Contribution of Bradyrhizobium

Transcription

1 Scientific registration number : 2612 Symposium n : 10 Presentation : Poster Contribution of Bradyrhizobium inoculation to the improvement of peanut production in Bangladesh Contribution de l'inoculation avec Bradyrhizobium à l'amélioration de la production d'arachide au Bangladesh HOQUE M.S. Department of Soil Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh Introduction Peanut (Arachis hypogaea) is an important crop in Bangladesh for its high protein and oil contents. But nitrogen is the most deficient element in the soils of Bangladesh limiting production of oilseed crops including peanut and urea is commonly used to supply this nutrient (Hoque, 1987, 1992). Peanut being a legume is capable of fixing and utilizing atmospheric nitrogen in symbiotic association with Bradyrhizobium bacteria. Hoque (1988) reported significant contribution of Bradyrhizobium inoculation on nodulation, shoot growth and seed yield of several food legume crops including peanut. Thus, use of inoculant technology appears to be an important substitute of urea fertilizer, which is now costly for most of the farmers. In the present study, a number of locally developed strains of Bradyrhizobium sp. (Arachis) were tested in several field trials along with some exotic strains at different locations in order to recommend the most effective strain for use in inoculant production. The study also included field trials to evaluate the effects of bradyrhizobial inoculation in absence and presence of chemical fertilizers. Method Two sets of field trials were carried out at different locations of the country. In one set of trials, there were 5 treatments consisting of Control (uninoculated and unfertilized), NPK Fertilizers, Bradyrhizobium inoculation, NPK + Inoculation and PK + Inoculation (results in Table 1). The fertilizer N was applied at the rate of 50 kg N ha -1 as urea, P at the rate of 26 kg ha -1 as triple superphosphate and K at the rate of 33 kg ha -1 as muriate of potash. The fertilizers were applied at sowing. In a second set of trials, the locally developed strains of Bradyrhizobium sp. (Arachis) designated as BAUR 700, BAUR 702, BAUR 710 and BAUR 711 were tested against some exotic strains such as TAL 169, TAL 295 and NC 92 and mixed culture (results in Table 2). Inoculants were prepared by broth culturing the strains, mixing the broth with sterilized peat carrier and incubating at 1

2 28 o C for two weeks. A basal dose of P and K fertilizers were added at sowing at the same rate as in the first set of trials. In both set of trials the peanut cultivar Dk-1 was used. The crop seeds were coated with inoculant before sowing using gum acacia as the sticker. The seeds were sown in rows in 18 m 2 plots having row x plant spacing of 40cm x 15cm. The trials were laid out in randomized complete block design with 4 replicates. Data on nodule count and shoot dry weight were recorded at flowering stage of the crop from 10 randomly selected plants from each plot. The crop was harvested at maturity and seed yield was recorded at 14% moisture. The data have been statistically analysed following F- test. Results Table 1 shows the effects of individual and combined use of chemical fertilizers and Bradyrhizobium inoculation on nodule number shoot weight and seed yield of Dk-1 peanut at different locations and in different years. In all the locations and years, the values of all these crop parameters were markedly higher in inoculation treatment used either alone or with NPK or PK fertilizers over control. However, these values were only slightly higher due to NPK treatment over control. Table 2 reports effects of different Bradyrhizobium inoculants on nodule number, shoot weight and seed yield. The values on these parameters sharply increased due to different strains over uninoculated control in all the trials conducted in different locations and years. Among the strains, BAUR 700 gave the highest values of all the crop characters. Mixed culture in many cases gave the highest values. In most cases, the local strains produced better results on all the crop parameters than the exotic strains. In all the trials, the lowest results were noted in the uninoculated and unfertilized control treatments. Discussion Bradyrhizobium inoculants gave distinctly better results on nodule number, shoot weight and seed yield of peanut than the uninoculated control and NPK treatments (Table 1). Application of NPK fertilizers produced only small and insignificant increases on these crop parameters while inoculation gave much greater increases Of these values. Nodulation of the crop in uninoculated control plots was low indicating the presence of insufficient number of native bacteria in soils effective to form nodules on this crop as reported by Hoque (1987, 1988). Inoculation increased the seed yield of peanut in different trials by 30 to 52% over control and by 22 to 50% over NPK treatment. Hoque (1993) and Hoque and Hashem (1992) also reported beneficial effects of Bradyrhizobium inoculation on the growth and yield of peanut. In the present study, all the crop parameters markedly increased due to use of inoculant either alone or with NPK or PK fertilizers. The higher results obtained from the use of NPK or PK fertilizers along with inoculation appeared to be due to beneficial effects of P and K particularly in soils where the levels of these nutrients were low. Khan et al. (1990) observed 61% increase in pod yield of Dk-1 peanut when P and S fertilizers were applied along with Bradyrhizobium inoculation. Khan et al. (1993) also reported that the protein content of peanut considerably increased due to Bradyrhizobium inoculation. 2

