AGRICULTURAL RESEARCH COMMUNICATION CENTRE

www.arccjournals.comAgric. Sci. Digest., 34 (1) : 26 - 30, 2014

EVALUATION OF NEEM BARK COATED UREA FORSLOW RELEASE OF NITROGEN

Chelvi Ramessh, A.R. Ramesh,1 Kokila1 and N.S. Venkataraman

Agricultural College and Research Institute,Tamil Nadu Agricultural University, Madurai – 625 104, India.

Received: 27-12-2012 Accepted: 24-07-2013

ABSTRACTThe neem bark powder coated urea fertilizer samples were prepared by adapting the spray

technique and characterized by using FT-IR and SEM studies. Incubation study was carried out tostudy the Nitrogen-release pattern with the help of Micro kjeldahl method. SEM studies revealed thepresence of Neem bark powder coating on urea. The increase in percentage of coating showed aslow nitrogen-release pattern holding the promise for further studies in this line.

Key words: Coated urea, FT-IR, Micro kjeldahl, Neem bark, Nitrogen – release, SEM.

1Department of Chemistry, Thiagrajar College, Madurai-625 009, India

INTRODUCTIONUrea is the widely used nitrogenous fertilizer

in agriculture because of its high nitrogen content(46%). However, 50-70 per cent of the appliednitrogen gets lost due to different losses viavolatilization, leaching etc, reducing the useefficiency of applied fertilizers (Shaviv and Mikkelsen,1993). This reduces the productivity and increasesthe cost of cultivation besides polluting theenvironment. Increasing the nitrogen use efficiencywill lead to increase in productivity substantially.Various methods recommended to increase fertilizeruse efficiency are increasing the organic mattercontent of soil through application of organicmanures, split application of fert i lizers andapplication of coated or slow release fertilizers. Inthis context, the controlled release technology bycoating urea with different materials such asphosphogypsum, sulphur, resin polymers, Dicyclopentadiene (DCPD), pine tree Kraft lignin and neemusing different techniques of rotating drum, fluidizedbed and spouted bed to increase the efficiency ofurea fertilizer has been investigated (Susherman andAnggoro,2011). It was reported that the thicknessof coating fertilizers, affects the release pattern ofnitrogen from fertilizers (Junejo et al., 2009).Furthermore, during recent past, there has been anincreasing interest in the use of biopolymers which

are completely degradable. Hence, this researchwas carried out to explore the possibility of coatingurea with neem bark powder, which is the cheapestsource of organic compound, biodegradable andavailable throughout the year everywhere in India.

MATERIALS AND METHODSThe experiment was carrid out at the

Department of Chemistry, Thiagrajar College,Madurai and at Agricultural College and ResearchInstitute., Y. Othakkadai, Madurai.

Synthesis of neem bark coated urea: Neem barkpowder was weighed and placed in ethanolseparately at 1 per cent, 2 per cent and 3 per centconcentrations for two days. These solutions werefiltered and coated on urea at optimum temperatureby using spray technique.

Characterization of neem bark coated urea: TheFTIR spectrum was recorded using a Perkin-ElmerFTIR spectrum RXI spectrometer by KBr pellettechnique in the range of 400-4000 cm-1 at roomtemperature. The Scanning Electron Microscope(SEM) images by scanning with higher energy beamof electrons were used to study the surfacetopography of the samples under investigation.

Estimation of ammonical and nitrate nitrogenIncubation process: Three separate containerseach having 250g of agricultural soil were taken and

DOI- 10.5958/j.0976-0547.34.1.005

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5g of the prepared urea samples were added. Waterwas sprinkled over these three soil samples. Theywere kept in the incubator at room temperature.Water was sprinkled at regular intervals of time tokeep the soil samples wet. Once in seven days,sample from each container was taken and estimatedfor the release of ammonical and nitrate nitrogen byusing “Micro-kjeldahl method”.

