Efectos de La Fertilizacion Nitrogenada y Uso Eficiente de Nitrogeno en Maiz de Temporal

7212019 Efectos de La Fertilizacion Nitrogenada y Uso Eficiente de Nitrogeno en Maiz de Temporal

httpslidepdfcomreaderfullefectos-de-la-fertilizacion-nitrogenada-y-uso-eficiente-de-nitrogeno-en-maiz 17

Effect of N fertilizer source and timing on yield and N use ef 1047297ciency of rainfed maize( Zea mays L) in KashmirndashPakistan

M Kaleem Abbasi Majid Mahmood Tahir Nasir Rahim

Department of Soil and Environmental Sciences The University of Poonch Rawalakot Azad Jammu and Kashmir Pakistan

a b s t r a c ta r t i c l e i n f o

Article history

Received 1 July 2012

Received in revised form 20 September 2012Accepted 20 November 2012

Available online 29 December 2012

Keywords

Maize yield

N sources

N utilization

Nitrogen use ef 1047297ciency

NUE

Split application

Ef 1047297cient N fertilization is considered one of the most important management strategies for sustaining or in-

creasing crop yield and quality and improving nitrogen use ef 1047297ciency (NUE) A 2-yr (2008ndash2009) 1047297eld ex-

periment with rainfed maize ( Zea mays L) was conducted in the hilly region of Rawalakot Azad Jammu

and Kashmir (AJK) Pakistan to evaluate the effect of time and source of N fertilizer application on the growth

yield N-uptake and NUE of maize The experiment consisted of a factorial arrangement of 2 years two

methodstimings and four N sources including a control arranged in a completely randomized block design

replicated three times Treatments included two application timings ie single application of N at planting

and a split application ie 12 at sowing+ 12 at V 6 stage and three N fertilizer sources ie urea calcium am-

monium nitrate (CAN) and ammonium sulfate (AS) and a control Results indicated that response of growth

characteristics to N sources was in the order CANgt ASgt urea Similarly straw and grain yields were highest

in CAN followed by AS while urea exhibited the lowest The relative increase in grain yield by CANand AS was

11 and 10 in 2008 and 8 and 5 in 2009 over urea N Split application of N increased grain yield between4 to

9 in 2008 and 3 in 2009 over single N application The amount of N taken up by plants depended upon the

source of N fertilizer and was in the order ureagt CANgt AS The NUE ranged between 31 to 61 in 2008 and 40

to 67 in 2009 and urea exhibited the highest NUE Split application of N increased NUE by 23 and 21 over

single N application Results of this study indicated that yield and N balance of maize was signi1047297cantly affect-

ed by N sources and application timing However response of both traits to N sources was distinctive Further

studies (long term basis) are suggested to explore the effects of N sources on maize productivity particularlyyield and N balance relationship

copy 2012 Elsevier BV All rights reserved

1 Introduction

Application of N through chemical fertilizers is the dominant and

main source of N input in the crop production systems world-wide

Currently 50 of the human population relies on N fertilizer for

food production while about 60 of global N fertilizer is used for pro-

ducing the worlds three major cereals rice wheat and maize (Ladha

et al 2005) Unfortunately fertilizer N is not utilized ef 1047297ciently in the

world agriculture and the recovery of N in soilminusplant system seldom

exceeds 50 of applied N In cereals N recovery ef 1047297ciency at global

level is reported to be less than 40 (Raun and Johnson 1999 Raun

et al 2002) The low recovery ef 1047297ciency of N is associated with its

losses by leaching denitri1047297cation volatilization and soil erosion

(Fageria and Baligar 2005) Furthermore the dynamic nature of N

its mobility and transformation processes in soil make it an element

not utilized ef 1047297ciently Raun and Johnson (1999) have calculated

that the unaccounted for 67 of applied N fertilizer represents a

$159 billion annual loss (assuming fertilizerndashsoil equilibrium) and

even a 1 increase in N recovery would result in global savings of

$234 million (Glass 2003)

Therefore nitrogen use ef 1047297ciency (NUE) of applied mineral N fertil-

izer is a real concern to the researchers engaged in N cycling and N

transformations To improve N ef 1047297ciency in agriculture N management

strategies that take into consideration improved fertilizer along with

soil and crop management practices are necessary Among these man-

agement strategies adequate rate appropriate source and timings of

fertilizer application during crop growth cycle play an important role

(Abbasi et al 2012 Fageria et al 2006) Such practices not only in-

crease yield but also reduce cost of production and environmental

pollution

Application timing is one of the management strategies that can

in1047298uence the ef 1047297ciency in which applied N is utilized by crops

(Randall and Vetsch 2005 Randall et al 2003 Ruiz-Diaz and Sawyer

2008) Split applications of N fertilizer are often recommended as a

way to reduce N losses and to improve NUE In maize split applica-

tion of N at six leaves stage (V 6) stage increased grain yield (105

vs 112 Mg haminus1) and N uptake (168 vs 192 kg haminus1) compared

with single N application at planting (Sainz Rozas et al 2004) In an-

other experiment N recovery was increased (from 58 to 71) and N

Geoderma 195ndash196 (2013) 87ndash93

Corresponding author Tel +92 5824960046 fax +92 5824960004

E-mail address kaleemabbasiyahoocom (MK Abbasi)

0016-7061$ ndash see front matter copy 2012 Elsevier BV All rights reserved

httpdxdoiorg101016jgeoderma201211013

Contents lists available at SciVerse ScienceDirect

Geoderma

j o u r n a l h o m e p a g e w w w e l s e v i e r c o m l o c a t e g e o d e r m a



losses were decreased (26ndash55 vs 04ndash1) in split application com-

pared with single N application at planting (Sainz Rozas et al 1997)

However there are also reports that split application of N fertilizer to

different crops did not affect their performance and productivity

(Garrido-Lestache et al 2005 Zebarth et al 2004) Liu and Wiatrak

(2011) reported that splitting N into two doses ie all N at planting

and at V 6 growth stage had no effect on maize grain yield and plant

characteristics

The form or the source of added N plays an important role in reg-ulating N transformations changing N loss patterns and in1047298uencing

NUE (Ladha et al 2005) Urea ammonium sulfate (AS) and ammoni-

um nitrate (AN) or calcium ammonium nitrate (CAN) are the main N

carriers used worldwide in crop production (Fageria and Baligar

2005) However urea is generally favored by the growers over AS

and AN or CAN due to lower application cost because urea has a

higher N analysis than AS and ANCAN (46 vs 21 33 and 26 N re-

spectively) Few studies had been reported previously on the compar-

ative effects of different N fertilizer sources on the growth and yields

of crops and response was generally inconsistent Fageria et al (2011)

conducted two greenhouse experiments on rice with urea and AS and

reported that the maximum grain yield and N-uptake at average N

rate (160 mg kgminus1) was 22 and 15 higher with AS compared to

urea The comparative effects of urea and AN on meadow bromegrass

(Bromus bibersteinii) at two sites in central Alberta Canada indicated

that AN generally produced higher DMY (16ndash26) protein yield (21

and 37) NUE (16 and 26) and N recovery (20 and 38) com-

pared with urea (Malhi 1997) In our previous study conducted on

grassland soil NH4+ source of N was found superior to NO3

minus source

In the plots where NO3minus

ndashN was added as the N source DMY was

1760ndash1870 kg haminus1 N recovery ef 1047297ciency was 24ndash43 while in

NH4+

ndash N added plots both DMY and N recovery ef 1047297ciency were in-

creased to 3190ndash3700 kg haminus1 and 39ndash48 respectively (Abbasi

et al 2005)

