NITROGEN IN SEMI ARID CONDITION

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1 Indian J. Agric. Res.., 46 (3) : , 2012 AGRICULTURAL RESEARCH COMMUNICATION CENTRE ccjournals.com / indianjournals.com nals.com IMPACT OF INTEGRATED TED USE OF FERTILIZER AND ENRICHED COMPOST ON YIELD, NITROGEN UPTAKE BY WHEAT AND FRACTIONS OF SOIL NITROGEN IN SEMI ARID CONDITION S.K. Singhal, R.D. Singh, V.K..K. Sharma ma and S.K. Sharma ma Division of Soil Science and Agricultural Chemistry Indian Agricultural Research Institute, New Delhi , India Received: Accepted: ABSTRACT A field experiment was conducted with integrated nutrient management on wheat at IARI research farm New Delhi. Grain yield of wheat with 50% NPK fertilizer + NPK enriched compost was significantly higher than that of 100% NPK fertilizer tilizer,, it was at par with 50% NPK fertilizer + NP enriched compost. The treatment 50% NPK fertilizer along with NPK enriched compost recorded maximum N uptake (105.0 kg ha -1 ). Application of fertilizer alone or in combination with compost led to a significant increase in total N, hydrolysable N (amino sugar-n, amino acid- N and hydrolysable NH 3 -N) and nonhydrolysable-n in soil as compared to initial status. The correlation studies revealed that amino sugar-n, amino acid-n and hydrolysable NH 3 -N fractions in soil were better indices of soil-n mineralization. A better correlation was observed between amino sugar-n with grain yield /N uptake by wheat. Key words: Organics, Fertilizer, Nitrogen fractions, Uptake, Wheat yield. INTRODUCTION Fertilizers play vital role in production and productivity of any crop but continuous and imbalanced use of high analysis chemical fertilizers in intensive cultivated area badly influences production and soil health. Subsequently, most of the productive soils become unproductive. Use of chemical fertilizer in combination with organic manure is essentially required to improve the soil health (Bajpai et al., 2006). The organics not only serve as sources of plant nutrients, but also improves the physical, chemical and biological health of soil (Chouksey et al., 1995). Nitrogen is the key element among the major nutrients in crop production and most of the Indian soils are deficient or low in this nutrient. Most of the nitrogen in the plough layer of arable soils is present in a continuum of complex organic form (Kelley and Stevension, 1995), hence only a small portion of total nitrogen is present in inorganic form. To supplement N, along with organic sources, extensive and continuous application of mineral fertilizers stimulate mineralization and immobilization, thereby influencing the biological transformation of the nitrogen in soil (Duhan et al., 2005). Some studies shows that addition of NPK fertilizer alone or in combination with farm yard manure (FYM) enhanced the contents of both hydrolysable and non-hydrolysable-n in inceptisol under maizewheat system (Kamat et al., 1982). Little is known about the bioavailability of the different forms of organic N in soils because these compounds are so complex and their availability depends upon mineralization (Johnson et al., 1999). During the initial years, N gets distributed in the easily mineralizable fractions such as amino acids and amino sugars. Therefore, information on the amount of these mineralizable fractions and its dynamics would be helpful in nitrogen nutrition (Mulvancy et al., 2001) for different crops. The variation in different forms and fractions of nitrogen as affected by integrated use of fertilizer and enriched compost in wheat are limited. Therefore, the present study was undertaken to investigate the effect of integrated use of fertilizer and enriched compost on various fractions of nitrogen contributing to the nitrogen nutrition under wheat.

