N

Pa

Eb

Bc

a

ARA

K1

SPS

1

kaatcppew

dSf

h0

Agricultural Water Management 148 (2015) 141–149

Contents lists available at ScienceDirect

Agricultural Water Management

jou rn al hom ep age: www.elsev ier .com/ locate /agwat

utrient leaching in an Ultisol cultivated with sugarcane

.J. Ghibertoa,b,∗, P.L. Libardib, P.C.O. Trivelinb,c

Departamento de Ciencias del Ambiente, Facultad de Ciencias Agrarias (FCA), Universidad Nacional del Litoral (UNL), Kreder 2805, CP S3080HOFsperanza, ArgentinaCurso de Pós-Graduac ão em Solos e Nutric ão de Plantas, Escola Superior de Agricultura “Luiz de Queiroz” (ESALQ), Universidade de São Paulo (USP), POox 09, CEP 13418-900 Piracicaba, BrazilLaboratório de Isótopos Estáveis, Centro de Energia Nuclear na Agricultura (CENA), USP, PO Box 96, CEP 13416-000 Piracicaba, Brazil

r t i c l e i n f o

rticle history:eceived 26 March 2014ccepted 29 September 2014

eywords:5N and 34S isotopeaccharum spp.ollutionustainable management

a b s t r a c t

Solute leaching below the crop-rooting zone represents not only a valuable loss of nutrients for the plant,but also a potential pollution source of groundwater. The objective of this work was to quantify nutrient-leaching losses at 0.9 m depth in an Ultisol that was cultivated with sugarcane, located in the county ofJaboticabal-SP, Brazil. The following ions were evaluated: nitrite, nitrate, ammonium, sulfate, phosphate,calcium, magnesium and potassium. The first ratoon cycle was monitored from November 16, 2006, toJuly 9, 2007. The experimental design was organized as four random blocks and three treatments: T1:without fertilizer; T2: 100 kg ha−1 of N and 114 kg ha−1 of S; and T3: 150 kg ha−1 of N and 172 kg ha−1 of S.To determine the fate of the N-fertilizer and S-fertilizer, four microplots were installed, in which 2.15%atoms of 15N- and 10.5% atoms of 34S-enriched ammonium sulfate were applied. The input and output ofanions and cations were quantified from the flux density of water and the ion concentration. The NO3

−,K+, Mg2+ and Ca2+ concentrations in the soil increased in January following both rainfall and drainage. Theleaching of N was between 3.9 and 34.9 kg ha−1. The N leached derived from the 100 kg ha−1 applied N

−1 −1 −1

fertilizer was 22.5 kg ha . The S leached was between 4.6 and 8.4 kg ha . From the 114 kg ha S appliedas fertilizer the leaching was 0.480 kg ha−1. The maximum leaching of P, K, Ca, and Mg were 1.2, 53.6,135.7 and 39.8 kg ha−1, respectively. From the results, it is not possible to determine whether the localgroundwater will be contaminated, but caution should be taken to maintain soil quality by reducing theleaching loss of nutrients.

© 2014 Elsevier B.V. All rights reserved.

. Introduction

While concerns about water quality in agricultural lands are wellnown, the focus on the problem has dominantly been in temperatereas (Thorburn et al., 2013). However, agricultural developmentnd/or intensification are accelerating in tropical regions. Sincehe initiation of the Proalcohol Program in Brazil in 1975, sugar-ane for producing ethanol has increased in cultivated area androductivity, mainly in São Paulo State. The expansion of ethanol

roduction from sugarcane generates discussions about social andnvironmental issues (Goldemberg et al., 2008; Hartemink, 2008),ith emphasis in the agricultural sector on the use of management

∗ Corresponding author at: Universidad Nacional del Litoral (UNL), Departamentoe Ciencias del Ambiente, Facultad de Ciencias Agrarias (FCA), Kredder 2805, CP:3080HOF Esperanza, Santa Fe, Argentina. Tel.: +54 3496 426400;ax: +54 3496 426400.

E-mail addresses: pjghiber@fca.unl.edu.ar, pjghiber@hotmail.com (P.J. Ghiberto).

ttp://dx.doi.org/10.1016/j.agwat.2014.09.027378-3774/© 2014 Elsevier B.V. All rights reserved.

systems that avoid negative impacts on soil, water and biodiversity(Goldemberg et al., 2008; Hartemink, 2008; Martinelli and Filoso,2008).

In view of the increased area of cultivated sugarcane in the stateof São Paulo (Brazil) and given the potential environmental prob-lems that might arise from this increase, several studies have beenpublished discussing the leaching of macronutrients in the agricul-tural cycle of sugarcane plant in 2005–2006 (Ghiberto et al., 2009)and the balance of soil water in the first ratoon cycle in 2006–2007(Ghiberto et al., 2011b).

Leaching is the removal of soluble materials by water movingfrom one area to another of the soil profile (SSSA, 2009). In additionto the potential pollution problems that can result from N leaching(Thorburn et al., 2013), agroecosystems can be degraded by the lossof other ions, such as Ca2+ and Mg2+, which are carried into deep soil

layers, thus leading to soil acidification (Ng Kee Kwong and Deville,1984; Poss and Saragoni, 1992; Hartemink, 2008). However, themovement of basic cations to the subsoil can be beneficial in pro-moting root growth at great depths in Ca- and Mg-deficient soils

142 P.J. Ghiberto et al. / Agricultural Water Management 148 (2015) 141–149

Table 1Particle size distribution, bulk density (�b), organic matter (O.M.) and saturated hydraulic conductivity (Ks) in the soil studied.