The effect of N fertilizer forms or sources on the growth yield and

NUE of maize under1047297eld conditions had not been reported extensive-

ly The importance of such studies under rainfed conditions becomes

critical because N availability to plants differs with N form as a result

of differences in mobility of each form in soil solution Keeping this inview the objective of the present study was to determine the effects

of different fertilizer N formssources applied at different timings on

growth and yield characteristics N uptake and NUE of maize in a

1047297eld experiment under rainfed mountainous conditions

2 Materials and methods

21 Study site

The experiment was conducted at Rawalakot Azad Jammu and

Kashmir (AJK) Faculty of Agriculture Experimental Farm in 2008

and 2009 The study area lies between the altitude of 1800 and

2000 m above sea level andlatitude33ndash36degin thenorth-east of Pakistan

under the foothills of the great Himalayas at Rawalakot district Poonch

division AJK Pakistan The detail of the study area had been described

earlier (Abbasi et al 2012) The monthly precipitation and temperature

of the experimental area are presented in Table 1

22 Experimental procedures and details

Before the onset of the experiment soil samples were collected and

analyzed for physical and chemical properties The soil in the study site

was clay loam in texture Humic Lithic Eutrudepts (Inceptisols) The

background soil sample had pH 74 ECe 058 dS mminus1 organic C

87 g kgminus1 total N 049 g kgminus1 available P 64 mg kgminus1 and exchange-

able K 101 mg kgminus1 For proper seed bed preparation the site was

plowed and left for 2 weeks The individual plots were prepared

according to the treatments and the plot size was 3-m long and 3-mwide

The treatments were composed of i) three N fertilizer sources

ie urea calcium ammonium nitrate (CAN) ammonium sulfate

(AS) and a control (no N) ii) two application timings ie a single N

application or split application In case of single application full

dose of N fertilizer was applied by broadcast method at planting

while in case of split application half dose was applied at planting

and the remaining half was applied at the time when plants were

grown up to six leaves stage (V 6) Nitrogen from different N sources

was applied at the rate of 120 kg N haminus1 Phosphorus and K were in-

corporated into the soil approximately 5 cm deep in all plots includ-

ing the control at the time of sowing Rates were 90 kg P2O5 haminus1

and 60 kg K2O haminus1 as single super phosphate (SSP) and sulfate of

potash (SOP) respectively All the fertilizers were well mixed intothe soil before sowing

Maize ( Zea Mays L) variety ldquoSwanrdquo was used in the experiment

Seeds were collected from National Agricultural Research Centre

(NARC) Islamabad Pakistan The experiment consisted of a factorial

arrangement of 2 years two methodstimings and four N sources in-

cluding a control arranged in a completely randomized block design

replicated three times Maize was sown in rows at 45-cm spacing

(leaving 15 cm border on each side of the plot) on 12 and 15 May

2008 and 2009 respectively After germination the plant to plant dis-

tance was thinned to 23 cm All standard local cultural practices were

followed when required throughout the growth period No irrigation

was provided and manual weeding was carried out when required

23 Measurements

The morphological characteristics of the crop like shoot length

leaf area (LA) and chlorophyll content were recorded in standing

crop by selecting 1047297ve plants from the centralinterior rows of each

plot Chlorophyll was measured at eight leaves stage (V 8) while

height and leaf area were measured at 1047297rst reproductive stage (R 1

occur about two to three days after 1047297nal vegetative stage ie VT)

Shoot length was measured from the base of the plant at ground

level to the top of the tassel with the use of a meter rod Leaf area

was determined (on a plant basis) by measuring the total length

and maximum width of each leaf at tasseling (Ma et al 2003) and

multiplied by a factor of 0747 (Yi et al 2006)

Chlorophyll content was measured following the method of

Bansal et al (1999) as reported by Amujoyegbe et al (2007) For

Table 1

Meteorological data ie total rainfall (mm) and minimum and maximum temperatures

(degC) of the experimental site during 2008 and 2009

Source The Director Regional Meteorological Centre 46-Jail Road Lahore Pakistan

Months Total

rainfall

(mm)

Min

temp

(degC)

Max

temp

(degC)

Total

rainfall

(mm)

Min

temp

(degC)

Max

temp

(degC)

Year 2008 Year 2009

January 103 minus46 100 158 minus08 128

February 148 minus30 121 128 00 129

March 145 46 218 140 32 181

April 200 60 208 222 59 217

May 41 99 269 101 95 266

June 160 160 264 176 114 284

July 215 173 263 192 153 286

August 167 161 260 187 164 274

September 82 114 250 116 117 272

October 29 61 193 13 53 233

November 39 20 205 14 10 192

December 38 11 162 173 minus08 149

Total 1367 1620

88 MK Abbasi et al Geoderma 195ndash196 (2013) 87 ndash93



this purpose 100 mg fresh leaf was taken (V 8 stage) crushed in

20 ml of 80 acetone and the extract centrifuged for 10 min at

1000 rpm Absorbance of the supernatant was recorded at 645 and

663 nm in a T-80 spectrophotometer Chlorophyll content (expressed

as mg gminus1 of each sample) was estimated according to Bansal et al

(1999) as follow

Total chlorophyll mggminus1 frac14 202 A645eth THORNndash802 A663eth THORN VWfrac12 =1000

where A = absorbance at the given wavelength W= weight of fresh

leaf sample V =1047297nal volume of chlorophyll solution

At maturity (on October 11 and 13 2008 and 2009 respectively)

the center two rows of each plot were hand-harvested tied into bun-

dles and then left in respective plots for drying for about a week The

weight of the bundles was recorded Grain yield was obtained after

removing ears from the harvested bundles and shelled while straw

yield was calculated from the difference in weights of the maize bun-

dles and grain yield Thousand-Kernel weight (TKW) was determined

from 200 grain samples randomly taken from the grains produced in

each plot and then multiplied by 5 Grain yield was recorded and

corrected to a 155 g kgminus1 water basis (Ma and Subedi 2005) Harvest

index (HI) was calculated as the ratio of grain yield to the total above-

ground biomass yield (Donald and Hamblin 1976)

24 Plant N concentration and N-uptake

For plant analysis the selected stover (used for straw yield) was

cleaned air dried chopped into smaller pieces and then oven dried at

65 degC to a constant weight The oven-dried plant material (stalk+

leaves) were ground to pass through a 1-mm sieve in a Micro Wiley

Mill Total N concentration was analyzed using Kjeldahls method

(Bremner and Mulvaney 1982) Nitrogen uptake by plant was calculat-

ed based on plant N concentration and weights of straw

25 Nitrogen use ef 1047297ciency and its components

The N data of samples were used for calculating the different

N ef 1047297ciency parameters and the percentage of N in plant tissue was

determined as a function of inorganic N applied in fertilizer (Abbasi

et al 2012)

Agronomic ef 1047297ciency of applied fertilizer N (NAE kg grain kg N

appliedminus1)=[grain yield (kg haminus1) in N added plots ndash grain yield

of control plots]Total amount of N fertilizer applied

Physiological ef 1047297ciency of applied N (NPE kg kgminus1)=[(dry mat-

ter (straw) yield (kg haminus1) in N addedminusdry matter (straw) yield of

control plots)(total N uptake by the fertilizer treatmentminus total N

uptake in the control)]