Principle: When fertilizer samples containing bothammonical and nitrate nitrogen are distilled withfreshly ignited MgO, Mg(OH)2 is formed which inturn liberates NH3 from NH4. The ammonia liberatedis absorbed in a known excess of standard acid andestimated. Later when Devarda’s alloy is added, itreacts with NaOH liberating hydrogen which in turnreduces the nitrate nitrogen to NH3. The liberatedNH3 is absorbed in known excess of standard acidand the nitrate content is estimated.

Reactions with MgO2NH4NO3 + Mg (OH)2’ Mg (NO3)2+ 2H2O+ 2NH3 2NH3 + H2SO4 (NH4)2SO4

RESULTS AND DISCUSSIONThe assignment of FTIR data of the

uncoated urea, neem bark powder and neem barkpowder coated urea (Table 1) shows the evidence

of presence of different functional groups. Ureahas dist inguishing absorptions, 1683 cm–1

corresponds to C-O stretching, and 1468 cm-1

corresponds to C-N stretching as well as N–Hstretches at 3347 and 3447 cm–1 respectively(Fig.1). The peak at 3297.75 cm-1 represents thesurface N-H stretching and 1606.41 cm-1 can beassigned to the amide C-O stretching of NeemBark Powder. Whereas in the case of differentpercentage coated urea, there is a decrease inwave number of O-H and C-O stretching. Thisindicates the proper coating of neem bark powderon the surface of urea. The SEM images ofuncoated urea, neem bark powder and neem barkcoated urea are given in Plate 1.

Release pattern of ammonical nitrogen: Withrespect to 1 % neem bark coated urea, the amountof ammonical nitrogen release ranged from 168ppm on seventh day and gradually increased up to280 ppm on 14th day and there was a declinethereafter on 21 and 28 days. Whereas, there wassteady increase in the release of ammonical nitrogenfrom 7th day onwards attaining the maximum value(420 ppm) at 21 days with 2 % coating. In case of3 % coating, there was gradual increase of NH4 –N with time.

Assignment Uncoated urea (pure)

Neem Bark powder

1% coated urea

2% coated urea

3% coated urea

Surface N-H(s) 3447,3347 (s) 3297.75 3197.98 3062.96 2056.12

Amide C-O(s) 1683 (s) 1606.40 1521.84 1496.32 1458.18

TABLE 1: FT-IR spectra data for uncoated urea, neem bark and neem bark coated urea

FIG.1: Ammonical N release pattern of neem bark coated urea

Neem bark coated 1%

Neem bark coated 2%

Neem bark coated 3%

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Uncoated urea

FIG.1: FT-IR spectra

1% Neem bark extract coated urea

Neem Bark powder

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2% Neem bark extract coated urea

3% Neem bark extract coated urea

CONCLUSIONNeem bark coated urea was synthesized at

1%, 2% and 3% concentrations using spraytechnique and characterized using FT-IR and SEM.The N release pattern was studied at weekly intervalsthrough Micro kjeldahl method. The FT-IR studies

and SEM images confirmed the coating of neembark over prilled urea. As regards, ammonical Nrelease, the slow release effect correlated positivelywith the concentration of neem bark coating, thus,holding the promise for further refinement and fieldstudies.

REFERENCESJunejo, N, Hanafi MM., Khanif YM., Yunus WMZ. (2009). Effect of Cu and palm stearin coatings on the

thermal behavior and ammonia volatilization loss of urea. Res. J. Agric. Biol. Sci., 5(5): 608 - 612.Shaviv, A and Mikkelsen R.L.(1993). Controlled – release fertilizers to increase efficiency of nutrient use

and minimize environmental degradation a review. Fertilizer Research 35:1 -12.Suherman and Anggoro.(2011). Producing slow release urea by coating with Starch/Acrylic acid in Fluid

Bed Spraying. IJET-IJENS 11(6): 77-80.