Dry Weight and Nitrogen Content of Chickpea and Winter Wheat Grown in Pots for Three Rotations

ABSTRACT

Chickpea [Cicer arietinum (L.)] cultivars ‘ICCV-2’ and ‘Sarah’ were studied along with a control, multistrain, TAL 1148, and TAL 480 Bradyrhizobium strains to determine the effect(s) of cultivar and inoculum on dry weight (DW) and nitrogen (N) content of the legume, as well as soil mineral N, DW, and N content of wheat [Triticum aestivum (L.) emend. Thell.] in a continuous wheat-legume rotation. Chickpeas were planted during the summer and harvested in the fall of 1992, 1993, and 1994. Vegetative growth from chickpeas was incorporated into the soil prior to wheat planting, and soil cores were taken at 35 to 48 d after chickpea harvests. Additional summer fallow treatments for the winter wheat part of the experiment received 0, 45, and 90 kg N ha⁻¹ each year. Wheat plants were removed the following spring and stubble was incorporated into the soil before planting chickpeas in the summer. ‘Sarah’ chickpeas accumulated about the same or more shoot DW and shoot N compared to ‘ICCV-2’; whereas ‘ICCV-2’ generally produced more pod DW and pod N compared to ‘Sarah.’ Inoculum had no significant effect on chickpea DW or N content. Wheat DW and N following legumes increased marginally after growing ‘Sarah’ chickpeas, as evidenced by higher values of some treatments. Only the multistrain or absence of inoculum in ‘Sarah’ chickpeas resulted in significantly greater wheat DW or N content compared to the fallow wheat receiving no added N fertilizer. The contributions from ‘ICCV-2’ chickpeas to wheat DW and N content were not significant. Soil mineral N, as well as wheat DW and N content, fluctuated or increased during this three-year study, which demonstrated some benefit from incorporation of chickpeas into a wheat-legume cropping system.

Keywords:

• Cicer arietinum
• cropping system
• legume
• nitrogen fixation
• soil
• wheat

ACKNOWLEDGMENTS

This project was funded by the USDA National Research Initiative Competitive Grants Program (Grant No. 93-37311-9580), Oklahoma Wheat Commission, University of Central Oklahoma (UCO) Office of Graduate Studies & Research, and the USDA-ARS Grazinglands Research Laboratory. Authors thank members of the UCO Plant Physiology Research Group for assisting with the project.

Notes

¹ The use of trade, firm, or corporation names in this publication is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the authors, University of Central Oklahoma, or USDA Agricultural Research Service, of any product or service to the exclusion of others that may be suitable.

^†Shoot = leaf + stem

^†Shoot = leaf + stem.

^‡Values within a column followed by the same letter are not significantly different at the 5% probability level according to the Tukey-Kramer mean separation test.

^†Values within a column followed by the same letter are not significantly different at the 5% probability level according to the Tukey-Kramer mean separation test.