Nitrogen use ef 1047297ciency (NUE )=[(N uptake by the fertilized

treatmentminusN uptake in the control)total amount of N fertilizer

applied]times100

26 Statistical analysis

Analysis of variance (ANOVA) and least signi1047297cant difference (LSD)

tests among means were conducted for each character separately

using a MSTAT-C statistical analysis package (Michigan State Univ

East Lansing) Comparison of means for the individual treatments was

doneat the 5probability level based on the F-test of theanalysis of var-

iance (Steel and Torri 1980) Correlations between some of the study

parameters ie growth characteristics vs yield traits N-uptake vs

yield and NUE were also calculated The program SPSS 12 (www

SPSScom) for Windows (IBM Armonk NY) was used for this pur-

pose Signi1047297cance levels were computed following Muhammad

(1995 p 252ndash

268)

3 Results and discussion

31 Weather conditions

Rainfall during the two years of the experiment contrasted mark-

edly (Table 1) Total rainfall during 2009 was 1620 mm compared

with 1367 mm in 2008 The rainfall distribution between growing

seasons differed during the planting month of May 101 mm in

2009 (planting month) compared with 41 mm in 2008 Similarlyrainfall during the reproductive stage (August and September) was

also higher in 2009 (187 and 116 mm) than in 2008 (167 and

82 mm) The one factor which may affect the variability in the mea-

sured characteristics of maize is the implications of the measured

weather data on plant response The rainfall pattern during both

years clearly indicated exceptionally dry conditions after September

that may be one of the major causes of low maize yield under rainfed

conditions In comparison with rainfall temperature difference be-

tween the two years was very small and generally both minimum

and maximum temperature for most part of the growing season

was the same (Table 1)

32 Growth characteristics

Analysis of variance showed that maize growth characteristic

ie leaf area (LA) and leaf chlorophyll content were signi1047297cantly

affected by methods and N sources while plant height was signi1047297-

cantly affected only by N sources (Table 2) The interactive effect for

different variables was not signi1047297cant except yrtimesmethod interaction

for plant height Similarly the signi1047297cance levels for other measured

characteristics are also presented in Table 2 Growth characteristics

of maize were signi1047297cantly increased by N application (Table 3)

The N de1047297cient plants showed signi1047297cantly lower plant height LA

and chlorophyll content when compared with the plants treated

with N fertilizer (Table 3) A substantial increase in growth in re-

sponse to N fertilization indicated the signi1047297cance of N fertilizer

for maize in N poor soil where many farmers grow this crop with lit-

tle to no N fertilizer application

Differences among N sources was signi1047297cant and generally CANdisplayed the highest plant height LA (2009) and chlorophyll content

while urea showed the lowest However LA in 2008 was higher in AS

treated plants compared to CAN and urea Averaged across methods

and year the relative increase in plant height LA and chlorophyll con-

tent by CAN was 5 and 8 minus 2 and 5 6 and 17 over AS and urea

respectively

The ef 1047297ciency of different N sources was in1047298uenced by the type of

N fertilizer Results indicated that urea was less effective (with regard

to maize growth traits) than CAN and AS This is in agreement with

the 1047297ndings of Malhi (1997) who reported that urea was less effective

than AN for meadow bromegrass Similarly AS showed higher re-

sponse than urea in rice (Fageria et al 2011) that maybe associated

with higher acidity producing capacity of AS compared with urea

The superiority of CAN compared to AS and urea in the presentstudy maybe due to the immediate supply of NO3

minus to plants in early

growth stages and then N will be available from NH4+ sources It has

been reported that a majority of plants grows best with a mixture

of NH4+ and NO3

minus and the former may cause growth inhibition in

many species when supplied as the exclusive N source (Mahmood

and Kaiser 2003)

33 Yield and yield components

Nitrogen fertilizers signi1047297cantly increased TKW from 2130 and

2187 g (in 2008 and 2009) in the control to the maximum of 2915 g

indicating 37 increase (Table 4) Nitrogen source had signi1047297cant effect

on TKW and among three N sources CAN exhibited the highest TKW

(Table 4) Averaged over methods TKW obtained from CAN was 6

89MK Abbasi et al Geoderma 195ndash196 (2013) 87 ndash93



and 15 higher than urea in 2008 and 2009 respectively The difference

between CAN and AS in 2008 was non-signi1047297cant while TKW from CAN

in 2009 was 8 higher than AS Similarly TKW was signi1047297cantly higher

(43) under AS compared to urea In contrast with our1047297ndings Fageria

et al (2011) reported that TKW of rice was 13 higher with urea com-pared to AS

Straw yields at physiological maturity were signi1047297cantly increased

by N fertilizer application (Table 4) Relative yield increments in re-

sponse to N fertilization ranged between 28 and 39 over the control

Increments in maize straw yield by N fertilizers were also reported

earlier under different soils and environmental conditions (Abbasi

et al 2012 Azeez et al 2006 Barbieri et al 2008 Hammad et al

2011)

Response of straw yield to different N sources was similar to that

shown for TKW and signi1047297cant differences were observed among N

sources (Table 4) Highest straw yield in both years was recorded in

CAN followed by the AS (except in split application in 2008) while

urea N showed the lowest yields Malhi (1997) reported 7 and 15

lower dry matter yield (DMY) of meadow bromegrass from the 1047297

eldamended with urea N compared with ammonium nitrate Our results

were consistent with those reported by Watson (1987) in perennial

ryegrass that ammonium nitrate gave the highest dry matter yield

and urea the lowest with AS being the intermediate Under green-

house conditions Watson (1988) conducted experiments on ryegrass

by applying KNO3 AS and urea N sources and reported a 39 and 23

increase in ryegrass DMY by KNO3 compared with urea and AS N

sources respectively However in the rice cultivation Reddy and

Patrick (1978) and Bufogle et al (1998) reported no differences in

straw or grain yields between AS and urea N sources

Split application of N showed signi1047297cant effect on straw yield

(Table 4) Generally straw yields signi1047297cantly increased when

fertilizers were applied in two splits compared with single N appli-

cation The relative increases in 2008 and 2009 were between 17 to

48 and 14 to 18 respectively Under similar environmental

conditions maize straw yield was increased by 22 when N fertiliz-

er was applied in splits compared with single N application(Amanullah and Shah 2010) The authors explained that split appli-

cation of N delayed phenological development increased crop

growth rate leaf area per plant and plant height that resulted in

higher strawdry-matter yield Straw yields also showed signi1047297cant re-

sponse to the years and in the year 2009 yields were relatively higher

(7356 kg haminus1) than the yields recorded in 2008 (7166 kg haminus1)