Depth (m) Clay Sand Silt �b (Mg m−3) Ks (mm h−1) O.M. (%)

(%)

0.15 30.2 (4.9) 65.4 (2.1) 4.4 (23.2) 1.532 (7.2) 49.4 (18.0) 1.51 (13.9)0.25 30.8 (5.8) 64.9 (2.5) 4.3 (17.5) 1.584 (5.1) 34.9 (14.6) 1.32 (13.1)0.35 34.4 (8.3) 61.7 (4.7) 3.9 (24.0) 1.589 (5.0) 13.9 (30.1) 1.19 (15.5)0.45 38.3 (4.0) 57.5 (3.7) 4.2 (26.5) 1.502 (4.1) 19.7 (23.1) 1.05 (18.4)0.55 38.4 (5.9) 57.4 (2.5) 4.1 (27.7) 1.452 (4.0) 46.9 (12.9) 0.97 (17.3)0.65 38.5 (5.7) 57.4 (3.1) 4.1 (16.4) 1.415 (5.5) 48.1 (18.8) 0.87 (21.8)0.75 38.6 (3.5) 57.3 (2.4) 4.2 (16.8) 1.424 (3.5) 47.1 (16.8) 0.75 (16.8)0.85 38.6 (2.9) 57.3 (2.2) 4.1 (18.5) 1.399 (5.3) 74.0 (14.7) 0.72 (26.0)0.95 38.4 (2.7) 57.5 (1.9) 4.1 (7.3) 1.422 (3.9) 59.9 (10.2) 0.69 (24.0)1.05 38.0 (3.0) 57.7 (2.4) 4.3 (12.0) 1.390 (5.2) 65.8 (10.7) 0.69 (26.4)

P m corW sented

(s

(sces

doeeumil

f(d(a

2

Si(w(c(

TC

pNa

article size distribution: pipette method; �b: undisturbed soil samples in 5 × 5 calkley–Black method converted into O.M. reaching a 1.724 factor. The values pre

Wong et al., 1992), thus avoiding the loss of nutrients from the rootystem and minimizing the problems of water-table pollution.

In tropical and subtropical regions, the transport of anionsnitrate, chloride and phosphate) and cations (calcium, magne-ium and potassium) and their mobility have been studied in soilolumns of highly weathered soils with variable charges (Bellinit al., 1996; Alcântara and Camargo, 2005); however, very few fieldurveys are available.

Field studies are difficult to conduct because leaching lossesepend on the applied dose and solubility of the fertilizer, timef application, water regime, development of the root system andspecially the quantification of water flux through the soil (Britot al., 2009; Ghiberto and Moraes, 2011; Blum et al., 2013). These of soil-solution extractors, together with the independent esti-ates of the soil water flux density using tensiometers and stable

sotope-labeled fertilizers, has been successfully used to quantify Neaching, but not S leaching, in sugarcane (Ghiberto et al., 2011a).

The present study aimed to (i) quantify the nitrogen and sul-ur losses due to leaching in an Ultisol in the State of São PauloBrazil) cultivated with sugarcane during the first ratoon cycle; (ii)etermine the amount of N and S leached from fertilizer source andiii) quantify leaching losses of N- and S-accompanying cations andnions.

. Materials and methods

The experiment consisted of quantifying the leaching of N and, both native to the soil and derived from the applied fertilizer,n addition to other accompanying cations and anions in an UltisolArenic Kandiustults) of sandy–clay–loam texture (Tables 1 and 2)

ith watertable over the depth of 7 m cultivated with sugarcane

cultivar SP81-3250) in the first ratoon cycle. The experiment wasonducted in the county of Jaboticabal, state of São Paulo, Brazil21◦20′20′′S, 48◦18′35′′W).

able 2hemical attributes of the soil studied.

Profile Depth (m) pH P (mg kg−1)

H2O KCl �pH

Ap 0.15 6 4.5 −1.5 10

A2 0.37 6.3 5.2 −1.1 11

BA 0.56 5.1 4.1 −1 3

Bw1 0.96 5.6 4.4 −1.2 1

Bw2 0.96+ 5.9 5.1 −0.8 1

HH2O: pH in water, ratio 1:2.5; pHKCl: pH in KCl 1 N ratio 1:2.5; �pH = pHKCl − pHH2O; Pa: extraction through Mehlich1 solution and determination by flame photometry; Ca, Mtomic absorption; H + Al: determination by calcium acetate 1 N, pH = 7; Cation exchange

es; Ks: permeameter of decreasing charge method; O.M.: organic carbon by the are an average of thirteen repetitions; in parenthesis the variation coefficients.

Prior to setting up the experiment, two harvests using a crop-harvesting machine were performed in the area of the previouscrop cycles, without sugarcane burning. Three years prior to theestablishment of the experiment, in 2002, vinasse application wasdiscontinued. The soil received 2 Mg ha−1 dolomitic limestone, andthen, the sugarcane was sowed from April 4 to 8, 2005, and har-vested from July 11 to 13, 2006. In the first year (plant caneagricultural cycle), the treatments consisted of sugarcane fertiliza-tion at doses of 40, 80 and 120 kg ha−1 N in the form of urea, appliedon the bottom of the planting furrows, in addition to a control treat-ment without N fertilization (0 kg ha−1 N). In addition, 120 kg ha−1

K and P2O5 were applied using potassium chloride (KCl) and triplesuperphosphate as sources, respectively (Faroni, 2008; Franco et al.,2011).

In the first ratoon cane cycle, on November 1, 2006, ammo-nium sulfate was applied manually over the harvest-residual strawat 0.2 m from the ratoon. Three treatments were established, dis-tributed in four randomized blocks with one replicate per block.Treatments to evaluate leaching consisted of a combination ofapplications of N during the plant cane and first ratoon periodsas follows: Treatment 1 (T1): 0 → 0 kg ha−1 N; Treatment 2 (T2):80 T → 100 kg ha−1 N and Treatment 3 (T3): 120 → 150 kg ha−1

N. To determine the fate of N and S from the fertilizer, fourmicroplots of 2.0 m of planting row were established, that is,with 2 m × 1.5 m size considering a 1.5 m row spacing (Trivelinet al., 1994). In the microplots, the fertilizer was applied in theform of a solution containing ammonium chloride and potas-sium sulfate enriched with 15N (2.15%At) and 34S (10.5%At) stableisotopes. In addition, 120 kg ha−1 K2O was applied in the formof KCl.