2 MATERIALS AND METHODS A field experiment was conducted during at IARI research farm, New Delhi with wheat (cv: HD-2285) by using ordinary compost and enriched compost as an organic source of nutrients and chemical fertilizer. Soil (Typic Haplustep) of IARI research farm belongs to subtropical semi arid agro climatic zone (annual rainfall 651 mm) of Upper Gangatic Plain ( N, E;) 250 m above mean sea level. The soil have sandy loam in texture with ph 7.9, EC 0.42 ds m -1, organic carbon 4.3 g kg -1, available N 186 kg ha -1, P 13.7 kg ha -1 and K 208 kg ha -1. The NH 4+ -N, NO 3 -N and total N content of the soil before sowing of wheat was observed 8.6, 15.8 and 587 mg kg -1, respectively. Four composts were prepared from rice straw alone and by mixing 2% N, 2% N + 2% P and 2% N + 2% P + 2% K along with rice straw on dry weight basis. The sources of N, P and K used for enrichment were urea, rock phosphate and waste mica respectively. The P and K content in rock phosphate and waste mica were 8% and 10% respectively. Sample of composts were analyzed for organic carbon and total N, P and K contents on dry weight basis by using standard procedures (Jackson, 1973). The composition of organic carbon, nitrogen, phosphorus, potash and C/N ratio in ordinary and enriched composts were given in Table 1. Wheat (cv: HD 2285) was grown with six treatments in randomized block design having three replications. Treatment T 1 Control T 2 50% RDF + 5 t ha -1, ordinary compost 50% RDF + 5 t ha -1, N enriched compost 50% RDF + 5 t ha -1, N and P enriched compost T 5 50% RDF + 5 t ha -1, N, P and K enriched compost T 6 RDF The recommended dose of fertilizer (RDF) of N, P 2 O 5 and K 2 O were 120, 60 and 60 kg ha -1, respectively. 1/3 rd of N and full dose of P and K were 263 applied as basal and remaining dose of N was divided into two split and applied at 30 and 45 days after sowing as per treatments. The sources of N, P and K were urea, SSP and MOP respectively. Composts were incorporated in soil one week before sowing. Surface soil samples (0-15 cm) were collected before sowing and after harvest and analyzed for different fractions of nitrogen and mineralizable N. Available N was estimated by the alkaline permanganate method by Subbiah and Asija (1956). Mineral nitrogen (NH 4+ -N and NO 3 -N) and total N in soil were determined by the method of Bremner (1960). The method by Bremner (1965) also adopted in order to determine the various organic N fractions of soil. Unidentified hydrolysable N (total hydrolysable N minus sum of hydrolysable NH 3 -N, amino sugar N and amino acid N); non hydrolysable N (total N minus total hydrolysable N fractions) were obtained by computing the data observed. After harvest the crop, nitrogen content in grain and straw samples was determined by standard procedure. Concentration of N was multiplied by yield for calculation of N uptake. The contents of different N fractions were correlated with grain and straw yield and N uptake by wheat. Statistical analysis of data obtained from the experiment was carried out according to the standard procedure outlined in Gomez and Gomez (1984). Correlations and regression analysis was carried out with the help of Microsta package. RESULTS AND DISCUSSION Grain and straw yield Perusal of data in Table 2 indicates that the grain yield of wheat increased from 32.6 to 84.2 % over control (27.3 q ha -1 ) with the application of compost + 50% NPK and the corresponding increase in straw yield was 41.9 to 82.3% over control (50.8q ha -1 ). The highest grain yield of wheat recorded with 50% NPK + 5 t ha -1 N, P and K enriched compost treatment (T 5 ) and it was greater than 100% NPK alone (45.7 q ha -1 ) indicating the possibilities of harnessing the values at the cost of TABLE 1: Nutrient composition of composts Composts O.C. (%) N(%) P(%) K(%) C:N Ordinary compost N enriched compost N,P enriched compost N, P and K enriched compost

3 264 50% NPK in the form of chemical fertilizer. The ( %) followed the similar trend as in wheat treatments (50% NPK + NP enriched compost) grain and significantly higher over the control. (100% NPK) registered grain yields of wheat Significant effect of integrated use of mineral 44.7 and 45.7 q ha -1 which was statistically at par. fertilizers with enriched compost was observed and Application of ordinary compost along with 50% the maximum N uptake (74.44 kg ha -1 ) in wheat NPK showed lower grain yield of wheat (36.2 q ha -1 ) grain was recorded under the treatment T 5 (50% as compared to other treatments. Ordinary compost NPK and NPK enriched compost) followed by could be attributed to the slow rate of nutrient supply (Table 2). Nitrogen uptake by wheat grain under the that failed to match the demands