Application of different N fertilizer sources signi1047297cantly increased

grain yield (Table 4) The relative increase in yield associated with N

fertilization ranged between 78 to 112 (2008) and 93 to 115

(2009) over the control In our previous study maize grain yields at

different N rates were increased by 80 to 88 over the control

(Abbasi et al 2012) Similarly in another study maize grain yields

were increased 2-fold (compared to the control) when urea N was

applied at the rate of 120 or 150 kg N ha

minus1

(Abbasi et al 2010)Barbieri et al (2008) reported that the relative increase in grain

yield of maize following the application of N fertilizers was 34 and

50 over the control

Grain yields were signi1047297cantly affected by N sources (Table 4) The

highest yields in both years were obtained from CAN followed by AS

while urea exhibited the lowest yield Averaged across application

methods the relative increases in grain yields by CAN and AS were

11 and 10 in 2008 and 8 and 5 in 2009 over the urea N source

The difference between CAN and AS in 2008 was non-signi1047297cant

while CAN showed signi1047297cantly higher yields (3) over AS in 2009

Our results were in accordance with the recent 1047297ndings of Hojka

(2012) who reported that application of CAN resulted in 7 and 11

Table 2

Analysis of variance (ANOVA) for growth yield and N accumulation of rainfed maize in response to N source (N) methodtimings of N application (M) years (Y) and their inter-

actions in 2008 and 2009 at Rawalakot Azad Jammu and Kashmir Pakistan

ANOVA

Source DF Plant height Leaf area (LA) Chlorophyll content 1000-kernel weight (TKW) Straw yield Grain yield Harvest index N concentration N-uptake

Years (Y) 1 nsa ns ns ns ns ns

Met hods ( M) 1 ns ns

N sources (N) 3

Y timesM 3 ns ns ns ns ns ns ns

Y timesN 3 ns ns ns ns ns ns ns

MtimesN 3 ns ns ns ns ns ns

Y timesMtimesN 3 ns ns ns ns ns ns ns ns ns

CV 541 316 1335 583 158 141 126 768 428

a ns not signi1047297cant Signi1047297cant at the 005 probability level

Signi1047297cant at the 001 probability level

Table 3

Effect of N fertilizer sources and timings of N application on the growth components of maize ie plant height leaf area (per plant basis) and chlorophyll content (on fresh weight

basis) grown under 1047297eld conditions at Rawalakot Azad Jammu and Kashmir in 2008 ndash09

N sources Plant height Leaf area Chlorophyll contents

2008 2009 2008 2009 2008 2009

Full Split Full Split Full Split Full Split Full Split Full Split

cm cm2 mg gminus1

Control 1923d 1923d 1963d 1963d 7384d 7384d 7437d 7437d 58b 58c 53c 53c

Urea 2144c 2027c 2003c 2216b 8044c 8155c 8018c 8235c 64b 91b 77b 98b

CAN 2307a 2228a 2177a 2354a 8403b 8621b 8463a 8675a 84a 101a 91a 109a

AS 2167b 2148b 2118b 2195b 8685a 9043a 8353b 8627b 89a 95b 82b 97b

Means of three replicates with different letters in the same column indicate signi1047297cant differences (P le005)




yield increases in maize compared with AS and urea respectively In a

greenhouse study Fageria et al (2011) reported that across six N

rates applied to rice AS produced 10 higher grain yield compared

with urea while application of AS at the rate of 160 mg N kgminus1 pro-

duced 22 higher grain yield compared with urea at the same rate

of N However our results suggested that under rainfed conditions

(without irrigation) CAN proved to be a superior N fertilizer for

maize grain yield compared with AS and urea

Grain yields exhibited a signi1047297cant response to split application(Table 4) The overall increase in grain yields due to split application

by different N sources ranged between 4ndash9 in 2008 and 3 in 2009

A 6 increase in maize grain yields due to split application was

recorded in our previous study (Abbasi et al 2012) Nazakat et al

(2004) reported that application of urea N during sowing (50)

and before the tasseling (50) resulted in the highest plant height

and cob length higher number of grains per cob and the highest

grain yield in maize The increase in grain yield due to split applica-

tion might be due to the availability of more N during later growth

periods or due to the enhanced N uptake (as found in the present

study) thereby increasing crop performance and grain yield

A signi1047297cant year effect for both straw and grain yields suggested

that crop growth conditions were slightly better in 2009 than in 2008

Both minimum and maximum temperatures of both years were com-parable ie 7 and 21 degC and 7 and 22 degC while the total rainfall in 2009

was 17 higher than that recorded for 2008 which might have affect-

ed both the growth and yield components of maize

The harvest indexes (HI) in thecontrol were 29 and 28 in 2008 and

2009 respectively (Table 5) Nitrogen fertilization signi1047297cantly in-

creased HI range between 36 and 39 The increase in HI due to N fertil-

ization may be due to increased leaf area per plant crop growth rate

and grain yield as described earlier by Amanullah and Shah (2010)

Among the three N fertilizer sources applied non-signi1047297cant difference

was recorded in 2009 while HI in 2008 was signi1047297cantly higher in CAN

and AS compared with urea N

34 Plant N balance

Shoot N was increased 2-fold (over the control) following N fertil-

izer application (Table 5) Among different N sources urea exhibited

the highest N concentration followed by CAN while AS showed the

lowest Split N application signi1047297cantly increased shoot N concentra-

tion and the relative increases due to split application were 10 to 15

in 2008 and 7 to 19 in 2009 over single N application at planting

Nitrogen fertilization increased crop N-uptake in both years of ex-

periment (Fig 1) In 2008 N uptake in the control was 40 kg N haminus1

which signi1047297cantly increased to 77 to 113 kg N haminus1 by N fertilizers

In 2009 the corresponding increase in N-uptake was 86 to 119 kg N

haminus1 compared with 38 kg N haminus1 in the control

Increased N uptake with N fertilization might be attributed to

increased above ground biomass yield as the N-uptake followed a

pattern similar to that for plant biomass and a signi1047297cant correlation

(r= 087) (Table 6) existed between the two The N-uptake in maize

due to N fertilization and the relationship between dry-matter yield

and N uptake was in accordance with our previous study (Abbasi et

al 2010 2012) High above ground dry matter yield has been

shown to correlate strongly with total above ground N uptake in trop-

ical maize populations (Azeez et al 2006) Results of this study also

demonstrated that both straw and grain yield in our conditionsdepended upon the growth characteristics and N balance of maize

There were signi1047297cant correlations of plant height LA chlorophyll

contents TKW and N contents with straw and grain yield (r=090

091 r= 092 095 r= 097 098 r= 095 096 and r= 091 087 re-

spectively) (Table 6) Similarly plant N-uptake showed a signi1047297cant

and positive correlation with straw and grain yield (r=087 082

respectively) indicating the importance of N availability and its

supply to plants for increasing yield and productivity

The amount of N taken up by plant depended upon the type of fer-

tilizer applied and signi1047297cant differences were observed among N

sources (Fig 1) Averaged across methods N-uptake in both years

was in the order ureagtCANgtAS The relative increases in N-uptake

by urea over CAN and AS were 10 and 25 in 2008 and 7 and 22

in 2009 respectively The corresponding increments in N-uptake byCAN over AS were 13 and 14 respectively However it should be

mentioned that the N-uptake described here included tissue (straw)

N-uptake not N in grains which may affect the N source response

differently

Split application of N fertilizers signi1047297cantly increased N uptake

(Fig 1) The relative increases in N-uptake (average across N source)

due to split application were 18 and 16 in 2008 and 2009 respec-

tively over single N application Among different N fertilizer sources

urea exhibited the highest response to split application in 2008

while in 2009 CAN showed the maximum response Response of AS

to split application was lowest in both years Increment in N-uptake

in maize due to split application was also observed in our previous

study where N-uptakes were increasedby 6 and 13 over single N ap-

plication at planting (Abbasi et al 2012) In another experiment on

Table 4

Effect of N fertilizer sources and timings of N application on the yield and yield components of maize grown under 1047297eld conditions at Rawalakot Azad Jammu and Kashmir in

