Proc. 17"1 Intern. Symp. of CIEC, 24-27 Nov. 2008 © NRC (Micronutrient Project). Cairo - Eqypt. pp. 279-284 (2008)

RELATIONSHIPS BETWEEN NITRIFICATION INHIBITORS AND

SOIL SALINATION

Diez-Lopez1, J., Arauzo1 M., Hernáiz1 P. and Sanz2 A.

'ito Ciencias Agrarias, Centro de Ciencias Medioambientales CCMA-CSIC. Serrano 115, 28006

Madrid, Spain.

E-mail: jadiez@ccma.csic.es. +34917452500 Ext 232. Fax +34915640800

2ETSI Agrónomos, Polythecnic University of Madrid. Ciudad Universitaria 28040 Madrid Spain

Abstract:

The use of Nitrification inhibitors (NI) has been extended with object to retard the

mineralization of nitrogenous organic compounds in soil and to reduce the nitrateconcentration in soil solution and consequently the nitrate leached. In a study projected to

valué the effect of NI on the nitrification, was observed that the application of thesecompounds produced an increase of conductivity and parallel of the Na concentration in soilsolution.

In a experiment with DMPP (dimethylpyrazole-phosphate) and DCD (dicyandiamide) added

to ammonium sulphate nitrate (ASN) as fertilizer, on irrigated maize crop, was observed thatthe increase of ammonium concentration in soil, displaces to Na ions of the soi! complexexchange, which drive finally to an increase of soil salination. Also, the water irrigation from

Jarama River contributed to salination, in spite of its excellent quality. The water wassampled 18 times during the season with the following valúes: Na 90 mg L~', eléctrica!conductivity (EC) 1.0 dSm"1, Na adsorption ratio (SAR) 1.55. The amounts of irrigationwater applied to the maize crops in 2006 and 2007 were 788 and 778 mm, rcspectively andthe Na contribution to soil by water irrigation was 688 and 663 kg Na ha"' in 2006 and 2007,respectively; Drainage and Na concentration in drainage zone (140 cm depth) were measured

during the season and the Na leached was determined. The treatments with NI (DCD andDMPP) showed greater Na concentrations in soil and consequently higher Na leached (in

1QQ7, DCD 1191, DMPP 1119, A£N 91& md Canteo!. 58.7 tg Ni tvi'v. A.UA, ammoswjm.fertilizers (ASN) increased the Na concentration in soil and Na leached, although with lower

valúes.

Introduction:

As a consequence of agricultura! practices, a control on nitrate leaching is necessary to

protect or improve water quality. To reduce the nitrate leaching has been frequently used thenitrification inhibitors (NI) at low concentrations (Amberger, 3981; Ashword et al. 1982),with subject of to accumulate ammonium in soil, retarding the oxidation to nitrate, due to its

bacteriostatic action on Niírosomonas.

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However, other secondary effects are produced in the soil due to the increase of ammonium

in soil, originated by displacing of other cations of the exchange complex, such as the

sodium, which could origínate a soil salination.

The aim of present work has been to valué the induced effect of DMPP and DCD as NI,added to ammonium sulphate nitrate (ASN) fertilizer on soil salination, in an irrigated maize

crop, under Mediterranean conditions.

Material and Methods:

The experimental site was located at the La Poveda Field Station in Arganda del Rey(Madrid) (40° 19'N, 3° 19' W), in the middle of the Jarama river basin. The soil, a Typic

Xerofluvent (Soil Survey Staff 1993), was a sandy-loam that became progressively sandier

with depth and had a gravel layer at a depth of 1.5-2.2 m. The most relevant soilscharacteristics at the study site of the top 0-50 cm are shown in Table 1. Soil samples wereanalyzed before planting for pH, organic matter (Walkley and Black, 1934) and carbonate

(ISO 10693,. 1995). Potassium and Ca levéis were determined by fíame emission photometry.

The depth of the water table fluctuated from 4-4.5 m below the soil surface, depending on

rainfall and river discharge. The average rainfall in this área is 460 mm yr" .

Twelfth 100-m2 experimental plots were selected and four treatments with three replicationsrandomized were applied in the first year. In the second year the plots received the sametreatments of the before year with the N fertilizer dose reviewed. Treatments included a

control (C), a single application (ASN), a single N application with DCD 5% (DCD) and asingle N application with DMPP (DMPP).

Table 1. Physicochemical properties of soil, before sowing.

Descriptor

PÍÍH2O

Organic Matter (g kg"1)

CaC03 (g kg1)

Sand %

Silt %

Clay %

Bulk density (Mg m'3)

Mean ± SD

8.110.1

14.0 ±0.2

34.010.8

38.715.6

47.5 1 9.0

13.815.2

1.47

The fertilization was realized with ASN and DCD or DMPP as NI. The ASN-DCD 5%fertilizer was prepared by Fertiberia S.A. 10 days before of its application with differentprocedure in 2006 respect to 2007. The ASN-DCD used in 2006 was prepared by singlemixture of powder DCD with ASN granulated, whil that the fertilizer used in 2007 was

prepared by mixture of both to which was added liquid Vaseline as adhesive. In the case ofASN-DMPP was used ENTEC commercial manufactured by COMPO. Treatments were

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applied only once, on June lst in 2006 and on June 7th in 2007, after sowing, as top-dress. The

N rates applied can be seen in Table 2.