3 In the present study, most of the inoculant strains showed highly favourable effect on different parameters of the crop. Among the strains, BAUR 700 appeared to be the best strain in producing nodule number shoot weight and seed yield of peanut. Mixed culture in some cases gave higher values but, in most cases, they were statistically identical to the values recorded with BAUR 700. In general, the locally developed inoculant strains performed better than the exotic strains. TAL 169 gave comparable results to that noted with BAUR 702, BAUR 710 and BAUR 711. Overall results suggest that use of Brdyrhizobium inoculant can be a dependable technology for improvement and sustenance of peanut production in Bangladesh. Moreover, inoculant is much cheaper than urea and does not cause any harm to the soil or to the environment. The strain BAUR 700 can be recommended as the best strain for inoculant production for use in the cultivation of peanut in this country. Bibliography Hoque M S 1987 BAU Res Prog. No. 1: Hoque M S 1988 In Proc. International Symposium on «Application of Biotechnology for Small Industries Development in Developing Countries», Bangkok, Thailand (1988), pp Hoque M S 1992 «Role of chemical and bio-fertilizers on some oilseed crops in Bangladesh», paper presented at the National Workshop on Oilseeds, held in Dhaka, Bangladesh (1992) sponsored by Bangladesh Agricultural Research Council. Khan M K, Ali M I and Hoque M S 1990 Bangladesh J. Soil Sci. 21(1): Hoque M S and Hashem M A 1993 In Proc.«Advances in Crop Science», Crop Science Society of Bangladesh, Mymensingh, Bangladesh, pp Hoque M S 1993 Plant and Soil 155/156: Khan M K, Hoque M S and Ali M I 1993 Prog. Agric. 4(1&2): Keywords : Bradyrhizobium, Inoculants, Peanut, Nodulation, Bangladesh Mots clés : Bradyrhizobium, inoculation, arachide, nodulation, Bangladesh 3

4 Table 1. Effect of fertilizers in presence and absence of Bradyrhizobium inoculation on peanut Treatment Nodules plant -1 Shoot weight plant -1 Seed yield ha 1 (Number) (g) (kg) : BAU farm Phulpur BAU farm Phulpur BAU farm Phulpur Control 22.0c 9.5c 8.5b 8.4b 1710b 1560b NPK 22.2c 12.4c 8.9b 8.6b 1758b 1593b Inoc 56.6a 41.5a 10.0ab 10.1a 2483a 2375a NPK+Inoc 47.5b 33.6ab 10.5a 10.3a 2508a 2270a PK +Inoc 46.6b 31.2b 9.7ab 10.0a 2501a 2380a SE ± : BAU farm Phulpur BAU farm Phulpur BAU farm Phulpur Control 24.4b 13.7b 10.6b 9.0b 1358b 1671b NPK 34.6b 13.7b 11.7b 9.2b 1436b 1839b Inoc 72.3a 66.7a 15.1a 15.1a 1940a 2494a NPK+Inoc 69.6a 58.3a 14.7a 14.3a 1923a 2587a PK +Inoc 75.1a 55.1a 15.3a 13.9a 2093a 2572a SE ± : BAU farm Phulpur BAU farm Phulpur BAU farm Phulpur Control 25.3c 3.8b 6.7d 7.0c 1491b 2614b NPK 34.3b 5.6b 8.0c 9.1b 1626b 2813b Inoc 48.6a 41.6a 9.4b 11.6a 1998a 3393a NPK+Inoc 48.3a 45.1a 11.1a 12.0a 2093a 3563a PK +Inoc 47.9a 41.0a 10.7a 11.9a 2013a 3636a SE ±

5 Table 2. Effect of some promising inoculant strains of Bradyrhizobium sp.(arachis) on peanut Inoculant Nodules plant - 1 Shoot wt. plant -1 Seed yield ha -1 strains (Number) (g) (kg) : BAU farm Iswardi BAU farm Iswardi BAU farm Iswardi Control d 3.6b 4.6b 814b 1287c BAUR a 5.1a 6.0a 1330a 1902a BAUR b 3.6b 5.3ab 1170a 1542b BAUR b 4.1b 5.3ab 1197a 1642b TAL c 4.4ab 3.8a 1133a 1474bc Mix.culture ab 4 4ab 5.8b 1338a 1886a SE ± NS : BAU farm Iswardi BAU farm Iswardi BAU farm Iswardi Control 14.3c 9.2d 5.8d 5.1e 1508d 1653b BAUR a 27.3a 9.5ab 8.6a 2303ab 2038a BAUR ab 14.7c 8.7b 7.5bc 1987cd 1953ab BAUR bc 20.2b 9.1ab 7.8b 2148bc 2080a BAUR ab 16.2bc 8.5bc 7.0cd 1996cd 2006ab TAL ab 14.6c 7.6c 6.7d 1917cd 2045a Mix.culture 25.7ab 25.0a 9.9a 8.2ab 2510a 2185a SE ± : BAU farm Phulpur BAU farm Phulpur BAU farm Phulpur Control 9.0b 8.5c 5.3d 5.6d 912b 981b BAUR a 26.3a 8.0a 7.5ab 1720a 1248a BAUR a 17.9b 6.9b 6.5c 712b 1201b TAL a 16.9b 6.2c 6.4cd 1062b 1211b TAL a 15.7b 7.0b 7.0bc 998b 1180b NC a 18.0b 6.6bc 6.5c 875b 1172b Mix.culture 25.4a 23.5a 7.9a 7.8a 1797a 1364a SE ± : BAU farm Phulpur BAU farm Phulpur BAU farm Phulpur Control 12.3c 2.8d 9.6c 6.2c 2333c 1788d BAUR a 32.3a 12.5a 8.3a 3833a 2875a BAUR b 20.5b 11.4b 7.2b 2967b 2250b TAL a 13.8c 10.9b 7.7b 3000b 2505b TAL b 12.3c 9.4c 7.1b 2667b 1910b NC b 23.2b 8.8c 6.5c 2520b 2075c Mix.culture 50.3a 30.6a 13.2a 9.0a 3667a 2876a SE ±