Browsing by Author "Zabinski, Catherine"

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Carbon and phosphorus exchange rates in arbuscular mycorrhizas depend on environmental context and differ among co-occurring plants
(Wiley, 2024-01) Lekberg, Ylva; Jansa, Jan; McLeod, Morgan; DuPre, Mary Ellyn; Holben, William E.; Johnson, David; Koide, Roger T.; Shaw, Alanna; Zabinski, Catherine; Aldrich-Wolfe, Laura
Phosphorus (P) for carbon (C) exchange is the pivotal function of arbuscular mycorrhiza (AM), but how this exchange varies with soil P availability and among co-occurring plants in complex communities is still largely unknown. We collected intact plant communities in two regions differing c. 10-fold in labile inorganic P. After a 2-month glasshouse incubation, we measured 32P transfer from AM fungi (AMF) to shoots and 13C transfer from shoots to AMF using an AMF specific fatty acid. AMF communities were assessed using molecular methods. AMF delivered a larger proportion of total shoot P in communities from high-P soils despite similar 13C allocation to AMF in roots and soil. Within communities, 13C concentration in AMF was consistently higher in grass than in blanketflower (Gaillardia aristata Pursh) roots, that is P appeared more costly for grasses. This coincided with differences in AMF taxa composition and a trend of more vesicles (storage structures) but fewer arbuscules (exchange structures) in grass roots. Additionally, 32P-for-13C exchange ratios increased with soil P for blanketflower but not grasses. Contrary to predictions, AMF transferred proportionally more P to plants in communities from high-P soils. However, the 32P for-13C exchange differed among co-occurring plants, suggesting differential regulation of the AM symbiosis.
Determining Nutrient Availabilty in Gallatin Valley Organic Systems Through Comprehensive Soil Testing
(2013-03) Lynn, Hamilton; Zabinski, Catherine
Our projects investigated the effects of different forms of organic matter and the effects of production intensity on plant available nitrogen in two separate agricultural operations in the Gallatin Valley; a research experiment located in Townes Harvest Garden and a commercially operative organic vegetable farm, Field Day Farm. In order to determine plant available nitrogen levels among different soil treatment plots and cropping areas on these farms, we cultivated annual ryegrass in greenhouse pots using soil composites collected from different treatments. The ryegrass pots were maintained for 8 weeks, at which time cuttings of biomass from each composite were taken and analyzed to determine nitrogen content within plant tissues. We compared our bioassay results to traditional laboratory analyses for KCl-extracted nitrate. The methods being performed were modeled after Liu, et al. (2011). The results from soil analysis show that the hay mulch provided the most plant available nitrogen, followed by the nitrogen mineral fertilizer treatment, the control, and the barley straw mulch. We will compare tissue nitrogen levels from the greenhouse assay to our soil results. Overall, understanding nitrogen uptake could provide information useful to farmers who are trying to maximize crop yield while lowering soil inputs.
Indaziflam controls non-native annual mustards but negatively affects native forbs in sagebrush steppe
(Cambridge University Press, 2021-10) Meyer-Morey, Jordan; Lavin, Matthew; Mangold, Jane; Zabinski, Catherine; Rew, Lisa J.
Nonnative plant invasions can have devastating effects on native plant communities; conversely, management efforts can have nontarget and deleterious impacts on desirable plants. In the arid sagebrush steppe rangelands of the western United States, nonnative winter annual species affect forage production and biodiversity. One method proposed to control these species is to suppress the soil seedbank using the preemergent herbicide indaziflam. Our goal was to evaluate the efficacy of indaziflam to control nonnative annual mustards (Alyssum spp.) and to understand potential nontarget effects of management on the diverse mountain sagebrush steppe plant communities within Yellowstone National Park. Six sites were established along an elevation gradient (1,615 to 2,437 m), each with high and low Alyssum spp. infestations. We applied 63g ai ha−1 of indaziflam in late summer of 2018 and evaluated plant community cover in situ for 2 yr after treatment and emergence of forb species from the soil seedbank ex situ. Indaziflam was highly effective at controlling emergence of Alyssum spp. for 2 yr. Richness and Shannon’s diversity of the nontarget plant community were significantly lower in sprayed plots than in the control, and both decreased along the elevation gradient. These reductions were due to a decrease in perennial forbs and native annual forbs in the sprayed plots; perennial graminoids were not affected. Overall, the aboveground and seedbank community composition was negatively impacted by indaziflam, and these effects were strongest for the native annual forbs that rely on annual regeneration from the seedbank. The effects of this herbicide to the nontarget community should be evaluated beyond the length of our study time; however, we conclude that indaziflam should likely be reserved for use in areas that are severely invaded and have seedbanks that are composed of nondesirable species rather than diverse, native mountain sagebrush communities.