Table 2.-N fertilizer treatments applied to maize crop (2006-2007) (kg N ha"').

Treatment

Control

ASN

DCD

DMPP

Fertiliser type

ASNa

ASN-DCDb

ASN-DMPPC

2006

0220

220

220

2007

0

180

180

, 180

a ammonium sulphate nitrate

ASN and 5% of DCD relati

ASN and DMPP 0.8% (w/w) of applied nitrogen

b ASN and 5% of DCD relative to NH4+-N.

Maize (Zea mays L. cv Helen ) was sown at the start of April in both years. The rows were 75

cm apart and plant density was 90,000 plants ha"1. During seedbed preparation, super-

phosphate (18% P2O5) and K2SO4 (50% K2O) were applied at 22 kg Pha"1 and 111 kg K ha"1.

The maize was grown using traditional farm practices for the área, and it was harvested in

October, when the grain was mature.

The water used throughout the experiment was taken from an irrigation channel fed by the

River Jarama. The amounts of irrigation water applied to the maize crops in 2006 and 2007

were 788 and 778 mm, respectively, in accordance with soil water reserves. The water was

sampled 18 times in the course of the experiment. Four EnviroSCAN probes (Sentek Pty Ltd,South Australia) (50 mm inside diameter) at a depth of 150 cm. were installed in plots

corresponding to Control, SPN, DCD and DMPP treatments to monitor volumetric soil water

contení (9V). In each probes there was five capacitance sensors based on frequency domain

reflectometry FDR measures (Pares et al. 2000) situated at 10, 40, 70, 120 and 150 cm depthto measure 9V. The device was programmed to take a reading every hour throughout the

cultivation period in both years. A data logger recorded the data.

To determine the Na leaching, a ceramic candle extraction system was used to obtain samplesof the soil solution (interstitial water) by installing two tubes at 1.4 m depth in each plot. It

was considered that any water reaching this level, near the gravel layer, was leached into the

groundwater (at an average depth of 4 m) because of the high hydraulic conductivity (Smithet al. 1991). Consequently, the amount of water drainage at a soil depth of 1.4 m was the

same as that at greater depths due to the textural characteristics of the soil profile. Water

samples extracted using the ceramic candle, were taken to represent the sodium concentrationof the drainage water. Soil solution was collected monthly by means of electric vacuum pump

connected to the nylon tube and transferred to a storage bottle. A vacuum of -80 kPa was

applied to the tubes and maintained during 7 to 10 days in each sampling. After this period,water samples were extracted using air pressure.

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Samples of the soil solution were extracted 9 times in 2006 and 9 times in 2007, during the

crop periods. Na concentration and electric conductivity (EC) were subsequently determined.

During drainage periods, Na leaching was calculated on a weekly basis by multiplying the

weekly drainage time the corresponding Na concentration at 1.4 m for each sampling event

(Diez et al. 1997). Na concentration was determined by fíame emission photometry and EC

with a Crison 525 conductivity meter.

Results and Discussion:

The drainage was higher in 2007 (161 mm) man 2006 (71 mm). The average quality

components of the irrigation water were: NCV, 5.1 ± 0.5 mg N L" ; Na, 90 ± 16 mg L"\l

solids, 650 + 50 mg L"1; eléctrica! conductivity (EC), 0.10 ± 0.01 S m"1; Na adsorption ratio

(SAR), 1.55; and pH, 7.6 ± 0.2. The Na contribution to soil by water irrigation was 688 and

663 kg Na ha'1 in 2006 and 2007, respectively.

Regardless of the N source, soil solution sodium concentrations were affected by the

treatments. In both years the higher Na concentration corresponded to DCD treatment. DMPP

and ASN show similar valúes (Fig 1) between then. The mean valúes and standard deviation

in both years in Na concentration in soil solution at 140 cm depth (mg Na L"1) were: DCD

691±132; DMPP 556±113: ASN 553±120 and C 353±40. The mean valúes and standard

deviation of EC (\iS cm"1) were: DCD 5780±1431; DMPP 5245±1170; ASN 5548±1380 and

C 3654±355. Can be seen appreciabie differences between NI treatments and Control.

Electric Conductivity 2006-07in water at 140 cm depth

8000

O 4000

-T

-DMPP

-DCD

-NSA

15-10-05 4-3-06 22-7-06 9-12-06 28-4-07 15-9-07 2-2-08

Na concentration 2006-07in water at 140 cm depth

1000

800

~¡ 600Cu

DJ 400E

200

-T

-DMPP

-DCD

-NSA

4-3-06

Fig. 1. Evolution of EC and Na concentration in relationship to DCD, DMPP and ASN

treatments during 2006 and 2007 with maize crop.