2008ndash09

N sources 1000-kernel weight Straw yield Grain yield

2008 2009 2008 2009 2008 2009


g kg haminus1 kg haminus1

Control 2130d 2130d 2187c 2187d 5748d 5748d 5816d 5816d 2335d 2335d 2378d 2378d

Urea 2590c 2690c 2350b 2516c 7386c 7741b 7672c 7810c 4155c 4544c 4588c 4716c

CAN 2820a 2770a 2693a 2915a 7621a 7867a 7961a 8098a 4739a 4942b 4976a 5106a

AS 2673b 2740b 2496b 2675b 7544b 7674c 7781b 7890b 4632b 4955a 4818b 4974b


Table 5

Effect of N fertilizer sources and timings of N application on harvest index and

N-concentration in maize shoot (stalk+leaves) grown under 1047297eld conditions at

Rawalakot Azad Jammu and Kashmir in 2008ndash09

N sources Harvest index N concentration

2008 2009 2008 2009

Full Split Full Split Full Split Full Split

g kgminus1

Control 29c 29c 28b 28b 69c 69d 66d 66d

Urea 36b 37b 37a 38a 127a 146a 131a 152a

CAN 38a 39a 38a 39a 112b 127b 116b 138b

AS 38a 39a 38a 39a 102b 112c 111c 119c

Means of three replicates with different letters in the same column indicate signi1047297cant

differences (P le005)




maize split application of N fertilizer increased N-uptake to 192 kg N

haminus1 compared with 168 kg N haminus1 applied at planting (Sainz Rozas

et al 2004) The authors explained that greater N-uptake due to split

application was associated with reduction in N losses ie denitri1047297ca-

tion immobilization and leaching

Variation in N sources signi1047297cantly affected the agronomic physi-

ological and NUE of applied N (Table 7) The agronomic ef 1047297ciency

(NAE) of maize from different N sources ranged between 15ndash22 and

18ndash23 kg kgminus1 while the physiological ef 1047297ciency (NPE) ranged be-

tween 27ndash48 and 25ndash41 in 2008 and 2009 respectively Among N

sources CAN and AS were comparable for NAE while urea exhibited

lower values Averaged across year and methods the NPE of maize

from urea CAN and AS were 29 37 and 42 kg kgminus1 respectively

showing AS superior to urea and CANNitrogen use ef 1047297ciency (NUE) of maize grown under different N

fertilizer sources varied with N sources and split application

(Table 7) Among N sources NUE values ranged between 31 to 61

in 2008 and 40 to 67 in 2009 Averaged across application methods

the NUE values of maize in 2008 were 52 42 and 35 for urea CAN

and AS while the corresponding values for the year 2009 were 60

53 and 43 respectively Relative increments () in NUE by urea

were 25 49 in 2008 and 12 38 in 2009 over CAN and AS respec-

tively Similarly the relative increments () in NUE by CAN was 19

and 23 over AS

Split application of N fertilizer showed signi1047297cant effect on NUE

(Table 7) The NUE values of maize were 37 and 46 (average over

N sources) when singlefull N was applied at planting (2008 and

2009) but these were increased to 48 and 58 when N was applied

as split dose indicating 23 and 21 increase over single N application

4 Conclusions

In order to increase NUE and optimize crop yield selection and

recommendation of the most appropriate N source under particular

conditions is an important management strategy Although urea is

the most dominant and main source of N applied throughout the

world yet a comparative study was conducted to examine the ef 1047297-

ciency of urea CAN and AS on the productivity and NUE of maizegrown under hilly region of Kashmir Pakistan Results of this study

indicate that CAN is superior to urea and AS with regard to growth

and yield of maize A signi1047297cant increase in growth characteristics

straw and grain yield of maize by CAN indicate that application of

CAN may be an economical option when maize is grown for both fod-

der and grain production in the rainfed mountainous ecosystems

However N balance studies exhibited superiority of urea to CAN

and AS The N balance studies were based on tissue (straw) N concen-

tration and N-uptake without grain N that may affect these results if

added The discrepancy between growth-yield traits and N balance

N Fertilizer sources N Fertilizer sources

N - u p t a

k e

( k g

h a - 1 )

N - u p t a k e

( k g

h a - 1 )

0

20

40

60

80

100

120

140

FullN

SplitN

Control UN CAN AS Control UN CAN AS

0

20

40

60

80

100

120

140 FullN

SplitN2008 2009

Fig 1 Effect of N fertilizer sources and timings of N application (single application at planting or split application) on N-uptake (kg ha minus1) of maize shoot (stalk+ leaves without

grain) grown under 1047297eld conditions at Rawalakot Azad Jammu and Kashmir Pakistan in 2008 and 2009 Vertical lines on each bar represent the LSD (P le005) among different

N sources

Table 6

Pearson correlation (r) coef 1047297cients between plant height leaf area chlorophyll content seed yield dry matter yield Harvest index N content and uptake of wheat in response to

different N fertilizer application at Rawalakot Azad Jammu and Kashmir

Par ameters Pla nt height Leaf a rea Chlorophyll content 1 000 k ernel weight Str aw yield Gr ain yield H arvest ind ex N c oncent ra tion

cm cm2 mg gminus1 g kg haminus1 g kgminus1

Leaf area 090

Chlorophyll content 096 096

1000 kernel weight 099 094 099

Dry ma tter yield 0 9 0 092 097 095

Grain yield 091 095 098 096 099

Harvest index 091 097 099 096 099 099

N content 071 069 081 078 091 087 084

N-uptake 051 055 073 065 087 082 081 099

Correlation is signi1047297cant at the 005 level





to N sources is not fully understood However the possible role of

changes in soil pH (if any) or disparity in N losses (among different

N sources) may be a potential cause of these differences

Acknowledgments

This work was funded by the Higher Education Commission

Islamabad Pakistan via project no 20ndash367RampD05

References

Abbasi MK Kazmi M Hussan F 2005 Nitrogen use ef 1047297ciency and herbage produc-tion of an established grass sward in relation to moisture and nitrogen fertilization

Journal of Plant Nutrition 28 1693ndash1708Abbasi MK Khaliq A Sha1047297q M Kazmi M Ali I 2010 Comparative effectiveness of

urea N poultry manure and their combination in changing soil properties andmaize productivity under rainfed conditions in Northeast Pakistan ExperimentalAgriculture 46 211ndash230

Abbasi MK Tahir MM Sadiq A Iqbal M Zafar M 2012 Yield and nitrogen useef 1047297ciency of rainfed maize response to splitting and nitrogen rates in KashmirPakistan Agronomy Journal 104 48ndash457

Amanullah Shah P 2010 Timing and rate of nitrogen application in1047298uence grainquality and yield in maize planted at high and low densities Journal of the Scienceof Food and Agriculture 90 21ndash29

Amujoyegbe BJ Opabode JT Olayinka A 2007 Effect of organic and inorganicfertilizer on yield and chlorophyll content of maize ( Zea mays L) and sorghumSorghum bicolour (L) Moench) African Journal of Biotechnology 6 1869 ndash1873