of the nutrients. treatments (65.26 and kg ha -1 ) were Substituting a part of inorganic nitrogen through N, at par. The lowest N uptake (37.67 kg ha -1 ) by wheat NP and NPK enriched composts compared grain was recorded under control (T 1 ). N uptake by favourably with 100% NPK (T 6 ) alone. Wheat straw wheat straw increased from kg ha -1 in control in treatments T4, T 5 with the values of 84.8, to kg ha -1 under treatment T 5. Treatments 92.6 and 86.8 q ha -1, respectively was observed nonsignificant. The finding indicates that the combined uptake (94.09 and kg ha -1 ). The lower total N were statistically at par in respect of total N application of well decomposed enriched composts uptake by wheat (77.0 kg ha -1 ) was noticed under as organic source and chemical fertilizers was the treatment 50% NPK + ordinary compost (T 2 ) as compared to enriched compost. Increase in N uptake superior to sole inorganic fertilizer application. with integrated use of organics with mineral fertilizers Pathak et al. (2005) also observed the similar might be due to early release of N as a result of findings. decomposition of organics. Application of N through Nitrogen content and uptake N, NP and NPK enriched compost along with 50% Nitrogen content in wheat grain was found NPK resulted in higher N uptake by wheat. This could non significant in treatments T 2 (1.47%), (1.43%), be explained by the ability of these treatments to (1.46%), T 5 (1.48%) (1.42%). The provide higher amounts of readily available N to meet significantly lowest value of N content (1.32 %) was the crop demand. Addition of organic sources recorded under control (T 1 ) as compared to other increased the microbial population which resulted treatments. The nitrogen content in wheat straw in enhanced availability of N. Prasad et al. (2010) TABLE 2: Yield, N content and N uptake of wheat influenced by integrated nutrient supply Treatment Yield (q ha -1 ) N content (%) N uptake (kg ha -1 ) Grain Straw Grain Straw Grain Straw T T T T CD at 5% TABLE 3: Different forms of nitrogen (mg kg -1 ) after harvest of wheat Treatments N Available N NH 4+ -N NO 3 -N T T T T CD at 5%

4 265 Treatment TABLE 4: Status of different hydrolysable N fractions (mg kg -1 ) after harvest of wheat acid-n sugar-n NH 3 -N Uni dentified hydrolysable-n hydrolysable-n Acid insoluble-n organic-n Initial T T T T CD at 5% TABLE 5: Correlation coefficient (r) among nitrogen fractions Parameters N Available N NH 4+ -N NO 3 -N organic-n ** 0.96** 0.84** acid-n ** sugar-n 0.81* * 0.97** Hydrolysable NH 3 -N ** Unidentified-N ** hydrolysable-n ** Acid insoluble-n 0.75* 0.82* * Significant at 5% ** Significant at 1% and Kumar and Prasad (2008) also observed the similar findings. Soil Studies and available N: Application of fertilizer along with compost influenced the different forms of N after harvest of wheat. Maximum total N in soil was recorded under (642 mg kg -1 ) followed by (636 mg kg -1 ). Treatments, T 5 were statistically at par in respect of total N (Table 3). Lowest total N (566 mg kg -1 ) was observed under control. Available N increased significantly with the integrated application of compost (94.8 to 99.4 mg kg -1 ) and chemical fertilizer over control (75.6 mg kg -1 ). The increase in available N content with the application of composts could be explained by the synergistic effect of enrichment of composts on N mineralization due to enhanced multiplication of microbes for the conversion of organically bound N to inorganic form. The NH 4+ -N in soil varied from 7.4 to 9.9 mg kg -1. The highest NH 4+ -N was observed under the treatment 50% NPK + NPK enriched compost (T 5 ) whereas lowest in control. Treatments T 2,,, T 5 were statistically non significant but had significantly higher amount of NH 4+ -N over control. The NO 3 -N varied between 14.8 and 28.8 mg kg -1. A positive effect of N substitution through composts was observed in terms of improved NH 4+ -N and NO 3 -N of the soil. Adding compost along with inorganic fertilizer had a favourable impact on NO 3 -N as compared under, and T 5 treatments and it supports the earlier results obtained by Khankhane and Yadav (2000). Application of enriched composts resulted in a higher microbial activity and enhanced mineralization resulting in the accumulation of NH 4+ -N in soil. This was in tune with the observation made by Santhy et al. (2001). The treatment T 5 maintained the highest level of NH 4+ - N (9.9 mg kg -1 ) and NO 3 -N (28.8mg kg -1 ) in the soil after harvest of wheat. Supplementing organic with inorganic N enhances the available N of soil (Sharma and Gupta, 1998) as a result of the hastening mineralization, once the requirement of N by microbes was fulfilled through inorganic nitrogen.