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In order to improve the poor results obtained in 2006 year, in relationship to nitrate leached,

due to low drainage (71 mm), in 2007 were probed increase the drainage, modifying the

irrigation frequency (living one day between two consecutive watering) obtaining a greater

drainage (161 mm) with similar irrigation doses. The water lost by drainage. represent an

average equivalen! to 10-20% of total irrigation water applied.

Fig 2 show the curves of Na leached in 2006 and 2007. In relationship with drainage, Na

leached in 2006 was lower than 2007. The Na valúes lost in 2006 were in a rank between 250

and 439 kg Na ha"1, on the contrary ín 2007 these valúes were in a rank between 1292 and

5 87 kg Na ha"1.

Attending to the results of 2007, the DCD treatment showed the greatest lost of Na (1292 kg

Na ha"1) as a consequence of displacing of Na from complex exchange by effect of higher

account of ammonium and Na contribution from water irrigation. Also, DMPP treatment

given high lost of Na (1019 kg Na ha"1). The ASN treatment due to that is an ammonium

fertilizer, also originated an increase of Na leached (928 kg Na ha"1) with respect to Control

(587 kg Na ha"1), although lower than the treatments with nitrification inhibitors.

2-6-0611-8-0620-10-06

Na leached 2007

1400

1200

1000

800

600 -

400 -

200

O -

-T

-DMPP

-DCD

•NSA

19-3-0728-5-076-8-0715-10-07

Fig 2. Cumulated curves of Na leached, originated by DCD, DMPP and ASN treatments

during 2006 and 2007 with maize crop.

In spite of these results, the properties of the soil were not disturbed and the salmation

observed had not effect on yield crop. In both experimental seasons, significant differences

(P<0.05) were detected only between the control and the fertilized treatments with respect to

DM, grain yield and N uptake. The results obtained in mis paper showed that NI treatments

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did not increase the production valúes but neither had depressive effect on either maize

yields.

As conclusión of the experiment, the NI treatments increase ammonium content in the soil,

which origínate a greater Na concentration by displacing of Na ions of the complex

exchange. Consequently, higher Na leached was observed.

Acknowledgements;

The authors are grateful to the Comunidad de Madrid and Fertiberia S.A. for financing this

research and proving us with the fertilisers and the inhibitor. It is a pleasure to acknowledge

ío A. de Diago because their assistance in laboratory.

References;

- Amberger, A. (1981). Dicyandiamide as a nitrification inhibitor. In Proceeding of the

technical Workshop on Dicyandiamide (R.D. Hauck and H. Behnke. eds) pp 3-17.

Germany: SKW Trostberg.

- Ashword, J., Widdowson, F.V., Penny, A., Gibbs, A.J., Hodgkinson, R.A., Hewit,

M.V. (1982). Results from an experiment on permanent grass evaluating the cumulative

effects of aqueous urea, injected alone or with a nitrification inhibitor, within those of

"Nitro-Chalk". Journal Agricultural Science, 98, 141-154.

- Diez, J.A., Román, R., Caballero, R., Caballero, A. (1997). Nitrate leaching from soils

under a maize-wheat-maize sequence, two irrigation schedules and three types of

fertilizers. Agriculture, Ecosystem and Environment, 65, 189-199.

- Fares, A., Alva, A.K. (2000). Soil water components based on capacitance probes in a

sandy soil. Soil Science Society American Journal, 64, 311-318.

- International Standard. ISO 10693 Soil quality (1995). Determination of carbonate

content. Volumetric method. Intern Org for Standardization ed. Switzerland, 1-7.

- Smith, K.A., Mullins, C.E. (ed.) (1991). Soil analysis. Physical methods. Marcel

Dekker, New York.

- Walkley, A., Black, A.I. (1934). An examination of the Degtjareff method for

determining soil organic matter, and proposed modification of the chromic acid titration

method. Soil Science, 37, 29-38.

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1956National Research Centre

(NRC)

1976Project Mícronutrients andPlant Nutrition Problems

CIECInternational Scientific

Centre of Fertilizers

Proceedings ofthe 17th International Symposium of CIEC

PLANT NUTRIENT MANAGEMENT

UNDER STRESS CONDITIONS

National Research Centre (NRC)24-27 Nov. 2008, Cairo - Egypt

2008

© National Research Centre (NRC), 2008-11-16Project Micronutrients and plant Nutrition Problems , Cairo - Dokki, Egypt.EI-Behooth Str., Dokki, Cairo, EgyptTel. : 00 202 33365223 - 33361225 - 33365199Fax: 00 202 37610850E-mail: nrc-mic@link.net

Layout:Prof. Dr. F.E. Abdalla and Dr. A.A. Abdel-MaguidFertilization Technology Dept., NRC.

Egyptian National Library Legal Deposit No. 22018/2008ISBN : 977 - 5041 - 60 - O

Printed in Egypt by:

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