Azeez JO Adetunji MT Lagoke STO 2006 Response of low-nitrogen tolerantmaize genotypes to nitrogen application in a tropical Al1047297sol in northern NigeriaSoil and Tillage Research 91 181ndash185

Bansal UK Saini RG Kaur A 1999 Genetic variability in leaf area and chlorophyllcontent of aromatic rice International Rice Research Notes 24 (1) 21

Barbieri PA Echeverriacutea HE Saiacutenz-Rozas HR Andrade FH 2008 Nitrogen use ef 1047297-ciency in maize as affected by nitrogen availability and row spacing Agronomy

Journal 100 1094ndash1100Bremner JM Mulvaney CS 1982 Nitrogenmdashtotal In Page AL Miller RH Keeney

DR (Eds) Methods of SoilAnalysis Part 2 Chemical andMicrobiologicalPropertiesSSSA Madison WI pp 595ndash624

Bufogle Jr A Bollich PK Kovar JL Lindau CW Macchiavellid RE 1998 Compar-ison of ammonium sulfate and urea as nitrogen sources in rice production Journalof Plant Nutrition 21 1601ndash1614

Donald CM Hamblin J 1976 The biological yield and harvest index of cereals asagronomic and plant breeding criteria Advances in Agronomy 28 361 ndash405

Fageria NK Baligar VC 2005 Enhancing nitrogen use ef 1047297ciency in crop plantsAdvances in Agronomy 88 97ndash185

Fageria NK Baligar VC Clark RB 2006 Physiology of Crop Production TheHaworth Press New York

Fageria NK dos Santos AB Coelho AM 2011 Growth yield and yield componentsof lowland rice as in1047298uenced by ammonium sulfate and urea fertilization Journalof Plant Nutrition 34 371ndash386

Garrido-Lestache E Loacutepez-Bellido RJ Loacutepez-Bellido L 2005 Durum wheat qualityunder Mediterranean conditions as affected by N rate timing and splitting Nform and S fertilization European Journal of Agronomy 23 265 ndash278

Glass ADM 2003 Nitrogen use ef 1047297ciency of crop plants physiological constraintsupon nitrogen absorption Critical Reviews in Plant Sciences 22 453ndash470

Hammad HM Ahmad A Khaliq T Farhad W Mubeen M 2011 Optimizing rate of nitrogen application for higher yield and quality in maize under semiarid environ-ment Crop amp Environment 2 38ndash41

Hojka Z 2012 Effects of the time of the application and the form of nitrogen on maizeinbred lines yield and 1000-grain weight Cereal Research Communications 40277ndash284

Ladha JK Pathack H Krupnik TJ Six J van Kessel C 2005 Ef 1047297ciency of fertilizernitrogen in cereal production retrospects and prospects Advances in Agronomy87 85ndash156

Liu K Wiatrak P 2011 Corn production and plant characteristics response toN fertilization management in dry-land conventional tillage system International

Journal of Plant Production 5 405 ndash416Ma BL Subedi KD 2005 Development yield grain moisture and nitrogen uptake of

Bt corn hybrids and their conventional near-isoline Field Crops Research 93199ndash211

Ma BL Dwyer LM Costa C 2003 Row spacing and fertilizer nitrogen effects onplant growth and grain yield of maize Canadian Journal of Plant Science 83241ndash247

Mahmood T Kaiser WM 2003 Growth and solute composition of the salt-tolerantkallar grass [Leptochloa fusca (L) Kunth] as affected by nitrogen source Plant andSoil 252 359ndash366

Malhi SS 1997 Rate source and time of N application for meadow bromegrass incentral Alberta Canada Nutrient Cycling in Agroecosystems 46 241 ndash247

Muhammad F 1995 Correlations Statistical Methods and Data Analysis 1st editionKitab Markaz Faisalabad Pakistan pp 252ndash268

Nazakat N Sarwar G Naseeb T Yousaf M 2004 The effect of the combined appli-cation of N and P on growth and yield of maize Sarhad Journal of Agriculture 20251ndash253

Randall GW Vetsch JA 2005 Corn production on a subsurface drained mollisol asaffected by fall versus spring application of nitrogen and nitrapyrin Agronomy

Journal 97 472ndash478Randall GW Vetsch JA Huffman JR 2003 Corn production on a subsurface-

drained mollisol as affected by time of nitrogen application and nitrapyrin Agron-omy Journal 95 1213ndash1219

Raun WR Johnson GV 1999 Improving nitrogen use ef 1047297ciency for cereal produc-tion Agronomy Journal 91 357ndash363

Raun WR Solie JB Johnson GV Stone ML Mullen RW Freeman KWThomason WE Lukina V 2002 Improving nitrogen use ef 1047297ciency in cerealgrain production with optical sensing and variable rate application Agronomy

Journal 94 815ndash820Reddy KR Patrick Jr WH 1978 Utilization of labeled urea and ammonium sulfate

by lowland rice Agronomy Journal 70 465 ndash467Ruiz-Diaz DA Sawyer JE 2008 Plant available nitrogen from poultry manure as

affected by time of application Agronomy Journal 100 1318 ndash1326Sainz Rozas HR Echeverrıaacute HE Andrade FH Studdert GA 1997 Effect of urease

inhibitor and fertilization time on nitrogen uptake and maize grain yield underno-tillage Revista de la Facultad de Agronomiacutea de la Plata 102 129 ndash136

Sainz Rozas HR Echeverriacutea HE Barbieri PA 2004 Nitrogen balance as affected byapplication time and nitrogen fertilizer rate in irrigated no-tillage maize Agronomy

Journal 96 1622ndash1631Steel RGD Torri JH 1980 Principles and Procedures of Statistics 2nd ed McGraw

Hill Book Co Inc New York USAWatson CJ 1987 The comparative effect of a mixed urea ammonium nitrate ammo-

nium sulphate granular formulation on the ef 1047297ciency of N recovery by perennialryegrass Fertilizer Research 14 193ndash204

Watson CJ 1988 An assessment of granular ureaammonium sulphate and ureapotassium nitrate fertilizers on nitrogen recovery by ryegrass Fertilizer Re-search 18 19ndash29

Yi ZX Wang P Zhang HF Shen LX Liu M Dai MH 2006 Effects of type andapplication rate of nitrogen fertilizer on source-sink relationship in summermaize in North China Plain Plant Nutrition and Fertilizer Science 12 294ndash300

Zebarth BJ Leclerc Y Moreau G 2004 Rate and timing of nitrogen fertilization of

Russet Burbank potato nitrogen use ef 1047297ciency Canadian Journal of Plant Science84 845ndash854

Table 7

Effect of N fertilizer sources and timings of N application on agronomic ef 1047297ciency (NAE

kgkg) physiological ef 1047297ciency (NPE kgkg) and nitrogen use ef 1047297ciency (NUE ) of

applied N in maize in 2008 and 2009

N

sources

NAE NPE NUE

2008 2009 2008 2009 2008 2009


kgkg kgkg

Control ndash ndash ndash ndash ndash ndash ndash ndash ndash ndash ndash ndash

Urea 15b 1 8b 18c 19b 32c 27c 30b 2 5c 43a 61a 52a 67a

CAN 20a 22a 22a 23a 41b 3 5b 40a 31b 38b 4 5b 45b 6 1b

AS 19a 22a 20b 22a 48a 42a 41a 37a 31c 3 9c 40c 4 6c






losses were decreased (26ndash55 vs 04ndash1) in split application com-

pared with single N application at planting (Sainz Rozas et al 1997)