The input and output flux of ions at a depth of 0.9 m were quan-

tified daily using tensiometers and soil-solution extractors withporous cups. One tensiometer was installed at each of the depthsof 0.8, 0.9 and 1.0 m and a solution extractor was installed at thedepth of 0.9 m, in each plot. The ion movement was measured

Na K Ca Mg Al H + Al CEC

mmolc kg−1

0.01 3.6 18 13 0 17 51.60.01 2.2 9 5 2 18 34.20.01 1.2 2 1 8 31 35.20.01 0.9 3 1 3 20 24.90.01 3.5 2 1 0 9 15.5

: extraction through ion exchanger resin and determination by colorimetry; K andg: extraction through ion exchanger resin and determination by spectrometry of

capacity: CEC = (Na + K + Ca + Mg + Al).

ater M

iE

q

w

s

nttoC

o(

q

wot

mowf

K

iTt

−fupfG

�

wt˛p

fiaHmtwnw9

%

wtt(

P.J. Ghiberto et al. / Agricultural W

ntegrating the daily ion flux density in the time as indicated inq. (1) for NO3

−:

NO−3

=tf∫t0

qwCNO−3

dt (1)

here qNO−3

(kg ha−1) is the flow of nitrate in the soil, qw is the

oil water flux density (m day−1), and CNO−3

is the concentration of

itrate in the soil solution (kg L−1) at the moment of measurement.0 and tf represent the initial time (equipment installation) and finalime (harvest) of the experiment. The same procedure was carriedut to estimate the flow of other ions (SO4

2−; PO43−; NO2

−; NH4+;

a2+; K+–Mg2+).The soil water flux density was estimated, since the installation

f equipments (November 16, 2006) until the sugarcane harvestJuly 9, 2007), by the Darcy–Buckingham equation:

w =−K

(�)�

( t

)L

(2)

here K(�) is the soil hydraulic conductivity (m day−1) as a functionf the volumetric water content (�), or K(�) function, and � t/L, ishe soil water total potential gradient at a depth of 0.9 m.

The K(�) function was determined by the instantaneous profileethod (Hillel et al., 1972). The volumetric soil water content was

btained from the daily readings of the tensiometers and the soilater retention curve at the depth of 0.9 m. Data was fitted to the

ollowing equation:(�)

= Ko exp �(� − �o

)(3)

n which Ko = 515.2 mm day−1; � = 67.435 and �o = 0.354 cm3 cm−3.he gradient (� t/L) was calculated from the daily readings ofensiometers at the depths of 0.8 m and 1.0 m.

The soil water retention curve, for the matric potentials −1; −2;3; −4; −6; −8; −10 kPa, was determined by using porous plate

unnels and, for −30, −50, −100, −300, −600 and −1500 kPa, bysing Richard’s pressure cells, which resulted in a curve with 13oints. A soil core (diameter of 5 cm and height of 5 cm) was usedor each point of the curve and data were adjusted to Eq. (4) (vanenuchten, 1980):

= �r +(�s − �r

)[1 +

(˛

∣∣ m∣∣)n]−m(4)

here �s = 0.434 cm3 cm−3 is the saturated soil water con-ent; �r = 0.182 cm3 cm−3 is the soil residual water content;

= 0.0461 cm−1, n = 1.6388 and m = (1 − 1/n) are adjustmentarameters; and m is the matric potential.

The solution taken from the soil was filtered (milipore celluloselter paper 0.45 �m) and the concentration of chloride, bicarbon-te and fluoride cations (NH4

+; Ca2+; K+; Mg2+) and anions (Cl−;CO3

−; F−; NO3−; NO2

−; SO42−; PO4

3−) determined by ion chro-atography (DIONEX ICS-90). The 15N and 34S analyses to quantify

he nitrogen the sulfur in the soil solution derived from fertilizerere made by means of the mass spectrometer. The percentage ofitrogen in the soil solution derived from the fertilizer (%FDNSS)as calculated by Eq. (5) adapted from Hauck et al. (1994, p.

07–943):

FDNSS =[

(%Atsolution − %Atsoil)(%Atfertilizer − %Atsoil)

]× 100 (5)

here %At is the abundance of 15N in the soil solution, from fer-ilizer and from soil (0.367%). The same procedure was carried outo estimate percentage of fertilizer-derived S in the soil solution%FDSSS).

anagement 148 (2015) 141–149 143

The following ions were evaluated: nitrite, nitrate, ammonium,sulfate, phosphate, calcium, magnesium, potassium, chloride,bicarbonate and fluoride, in addition to 15N and 34S in the soil solu-tion. The procedures used were the same as those used for the plantcane (Ghiberto et al., 2009). The total dissolved solids (TDS) werecalculated as the arithmetic sum of the mean concentration of ionspresent in the samples, expressed in mg L−1, and the percentageof dissolved inorganic nitrogen (DIN) was calculated based on thesum of nitrite, nitrate and ammonium relative to the total dissolvedsolids (TDS).

2.1. Statistical analysis

In each treatment and for each study period, the mean andstandard deviation of four replicates of the different leachedions were calculated. Next, the method of error propagation(Allmaras and Kempthorne, 2002) was used to obtain the prop-agated standard deviation. The calculation, for nitrogen (N), isexemplified in the following equation:

s (N) =√s2(1) + s2(2) + · · · + s2(10) + s2(11) (6)

where s(N) is the propagated standard deviation of leached N fromperiod P = 1 to P = 11, and s(n)

2 is the variance of the drainage compo-nent for n = 4 replicates in each period. The extent to which the erroraffected the measurement was calculated by dividing the absoluteerror by the measured value (in this case, the N leached in the cycle)and expressed as a percentage.

The experimental design was organized as random blocks, total-ing four blocks with three treatments and one replicate per block.The comparison was performed for each period, using the F-testof analysis of variance. The means of the leached ions at eachperiod were compared using the least significant difference (LSD)test using the Statistical Analysis System Institute (SAS) statisticalsoftware (SAS, 1991).

3. Results and discussion

3.1. Concentrations of cations and anions in the soil solution

Depending on the treatment, the concentrations of the evalu-ated ions increased in the soil solution, coinciding with the periodof higher rainfall and drainage at 0.9 m depth (Ghiberto et al.,2011b;Fig. 1a and b). The total dissolved solids (TDS) content wassignificantly higher in the treatment fertilized with 100 kg ha−1 N(T2) than in the control (LSD test; P > 0.1). T3 was in an intermedi-ate position and did not differ from T1 and T2. In T1, the mean TDSwas 85.6 mg L−1 (maximum TDS = 309.6 and minimum TDS = 26.6);in T2, the mean TDS was 143.5 mg L−1 (maximum TDS = 675.3 andminimum TDS = 27.5), and for T3, the mean TDS was 90.5 mg L−1

(maximum TDS = 435.3 and minimum TDS = 25.1). The percentageof dissolved inorganic nitrogen (DIN) was 5.9% for T1, 21.1% forT2 and 23.3% for T3. The increase in the contribution of differ-ent N-containing ionic species was significant (LSD test; P > 0.1)and reflects the influence of N fertilization on the soil solution at0.9 m depth, mainly due to the increase in the NO3

− concentration(Table 3).

