Annual Grass Research Articles

Sericea lespedeza control with postemergence and preemergence herbicide applications in fields managed for northern bobwhite

AbstractSericea lespedeza (Lespedeza cuneata) is an invasive nonnative legume that commonly occurs on sites managed for northern bobwhite (Colinus virginianus). Sericea reduces bobwhite habitat availability by outcompeting native plants that provide food and cover. Sericea can be controlled with postemergence herbicides such as glyphosate as well as a mixture of triclopyr with fluroxypyr, but these herbicides do not provide preemergence control. Imazapic has been effective at controlling a limited number of planted sericea seeds, but the efficacy of imazapic at various application rates to control sericea seedbank response following treatment with a postemergence herbicide has not been evaluated. We designed a field experiment to evaluate sericea control and changes in the plant community as related to bobwhite habitat with 2 postemergence herbicides followed by preemergence treatment of imazapic at 3 sites in Tennessee and Alabama, USA, 2018–2022. Specifically, we treated sericea with postemergence broadcast applications of glyphosate or triclopyr with fluroxypyr in 2018 and applied spot treatment with the same herbicides in 2019–2021. We applied imazapic at 4 rates following prescribed fire in 2019 and 2022. We measured coverage of sericea, native forbs, annual grasses, perennial grasses, and bobwhite food plants before treatment in 2018 and after all treatments in 2022. Nearly all postemergence treatments reduced sericea coverage, but imazapic did not increase control compared to postemergence herbicides alone. Perennial grasses used for nesting and bobwhite foraging were maintained following treatments. We recommend managers use either glyphosate or triclopyr with fluroxypyr to control sericea postemergence and consider using a low rate of imazapic to reduce annual grasses if coverage is a problem on the site.

Is Crested Wheatgrass Invasive in Sagebrush Steppe with Intact Understories in the Great Basin?

Seeding crested wheatgrass (Agropyron desertorum [Fisch.] Schult.) in the sagebrush steppe is a controversial management action. There are concerns that crested wheatgrass may invade new areas and exclude native vegetation because many former crested wheatgrass seedings are near monocultures. However, crested wheatgrass is often seeded to prevent exotic annual grass invasion and stabilize soils after disturbances in areas where native vegetation is unlikely to establish. These areas can be difficult to identify and, consequentially, crested wheatgrass may be seeded in areas it is not needed, such as sagebrush steppe with understories dominated by native perennial grasses and forbs (intact understories). Thus, land managers need to know the potential effects of seeding crested wheatgrass, especially if it can invade and exclude native vegetation in sagebrush steppe with intact understories. We investigated the ability of crested wheatgrass to invade and exclude native vegetation by drill seeding crested wheatgrass into intact sagebrush steppe understories at five sites. To be invasive, crested wheatgrass would need to increase in abundance beyond initial establishment from drill seeding, causing decreases in native vegetation. We measured vegetation cover and density for 7 yr after seeding to evaluate the effects of seeding crested wheatgrass. Crested wheatgrass established with drill seeding but did not increase from its original density. Cover of crested wheatgrass increased with time but was < 2% seven yr after seeding. We found no evidence that seeding crested wheatgrass decreased the cover or abundance of native vegetation. These results suggest that intact sagebrush steppe understories are competitive with crested wheatgrass and, thereby, limit its recruitment and growth. Though crested wheatgrass did not show indications of being invasive in intact sagebrush steppe understories, longer-term evaluations with the inclusion of disturbances that might open safe sites in these communities would be prudent to fully understand its potential effects.

Wave attenuation by flattened vegetation (Scirpus mariqueter)

With the capacity to reduce wave energy and trap sediment, Scirpus mariqueter has become an important native species of annual grass for ecology restoration at the Yangtze Estuary in eastern China. Due to seasonal variances of biophysical characteristics, S. mariqueter usually bends and breaks in winter, resulting in flattened stems that may reduce its wave attenuation capacity. To investigate the effects of vegetation flattening on wave attenuation, a set of flume experiments were conducted for flattened and standing vegetation under different wave conditions. The model vegetation was designed to represent the wilted S. mariqueter collected in winter with dynamic similarity. Results showed that the wave damping coefficient for flattened vegetation (βF) was 33.6%-72.4% of that for standing vegetation (βS) with the same vegetation length. Both βF and βS increased with wave height but decreased with water depth. A wave attenuation indicator (WAI) was defined to generate empirical formulas for βS and βF as well as their ratio βF/βS. The empirical formulas were then applied to modify the existing standing vegetation-based wave attenuation model for flattened vegetation and performed successfully. Understanding the wave attenuation characteristics of flattened vegetation is essential for the management of ecological restoration and coastal protection.