5 266 TABLE 6: Correlation coefficient (r) among yields, N uptake and inorganic and organic fractions of N of the soil Acid insoluble- N (X 11 ) hydrolysable-n (X 10 ) Unidentified-N (X 9 ) Hydrolysable NH 3 -N (X 8 ) sugar-n (X 7 ) acid-n (X 6 ) organic-n (X 5 ) NO 3 -N (X 4 ) + NH 4 -N (X 3 ) Available-N (X 2 ) Parameters -N (X 1 ) 0.84* ** 0.95** 0.86* 0.79* 0.90** 0.85* -0.80* 0.79* 0.36 Grain yield (Y 1 ) 0.96** 0.92** 0.76* 0.94** 0.85* -0.83* 0.77* 0.46 Straw yield ( Y 2 ) 0.91** ** 0.96** 0.91** 0.78* 0.93** 0.85* -0.83* 0.78* 0.43 Grain + str aw yield ( Y3) 0.89** ** 0.77* 0.42 N uptake by grain (Y 4 ) 0.84* 0.78* 0.92** 0.87** 0.89** 0.75* 0.88** 0.80* * * N uptake by straw (Y 5 ) 0.98** 0.82* 0.99** 0.90** 0.99** N uptake by grain + straw (Y6) 0.91** 0.81* 0.97** 0.90** 0.95** ** 0.79* -0.75* * Significant at 5% ** Significant at 1 % Organic fractions of soil N: There was a slight decrease in total organic N (540 mg kg -1 ) and total hydrolysable N (418.5 mg kg -1 ) of soil in control at harvest of wheat as compared to its initial status (Table 4). The extent of depletion of non-hydrolysable-n in soil (by 1.6%) was less as compared to total hydrolysable-n over its initial status. It supported the view that hydrolysable-n was more susceptible to mineralization than non-hydrolysable-n (Subba Rao and Ghosh, 1981). This could be attributed to the continuous mineralization process and removal of N from soil by crop uptake and various loss mechanisms. Sammi Reddy et al. (2003) reported that continuous cultivation led to losses in total hydrolysable N. organic N varied from 540 to 611 mg kg -1 and it was maximum under the treatment T 5 (50% NPK + NPK enriched compost). The highest amino acid N content (161 mg kg -1 ) was obtained under the treatment T 6 (100% NPK) whereas integrated use of NPK fertilizer along with enriched compost or ordinary compost increased the content of amino acid-n, amino sugar-n, NH 3 -N in soil as compared to control. Application of 100% NPK (T 6 ) increased significantly the status of hydrolysable amino acid-n, amino sugar-n and NH 3 N fractions in soil as compared to all other treatments. This might be attributed to higher amount of N (120 kg N ha -1 ) added to wheat. The rate of increase in the content of amino acid-n and ammonia-n with the application of enriched compost along with 50% NPK was the highest as compared to hydrolysable amino sugar-n. Organic manures are also known to enhance the content of hydrolysable-n (Asami, 1971). Unidentified hydrolysable-n fraction in soil was decreased in different treatments as compared to control. Acid insoluble-n fraction in treatments comprised of compost increased significantly over control except treatment T 6 (100% NPK). It supported the view that non hydrolysable-n is not susceptible to mineralization than hydrolysable-n (Subba Rao and Ghosh, 1981). It means that tendency for the chemical composition of the organic-n pools to be preserved in the soil, irrespective of the application of inorganic and organic sources of N. hydrolysable-n was found to be highest under T 6 (468.6 mg kg -1 ) and lowest under control (418.5 mg kg -1 ) with the rest of the treatments falling in between. The above results

6 267 TABLE 7: linear regression equations for yields and N uptake by wheat Linear regression equation R 2 Y 1 = X ** Y 2 = X X ** Y 3 = X X ** Y 4 = X ** Y 5 = X X X X ** Y 6 = X ** ** Significant at 1% Where, Y 1 = Grain yield; Y 2 = Straw yield; Y 3 = grain + straw yield; Y 4 = N uptake by grain; Y 5 = N uptake by straw and Y 6 = N uptake by grain + straw X 1 = -N; X 2 = Available-N; X 3 = NH 4+ -N; X 4 = NO 3 -N; X 5 = organic-n; X 6 = acid-n; X 7 = sugar- N; X 8 = Hydrolysable NH 3 -N; X 9 = Acid insoluble-n; X 10 = hydrolysable-n and X 11 = Acid insoluble-n revealed that all the forms of hydrolysable-n viz. amino acid-n, amino sugar-n and ammonia-n were recorded at