Using the percentage of anions or cations calculated on a molarbasis (%), a predominance of Cl− and a significant contribution ofHCO3

− to the anions were observed. Chloride, bicarbonate andnitrate represented approximately 90% of the anions in the soilsolution. Although the percentage of NO3

− was low in the treat-

ment without fertilizer, when NO3

− increased in the fertilizedtreatments, the Cl− or HCO3

− decreased. Unlike NO3−, which

increased in the fertilized treatments, the SO42− anion showed no

defined behavior, with its amount in T2 being lower than in T1

144 P.J. Ghiberto et al. / Agricultural Water Management 148 (2015) 141–149

0

20

40

60

80

100

120

140

160

180

200

6/175/184/183/192/171/1812/1911/1910/20

Con

cen

trati

on

(m

g L

-1)

Date

Bica rbonate

Fluoride

Chlori de

Nitrite

Nitrate

Pho spha te

Sulfate

(a)

0

20

40

60

80

100

120

140

160

180

200

6/175/184/183/192/171/1812/1911/1910/20

Co

nce

ntr

ati

on

(m

g L

-1)

Date

Sodium

Ammo nium

Potassium

Magnesium

Calci um

(b)

0

10

20

30

40

50

60

70

80

5/284/283/292/271/2812/2911/2910/30

Con

cen

tra

tio

n (

mg

L-1

)

Date

(c)

0

1

2

3

4

5

6

7

1/2812/2911/2910/30 5/284/283/292/27C

on

cen

tra

tio

n (

mg

L-1

)

Date

(d)

F ncentr( SSS) s

aasTta

wooi

TMo

M

ig. 1. The concentration of anions (a) and cations (b) in the soil solution; the coFDNSS) (c) and the concentration of soil-derived (SDSSS) and fertilizer-derived (FD

nd T3. Phosphate and fluoride showed low proportions among thenions evaluated because they are minor components of the soilolution and due to the low P levels in the soil (Ghiberto, 2009).he results coincide with those of Blum et al. (2013), who attributedhe small amount of leached P to absorption by the sugarcane anddsorption by the highly weathered soil.

Ca2+ was the predominant cation, followed by K+ and Mg2+,

hen compared on a molar basis. When summing the contributions

f Ca2+ and K+, these two cations represented approximately 70%f the cations evaluated. NH4

+ behavior was independent of fertil-zation, similarly to NO3

−, and had a low contribution. The low soil

able 3ean concentration (C, mg L−1), minimum mean concentration (CMin., mg L−1), maximum

n a molar basis. Percentage of anions or cations in CMin. and CMax. (%Min. and %Max.) calcul

HCO3− F− Cl− NO2

− NO3− PO4

3−

Treatment 1: without fertilizerC 11.6 0.2 22.8 0.2 3.9 1.1

CMin. 4.9 0.2 2.2 0.0 0.1 0.1

CMax. 27.4 0.2 124.0 1.0 16.8 5.1

% 18.7ab 1.0a 62.5a 0.5ab 6.1b 1.1a

%Min. 40.6 5.2 34.3 0.1 1.0 0.5

%Max. 11.3 0.3 75.1 0.5 7.1 1.4

Treatment 2: 100 kg ha−1 N and 114 kg ha−1 SC 9.3 0.2 45.0 0.2 28.9 1.1

CMin. 4.3 0.1 2.3 0.0 4.9 0.0

CMax. 24.3 0.2 204.6 0.6 181.5 8.9

% 9.8b 0.5a 62.3a 0.3b 23.7a 0.7a

%Min. 27.7 2.6 33.5 0.2 29.1 0.1

%Max. 6.8 0.2 59.6 0.2 29.9 1.2

Treatment 3: 150 kg ha−1 N and 172 kg ha−1 SC 12.4 0.2 11.9 0.3 19.9 0.9

CMin. 5.9 0.1 0.9 0.0 1.4 0.1

CMax. 33.8 0.2 92.2 1.1 142.9 7.2

% 24.1a 1.1a 32.5b 0.6a 31.2a 1.2a

%Min. 54.3 4.0 14.7 0.1 13.7 0.4

%Max. 13.7 0.3 45.3 0.6 32.7 2.5

ean values followed for the same letters in each column are not significantly different (

ations of soil-derived (SDNSS) and fertilizer-derived nitrogen in the soil solutionulfur in the soil solution (d) in the monitoring months. (a)–(d) in Treatment 2.

Na+ content explains the low concentration of this cation in the soilsolution at 0.9 m depth.

3.2. Concentration of N and S in the soil solution

The mean concentration of mineral N was 1.52 mg L−1 in T1,7.49 mg L−1 in T2 and 5.28 mg L−1 in T3, within mean maximum

values of 5.79, 41.55 and 33.18 mg L−1 N and mean minimum val-ues of 0.31, 1.70 and 0.80 mg L−1 N for T1, T2 and T3, respectively.The N concentration remained low without significant variationduring the entire monitoring period in the control treatment (T1).

mean concentration (CMax., mg L−1). Percentage of anions or cations (%) calculatedated on a molar basis.

SO42− Na+ NH4

+ K+ Mg2+ Ca2+

10.0 2.7 0.9 12.8 3.5 15.93.6 0.9 0.1 6.7 1.2 6.7

18.4 9.1 3.6 36.6 13.8 53.610.0a 11.4a 4.7a 30.6a 14.1a 39.2a18.3 9.2 1.0 35.4 12.1 42.4

4.4 11.9 5.9 27.1 16.5 38.7

4.0 2.2 1.2 17.4 7.5 26.51.6 1.0 0.1 4.2 1.4 7.6

11.6 7.0 5.9 65.5 58.2 107.12.7b 6.7b 4.5a 29.3a 18.2a 41.4a6.8 11.3 1.1 24.8 14.6 48.22.1 5.8 5.4 26.7 25.5 36.6

10.0 2.4 1.0 11.0 3.6 17.02.4 0.9 0.2 3.8 1.4 8.1

23.6 7.9 3.2 35.9 19.6 67.89.1a 11.5a 5.8a 25.4a 14.6a 42.7a

12.8 9.8 2.3 21.0 15.7 51.24.9 10.3 4.8 26.7 18.1 40.2

teste LSD test, P < 0.1).

ater Management 148 (2015) 141–149 145

Con

w(accpt1

dht%

cS1vvtfdo

3

ccna(fNallPm

wi(omJOap

paffda((

ertt

NO2--N

NO3--N

47%

NH4+-N

51%

(a)

(b)

(c)

NO2--N

0%

NO3--N

92%

NH4+-N

8%

NO2--N

0%

NO3--N

94%

NH4+-N

6%

P.J. Ghiberto et al. / Agricultural W

onversely, in the treatments with ammonium sulfate, the rangef mean maximum and minimum values was higher than in theon-fertilized treatment.

