Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2001
Publication Date: 3/1/2001
Citation: BIDLACK, J.E., RAO, S.C., DEMEZAS, D.H. NODULATION, NITROGENASE ACTIVITY, AND DRY WEIGH OF CHICKPEA AND PIGEON PEA CULTIVERS USING DIFFERENT BRADYRHIZOBIUM STRAINS. JOURNAL OF PLANT NUTRITION. 2001. 24:549-560. Interpretive Summary: Chickpea and pigeon pea have potential as part of wheat-legume crop rotations because of their ability to grow during the hot, dry summers of the southern Great Plains. This research was implemented to determine if these legumes can fix nitrogen, to be used as fertilizer by the following wheat crop, and provide forage yield during the summer months before winter rwheat. Two varieties of chickpea and pigeon pea were grown, along with four inoculum treatments of legume seed, in large clay pots from July through September for each of three years. Wheat was grown during the winter and harvested before each legume planting. During legume harvests, plants were removed with intact soil to assess nodules on the roots and enzyme activity responsible for fixing nitrogen. Forage yield was also determined. Results indicated that pigeon pea fixes more nitrogen and produces more forage yield than chickpea. The 'Georgia-1' pigeon pea variety produced more nitrogen and forage yield than 'ICPL-87' pigeon pea, as did 'Sarah' chickpea compared with 'ICCV-2.' Pure seed inoculum provided pigeon pea with greater nitrogen fixing capacity; whereas multistrain inoculum provided chickpea with higher forage yield, as well as greater nitrogen fixing capacity. These results indicate that specific chickpea and pigeon pea varieties, along with appropriate seed inoculum, may improve nitrogen fixation and forage yield of these species.
Technical Abstract: Chickpea [Cicer arietinum (L.)] and pigeon pea [Cajanus cajan (L.) Millsp.] were grown outside in large clay pots from 1992 to 1995 in Edmond, Oklahoma. Plants were studied to evaluate nodulation, nitrogenase activity, and shoot dry weight (DW) of 'ICCV-2' and 'Sarah' chickpea inoculated with multistrain, TAL 1148, and TAL 480 Bradyrhizobium, as well as 'Georgia-1' and 'ICPL-87,' pigeon pea inoculated with multistrain, TAL 1127, and TAL 1132 Bradyrhizobium. Following wheat [Triticum aestivum (L.) emend. Thell.] harvests in the spring, legumes were planted in the summer and harvested at three successive dates during the following months. Leaves and stems from remaining plants were incorporated into the soil after the last harvest. Across years, chickpea measurements were sensitive to temperature and precipitation whereas pigeon pea measurements were sensitive to length of growing season as well as climate. Pigeon pea consistently demonstrated higher nitrogen-fixing capacity and shoot DW compared with chickpea. Nodule and shoot DW of both species increased with plant age whereas nodule count and nitrogenase activity generally increased with plant age and levelled off or decreased at flowering. Sarah chickpea demonstrated higher nodule count and nodule DW than ICCV-2, as did the Georgia-1 pigeon pea compared with ICPL-87. Shoot DW of Georgia-1 pigeon pea was generally higher than that of ICPL-87. Multistrain inoculum improved nodulation and shoot DW of chickpea, and TAL 1127 improved nodulation of pigeon pea compared with other treatments. These results indicate that specific chickpea and pigeon pea cultivars, along with appropriate Bradyrhizobium strains, may improve nitrogen fixation and DW of these species.