However there are also reports that split application of N fertilizer to

different crops did not affect their performance and productivity

(Garrido-Lestache et al 2005 Zebarth et al 2004) Liu and Wiatrak

(2011) reported that splitting N into two doses ie all N at planting

and at V 6 growth stage had no effect on maize grain yield and plant

characteristics

The form or the source of added N plays an important role in reg-ulating N transformations changing N loss patterns and in1047298uencing

NUE (Ladha et al 2005) Urea ammonium sulfate (AS) and ammoni-

um nitrate (AN) or calcium ammonium nitrate (CAN) are the main N

carriers used worldwide in crop production (Fageria and Baligar

2005) However urea is generally favored by the growers over AS

and AN or CAN due to lower application cost because urea has a

higher N analysis than AS and ANCAN (46 vs 21 33 and 26 N re-

spectively) Few studies had been reported previously on the compar-

ative effects of different N fertilizer sources on the growth and yields

of crops and response was generally inconsistent Fageria et al (2011)

conducted two greenhouse experiments on rice with urea and AS and

reported that the maximum grain yield and N-uptake at average N

rate (160 mg kgminus1) was 22 and 15 higher with AS compared to

urea The comparative effects of urea and AN on meadow bromegrass

(Bromus bibersteinii) at two sites in central Alberta Canada indicated

that AN generally produced higher DMY (16ndash26) protein yield (21

and 37) NUE (16 and 26) and N recovery (20 and 38) com-

pared with urea (Malhi 1997) In our previous study conducted on

grassland soil NH4+ source of N was found superior to NO3

minus source

In the plots where NO3minus

ndashN was added as the N source DMY was

1760ndash1870 kg haminus1 N recovery ef 1047297ciency was 24ndash43 while in

NH4+

ndash N added plots both DMY and N recovery ef 1047297ciency were in-

creased to 3190ndash3700 kg haminus1 and 39ndash48 respectively (Abbasi

et al 2005)

The effect of N fertilizer forms or sources on the growth yield and

NUE of maize under1047297eld conditions had not been reported extensive-

ly The importance of such studies under rainfed conditions becomes

critical because N availability to plants differs with N form as a result

of differences in mobility of each form in soil solution Keeping this inview the objective of the present study was to determine the effects

of different fertilizer N formssources applied at different timings on

growth and yield characteristics N uptake and NUE of maize in a

1047297eld experiment under rainfed mountainous conditions

2 Materials and methods

21 Study site

The experiment was conducted at Rawalakot Azad Jammu and

Kashmir (AJK) Faculty of Agriculture Experimental Farm in 2008

and 2009 The study area lies between the altitude of 1800 and

2000 m above sea level andlatitude33ndash36degin thenorth-east of Pakistan

under the foothills of the great Himalayas at Rawalakot district Poonch

division AJK Pakistan The detail of the study area had been described

earlier (Abbasi et al 2012) The monthly precipitation and temperature

of the experimental area are presented in Table 1

22 Experimental procedures and details

Before the onset of the experiment soil samples were collected and

analyzed for physical and chemical properties The soil in the study site

was clay loam in texture Humic Lithic Eutrudepts (Inceptisols) The

background soil sample had pH 74 ECe 058 dS mminus1 organic C

87 g kgminus1 total N 049 g kgminus1 available P 64 mg kgminus1 and exchange-

able K 101 mg kgminus1 For proper seed bed preparation the site was

plowed and left for 2 weeks The individual plots were prepared

according to the treatments and the plot size was 3-m long and 3-mwide

The treatments were composed of i) three N fertilizer sources

ie urea calcium ammonium nitrate (CAN) ammonium sulfate

(AS) and a control (no N) ii) two application timings ie a single N

application or split application In case of single application full

dose of N fertilizer was applied by broadcast method at planting

while in case of split application half dose was applied at planting

and the remaining half was applied at the time when plants were

grown up to six leaves stage (V 6) Nitrogen from different N sources

was applied at the rate of 120 kg N haminus1 Phosphorus and K were in-

corporated into the soil approximately 5 cm deep in all plots includ-

ing the control at the time of sowing Rates were 90 kg P2O5 haminus1

and 60 kg K2O haminus1 as single super phosphate (SSP) and sulfate of

potash (SOP) respectively All the fertilizers were well mixed intothe soil before sowing

Maize ( Zea Mays L) variety ldquoSwanrdquo was used in the experiment

Seeds were collected from National Agricultural Research Centre

(NARC) Islamabad Pakistan The experiment consisted of a factorial

arrangement of 2 years two methodstimings and four N sources in-

cluding a control arranged in a completely randomized block design

replicated three times Maize was sown in rows at 45-cm spacing

(leaving 15 cm border on each side of the plot) on 12 and 15 May

2008 and 2009 respectively After germination the plant to plant dis-

tance was thinned to 23 cm All standard local cultural practices were

followed when required throughout the growth period No irrigation

was provided and manual weeding was carried out when required

23 Measurements

The morphological characteristics of the crop like shoot length

leaf area (LA) and chlorophyll content were recorded in standing

crop by selecting 1047297ve plants from the centralinterior rows of each

plot Chlorophyll was measured at eight leaves stage (V 8) while

height and leaf area were measured at 1047297rst reproductive stage (R 1

occur about two to three days after 1047297nal vegetative stage ie VT)

Shoot length was measured from the base of the plant at ground

level to the top of the tassel with the use of a meter rod Leaf area

was determined (on a plant basis) by measuring the total length

and maximum width of each leaf at tasseling (Ma et al 2003) and

multiplied by a factor of 0747 (Yi et al 2006)

Chlorophyll content was measured following the method of

Bansal et al (1999) as reported by Amujoyegbe et al (2007) For

Table 1

Meteorological data ie total rainfall (mm) and minimum and maximum temperatures

(degC) of the experimental site during 2008 and 2009

Source The Director Regional Meteorological Centre 46-Jail Road Lahore Pakistan

Months Total

rainfall

(mm)

Min

temp

(degC)

Max

temp

(degC)

Total

rainfall

(mm)

Min

temp

(degC)

Max

temp

(degC)

Year 2008 Year 2009

January 103 minus46 100 158 minus08 128

February 148 minus30 121 128 00 129

March 145 46 218 140 32 181

April 200 60 208 222 59 217

May 41 99 269 101 95 266

June 160 160 264 176 114 284

July 215 173 263 192 153 286

August 167 161 260 187 164 274

September 82 114 250 116 117 272

October 29 61 193 13 53 233

November 39 20 205 14 10 192

December 38 11 162 173 minus08 149

Total 1367 1620









(1999) as follow




























et al 2012)










applied]times100












(1995 p 252ndash

268)






































respectively












of NH4+ and NO3



and Kaiser 2003)





