There was an increase in N concentration at a depth of 0.9 mhen 100 kg ha−1 N enriched with 15N (2.15%At 15N) was applied

Fig. 1c). The abundance of 15N was higher than the naturalbundance of the isotope in the periods that produced peak con-entrations of mineral N, decreasing thereafter until the end of theycle. The mean abundance of the isotope-labeled N from all sam-les analyzed in the four replicates was 0.99%At. Considering thathe fertilizer contained 2.15%At and that the natural abundance of5N in the soil was 0.367%At, the mean percentage of fertilizer-erived N in the soil solution was 34.9% (%FDNSS). The %At wasigher than the value measured in the plant cane cycle (0.4296)o which urea enriched with 5.04%At was applied, resulting in aFDNSS of 1.34 (Ghiberto et al., 2009).

In the case of S, there was no well-defined stage in which S con-entration increased, as was the case for N (Fig. 1d). The mean

concentration during the assessments was 3.35 mg L−1 in T1,.31 mg L−1 in T2 and 3.33 mg L−1 in T3, whereas the maximumalues were 3.88, 6.14 and 7.86 mg L−1 S and the mean minimumalues were 1.21, 0.49 and 0.80 mg L−1 S for T1, T2 and T3, respec-ively. The mean abundance of 34S of all samples analyzed in theour replicates was 5.476%At. The mean percentage of fertilizer-erived S in the soil solution (FDSSS) was 19.24%, with the 34S %Atf the fertilizer at 10.5% and the soil at 4.28%.

.3. Leaching of macronutrients

N moved mainly as NO3−, similarly to the pattern in the plant

ane cycle (Ghiberto et al., 2009; Fig. 2), due to the low affinity forlay minerals and negatively charged organic matter and to the fastitrification rate in tropical soils (Renk and Lehmann, 2004; Salcedond Sampaio, 1984). Similar results were obtained by Blum et al.2013), who showed that 92.3% of leached mineral N was in theorm of NO3

−. However, for T1, in which the amount of leached was low, N was found mainly in the form of NH4

+, as observedlso by Ghiberto et al. (2011a). Comparing the contribution to theeaching of each N ionic species among treatments, the amount of Neached derived from NO3

− was significantly higher in T2 (LSD test; < 0.1). No significant differences were observed between treat-ents for NO3

− or for NH4+.

The amount of leached N from both native and fertilizer sourcesas high in the treatment fertilized with 100 kg ha−1 N and signif-

cantly higher than in the non-fertilized treatment. Thorburn et al.2013) correlated the export of DIN with an increase in the amountf N applied as fertilizer. In the State of São Paulo (Brazil), in cli-ates with annual water surpluses of similar magnitude as that in

aboticabal and using the same methodology, Blum et al. (2013) andliveira et al. (2001) reported similar N losses when the drainaget the control depth was greater than 200 mm, as occurred in theresent experiment.

In contrast, Ghiberto et al. (2011a), studying N leaching in thelant cane cycle in a Typic Eutrustox, applied 120 kg ha−1 urea–15Nnd found leaching losses of 1.1 kg ha−1 with 0.054 kg ha−1 derivedrom the fertilizer, with 91 mm drainage in the cycle. The main dif-erence observed between the experiments was the amount andistribution of rainfall during the period of water surpluses, withn amount of rainfall smaller than normal in the wettest monthJanuary); similar results were obtained by Poss and Saragoni1992).

In contrast to the conditions in the plant cane cycle (Ghiberto

t al., 2009), in the ratoon cane cycle (present experiment), theainfall was greater than in the plant cane and was higher thanhe historical mean in January (Ghiberto et al., 2011b). This mois-ure led to favorable conditions for drainage that, along with the

Fig. 2. Proportion of leached nitrogen in different ionic species: (a) Treatment 1; (b)Treatment 2 and (c) Treatment 3.

N availability, favored leaching (see period 4 in Tables 4–6). In T2,even with less fertilizer applied (100 kg ha−1 N) than that used forthe plant cane, the amount of leached N was higher coincidentallywith the drainage (206 mm in plant cane versus 352 mm in ratoon).In T3, the amounts of water drained and of N leached were similarto those observed for the plant cane cycle.

In the ratoon cane cycle, there was a significant amount ofN leached in T2 (Tables 4–6), unlike the results during the plantcane cycle when a low proportion of the fertilizer was leached(Ghiberto et al., 2009). One year after renovating the sugar planta-tion, already in the first ratoon, the C/N/S ratio is expected be lowerthan at the time of incorporation of crop residues (Vitti et al., 2008;Robertson and Thorburn, 2007), and therefore, the immobilizationof the applied fertilizer should be less significant. Furthermore,given that a significant amount of NH4

+ was added under condi-tions favorable to the aerobic activity of nitrifying microorganisms(50 to 70% of the porous space occupied by water and soil temper-ature between 25 and 35 ◦C) (Ghiberto, 2009), the fertilizer NH4

+

would have been quickly transformed into NO3−, thus becoming

susceptible to leaching.Analysis of the 15N isotope in the extracted soil solution showed

that from the total N leached in the crop cycle, 22.5 kg ha−1 Nderived from the applied N fertilizer (100 kg ha−1 N). Faroni (2008)evaluated the fate of the N fertilizer in this same treatment and

146 P.J. Ghiberto et al. / Agricultural Water Management 148 (2015) 141–149

Table 4Rainy precipitation (Pr), internal drainage (D) or capillary rise (CR) and macronutrients leaching in the soil in various studied periods of Treatment 1.