higher level under the treatment T 6 (100% NPK) followed by T 5,, and T 2 where composts were applied along with fertilizers. This emphasizes the need to go for N application in balanced and integrated manner to ensure continuous N supply to the crop through the hydrolysable N fraction. Relationship between organic fractions of N and mineral N: Simple linear correlation were calculated to disclose N fractions contribute to mineralizable soil N. organic N, amino acid N, amino sugar N, hydrolysable ammonia N and total hydrolysable N fractions were significantly related to the mineralizable N (Table 5). Among the fractions of N the best correlation of mineralized NO 3 -N was found with amino sugar N (r=0.97**) followed by hydrolysable ammonia-n (r=0.95**). Acid insoluble-n fraction is also significantly correlated with available mineral-n (r=0.82*) this indicated that non-hydrolysable-n in soil may be degraded microbiological to potentially available N source. N was found to be highly correlated with inorganic and organic fractions of N in soil which proved the dynamic equilibrium among these forms. Relationship among different fractions of N, grain and straw yield and N uptake by wheat: Simple linear correlations were computed to find out which N fractions contributed to grain and straw yield and N uptake by the wheat. The grain yield of wheat exhibited significant correlations with NO 3 -N (r=0.95**), NH 4+ -N (r=0.94**), amino sugar-n (r=0.90**), total organic-n (r=0.86*), hydrolysable NH 3 -N (r=0.85*) and total N (r=0.84*) content of soil (Table 6). The straw yield of wheat showed a significant correlation at 1% level with total-n, NH 4+ -N, NO 3 -N, total organic N and amino sugar N content of soil. The N uptake by wheat grain were highly correlated with NH 4+ -N (r=0.92**), NO 3 -N (r=0.87**), total organic N (r=0.89**) and amino sugar N (r=0.88**). Among hydrolysable N fractions amino sugar N strongly and positively influenced the wheat yield and N uptake. No significant relationship could be obtained between acid insoluble N and yield and N uptake by wheat. Unidentified-N fraction of soil organic N was found to be correlated with both yield and N uptake but the relationship was negative. These results clearly showed that organic N fractions such as amino sugar-n, hydrolysable ammonia-n and amino acid-n controled the availability of N in soil and were major sources of nitrogen to crop uptake. Linear regression related to yield and N uptake with various fractions of N: Stepwise linear regression equations were workout and NO 3 -N was found to influence grain yield of wheat to the extent of 89.5% (Table 7). Inclusion of NH 4+ -N and amino acid-n in the regression equation increased the predictability of straw yield of wheat to 99.7%. NH 4+ -N and acid insoluble-n could predict the grain plus straw yield of wheat to the extent of 99.6%. Nitrogen uptake by wheat grain was explained to the tune of 95.1% by the NH 4+ -N. In case of straw available-n, NH 4+ -N, hydrolysable ammonia-n, unidentified hydrolysable- N and acid insoluble-n together accounted for 98.7% variability in N uptake. N uptake by

7 grain plus straw of wheat could be better explained by soil NH 4+ -N form which accounted for 96.5% predictability. It is concluded that the organic N fractions progressively increased in soil with the integrated use of composts along with chemical fertilizer. sugar-n, hydrolysable ammonia-n and total organic- N in soil were found to be better indices of soil-n mineralization and its availability. These results also 268 suggest that there is a need for supplying N as per crop requirement along with other nutrients and organic manure to sustain N reserves and enhance the N availability in soil. Therefore, the integrated use of inorganic fertilizers with enriched composts could be the better option in view of the above findings as well as creating a favourable