2008 Joint Annual Meeting (5-9 Oct. 2008): Improving Nutrient Uptake in Organic Dryland Wheat Cropping Systems through Cultivar Specific Interaction with Azospirillum.

542-4 Improving Nutrient Uptake in Organic Dryland Wheat Cropping Systems through Cultivar Specific Interaction with Azospirillum.



Monday, 6 October 2008: 2:00 PM
George R. Brown Convention Center, 371D
Lori Hoagland1, Kevin M. Murphy1, Lynne Carpenter-Boggs2 and Stephen S. Jones1, (1)Dept Crop & Soil Science, Washington State University, 201 Johnson Hall, Pullman, WA 99164-6420
(2)Crop & Soil Science, Washington State University, 201 Johnson Hall, PO box 646420, Pullman, WA 99164-6420
Obtaining sufficient plant available nitrogen (N) in organic dryland wheat cropping systems is difficult. Plant root association with beneficial bacteria that actively fix N is one alternative that can help supplement N needs in low-input systems. This study was conducted to determine whether inoculation with Azospirillum could improve nitrogen uptake and increase crop yield, whether differences exist in the ability of wheat cultivars to benefit from inoculation of these diazotrophic bacteria, and the impact of N availability on this beneficial interaction. Seed from ten historic, ten modern and ten wheat cultivars from the advanced organic breeding program were either left untreated, or treated with a commercial inoculant of Azospirillum, and planted at thee locations under certified organic management, and two locations under conventional management. Preliminary results indicated that in one certified organic location with lower fertility, inoculation significantly increased yield and protein, and clear differences existed among individual cultivars in response to the inoculant. In another location with higher fertility, none of the cultivars responded as favorably to the inoculant, and yield in some cultivars was reduced. Plant breeders should be able to select for beneficial cultivar interactions with Azospirillum to increase wheat yield and protein levels. On-going research will determine the impact of site-specific soil conditions on the effectiveness of Azospirillum in organic and conventional systems.