Period Pr (mm) D/CR (mm) Macronutrients leaching (kg ha−1)

No Date N S P K Ca Mg

1 16/11 152 −40.5 (28.1) −1.2 (0.8) −1.6 (1.5) −0.1 (0.1) −4.2 (2.8) −6.6 (5.3) −1.4 (1.1)2 17/11–6/12 85 −13.0 (5.2) −0.3 (0.1) −0.5 (0.4) −0.0 (0.0) −2.7 (1.5) −2.8 (0.7) −0.7 (0.3)3 7/12–18/12 41 −17.1 (9.0) −0.2 (0.1) −0.5 (0.6) −0.0 (0.0) −3.6 (2.9) −4.9 (2.4) −1.3 (0.7)4 19/12–19/1 481 −107.9 (43.4) −0.9 (0.4) −2.3 (1.0) −0.2 (0.3) −18.9 (10.8) −40.2 (30.2) −10.8 (8.0)5 20/1–8/2 94 −38.0 (19.4) −0.4 (0.2) −1.2 (0.6) −0.1 (0.0) −2.5 (1.6) −3.6 (2.1) −0.6 (0.3)6 9/2–2/3 154 −30.8 (30.8) −0.3 (0.2) −0.8 (0.6) −0.0 (0.1) −1.5 (1.0) −3.0 (3.2) −0.5 (0.5)7 3/3–23/3 124 −19.3 (20.4) −0.2 (0.2) −0.5 (0.5) −0.0 (0.1) −0.9 (0.6) −1.6 (1.8) −0.3 (0.3)8 24/3–20/4 23 −14.2 (11.9) −0.3 (0.3) −0.5 (0.5) −0.0 (0.0) −1.4 (1.9) −1.2 (0.9) −0.2 (0.2)9 21/4–25/5 100 −2.1 (13.6) 0.1 (0.2) 0.0 (0.4) 0.0 (0.0) 0.3 (1.4) −0.2 (1.1) 0.0 (0.2)10 26/5–21/6 12 −15.3 (8.7) −0.2 (0.2) −0.5 (0.3) −0.0 (0.0) −1.0 (1.1) −1.2 (0.7) −0.2 (0.1)11 22/6–9/7 – −1.8 (2.5) 0.0 (0.0) 0.0 (0.1) −0.0 (0.0) −0.0 (0.2) −0.1 (0.2) −0.0 (0.0)

Total 1266 −300.0 (70.2) −3.9 (1.1) −8.4 (2.3) −0.4 (0.3) −36.4 (12.1) −65.4 (31.1) −16.0 (8.2)

In Tables 2–4, the value that appears for each period is the average of the four repetitions and the respective standard deviation; that for the total of the cycle is the summationof each period and the respective propagated standard deviation. Positive numbers indicate gains and negative numbers indicate losses of water and macronutrients at thedepth of 0.9 m.

Table 5Rainy precipitation (Pr), internal drainage (D) or capillary rise (CR) and macronutrients leaching in the soil in various studied periods of Treatment 2.

Period Pr (mm) D/CR (mm) Macronutrients leaching (kg ha−1)

No Date N S P K Ca Mg

1 16/11 152 −47.9 (30.2) −2.0 (1.1) −1.2 (1.5) −0.6 (1.1) −6.6 (4.1) −7.0 (4.4) −1.1 (0.9)2 17/11–6/12 85 −7.8 (15.1) −0.9 (1.7) −0.1 (0.2) −0.0 (0.1) −3.9 (7.3) −1.6 (2.9) −0.3 (0.6)3 7/12–18/12 41 −18.0 (7.5) −2.2 (1.6) −0.2 (0.2) −0.0 (0.0) −7.0 (8.2) −6.5 (7.4) −2.0 (2.8)4 19/12–19/1 481 −122.3 (65.4) −23.0 (17.5) −1.3 (1.6) −0.3 (0.2) −27.7 (20.4) −88.3 (77.2) −28.0 (23.8)5 20/1–8/2 94 −58.7 (39.4) −2.8 (4.0) −0.6 (1.0) −0.1 (0.1) −2.9 (3.3) −19.6 (29.1) −5.5 (9.0)6 9/2–2/3 154 −27.4 (29.0) −1.1 (1.6) −0.4 (0.8) −0.0 (0.1) −1.5 (1.9) −6.1 (8.4) −1.7 (2.6)7 3/3–23/3 124 −25.2 (10.8) −1.1 (1.2) −0.3 (0.3) −0.1 (0.0) −1.8 (0.9) −4.9 (5.0) −1.3 (1.7)8 24/3–20/4 23 −13.8 (9.9) −0.5 (0.4) −0.1 (0.1) −0.1 (0.1) −0.7 (0.4) −1.5 (0.8) −0.3 (0.3)9 21/4–25/5 100 −14.2 (19.6) −0.3 (0.4) −0.2 (0.3) −0.0 (0.0) −0.5 (1.8) 1.5 (6.4) 0.7 (1.8)

10 26/5–21/6 12 −12.7 (9.9) −0.3 (0.2) −0.2 (0.2) −0.0 (0.0) −0.8 (0.5) −1.4 (1.1) −0.3 (0.3)0.0 (0

4.6 (2

obth(lbn

tlr

TR

11 22/6–9/7 – −3.8 (3.5) −0.1 (0.1) −Total 1266 −351.8 (92.6) −34.3 (18.3) −

bserved that from the 100 kg ha−1 N applied, 36.1% was recoveredy the sugarcane, and 21.9% remained in the soil. However, from theotal amount applied, 18.5 kg ha−1 were not accounted for and mayave been lost by the shoots of the plants, denitrified or volatilizedTrivelin et al., 2002). Because ammonium sulfate was applied, theosses by volatilization should be low (Wood, 1991). Thus, the lossesy the sugarcane shoots and by denitrification should be more sig-ificant; however, these losses were not quantified.

