especially for K. But the balanced K uptake in our study was very close to Setiyono et al. (2010)
study, and similar to the average of 15.7 kg K per ton with the OPT
treatment of spring maize in the Northeast and Northwest reported
by Gao et al. (2009). However, the balanced P uptake by summer
maize showed no significant difference to Liu et al. (2006) study,
indicating P nutrient currently is still not used efficiently. The balanced nutrient uptake curve for N and P obtained from the current
study was very close to the bottom border of Setiyono et al. (2010)
suggesting the luxury absorption of N and P nutrients in China as
compared to USA and Southeast Asia (Fig. 4). Over-fertilization by
farmers driven by pursuing high yield led to nutrient luxury uptake,
and resulted in not only fertilizer waste, but also some negative
effects to the environment (Ju et al., 2009; He et al., 2009). Caution is needed to avoid excessive uptake of nutrients due to over
fertilization.
To maintain soil fertility, nutrients removed by the grain or harvested plant parts must be returned to the soil. The calculation of
grain nutrient uptake can provide guidance for the rational fertilization and avoid fertilizer waste. For spring maize in China, all
the above-ground residues were removed from the field after harvest. Straw from summer maize were generally returned to the
soil after harvest at maturity, except for some used for livestock
feed. Therefore, when making fertilizer recommendations where
complete crop removal is practiced, the removed straw needs be
considered as well as the grain.
QUEFTS analysis also indicated that a balanced N, P and K
removal by grain to produce 1000 kg grain were 11.6 kg N, 3.0 kg P
and 3.5 kg K for all maize, and 9.0 kg N, 2.4 kg P and 3.5 kg K for
spring maize, and corresponding values were 13.1 kg N, 3.6 kg P and
3.5 kg K for summer maize (Fig. 5). The model also predicted a linear
increase in grain yield if grain nutrients were taken up in balance
until yield reached about 60–70% of the yield potential. When the
target yield reached 80% of potential yield, the grain absorption of
N, P and K accounted for 65%, 77% and 24% of above-ground N, P
and K uptake for all maize data, 54%, 69% and 23% for spring maize,
and 67%, 85% and 23% for summer maize, respectively. The earlier study by Setiyono et al. (2010) calculated that balanced grain
nutrient removal was 59%, 77%, and 19% of total N, P and K uptake,
respectively. The N and P uptake of grain yield were higher for summer maize in our study, especially for P, which indicated that more P
was needed to produce 1000 kg grain and P luxury uptake occurred
and should be considered in making fertilizer recommendation for
summer maize.
Fig. 4. Comparisons of the balanced N, P and K requirements simulated by the QUEFTS model. Boundaries are calculated from this study (spring maize and summer maize),
those reported by Liu et al. (2006), and those proposed by Setiyono et al. (2010). YU represent balanced N, P and K uptake in the above ground plant dry matter to achieve a
certain maize grain yield target for the given boundaries as predicted by QUEFTS model. The yield levels are set at 10 and 18 t ha−1 .
X. Xu et al. / Field Crops Research 150 (2013) 115–125
123
Fig. 5. Grain nutrient removal of N, P and K under different yield potential (10–20 t ha−1 ) as simulated by the QUEFTS model for all maize (a–c), spring maize (d–f) and summer
maize (g–i). YA, YD and YU are the maximum accumulation, maximum dilution and balanced N, P and K uptake in the grain nutrient removal, respectively, calculated by the
QUEFTS model from excluding the upper and lower 2.5 percentiles of all internal efficiency data (HI ≥ 0.40).
Fig. 6. Comparisons of the observed and simulated uptake of N, P and K for spring maize and summer maize. The observed nutrient uptake is from NE based fertilizer
recommendation in Heilongjiang, Jilin, Liaoning, Hebei, Henan, Shandong and Shanxi Provinces, and the simulated nutrient uptake comes from the QUEFTS model.
124
X. Xu et al. / Field Crops Research 150 (2013) 115–125
3.4. Model validations
Observed and simulated nutrient uptake was analyzed in the
current study from experiments in 2010 and 2011 at Northeast and
North central of China, including spring maize and summer maize
producing regions (Fig. 6).
The root mean square error (RMSE), normalized-RMSE (nRMSE) and mean error (ME) were used to evaluate the QUEFTS
model. The reference data used for validation were experimental
data from actual field trials where fertilizer rates were recommended by NE. RMSE, n-RMSE and ME were 25.1 kg ha−1 , 13.5%
and −6.1 kg ha−1 for N, 14.3 kg ha−1 , 42.0% and 5.1 kg ha−1 for P, and
41.8 kg ha−1 , 27.5% and -2.7 kg ha−1 for K, respectively. While there
was some deviation for P and K, the cluster of points around the
1:1 line showed that the simulated nutrient uptake were similar
to the observed nutrient uptake. The experimental results indicated that the nutrient uptake estimated by QUEFTS model can
be used to develop fertilizer recommendations, help to optimize
nutrient management practices and prevent nutrient losses. The
results of this study showed a good agreement between simulated
and observed nutrient uptake.
4. Conclusions
There were great differences in the grain yield and nutrient
uptake characteristics between spring maize and summer maize.
The average grain yield and nutrient HI for spring maize were
higher than summer maize, but the concentrations of N, P and K
were less than summer maize. There was a considerable gaps for IE
and RIE between spring maize and summer maize in our study.
The constants a and d used for running the QUEFTS model
reflected the recent status of nutrient uptake of maize in China.
The datasets collected in our study represented a wide range of
maize environments, and there were different a and d values for
spring maize and summer maize. The constant a and d of N, P and K
were 36 and 89, 135 and 558, 30 and 132 kg kg−1 for spring maize,
31 and 70, 108 and 435, 32 and 110 kg kg−1 for summer maize
were proposed as model parameters to estimate balanced nutrient
requirements by QUEFTS model, respectively. Regardless of yield
potential, the model predicted a linear increase in above-ground
dry matter or grain yield if nutrients were taken up in balance
until yield reached about 60–70% of the yield potential. The QUEFTS
model predicted balanced N, P and K uptake were lower for spring
maize than summer maize. The N, P and K nutrient removal by grain
was also analyzed by QUEFTS model for development of fertilizer
recommendations.
Field validation indicated that balanced nutrient requirements
estimated by the QUEFTS model had a good correlation with
observed nutrient uptake. Therefore, fertilizer recommendation
based on QUEFTS simulated nutrient uptake is a feasible nutrient
management practice, which helps to avoid excess application of
nutrients and reduce the potential risk to the environment.
Acknowledgements
This research was supported by the National Basic Research Program of China (973 Program) (2007CB109306 and 2013CB127405),
National Natural Science Foundation of China (No. 31272243) and
International Plant Nutrition Institute (IPNI). The authors also thank
local collaborators from the Academy of Agricultural Sciences of
each province for help with the field experiment.
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