Expression of macromolecular organic nitrogen degrading enzymes identifies potential mediators of soil organic N availability to an annual grass

Nitrogen (N) is frequently limiting to plant growth, in part because most soil N is present as polymeric organic compounds that are not readily taken up by plants. Microbial depolymerization of these large macromolecular N-substrates gradually releases available inorganic N. While many studies have researched and modeled controls on soil organic matter formation and bulk N mineralization, the ecological—spatial, temporal and phylogenetic—patterns underlying organic N degradation remain unclear. We analyzed 48 time-resolved metatranscriptomes and quantified N-depolymerization gene expression to resolve differential expression by soil habitat and time in specific taxonomic groups and gene-based guilds. We observed much higher expression of extracellular serine-type proteases than other extracellular N-degrading enzymes, with protease expression of predatory bacteria declining with time and other taxonomic patterns driven by the presence (Gammaproteobacteria) or absence (Thermoproteota) of live roots and root detritus (Deltaproteobacteria and Fungi). The primary chitinase chit1 gene was more highly expressed by eukaryotes near root detritus, suggesting predation of fungi. In some lineages, increased gene expression over time suggests increased competitiveness with rhizosphere age (Chloroflexi). Phylotypes from some genera had protease expression patterns that could benefit plant N nutrition, for example, we identified a Janthinobacterium phylotype and two Burkholderiales that depolymerize organic N near young roots and a Rhizobacter with elevated protease levels near mature roots. These taxon-resolved gene expression results provide an ecological read-out of microbial interactions and controls on N dynamics in specific soil microhabitats and could be used to target potential plant N bioaugmentation strategies.

Cover Crops and No-Tillage Show Negligible Effects on Grapevine Physiology in Mediterranean Vineyard Agroecosystems

This study aimed to evaluate the effects of annual or perennial cover crops and tillage regimes on whole grapevine physiology and berry composition. We studied the interactive effects of tillage and cover crops on grapevine water status, leaf gas exchange, components of yield, berry composition and resulting water footprint in two contrasting production regions (Fresno County-hot climate and Napa County-warm climate) of California. The treatments included a perennial grass (PG), resident vegetation (RV), and an annual grass (AG) grown under conventional tillage (CT) and no-till (NT) settings. Neither cover crop nor tillage affected grapevine leaf gas exchange. However, at the Napa County vineyard, NT detrimentally affected grapevine water status compared to CT. Grapevine mineral nutrition, when assessed during anthesis revealed no effects of cover cropping in either year or at either location. Cover crop type did not affect yield components or berry composition, however CT increased titratable acidity (TA) at both sites. The water footprint of vineyards at either location was not affected by cover crops or tillage. Our results provided evidence that both in hot and warm climate vineyards cover cropping had negligible beneficial effects on grapevine physiology, mineral nutrition or productivity with no detrimental effects on vineyard water footprint; tillage was beneficial in younger vineyards to improve plant water status in semi-arid regions.

Adsorption, mobility, and degradation of the pesticide propaquizafop in five agricultural soils in China

Propaquizafop is a fatty acid synthetic herbicide used to control annual and perennial grasses. To understand the potential environmental risks of propaquizafop to crops and food safety, the adsorption, mobility, and degradation of propaquizafop in five different soils were studied. At an initial concentration of 5 mg L−1 propaquizafop, its adsorption equilibrium was reached within 24 h, and the adsorption rates were between 46.98 and 57.76%. The Elovich kinetic model provided the best fit for the kinetic model, with R2 values between 0.9882 and 0.9940. For the isothermal adsorption tests, the Freundlich model was used to better fit the adsorption characteristics of propaquizafop in different soils, with R2 values between 0.9748 and 0.9885. Increasing the concentration of Ca2+ was beneficial for propaquizafop adsorption. In the soil thin-layer chromatography tests, the Rf of propaquizafop in the five soil samples ranged from 0.076 to 0.123. The results of the soil column leaching tests showed that propaquizafop did not migrate in the five soil columns; it was not detected in the leachate of each soil column, and propaquizafop in the soil columns only existed in the 0–5 cm soil layer. The results of soil thin-layer chromatography and soil column leaching tests showed that propaquizafop is a pesticide with a weak migration ability. Under the same environmental conditions, the degradation rate of propaquizafop in different soils followed the order LF fluvo–aquic soil (T1/2 = 1.41 d) > CS red loam (T1/2 = 2.76 d) > SX paddy soil (T1/2 = 3.52 d) > CC black soil (T1/2 = 5.74 d) > BS ginseng soil (T1/2 = 7.75 d). Considering the effects of soil moisture, incubation temperature, and microorganisms on propaquizafop degradation in the soil, temperature was found to have the greatest influence on its degradation rate.

Forage mixture productivity and silage quality from a grass/legume intercrop in a semiarid Mediterranean environment

AbstractIn semiarid environments of the Mediterranean region, intercropping is a sustainable agricultural system of long standing. In this area, the pea (Pisum sativum L.) is one of the most commonly grown legume crops. Little information is available on the quality of silages to be obtained from forage mixtures of pea intercropped with cereals or annual grasses. In this study, two experiments were conducted over the course of two growing seasons in Sicily (Italy) with the aim to determine the biomass production of forage crop mixtures and assess, only in the second experiment, the silage quality of grass and legumes. Four cereals and one annual grass species were grown in pure stand and in mixture with pea, and their main agronomic traits were determined. The land equivalent ratio (LER), competitive ratio, and aggressivity index were also calculated. A number of parameters were considered to assess the quality of silage obtained from fermented biomasses derived from pea–ryegrass (Lolium multiflorum Lam. var. Westerwoldicum) intercropping. In the first experiment, the best performance between the intercrops was recorded for the pea–wheat mixture. The total LER calculated for fodder yields was always greater than 1, indicating crop yield advantages ranging from 2.0% to 47.0%. In the second experiment, the pea–ryegrass mixture appeared to respond well, depending on plant arrangement and seeding ratio factors: the ratios 50:50 and 100:50 showed the greatest crop yield advantages, of 12.0% and 11.0%, respectively. All silages revealed a very good suitability of a pea–ryegrass intercropping system with high‐quality silage production in the Southern Mediterranean region.

Survey of Weeds in Sesame in the Major Growing Area of Ethiopia

The survey of weeds was conducted in high sesame growing areas of Ethiopia namely, Metekel, Gonder, and Humera Zones during 2018/19 cropping season to assess the abundance and distribution. It was done at the crop seedling stage using a systematic sampling technique and in quadrant counts (0.5 m²). Weed species composition and their quantitative measures were calculated using descriptive formulas. The result showed 23 weed families that comprised 135 weed species. The most dominant families were Commelinaceae (5.92%), Asteraceae (11%), Cyperaceae (7.40%), Fabaceae (12.59%), and Poaceae (18.51%) respectively. Most of the species (70%) were erect annual herbs and grasses, the rest were perennials that had vegetative propagating structures, annual prostrate herbs, annual, perennial climbers, or perennial shrubs. In the morphological classification, 88 species of broadleaf weeds (65.18%) were found, followed by 33 grasses (24.44%) and 14 (10.37%) types of sedge weeds. Dicotyledonous species were found to be more dominant than monocotyledonous ones in the survey area. The highest weed densities were recorded near the crop harvest stage. Weed species composition varied between crop stages within the same location and across locations at both crop stages. Also, weed composition varied in both crop stages at different locations, indicating a devising different weed management options, which would be considered for different locations in weed flora composition. From this investigation, it can be deduced that Sorghum halepense, Convolvulus arvensis, Amaranthus spp, and Cyperus rotundus turned into a drawback in the sesame production areas.

Use experience of cattle effluents and manure in the Belgorod region

In the real farming conditions of the south-west of the Central Chernozem region (Belgorod oblast), it was found that the using local organic fertilizers – cattle effluents and manure, which differ in agrochemical composition and the degree of availability of nutrients, has an unequal effect on soil fertility and crop productivity. The use of cattle litter manure contributed to a significant improvement in soil fertility indicators such as organic matter content (by 0.4% abs.), degree of acidity (by 0.4 units.) and hydrolytic acidity (by 1.32 mmol/ 100 g of soil). Using of cattle effluents led to a significant excess of the agrocenoses productivity (by 1.2 thousand GU/ha or 30.4%) compared to the application of cattle manure. The most responsive crops for the cattle effluents application were sunflower, corn, perennial and annual grasses, which provided the harvest increasing by 23-113%. The use of cattle effluents was more economic effective compared to the application of cattle manure: profit and profitability were 2.9 and 3.1 times higher, respectively, and the cost price was 1.4 times lower.

Functional Groups Response to Water Deficit in Mediterranean Ecosystems.

Enhanced drought, more frequent rainfall events and increased inter-annual variability of precipitation are the main trends of climate expected for the Mediterranean. Drought is one of the most important stressors for plants and significantly impacts plant communities causing changes in plant composition and species dominance. Through an experiment under controlled conditions, we assessed the response of Mediterranean species from different functional groups (annual grass, annual forb, annual legume, and perennial shrub) to moderate and severe water deficit. Changes in plant traits (leaf dry matter), biomass and physiology (water status, photosynthesis, pigments, and carbohydrate) were evaluated. The studied species differed in their response to water deficit. Ornithopus compressus, the legume, showed the strongest response, particularly under severe conditions, decreasing leaf relative water content (RWC), pigments and carbohydrates. The grass, Agrostis pourreti and the forb, Tolpis barbata, maintained RWC, indicating a higher ability to cope with water deficit. Finally, the shrub, Cistus salviifolius, had the lowest response to stress, showing a higher ability to cope with water deficit. Despite different responses, plant biomass was negatively affected by severe water deficit in all species. These data provide background for predicting plant diversity and species composition of Mediterranean grasslands and Montado under climate change conditions.

Rehabilitating Invaded Rangeland in Central South Dakota with Grazing, Seeding, and Herbicides

Rangelands in the northern Great Plains are threatened by invasive C3 annual and perennial grasses that displace native C4 grasses. Rehabilitating these rangelands by reintroducing native C4 grass species could extend the season in which relatively higher-quality forage is available for livestock grazing and improve wildlife habitat. Three seeding treatments, four herbicide treatments, and two stocking densities were applied to a pasture in central South Dakota, United States, that was dominated by invasive C3 grasses. Grazing and herbicide treatments were designed to suppress exotic cool season grasses. Drought limited establishment during the first 2 yr, but C3 grasses were successfully controlled during this time. Plots drill-seeded and sprayed with glyphosate established a mean of 1.0 seeded grasses m−2 by the third yr. Unseeded plots and plots that did not receive glyphosate failed. This trend continued into yr 5, when the most successful treatments were composed of 10−14% seeded C4 grasses, as determined by a modified step-point count technique. Stocking density did not affect establishment success. It is possible to suppress C3 invasive grasses with herbicide and establish native C4 tallgrasses in central South Dakota, but drought makes it a risky proposition in this semiarid region.

Resistant xylem from roots to peduncles sustains reproductive water supply after drought-induced cavitation of wheat leaves.

Many annual grasses exhibit drought avoiding life cycles where rapid reproduction must be completed before soil water is exhausted. This strategy would seem to require a hydraulic system capable of sustaining reproduction at all costs to the rest of the plant, yet little is known about the whole-plant structure of hydraulic vulnerability in grasses. We examine vulnerability to water-stress induced xylem cavitation in roots, flag leaves, basal and apical regions of peduncles of wheat (Triticum aestivum var Krichauff) to understand the staged failure of xylem function in severe drought. The functionality of segmented vulnerabilities is tested by conducting rehydration experiments after acute dehydration. We show the water supply to peduncles is more drought resistant than in leaves due to greater xylem cavitation resistance, ensuring a pathway of water can be maintained from the roots to the reproductive tissues even after severe water deficit. Differential rehydration of peduncles compared to leaves following drought confirmed the functionality of xylem supply from roots to seed after water stress sufficient to completely cavitate flag leaf vessels. These results demonstrate that a proportion of the hydraulic pathway between roots and seeds remains functional under extreme dehydration, suggesting that vulnerability traits in this key grass species reflect its reproductive strategy.

Improvement of cost calculation of seed grass products

The cost price is one of the main qualitative indicators for evaluating the efficiency of production. Therefore, a scientifically based calculation of the cost of seeded grass production is of great practical importance for agricultural organizations. In this regard, the article provides a critical assessment of the current method for calculating the cost of production of sown annual and perennial grasses. Three new methods for calculating the cost of production of annual and perennial grasses have been developed, from which any agricultural organization can choose one option for practical use.

Evaluating the Efficacy of Targeted Cattle Grazing for Fuel Break Creation and Maintenance

Invasive and highly flammable annual grasses continue to alter wildfire regimes across rangelands of the western United States. These hazardous fuels have contributed to the increasing prevalence of western megafires in recent decades. It is clear that existing rangeland fuel management strategies are challenged to keep pace with this growing threat. Targeted livestock grazing, however, might serve as a novel and effective fuels management tool that could be wielded at a scale commensurate with the annual grass–wildfire problem. Unfortunately, this practice has lacked a rigorous scientific foundation to support broad-scale application and decision making. We evaluated the efficacy of targeted beef cattle grazing, applied during the spring, for reducing herbaceous fuel heights, loads, and continuity while maintaining ecosystem health in fuel breaks strategically positioned between invaded, fire-prone landscapes and wildland-urban interface, greater sage-grouse (Centrocercus urophasianus) habitat, and other critical resources threatened by wildfire damage. Our broad-scale experiment was conducted during 2017–2021 as three replicate research projects distributed across the northern Great Basin of Idaho, Nevada, and Oregon. We found targeted grazing in spring reduced total herbaceous and cheatgrass fuel heights and, in some cases, total 1-h and cheatgrass fuels loads and fuel continuity, while producing no consistent adverse effects or trends in ecosystem health within the fuel break treatments relative to nominally grazed controls. One targeted grazed fuel break in this research successfully intercepted three wildfires in 4 yr conserving sage-grouse habitat downwind. Although additional research is required, these findings suggest targeted grazing provides an effective means of reducing fine fuels while avoiding adverse ecosystem impacts. Some expected outcomes from the use of this tool would be improved wildland firefighting safety and efficacy, reduced wildfire size, and enhanced protection of human lives, property, and critical natural and cultural resources within the broad scope of annual grass-wildfire problem.

Pathways of glyphosate effects on litter decomposition in grasslands

AbstractGrasslands store a third of global terrestrial carbon but are vulnerable to carbon loss due to inappropriate livestock grazing. Grasslands management can be improved with a mechanistic understanding of biogeochemical processes that determine carbon storage, such as plant litter decomposition.Herbicides, such as glyphosate, are used to improve the quantity and quality of the forage. In the Flooding Pampa, the most extensive cattle grazed natural grassland and one of the few remnants' temperate grasslands in South America—glyphosate is applied to promoteLolium multiflorum, a forage grass associated with a fungal endophyte nontoxic for cattle.We studied five mechanistic pathways in which the application of glyphosate can alter litter decomposition. We grouped them into single application pathways, through effects on living plants (1), leaf litter (2) and bare soil (3), and repeated annual application pathways, through legacies on ecosystem properties (4) and through the growth of an annual forage grass with a fungal endophyte (5). Single application pathways were tested in a greenhouse experiment using leaf litter ofL. multiflorumand of a native dominant grass. Repeated annual application pathways were tested through a field experiment with 3‐year annual glyphosate application using leaf and root litter ofL. multiflorumwith and without endophyte association.Glyphosate application on living plants produced leaf litter with 70% higher nitrogen content and 140% higher decomposition constant than naturally senesced litter. In contrast, glyphosate application on naturally senesced leaf litter reduced decomposition constant by 20%. Glyphosate application on the soil did not affect the decomposition of naturally senesced leaf litter but accelerated the decomposition of the glyphosate‐killed plants even more.Legacies of repeated annual application of glyphosate resulted in a notable reduction in plant cover (45%) and potential soil respiration (57%), with a consistent acceleration of leaf (53%) and root (18%) litter decomposition. Furthermore, endophytes inL. multiflorumplants reduced leaf litter decomposition by 22%. On the contrary, endophytes did not alter root litter decomposition.Glyphosate application on living plants and legacies of repeated application on the ecosystem stimulate litter decomposition, which can result in a net carbon loss from grasslands. In other ecosystems, the net result on decomposition would depend on the relative cover of vegetation, above‐ground litter and bare soil. This study highlights that glyphosate application should be considered when evaluating sustainable management to preserve and enhance soil carbon storage in grasslands.Read the freePlain Language Summaryfor this article on the Journal blog.

Extracting exotic annual grass phenology and climate relations in western U.S. rangeland ecoregions

This research builds upon the extensive body of work to model exotic annual grass (EAG) characteristics and invasion. EAGs increase wildland fire risk and intensifies wildland fire behavior in western U.S. rangelands. Therefore, understanding characteristics of EAG growth increases understanding of its dynamics and can inform rangeland management decisions. To better understand EAG phenology and spatial distribution, monthly weather (precipitation, minimum and maximum temperature) variables were analyzed for 24 level III ecoregions. This research characterizes EAGs’ phenology identified by a normalized difference vegetation index (NDVI) threshold-based interpolation technique. An EAG phenology metric model was used to estimate a growing season dynamic for the years 2017–2021 for shrub and herbaceous land cover types in the western conterminous United States (66% of the area). The EAG phenology metrics include six growing season metrics such as start of season time, end of season time, and time of maximum NDVI during the growing season. The models’ cross validation results for Pearson’s r ranged from 0.88 to 0.95. Increased understanding of the effects that weather conditions have on EAG growth and spatial distribution can help land managers develop time-sensitive plans to protect entities deemed valuable to society like native habitat, wildlife, recreational areas, and air quality.

Current insights into the microbial degradation of nicosulfuron: Strains, metabolic pathways, and molecular mechanisms

Nicosulfuron is among the sulfonylurea herbicides that are widely used to control annual and perennial grass weeds in cornfields. However, nicosulfuron residues in the environment are likely to cause long-lasting harmful environmental and biological effects. Nicosulfuron degrades via photo-degradation, chemical hydrolysis, and microbial degradation. The latter is crucial for pesticide degradation and has become an essential strategy to remove nicosulfuron residues from the environment. Most previous studies have focused on the screening, degradation characteristics, and degradation pathways of biodegrader microorganisms. The isolated nicosulfuron-degrading strains include Bacillus, Pseudomonas, Klebsiella, Alcaligenes, Rhodopseudomonas, Ochrobactrum, Micrococcus, Serratia, Penicillium, Aspergillus, among others, all of which have good degradation efficiency. Two main intermediates, 2-amino-4,6-dimethoxypyrimidine (ADMP) and 2-aminosulfonyl-N,N-dimethylnicotinamide (ASDM), are produced during microbial degradation and are derived from the C–N, C–S, and S–N bond breaks on the sulfonylurea bridge, covering almost every bacterial degradation pathway. In addition, enzymes related to the degradation of nicosulfuron have been identified successively, including the manganese ABC transporter (hydrolase), Flavin-containing monooxygenase (oxidase), and E3 (esterase). Further in-depth studies based on molecular biology and genetics are needed to elaborate on their role in the evolution of novel catabolic pathways and the microbial degradation of nicosulfuron. To date, few reviews have focused on the microbial degradation and degradation mechanisms of nicosulfuron. This review summarizes recent advances in nicosulfuron degradation and comprehensively discusses the potential of nicosulfuron-degrading microorganisms for bioremediating contaminated environments, providing a reference for further research development on nicosulfuron biodegradation in the future.

Effects of Using Indaziflam and Activated Carbon Seed Technology in Efforts to Increase Perennials in Ventenata dubia–Invaded Rangelands

Reestablishing perennial vegetation dominance in ventenata (Ventenata dubia)– and other annual grass–invaded rangelands is critical to restoring ecological function and increasing ecosystem goods and services. Recovery of perennial dominance in ventenata-invaded rangelands is challenging and constrained by a lack of established best management practices; however, preemergent herbicides can, at least temporarily, reduce ventenata. Indaziflam is a preemergent herbicide that has longer soil activity than other commonly used preemergent herbicides that needs evaluated to determine if it offers multiple-year control of ventenata and to determine its effects on residual perennial vegetation. Some ventenata-invaded rangelands may not have enough residual vegetation to occupy the site after ventenata control, but longer soil activity with indaziflam likely limits establishment of seeded species. However, incorporating seeds in activated carbon pellets, which can limit herbicide damage, may be a strategy for establishing perennial vegetations simultaneously with indaziflam application. We evaluated 1) applying indaziflam to control ventenata and 2) broadcast-seeding perennial grass seed incorporated in activated carbon pellets with a simultaneous indaziflam application at two sites for 3 yr post treatment. Indaziflam controlled ventenata for the 3 yr sampled. Perennial grasses increased with indaziflam at the site that had more residual perennial grasses before treatment. At the other site, perennial forbs increased with indaziflam. Indaziflam offers multiple-year control of ventenata; however, plant community response depends on composition before treatment. Seeding perennial grass seeds incorporated in activated carbon pellets while indaziflam controlled ventenata did not increase perennial grass abundance. Though this was likely associated with low establishment due to below-average precipitation post seeding and because broadcast seeding is often an ineffective seeding method, we cannot rule out nontarget herbicide damage. Further evaluations of activated carbon technologies used in conjunction with indaziflam are needed to determine if this can be an effective management strategy.

Effect of Long-Term Use of Organic and Miineral Fertilizers on the Agrochemical Properties of Sod-Podzolic Soils and Productiviny of Annual Grasses in the Fodder Crop Rotation of the European North

In a field long-term experiment on sod-podzolic soil, the effectiveness of the complex application of fertilizers and their effect on soil fertility and productivity of annual grasses in the feed 6-pole crop rotation was determined. It is shown that the combined use of fertilizers most effectively affected the increase in the fertility of sod-podzolic soil and the productivity of the vico-oat mixture. The amount of humus increased by 0.30.8%, mobile phosphorus - by 60-140 mg/kg, the exchange and hydrolytic acidity and the content of exchangeable potassium in the soil decreased. The complex application of fertilizers in high doses significantly increased the yield and quality of annual grasses.

Strategic Partnerships to Leverage Small Wins for Fine Fuels Management

Rangeland wildfire is a wicked problem that cuts across a mosaic of public and private rangelands in the western United States and countless countries worldwide. Fine fuel accumulation in these ecosystems contributes to large-scale wildfires and undermines plant communities’ resistance to invasive annual grasses and resilience to disturbances such as fire. Yet it can be difficult to implement fuels management practices, such as grazing, in socially and politically complex contexts such as federally managed rangelands in the United States. In this Research-Partnership Highlight, we argue that private-public partners in such settings must be strategic in their selection of tasks to generate “small wins” in order to build the trust, competency, and legitimacy needed to advance an approach for landscape-scale fine fuels management. We highlight a fine fuels reduction partnership consisting of public and private entities in southeastern Oregon that established a research and education project and applied dormant-season grazing on three pastures within the Vale District Bureau of Land Management. We describe the impetus for the partnership, antecedents, strategic tactics, and ongoing learning and reflection used to revise processes. In this example, implementing dormant-season grazing as a research and education project allowed the partners to assess the efficaciousness of the treatment, as well as the operational logistics and administrative competencies necessary to apply the treatment to manage fine fuels at broader scales. Because dormant-season grazing may, in some instances, conflict with established practices and norms, small-scale projects such as this allow partners to refine understandings of the social and administrative conditions that make implementation possible. Generating small wins through projects such as this is a critical precursor for partnerships seeking to take on larger, more complex endeavors that involve increasing ecological, economic, and social uncertainty.