Given that the crop absorbed mainly native N (Faroni, 2008),

he low recovery of N fertilizer in this cycle can be attributed to N-eaching losses. In contrast, other studies have shown that the lowecovery of N fertilizer was not due to high leaching losses (Ng Kee

able 6ainy precipitation (Pr), internal drainage (D) or capillary rise (CR) and macronutrients le

Period Pr (mm) D/CR (mm) Macronutrients leaching

No Date N S

1 16/11 152 −20.8 (22.5) −0.4 (0.5) −0.7

2 17/11–6/12 85 −1.8 (3.6) −0.2 (0.2) −0.1

3 7/12–18/12 41 −11.7 (4.9) −0.6 (0.3) −0.2

4 19/12–19/1 481 −75.6 (46.8) −17.9 (27.8) −1.2

5 20/1–8/2 94 −28.8 (9.2) −1.0 (0.6) −1.4

6 9/2–2/3 154 −23.4 (9.1) −0.8 (0.6) −1.4

7 3/3–23/3 124 −16.1 (8.5) −0.4 (0.2) −0.8

8 24/3–20/4 23 −9.9 (5.9) −0.2 (0.1) −0.3

9 21/4–25/5 100 −2.2 (6.0) −0.0 (0.1) 0.1

10 26/5–21/6 12 −7.7 (5.5) −0.1 (0.1) −0.2

11 22/6–9/7 – −0.8 (2.3) −0.0 (0.1) 0.0

Total 1266 −198.8 (55.5) −21.6 (27.8) −6.2

.0) −0.0 (0.0) −0.2 (0.2) −0.3 (0.3) −0.0 (0.1)

.5) −1.2 (1.2) −53.6 (23.9) −135.7 (83.8) −39.8 (25.9)

Kwong and Deville, 1987; Trivelin et al., 2002; Bologna-Campbell,2007; Ghiberto et al., 2009). This apparent contradiction arisesfrom the fact that the experiments were conducted with differentmethods and under different agro-ecological conditions, showingthe complexity of such studies and the inability to generalize theresults.

Assessing the leaching losses at 0.9 m depth of non-N macronu-trients, the low loss of S and P in contrast to Ca, Mg and K stoodout (Tables 4–6). A similar result was obtained in the plant cane

cycle (Ghiberto et al., 2009). Wong et al. (1992) observed increasedNO3

− losses with urea application associated with high losses of Ca(312 kg ha−1 in two seasons) and Mg in a Typic Paleudult with the

aching in the soil in various studied periods of Treatment 3.

(kg ha−1)

P K Ca Mg

(0.6) −0.1 (0.1) −2.1 (2.6) −5.0 (6.6) −0.5 (0.5)(0.1) −0.0 (0.0) −0.6 (0.7) −0.4 (0.4) −0.1 (0.1)(0.1) −0.0 (0.0) −1.7 (1.1) −2.2 (1.3) −0.5 (0.3)(1.2) −0.1 (0.0) −14.9 (18.4) −36.5 (41.9) −9.9 (11.1)(2.1) −0.1 (0.0) −2.3 (2.8) −3.8 (1.3) −0.7 (0.2)(2.3) −0.0 (0.0) −2.6 (3.7) −3.2 (2.3) −0.6 (0.4)(1.4) −0.0 (0.0) −1.5 (2.1) −2.1 (1.5) −0.4 (0.3)(0.2) −0.0 (0.0) −0.5 (0.3) −1.1 (0.5) −0.2 (0.1)(0.4) −0.0 (0.0) 0.2 (0.7) −0.0 (0.9) −0.0 (0.2)(0.1) −0.0 (0.0) −0.3 (0.2) −0.7 (0.4) −0.1 (0.1)(0.1) −0.0 (0.0) 0.0 (0.2) −0.0 (0.2) −0.0 (0.0)

(3.7) −0.3 (0.1) −26.3 (19.3) −55.0 (42.6) −13.0 (11.1)

P.J. Ghiberto et al. / Agricultural Water Management 148 (2015) 141–149 147

0

5

10

15

20

25

30

35

40

6/175/184/183/192/171/1812/1911/1910/20

Lea

chin

g (

kg h

a-1

)

Date

Bicarbonate

T.1

T.2

T.3

0

25

50

75

100

125

150

175

200

225

250

6/175/184/183/192/171/1812/1911/1910/20

Lea

chin

g(k

g h

a-1

)

Date

Chloride

T.1

T.2

T.3

0

25

50

75

100

125

150

6/175/184/183/192/171/1812/1911/1910/20

Lea

ch

ing

(k

g h

a-1

)

Date

Nitrate

T.1

T.2

T.3

0

1

2

3

4

5

6/175/184/183/192/171/1812/1911/1910/20

Lea

chin

g (

kg

ha

-1)

Date

Phosphate

T.1

T.2

T.3

0

5

10

15

20

25

30

6/175/184/183/192/171/1812/1911/1910/20

Lea

chin

g (

kg h

a-1

)

Date

Sulfate

T.1

T.2

T.3

0

1

2

3

4

5

6

7

8

9

10

6/175/184/183/192/171/1812/1911/1910/20

Lea

chin

g (

kg h

a-1

)

Date

Sodium

T.1

T.2

T.3

0

1

2

3

4

5

6/175/184/183/192/171/1812/1911/1910/20

Lea

chin

g (

kg

ha

-1)

Date

Ammonium

T.1

T.2

T.3

0

10

20

30

40

50

60

6/175/184/183/192/171/1812/1911/1910/20

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. Acu

m.

(kg

ha

-1)

Date

PotassiumT.1

T.2

T.3

0

10

20

30

40

50

60

6/175/184/183/192/171/1812/1911/1910/20

Lea

chin

g (

kg

ha

-1)

Date

MagnesiumT.1

T.2

T.3

0

25

50

75

100

125

150

6/175/184/183/192/171/1812/1911/1910/20

Lea

chin

g (

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ha

-1)

Date

CalciumT.1

T.2

T.3

point

ca

w

Fig. 3. Cumulative leaching of anions and cations. Each experimental

lay fraction dominated by kaolinite, a small amount of goethitend low cation-exchange capacity (CEC).

The cumulative leaching of Cl−, NO3−, K+, Mg2+ and Ca2+ ions

as different from that of HCO3−, PO4

3−, Na+ and NH4+ (Fig. 3). The

represents the mean of the four replicates in the different treatments.

first group corresponds to the ions that, at the maximum concen-tration peak, had the highest levels in the soil solution calculatedon a molar basis (Table 3). These ions were displaced faster and ingreater amounts than the ones in the second group.