2011)





































minus1



50 over the control










Table 2



ANOVA




N sources (N) 3





CV 541 316 1335 583 158 141 126 768 428



Table 3




2008 2009 2008 2009 2008 2009


cm cm2 mg gminus1




AS 2167b 2148b 2118b 2195b 8685a 9043a 8353b 8627b 89a 95b 82b 97b





































34 Plant N balance
























091 r= 092 095 r= 097 098 r= 095 096 and r= 091 087 re-













differently











Table 4


2008ndash09


2008 2009 2008 2009 2008 2009






AS 2673b 2740b 2496b 2675b 7544b 7674c 7781b 7890b 4632b 4955a 4818b 4974b


Table 5





2008 2009 2008 2009


g kgminus1


Urea 36b 37b 37a 38a 127a 146a 131a 152a

CAN 38a 39a 38a 39a 112b 127b 116b 138b

AS 38a 39a 38a 39a 102b 112c 111c 119c




























and 23 over AS






4 Conclusions

















N - u p t a

k e

( k g

h a - 1 )

N - u p t a k e

( k g

h a - 1 )

0

20

40

60

80

100

120

140

FullN

SplitN


0

20

40

60

80

100

120

140 FullN

SplitN2008 2009



N sources

Table 6





Leaf area 090




Grain yield 091 095 098 096 099

Harvest index 091 097 099 096 099 099

N content 071 069 081 078 091 087 084

N-uptake 051 055 073 065 087 082 081 099









Acknowledgments



References















































Table 7




N

sources

NAE NPE NUE

2008 2009 2008 2009 2008 2009


kgkg kgkg




AS 19a 22a 20b 22a 48a 42a 41a 37a 31c 3 9c 40c 4 6c











(1999) as follow




























et al 2012)










applied]times100












(1995 p 252ndash

268)






































respectively












of NH4+ and NO3



and Kaiser 2003)





















2011)





































minus1



50 over the control










Table 2



ANOVA




N sources (N) 3





CV 541 316 1335 583 158 141 126 768 428



Table 3




2008 2009 2008 2009 2008 2009


cm cm2 mg gminus1




AS 2167b 2148b 2118b 2195b 8685a 9043a 8353b 8627b 89a 95b 82b 97b





































34 Plant N balance
























091 r= 092 095 r= 097 098 r= 095 096 and r= 091 087 re-













differently











Table 4


2008ndash09


2008 2009 2008 2009 2008 2009






AS 2673b 2740b 2496b 2675b 7544b 7674c 7781b 7890b 4632b 4955a 4818b 4974b


Table 5





2008 2009 2008 2009


g kgminus1


Urea 36b 37b 37a 38a 127a 146a 131a 152a

CAN 38a 39a 38a 39a 112b 127b 116b 138b

AS 38a 39a 38a 39a 102b 112c 111c 119c




























and 23 over AS






4 Conclusions

















N - u p t a

k e

( k g

h a - 1 )

N - u p t a k e

( k g

h a - 1 )

0

20

40

60

80

100

120

140

FullN

SplitN


0

20

40

60

80

100

120

140 FullN

SplitN2008 2009



N sources

Table 6





Leaf area 090




Grain yield 091 095 098 096 099

Harvest index 091 097 099 096 099 099

N content 071 069 081 078 091 087 084

N-uptake 051 055 073 065 087 082 081 099









Acknowledgments



References















































Table 7




N

sources

NAE NPE NUE

2008 2009 2008 2009 2008 2009


kgkg kgkg




AS 19a 22a 20b 22a 48a 42a 41a 37a 31c 3 9c 40c 4 6c

















2011)





































minus1



50 over the control










Table 2



ANOVA




N sources (N) 3





CV 541 316 1335 583 158 141 126 768 428



Table 3




2008 2009 2008 2009 2008 2009


cm cm2 mg gminus1




AS 2167b 2148b 2118b 2195b 8685a 9043a 8353b 8627b 89a 95b 82b 97b





































34 Plant N balance
























091 r= 092 095 r= 097 098 r= 095 096 and r= 091 087 re-













differently











Table 4


2008ndash09


2008 2009 2008 2009 2008 2009






AS 2673b 2740b 2496b 2675b 7544b 7674c 7781b 7890b 4632b 4955a 4818b 4974b


Table 5





2008 2009 2008 2009


g kgminus1


Urea 36b 37b 37a 38a 127a 146a 131a 152a

CAN 38a 39a 38a 39a 112b 127b 116b 138b

AS 38a 39a 38a 39a 102b 112c 111c 119c




























and 23 over AS






4 Conclusions

















N - u p t a

k e

( k g

h a - 1 )

N - u p t a k e

( k g

h a - 1 )

0

20

40

60

80

100

120

140

FullN

SplitN


0

20

40

60

80

100

120

140 FullN

SplitN2008 2009



N sources

Table 6





Leaf area 090




Grain yield 091 095 098 096 099

Harvest index 091 097 099 096 099 099

N content 071 069 081 078 091 087 084

N-uptake 051 055 073 065 087 082 081 099









Acknowledgments



References















































Table 7




N

sources

NAE NPE NUE

2008 2009 2008 2009 2008 2009


kgkg kgkg




AS 19a 22a 20b 22a 48a 42a 41a 37a 31c 3 9c 40c 4 6c






































34 Plant N balance
























091 r= 092 095 r= 097 098 r= 095 096 and r= 091 087 re-













differently











Table 4


2008ndash09


2008 2009 2008 2009 2008 2009






AS 2673b 2740b 2496b 2675b 7544b 7674c 7781b 7890b 4632b 4955a 4818b 4974b


Table 5





2008 2009 2008 2009


g kgminus1


Urea 36b 37b 37a 38a 127a 146a 131a 152a

CAN 38a 39a 38a 39a 112b 127b 116b 138b

AS 38a 39a 38a 39a 102b 112c 111c 119c




























and 23 over AS






4 Conclusions

















N - u p t a

k e

( k g

h a - 1 )

N - u p t a k e

( k g

h a - 1 )

0

20

40

60

80

100

120

140

FullN

SplitN


0

20

40

60

80

100

120

140 FullN

SplitN2008 2009



N sources

Table 6





Leaf area 090




Grain yield 091 095 098 096 099

Harvest index 091 097 099 096 099 099

N content 071 069 081 078 091 087 084

N-uptake 051 055 073 065 087 082 081 099









Acknowledgments



References















































Table 7




N

sources

NAE NPE NUE

2008 2009 2008 2009 2008 2009


kgkg kgkg




AS 19a 22a 20b 22a 48a 42a 41a 37a 31c 3 9c 40c 4 6c




























and 23 over AS






4 Conclusions

















N - u p t a

k e

( k g

h a - 1 )

N - u p t a k e

( k g

h a - 1 )

0

20

40

60

80

100

120

140

FullN

SplitN


0

20

40

60

80

100

120

140 FullN

SplitN2008 2009



N sources

Table 6





Leaf area 090




Grain yield 091 095 098 096 099

Harvest index 091 097 099 096 099 099

N content 071 069 081 078 091 087 084

N-uptake 051 055 073 065 087 082 081 099









Acknowledgments



References















































Table 7




N

sources

NAE NPE NUE

2008 2009 2008 2009 2008 2009


kgkg kgkg




AS 19a 22a 20b 22a 48a 42a 41a 37a 31c 3 9c 40c 4 6c









Acknowledgments



References















































Table 7




N

sources

NAE NPE NUE

2008 2009 2008 2009 2008 2009


kgkg kgkg




AS 19a 22a 20b 22a 48a 42a 41a 37a 31c 3 9c 40c 4 6c




Efectos de La Fertilizacion Nitrogenada y Uso Eficiente de Nitrogeno en Maiz de Temporal

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