Agric. Sci. Digest., 34 (1) : 26-30, 2014 DOI- 10.5958/j.0976-0547.34.1.005 AGRICULTURAL RESEARCH COMMUNICATION CENTRE www.arccjournals.com EVALUATION OF NEEM BARK COATED UREA FOR SLOW RELEASE OF NITROGEN Chelvi Ramessh, A.R. Ramesh, 1 Kokila 1 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 ABSTRACT The neem bark powder coated fertilizer samples were prepared by adapting the spray technique and characterized by using FT-IR and SEM studies. Incubation study was carried out to study the Nitrogen-release pattern with the help of Micro kjeldahl method. SEM studies revealed the presence of Neem bark powder coating on. The increase in percentage of coating showed a slow nitrogen-release pattern holding the promise for further studies in this line. Key words: Coated, FT-IR, Micro kjeldahl, Neem bark, Nitrogen release, SEM. INTRODUCTION Urea is the widely used nitrogenous fertilizer in agriculture because of its high nitrogen content (46%). However, 50-70 per cent of the applied nitrogen gets lost due to different losses via volatilization, leaching etc, reducing the use efficiency of applied fertilizers (Shaviv and Mikkelsen, 1993). This reduces the productivity and increases the cost of cultivation besides polluting the environment. Increasing the nitrogen use efficiency will lead to increase in productivity substantially. Various methods recommended to increase fertilizer use efficiency are increasing the organic matter content of soil through application of organic manures, split application of fertilizers and application of coated or slow release fertilizers. In this context, the controlled release technology by coating with different materials such as phosphogypsum, sulphur, resin polymers, Dicyclo pentadiene (DCPD), pine tree Kraft lignin and neem using different techniques of rotating drum, fluidized bed and spouted bed to increase the efficiency of fertilizer has been investigated (Susherman and Anggoro,2011). It was reported that the thickness of coating fertilizers, affects the release pattern of nitrogen from fertilizers (Junejo et al., 2009). Furthermore, during recent past, there has been an increasing interest in the use of biopolymers which 1 Department of Chemistry, Thiagrajar College, Madurai-625 009, India are completely degradable. Hence, this research was carried out to explore the possibility of coating with neem bark powder, which is the cheapest source of organic compound, biodegradable and available throughout the year everywhere in India. MATERIALS AND METHODS The experiment was carrid out at the Department of Chemistry, Thiagrajar College, Madurai and at Agricultural College and Research Institute., Y. Othakkadai, Madurai. Synthesis of neem bark coated : Neem bark powder was weighed and placed in ethanol separately at 1 per cent, 2 per cent and 3 per cent concentrations for two days. These solutions were filtered and coated on at optimum temperature by using spray technique. Characterization of neem bark coated : The FTIR spectrum was recorded using a Perkin-Elmer FTIR spectrum RXI spectrometer by KBr pellet technique in the range of 400-4000 cm -1 at room temperature. The Scanning Electron Microscope (SEM) images by scanning with higher energy beam of electrons were used to study the surface topography of the samples under investigation. Estimation of ammonical and nitrate nitrogen Incubation process: Three separate containers each having 250g of agricultural soil were taken and
5g of the prepared samples were added. Water was sprinkled over these three soil samples. They were kept in the incubator at room temperature. Water was sprinkled at regular intervals of time to keep the soil samples wet. Once in seven days, sample from each container was taken and estimated for the release of ammonical and nitrate nitrogen by using Micro-kjeldahl method. Principle: When fertilizer samples containing both ammonical and nitrate nitrogen are distilled with freshly ignited MgO, Mg(OH) 2 is formed which in turn liberates NH 3 from NH 4. The ammonia liberated is absorbed in a known excess of standard acid and estimated. Later when Devarda s alloy is added, it reacts with NaOH liberating hydrogen which in turn reduces the nitrate nitrogen to NH 3. The liberated NH 3 is absorbed in known excess of standard acid and the nitrate content is estimated. Reactions with MgO 2NH 4 NO 3 + Mg (OH) 2 Mg (NO 3 ) 2 + 2H 2 O+ 2NH 3 2NH 3 + H 2 SO 4 (NH 4 ) 2 SO 4 RESULTS AND DISCUSSION The assignment of FTIR data of the uncoated, neem bark powder and neem bark powder coated (Table 1) shows the evidence Assignment Uncoated (pure) Vol. 34, No. 1, 2014. Neem Bark powder 27 of presence of different functional groups. Urea has distinguishing absorptions, 1683 cm 1 corresponds to C-O stretching, and 1468 cm -1 corresponds to C-N stretching as well as N H stretches at 3347 and 3447 cm 1 respectively (Fig.1). The peak at 3297.75 cm -1 represents the surface N-H stretching and 1606.41 cm -1 can be assigned to the amide C-O stretching of Neem Bark Powder. Whereas in the case of different percentage coated, there is a decrease in wave number of O-H and C-O stretching. This indicates the proper coating of neem bark powder on the surface of. The SEM images of uncoated, neem bark powder and neem bark coated are given in Plate 1. Release pattern of ammonical nitrogen: With respect to 1 % neem bark coated, the amount of ammonical nitrogen release ranged from 168 ppm on seventh day and gradually increased up to 280 ppm on 14 th day and there was a decline thereafter on 21 and 28 days. Whereas, there was steady increase in the release of ammonical nitrogen from 7 th day onwards attaining the maximum value (420 ppm) at 21 days with 2 % coating. In case of 3 % coating, there was gradual increase of NH 4 N with time. TABLE 1: FT-IR spectra data for uncoated, neem bark and neem bark coated Surface N-H(s) 1% coated 2% coated 3% coated 3447,3347 (s) 3297.75 3197.98 3062.96 2056.12 Ami de C-O(s) 1683 (s) 1606.40 1521.84 1496.32 1458.18 Neem bark coated 1% Neem bark coated 2% Neem bark coated 3% FIG.1: Ammonical N release pattern of neem bark coated
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Vol. 34, No. 1, 2014. 29 FIG.1: FT-IR spectra Uncoated Neem Bark powder 1% Neem bark extract coated
30 AGRICULTURAL SCIENCE DIGEST 2% Neem bark extract coated CONCLUSION Neem bark coated was synthesized at 1%, 2% and 3% concentrations using spray technique and characterized using FT-IR and SEM. The N release pattern was studied at weekly intervals through Micro kjeldahl method. The FT-IR studies 3% Neem bark extract coated and SEM images confirmed the coating of neem bark over prilled. As regards, ammonical N release, the slow release effect correlated positively with the concentration of neem bark coating, thus, holding the promise for further refinement and field studies. REFERENCES Junejo, N, Hanafi MM., Khanif YM., Yunus WMZ. (2009). Effect of Cu and palm stearin coatings on the thermal behavior and ammonia volatilization loss of. 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 by coating with Starch/Acrylic acid in Fluid Bed Spraying. IJET-IJENS 11(6): 77-80.