1 ater M

ss0s4Tpitcampr

abriefCom

totct

oetlttgaddlIfaec

sdhi(tcttaamSspii

48 P.J. Ghiberto et al. / Agricultural W

Making an analogy with miscible displacement experiments inoil columns with the fertilizer applied as a pulse of the solute to betudied and considering that the volume of mobile water between

and 0.9 m depth in the soil (V0) is between the water contents ataturation and field capacity, 1.0 pore volume (Vp) corresponded to3 mm of water. It was estimated that 7.0 Vp in T1, 8.2 in T2 and 4.6 in3 percolated through the profile. When calculated this way, 1.0 Vp

ercolated through the profile on 11/16/2006 in T1, on 11/10/2006n T2 and on 12/29/2006 in T3, always prior to the inflection point ofhe curves in the fertilized treatments (Fig. 3). The inflection pointorresponds to the maximum leaching rate of the solute in questionnd occurred approximately on 1/8/2007 in the fertilized treat-ents for Cl−, NO3

−, K+, Mg2+ and Ca2+. On this date, 3.5, 3.4 and 2.1ore volumes had passed through the soil profile in T1, T2 and T3,espectively.

The delay in the appearance of the fertilizer pulse and theccompanying elements was evidenced by the displacementetween the date on which 1.0 Vp was drained and the date cor-esponding to the inflection point of the curves. This displacements characteristic of elements that, when transported, react in thexchange complex and are adsorbed (Skaggs and Leij, 2002). In theertilized treatments, the curves of the ions Cl−, NO3

−, K+, Mg2+ anda2+ show the mentioned behavior and also show greater mobilityf these ions compared to PO4

3− and SO42− in the present experi-

ent.The amount of leached Cl−, NO3

−, Ca2+, K+ and Mg2+ indicateshat the soil retention of these ions was not high. The low retentionf the mentioned cations and anions can be explained by the facthat the soil is highly weathered and has a low cation-exchangeapacity, with evidence that kaolinite dominates the mineral frac-ion of the soil (Ghiberto, 2009; Qafoku and Sumner, 2001).

The possible effect of the application of lime and P fertilizationn generating a negative net charge should not be ignored (Naidut al., 1990; Qafoku and Sumner, 2001). This effect would favorhe exclusion of NO3

− and, therefore, N leaching from the surfaceayers. In studies of soil columns, Bellini et al. (1996) showed thathe application of lime led to reduced anion-exchange capacity andhat Cl−, NO3

− and SO42− appeared rapidly in the leachate, sug-

esting the release of anions previously held at exchange sites. Theuthors also observed in the NO3

− elution curve that the retar-ation factor, dispersion and symmetry of the curve markedlyecreased compared to the patterns in the treatment without

iming, thus indicating low NO3− adsorption in the columns.

n the present field experiment, the presence of NO3− derived

rom the fertilizer and Cl− were detected soon after between 2.1nd 3.4 pore volumes were drained during the period of high-st rainfall, similarly to what occurred in the experiment in soilolumns.

The analysis of the 34S isotope in the extracted soil solutionhowed that from the total S leached in the crop cycle, 0.480 kg ha−1

erived from the 114 kg ha−1 S applied as fertilizer in T2. SO42−

ad a different behavior than NO3−, with no significant differences

n the amount of leached S among the treatments. Halvin et al.2005) cite a number of soil-related factors that affect the adsorp-ion/desorption of SO4

−, which, in this experiment, would haveontributed to prevent SO4

− leaching: the presence of Fe/Al oxides;he profile of the kaolinitic soil; the large amount of organic mat-er on the surface; and the increasing acidity with depth causing

decrease in the net negative charge. In addition to these factorsnd because the initial soil S content was lower than that recom-ended for sugarcane (Faroni, 2008), the crop was treated with

fertilizer, thus avoiding losses by leaching of the element. The

ynergistic effect of increased S absorption by sugarcane in theresence of higher N doses, with a consequent decrease in S leach-

ng, was also observed by Bologna-Campbell (2007) in experimentsn 220-L pots.

anagement 148 (2015) 141–149

In view of the large amounts of leached Ca and Mg (Tables 4–6),one should not overlook that the experimental area was a vinasse-application sector, rich in K+ and N, and that 120 kg ha−1 K2O wereadded in the first ratoon. This K+ could displace Ca and Mg fromthe exchange sites, thus favoring the leaching of these elements.A similar mechanism is given by the effect of protons released inthe transformation of NH4

+ into NO3− during the nitrification pro-

cess, which would be exchanged with cations held on the exchangecomplex. The described mechanism has been reported by severalauthors who measured NO3

−, Ca, K and Mg leaching using lysime-ters or in the field with tensiometers and soil-solution extractorsin Oxisols (Poss and Saragoni, 1992; Wong et al., 1992;).

In the ratoon cane cycle, N leaching was significantly higher inT2, which also showed significant amounts of leached K, Ca andMg. Even considering the leaching losses obtained and the highhydraulic conductivity measured at 0.9 m depth (see K0 of the func-tion K(�) Eq. (3)), the results are not sufficient to state that the watertable is negatively affected. From the abovementioned results, onecan conclude that, due to nutrient losses observed at 0.9 m depth,the recycling of nutrients is important when taking measures toimprove the subsoil and to consequently avoid nutrient losses fromthe root system. The results show that comprehensive studies of thesoil–plant system must be developed to understand and be able tomanipulate subsoil acidity, aiming for better development of thecultivated plants.

4. Conclusions

The leaching of N was between 3.9 and 34.9 kg ha−1. The Nleached derived from the 100 kg ha−1 applied N fertilizer was22.5 kg ha−1. The S leached was between 4.6 and 8.4 kg ha−1. Theleaching derived from the 114 kg ha−1 applied S fertilizer was0.480 kg ha−1. P leaching was between 0.3 and 1.2 kg ha−1 and wastherefore not an environmental concern. The maximum leaching ofP, K, Ca, and Mg were 1.2, 53.6, 135.7 and 39.8 kg ha−1, respectively.The information obtained in the present study does not allow aninference that the water table will be negatively affected, nor doesit associate the sugarcane crop with pollution of the water table.

Acknowledgements

The authors are thankful: (i) for the financial support by“Fundac ão de Amparo à Pesquisa do Estado de São Paulo”(FAPESP—Foundation of Support to Research of São Paulo State),and to “Coordenac ão de Aperfeic oamento de Pessoal de Nível Supe-rior” (CAPES—Coordination of Personal Improvement at HigherLevels), (ii) by the logistic support of Santa Adélia Mill and (iii)by the support in the laboratory analyses by the workers at thelaboratory of stable isotopes at CENA.

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