environment in terms of improved physical and biological properties of soil. REFERENCES Asami, T. (1971). Immobilization and mineralization of nitrogen compounds in paddy soils. V. Distribution of immobilized nitrogen to various organic N fractions. J. Sci. Soil Manure, 42: Bajpai, R.K., Chitale, S., Upadhyay, S.K. and Urkurkar, J.S. (2006). Long term studies on soil physico-chemical properties and productivity of rice-wheat system as influenced by integrated nutrient management in inceptisol of Chhatisgarh. J. Indian Soc. Soil Sci., 54: Bremner, J.M. (1960). Determination of nitrogen in soil by the Kjeldahal method. J. Agric. Sci. Cambridge, 55: Bremner, J.M. (1965). Organic forms of soil nitrogen. In: C.A Black et al. (eds.) Methods of Soil Analysis, Part-II. Agronomy. 9: American Society of Agronomy, Madison, Wisconsin. Chouksey, V.P., Vaishya, U.K, Tembhare, B.R., Rathore, G.S. and Johar, M.S. (1995). Effect of continuous cropping and manuring in a soybean-wheat-maize fodder sequence on microbial population, nodulation and nitrogen fixation by soybean. JNKVV Res. J., 27: Duhan, B.S., Kataria, J.P., Kuhad, J.P. and Dahiya, S.S. (2005). Effect of nitrogen, farmyard manure and metribuzin on nitrogen transformation. J. Indian Soc. Soil Sci., 53: Gomez Kwanchi, A. and Gomez Arturo, A. (1984). Statistical Procedures for Agricultural Research. John Wiley and Sons, Inc. Jackson, M.L. (1973). Soil Chemical Analysis, Prentice Hall of India, Pvt. Ltd., New Delhi. Johnson, L., Berggren, D. and Karen, O. (1999). Content and bioavailability of organic forms of nitrogen in the O horizon of a podzol. European J. Soil Sci., 50: Kamat, V.N., Mahankar, S.T., Puranik,, R.B., Kohadker, W.S. and Joshi, R.P. (1982). Effect of long-term application of FYM and NPK on organic nitrogen fractions in vertisol. J. Indian Soc. Soil Sci., 30: Kelley, K.R. and Stevenson, F.J. (1995). Forms and nature of organic nitrogen in soil. Fert. Res., 42: Khankhane, P.J. and Yadav, B.R. (2000). Relative mineralization of nitrogen and phosphorus from FYM, biogas slurry and sewage sludge. J. Indian Soc. Soil Sci., 48: Kumar, V. and Pradad, R.K. (2008). Integrated effect of mineral fertilizer and green manure on crop yield and nutrient availability under rice-wheat cropping system in Calciorthents. J. Indian Soc. Soil Sci., 56: Mulvaney, R.L., Khan, S.A., Hoeff, R.G. and Browes, H.M. (2001). A soil organic nitrogen fraction that reduces the use for nitrogen fertilization. Soil Sci. Soc. Am. J., 65: Pathak, S.K., Singh, S.B., Jha, R.N. and Sharma, R.P. (2005). Effect of nutrient management on nutrient uptake and changes in soil fertility in maize (Zea mays)-wheat (Triticum aestivum) cropping system. Indian J. Agron., 50: Prasad, R.K., Kumar, V. Prasad, B. and Singh, A.P. (2010). Long-term effect of crop residues and zinc fertilizer on crop yield, nutrient uptake and fertility build-up under rice-wheat cropping system in Calciorthents. J. Indian Soc. Soil Sci., 58: Sammi Reddy, K., Singh, M., Tripathi, A.K., Singh, M.V. and Saha, M.N. (2003). Changes in amount of organic and inorganic fractions of nitrogen in an Eutrochrept soil after long term cropping with different fertilizer and organic manure inputs. J. Soil Sci. Plant Nutr., 166: Santhy, P., Muthuvel, P. and Selvi, D. (2001). Nitrogen fractions, status and impact of yield, uptake and available nitrogen in long-term fertilizer experiment. Madras Agric. J., 88: Sharma, P.K. and Gupta, J.P. (1998). Effect of organic materials on grain yield and soil properties in maize (Zea mays)- wheat (Triticum aestivum) cropping system. Indian J. Agric. Sci. 68: Subba Rao, A. and Ghosh, A.B. (1981). Effect of continuous cropping and fertilizer use on the organic nitrogen fractions in a Typic Ustochrept Soil. Plant and Soil, 62: Subbiah, B.V. and Asija, G.L. (1956). A rapid method for the estimation of available nitrogen in soils. Current Sci., 25: