Season Grasses Research Articles

Agronomic evaluation of 15 warm season grasses grown in temporarily waterlogged soils in Northeastern Argentina

Soils with temporarily waterlogged conditions are common in Northeastern Argentina. Fifteen accessions and hybrids of cultivated and native warm season grasses (Acroceras macrum, Urochloa species, Hemarthria altissima and Paspalum species) were planted in Basail, Chaco, in a completely randomized block design in November 2019. Initial, autumn and spring forage yield were measured in February 2020, July 2021 and December 2021, respectively. Plant height and plant diameter were evaluated in February 2020. Cold tolerance was estimated after the first frost in July 2021. Initial forage yield was between 29 and 181 g/plant. Urochloa mutica exhibited the greatest initial forage yield. Autumn and spring forage yield varied from 306 to 2,183 g/m2 and from 153 to 710 g/m2, respectively. U. mutica showed the highest autumn forage yield, however, it was the most damaged by cold weather. H. altissima hybrids were the most productive during spring and were cold tolerant. There were differences in plant height (7.5–49 cm) and plant diameter (68–268 cm) among the grasses. Grasses with prostrate, intermediate and upright growth habits were identified. Results indicate all grasses tested were adapted to humid Northeastern Argentina and varied in their morphological and agronomic traits.

455 Evaluating the effect of a phenology-based timeline on the interpretation of enteric methane emission results

Abstract The methodology of analyzing methane emissions in cattle grazing native rangeland is imperative for producing reliable and repeatable estimations of total enteric emissions on an individual and herd basis. However, due to seasonal differences in climate from year to year, there are distinct differences in forage biomass availability and nutrient composition on extensive rangelands. Thus, our objective was to evaluate the differences in methane emissions using phenological forage phases compared with specific time periods. Yearling Angus steers (n = 127) were allocated to one of six pastures grazed from June to September (2023) at the South Dakota State University Cottonwood Field Station (Cottonwood, SD). Each pasture was equipped with a GreenFeed (C-Lock Inc., Rapid City, SD) pasture system to measure individual animal CH4 emissions. A subset of CH4 data from two cool-season-dominated pastures were aggregated from the overall study. We used two methods to segment CH4 by either 1) month (June, July, August) or 2) phenology (vegetative, reproductive, and senescence) to derive average CH4 (gּ animalּ -1ּ d-1) for each period. Western wheatgrass (WWG), a cool-season native, was used as a proxy for cool season grass development. On May 28th, 2023, the growing degree days (GDD) reached 632, representing the 3.5 leaf stage. WWG has been documented to reach maturity at approximately 1,100 GDD, which occurred on June 20th, 2023. Nutrient content of the forage (i.e., lignin) was used to approximate the start of senescence on August 11th. These developmental markers created estimates of the vegetative, reproductive, and senescence periods within our emissions data. Differences in enteric emissions for each approach were analyzed using a linear mixed effects model in R, and post-hoc contrast between methods was assessed using the lsmeans package. There were no statistical differences in CH4 by month (P > 0.05), and the means for June, July, and August were 217, 214, and 211 ± 4, respectively. By phenological phases, there was a difference (P < 0.05) between maturity and senescence, with means for vegetative, reproductive, and senescence as 214, 219, and 206 ± 4, respectively. Methane intensity (gּ animal-1ּ d-1) per period was then multiplied by the number of days in each month or phase to estimate total emissions for the entire grazing season (86 d). The monthly approach totaled 18,383 g CH4 per animal, while phenology totaled 18,504 g for the grazing season. This is a difference of 0.654% between the same data segmented by month or by phenology. Therefore, because of the dynamic nature of forage and cattle production, it is likely that accounting for phenology will provide greater clarity for GHG on rangeland systems rather than arbitrary periods of time and will require the use of dynamic models to handle the complexity of enteric emissions of grazing animals.

Sorghum–Legume Mixtures to Improve Forage Yield and Nutritive Value in Semiarid Regions

In a continued search for legumes to grow with forage sorghum (FS) [Sorghum bicolor (L.) Moench] in semi-arid environments, studies in 2019 and 2022 at New Mexico State University Rex E. Kirksey Agricultural Science Center at Tucumcari, NM USA, evaluated FS mixed with cowpea [Vigna unguiculata (L.) Walp.], lablab (Lablab purpureus L.), both previously evaluated, and a native legume, big-pod sesbania (Sesbania macrocarpa), for yield and nutritive value in four randomized complete blocks each year. At harvest legume proportions of approximately 15% of the dry matter yield, there were no differences in the yield (mean = 15.97 Mg ha−1, p > 0.40) or land equivalency ratio between sole FS and any mixture or among mixtures; however, the crude protein of FS+Lablab was greater than sole FS, with FS+Cowpea and FS+Sesbania intermediate (67, 77, 87, and 79 g kg−1 for sole FS, FS+Cowpea, FS+Lablab, and FS+Sesbania, respectively; 5% LSD = 14). The neutral detergent fiber digestibility of FS+Sesbania was less than all other treatments (p = 0.0266). Although the sesbania did not improve forage yield or nutritive value when grown with FS and harvested near sesbania maturity, perhaps growing with a shorter season grass and harvesting earlier may show benefit, as sesbania’s nutritive value is known to be greater at earlier stages.

Evolution of drought and frost responses in cool season grasses (Pooideae): was drought tolerance a precursor to frost tolerance?

Frost tolerance has evolved many times independently across flowering plants. However, conservation of several frost tolerance mechanisms among distant relatives suggests that apparently independent entries into freezing climates may have been facilitated by repeated modification of existing traits ('precursor traits'). One possible precursor trait for freezing tolerance is drought tolerance, because palaeoclimatic data suggest plants were exposed to drought before frost and several studies have demonstrated shared physiological and genetic responses to drought and frost stress. Here, we combine ecophysiological experiments and comparative analyses to test the hypothesis that drought tolerance acted as a precursor to frost tolerance in cool-season grasses (Pooideae). Contrary to our predictions, we measured the highest levels of frost tolerance in species with the lowest ancestral drought tolerance, suggesting that the two stress responses evolved independently in different lineages. We further show that drought tolerance is more evolutionarily labile than frost tolerance. This could limit our ability to reconstruct the order in which drought and frost responses evolved relative to each other. Further research is needed to determine whether our results are unique to Pooideae or general for flowering plants.

Effect of turfgrass care products on soil biological health, disease suppression, and turfgrass quality

Despite the wide use of turfgrass care products such as wetting agents (WAs), plant growth regulators (PGRs), and biological products (BPs), little is known about their effect on soil biological health, turfgrass quality, and disease suppression. Studies were conducted to evaluate the effect of some commonly used turfgrass care products on soil biological health, dollar spot suppression, and turfgrass quality. The turfgrass care products were: nine WAs (Vivax, Fleet, Magnus, Cascade, Dispatch, Duplex, Pervade, Sixteen90, and Revolution); four PGRs (Anuew, Trimmit, Proxy, and Cutless) and; three BPs (Plant Helper, KaPreRemeD8-NSL, and KaPreRemeD8-NSP). Potted bentgrass (Agrotis stolonifera L.) were treated independently with the WAs, PGRs, and BPs, and deionized water was used as a control. Soil samples were collected from the pots at 7 and 14 weeks after treatment (WAT) and analyzed for soil biological health using soil respiration, urease, and phosphatase activities as indicators. Disease suppression was evaluated by inoculating potted bentgrass with an isolate of Clarireedia jacksonii, the causal agent of dollar spot of cool season grasses and the infection was visually assessed at intervals of 10 days. The WAs Dispatch, Fleet, Magnus, and Vivax stimulated rate of soil respiration at 7 WAT compared to the control. The PGRs Cutless, Trimmit, and Proxy had no effect on soil respiration whereas Anuew suppressed soil respiration. Turfgrass quality was improved by the WAs Revolution, Cascade, Pervade, Duplex, and Sixteen90 at 7 WAT, but none of the PGRs and BPs improved turf quality. Cascade stimulated phosphatase activity and was the only product to impact this indicator. None of the products had a significant effect on dollar spot suppression. These results could guide turfgrass growers and professionals in making decisions that enhance the quality of turfgrass without compromising the health of the soil that sustains it.

Tall Fescue and Endophyte Genetics Influence Vertical Transmission and Seed Characteristics Under Climate Change Scenarios

Cool season grasses, including tall fescue, are dominant plants within managed grassland systems. A symbiotic relationship between tall fescue ( Lolium arundinaceum) and the fungal endophyte Epichloë coenophiala can affect grassland response to perturbations, including changing rainfall patterns and increasing temperatures associated with climate change. Because E. coenophiala reproduces asexually, there is concern that climate change may negatively impact vertical transmission, resulting in subsequent fescue stands with lower infection frequencies and reduced grassland resiliency. This 3-year field study evaluated the impact of increased temperature, altered precipitation, and their combination on vertical transmission, seed number, and seed weight in tall fescue clones containing common toxic (CTE) or novel nonmammalian toxic (NTE) E. coenophiala. NTE clones exhibited greater transmission than CTE clones. Temperature did not affect transmission, but altered precipitation reduced transmission in CTE clones. On average, NTE clones responded to increased temperatures by reducing seed number, while CTE clones responded oppositely. NTE clones produced seeds of similar masses across all growing years, suggesting greater stability under varying environmental conditions. Our work illustrates that both plant and endophyte genetics influence vertical transmission and that climate change is unlikely to significantly impact endophyte transmission in the southeastern transition zone of the United States. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Equine relative preferences regarding selected cool-season grass hays

Horse preferences for cool season grass cultivars under grazing has been described. However, preference for cool-season grass cultivars as hays has not been widely evaluated in horses, particularly the new varieties of Tall Fescue with novel endophytes designed to produce less ergovaline, the compound to which fescue toxicosis is attributed. First cutting hay was harvested in 2019 and 2020 from seven cool season grasses: Tall Fescue v. KY 31; Tall Fescue v. Bronson, endophyte free; Tall Fescue v. Texoma MaxQ, novel/non-toxic endophyte; Meadow Fescue v. Preval; Festulolium v. Spring Green; Perennial Ryegrass v. Elgon; and Orchardgrass v. Crown Royal. First cutting yield was determined on a dry weight basis. Sub-samples were analyzed for forage quality parameters and ergovaline concentrations. The effect of cultivar on mean hay yields was analyzed using a one-way ANOVA, and since the F-Value was significant (< 0.001) the least significant differences were further determined to compare yield differences among the cultivars. All three Tall Fescue cultivars, Meadow Fescue, and Festulolium had significantly greater yields than the Perennial Ryegrass and Orchardgrass (P < 0.05). All samples tested for ergovaline were below the reporting threshold of the laboratory. Subsequently, tillers of the Tall Fescue cultivars were evaluated for endophyte presence. Endophyte was detected in only 3.3 % and 16.7 % of v Bronson and Texoma MaxQ tillers, respectively. No endophyte was detected in v KY 31. To evaluate preference four mature idle horses (6 ± 1.08 yrs) were fasted 30 min prior to being in the test stalls for 30 min. First choice and weight consumed were recorded. Preference testing occurred within harvest year. Equine preference data were analyzed within year using a one-way ANOVA pairwise comparison with the Tukey-Kramer adjustment for multiple comparisons. Both forward and backward stepwise regression modelling were used to investigate proximate analyses values as potential predictors of cultivar consumption by the horses during the preference tests. The best performing model explained 36 % of the variation in cultivar consumption. Based on amounts consumed horses had similar preferences each year; the overall rank of the cultivars was very similar with only the two least preferred cultivars transposed from 2019 to 2020. Horses most preferred the lowest yielding cultivars (Perennial Ryegrass and Orchardgrass). Despite low ergovaline and endophyte content in the Tall Fescue varieties, adult horses preferred hay of other cultivars. Festulolium is an option for hay producers that balances both yield and horse preference.

Widespread annual occurrence of pesticides within designated critical habitats for endangered prairie butterflies

Insect declines have become pronounced in prairie ecosystems, particularly in areas of agricultural intensification. Non-target pesticide exposure has been raised as a key concern for prairie remnant health. Over seven years, we screened grass and soil samples for the presence and quantities of hundreds of pesticides from five prairies in Minnesota and South Dakota that are designated as Critical Habitat for two globally endangered butterflies: Poweshiek skipperling and Dakota skipper. We documented dozens of pesticides across all sites and years on their larval host grasses. Interiors of prairies were not less likely to have detectable pesticides than along prairie-agriculture edges. Broad-spectrum organophosphate and pyrethroid insecticides were common in late season. Chlorpyrifos quantities were higher at sites where both endangered species have been extirpated. Neonicotinoid insecticides, which have been frequently attributed to declines in insect pollinators, did not present a significant exposure signal in these prairie habitats. Few pesticides were detected in soil or early season grass samples. The prevalence and quantities of pesticides we observed are likely underestimates, and additional research is needed on the landscape of risk at small and large scales. Implications for Conservation: Protected prairies are not immune to the risk of pesticide exposure, which may impact efforts to re-establish lost populations of imperiled prairie insects, including endangered butterflies.

Surface Resistance Controls Differences in Evapotranspiration Between Croplands and Prairies in U.S. Corn Belt Sites

AbstractWater returned to the atmosphere as evapotranspiration (ET) is approximately 1.6x global river discharge and has wide‐reaching impacts on groundwater and streamflow. In the U.S. Midwest, widespread land conversion from prairie to pasture to cropland has altered spatiotemporal patterns of ET, yet there is not consensus on the direction of change or the mechanisms controlling changes. We measured ET at three locations within the Long‐Term Agroecosystem Research network along a latitudinal gradient with paired rainfed cropland and prairie sites at each location. At the northern locations, the Upper Mississippi River Basin (UMRB) and Kellogg Biological Station (KBS), the cropland has annual ET that is 84 and 29 mm/year (22% and 5%) higher, respectively, caused primarily by higher ET during springtime when fields are fallow. At the southern location, the Central Mississippi River Basin (CMRB), the prairie has 69 mm/year (11%) higher ET, primarily due to a longer growing season. Differences in climate and that the CMRB prairie is remnant native prairie, while the UMRB and KBS prairies are restored, make it challenging to attribute differences to specific mechanisms. To accomplish this, we examine the energy balance using the Two‐Resistance Method (TRM). Results from the TRM demonstrate that higher surface conductance in croplands is the primary factor leading to higher springtime ET from croplands, relative to prairies. Results from this study provide insight into impacts of warm season grasses on the hydrology of the U.S. Corn Belt by providing a mechanistic understanding of how land use change affects the water budget.

74 Effect of grazing native warm season grasses on parasitism and growth in weaned Katahdin lambs

Abstract Parasitism in lambs during the post-weaning period has effects on growth, survival, and sheep enterprise profitability. Opportunities to minimize exposure to infective larvae during this period may reduce clinical effects and improve lamb performance. Native warm season grasses (NWSG) offer increased growth during summer months and taller plants that allow grazing at greater heights. The objective here was to evaluate NWSG as a forage for post-weaning development of lambs in spring lambing, forage-based systems. Over 2 yr, Katahdin lambs (Yr 1, n = 30; Yr 2, n = 31) were managed at a producer farm in the piedmont region of North Carolina. Beginning 2 wk post-weaning, lambs were randomly assigned to graze on either NWSG (Big Bluestem and Indiangrass) or cool season grass (CSG, Kentucky 31 Tall Fescue base) pasture. Lambs were continuously grazed for 70 d in Yr 1 and 55 d in Yr 2. Fecal egg count (FEC), FAMACHA score, and body weight (BW) were measured every two weeks. Lambs were dewormed at FAMACHA ≥ 3. Forage analysis was conducted at the start and end of the grazing period. Statistical analysis were performance using the PROC Mixed procedure of SAS. Lambs in each group were raised in similar litter sizes and sire and sex were evenly distributed between groups. Fecal egg count and growth estimated breeding values (EBV) were similar between NWSG and CSG groups. In Yr 1 and 2, no differences were observed in FEC between grazing groups (P &amp;gt; 0.05). However, FEC did increase in both groups throughout the grazing period (P &amp;lt; 0.05). In Yr 1, no differences were observed in total BW gain (P = 0.74). However, in Yr 2, lambs grazing CSG had greater total BW gain than the NWSG group (P &amp;lt; 0.05). In both years, there were no differences in the percentage of lambs requiring deworming (Yr 1, P = 0.36; Yr 2, P = 0.47) but lambs requiring treatment had greater FEC EBVs (P &amp;lt; 0.05). Nutrient quality of NWSG pasture was reduced compared with CSG pastures. Total digestible nutrients and crude protein were less in NWSG compared with CSG pastures (Yr 2: 61.5% vs. 63.9% and 8.9% vs. 13.6%, respectively) and neutral detergent fiber was greater (Yr 2: 74.1% vs. 65.2%, respectively) resulting in decreased nutrient availability for NWSG group. While NWSG may provide additional biomass for summer grazing, rapid maturity rates may limit nutrient availability for lambs resulting in decreased growth performance despite similar levels of parasitism. Lamb FEC EBV may have a role in parasite resistance and deworming requirements regardless of forage type. Thus, genetics must be considered along with grazing management as part of an integrated parasite management plan.

145 The effect of a plant secondary metabolite blend on energy metabolism and nutrient balance of beef cattle consuming low-quality warm season grass hay

Abstract Plant secondary metabolites (PSM) such as condensed tannins, hydrolysable tannins, saponins and essential oils purportedly impact rumen fermentation at low inclusion rates in beef cattle diets. Twelve steers (347 ± 23 kg BW) of British and continental influence were allocated to 1 of 4 replicated 3 x 3 Latin squares. Latin squares each had 14 d periods (10 d adaptation and 4 d for sample collection). All cattle were fed ground warm-season hay (89.5% DM, 92.8% OM, 65.9% NDF, 43.6% ADF, 6.70% CP) at 1.5% of BW (DM-basis) and supplemented with soybean meal at 0.18% of BW (DM-basis) once daily. Treatments consisted of a blend of tannins, saponins and essential oils provided at 0% (Control), 0.1% (Low) and 0.3% (High) of hay offering. Treatments were mixed with daily soybean meal allotment and provided before feeding of hay. Urine and feces were completely collected from d 11 through 14 at 0730 h and daily amounts of urine and feces produced were measured gravimetrically. Measures of gaseous exchange were determined via indirect calorimetry on d 13 and 14. Open-circuit respiration calorimeters (91.4 × 91.4 × 191.2 cm) were used to collect respired gas and ruminal methane production. Total oxygen consumption and production of carbon dioxide and methane were calculated from the difference in concentration of oxygen, carbon dioxide, and methane from air exhausted from each calorimeter and concentration of oxygen, carbon dioxide, and methane in ambient air and multiplied by amounts of air flowing from each calorimeter standardized for temperature, pressure, and humidity. Data were analyzed for a Latin square using the MIXED procedure of SAS with fixed effect of treatment, period and square and random effect of steer. Linear and quadratic contrast coefficients were assigned using PROC IML for uneven spacing of treatments. Significance was declared when P ≤ 0.05. Per experimental design, forage N and OM intake did not differ (P ≥ 0.77). Apparent total tract digestion of OM, NDF and ADF did not differ (P ≥ 0.66) among treatments. Fecal nitrogen excretion, and the percentage of N excreted in feces increased linearly (P = 0.01). N balance tended (P = 0.08) to decrease linearly with increasing PSM supplemented. Methane (L/kg DMI) was not affected (P = 0.28) by treatments. Methane, GE, DE, and ME (mcal/kg DMI) was unaffected (P = 0.19) by treatment. Under the conditions of this experiment, a blend of PSM had little effect on rumen fermentation or energy metabolism in beef steers.

80 Effect of copper bolus administration on circulating copper concentration, blood metabolites and parasite load

Abstract In Texas and Southeastern United States Cu concentration in the soil is in the lower 50th percentile, this leads low bioavailability of copper for livestock. Therefore, a 70-d completely randomized block design study was conducted to determine the effects of Cu and fecal egg count in grazing beef cows (n = 40). Cows were blocked by parity and body weight (BW) then randomly assigned to 1 of 2 treatments: standard offering of copper via free choice mineral (CON; Ragland Sweet Mag Mineral Mix, 425 ppm Cu) and those receiving a 25 mg Cu rumen bolus in addition to the standard offering (Santa Cruz Animal Health, Dallas, TX). Cattle were managed as a single herd at the with equal access to water, a grain supplement, and a warm season grass pasture. Fecal samples via rectal grab, blood via coccygeal venipuncture, BW, BCS, hair coat (1 being the healthiest) and shedding (1 being the most slick) scores were all collected on d 0, 10, 24, 38, and 66 relative to treatment initiation. Sera were analyzed to determine circulating Cu, macrominerals, urea, creatinine, and various blood proteins. Fecal egg counts were conducted to determine Coccidial, Moniezia, and Trichostrongyle egg content. Data were analyzed using the GLIMMIX procedure of SAS 9.4 (SAS inst. Inc, Cary, NC). No treatment × day interaction (P = 0.988) was observed for circulating Cu; however, Cu decreased (P &amp;lt; 0.001) in all cattle over time, and TRT tended (P = 0.090) to have increased Cu compared with CON. No interactions or main effects occurred (P &amp;gt; 0.509) for BW. No interaction (P = 0.4389) occurred for BCS, hair, or shedding scores. Hair scores (P &amp;lt; 0.001), shedding scores (P &amp;lt; 0.041), and BCS(P &amp;lt; 0.001) decreased in all cattle over time. Body condition for TRT (5.2 ± 0.056) was greater (P =.0024) than CON (4.9 ± 0.057). Hair score by day decreased (P &amp;lt; 0.001) in TRT, while the shedding had a tendency of increasing (P = 0.0411) by TRT. There were no interactions or main effects on Coccidial (P &amp;lt; 0.220) or Trichostrongyle (P &amp;lt; 0.274) egg content. While no interaction (P = 0.673) for Moniezia was observed, TRT tended (P = 0.095) to have fewer Moniezia eggsthan CON. No interactions (P &amp;gt; 0.100) were observed for any of the blood metabolites, and while they differed (P &amp;lt; 0.05) day to day for all cows, no treatment effects occurred (P &amp;gt; 0.10). Although Cu bolus administration at this concentration did tend to change Cu copper in the animal, effects resulting from it were minimal.

Sodium acetate and sodium butyrate attenuate diarrhea in yak calves by regulating gut microbiota and metabolites

Diarrhea is a severe issue in calves that causes fertility problems and economic issues worldwide. Sodium acetate/sodium butyrate (SA/SB) alleviates diarrhea in mice; however, little information is available about the preventive effect of SA/SB on diarrheic yak calves living on the Tibet plateau. Yak calves (n = 19) of age ≥4 months and weight 37 ± 2 Kg were randomly divided into control (C, n = 10) and supplement groups (S, n = 9). Yaks belonging to the supplement group were given sodium butyrate (10 g/kg) and sodium acetate (5 g/kg) for 28 days, along with normal feed, seasonal grasses, pasture, and water. The blood and fecal samples from yak calves were collected for assessment of antioxidant capacity, inflammatory cytokines, microbiome, and short-chain fatty acids (SCFAs) concentration analysis. Results of this study revealed that a lower diarrhea rate, higher weight, and net weight gain were recorded in yaks belonging to group S supplemented with SA/SB. Similarly, increased antioxidant capacity with higher levels of T-AOC, SOD, and GSH-px and decreased inflammatory reactions by decreasing both TNF-α and IL-1β concentrations were recorded in yaks of group S. The concentration of SCFAs was significantly higher (p < 0.05) in yaks from group S than group C. Microbiome analysis revealed that 8 phyla and 54 genera were significantly different (p < 0.05) in both yak groups, with increased probiotics (Akkermansia, Oscillospira), SCFAs producing genera (Oscillospira, ASF356, Anaerosporobacter and Phascolarctobacterium), and decreased inflammatory related genus (Flavonifractor, Fournierella) and harmful bacteria (Oscillibacter, Achromobacter) in group S. In conclusion, the results demonstrated that SA and SB could decrease diarrhea rates in yak calves on the plateau via increasing antioxidant ability and SCFAs, while decreasing inflammatory responses in yaks by moderating gut microbiota. The current results provide new insights for the prevention and treatment of diarrhea in yaks.

Will trees or grasses profit from changing rainfall regimes in savannas?

Increasing rainfall variability is widely expected under future climate change scenarios. How will savanna trees and grasses be affected by growing season dry spells and altered seasonality and how tightly coupled are tree-grass phenologies with rainfall? We measured tree and grass responses to growing season dry spells and dry season rainfall. We also tested whether the phenologies of 17 deciduous woody species and the Soil Adjusted Vegetation Index of grasses were related to rainfall between 2019 and 2023. Tree and grass growth was significantly reduced during growing season dry spells. Tree growth was strongly related to growing season soil water potentials and limited to the wet season. Grasses can rapidly recover after growing season dry spells and grass evapotranspiration was significantly related to soil water potentials in both the wet and dry seasons. Tree leaf flushing commenced before the rainfall onset date with little subsequent leaf flushing. Grasses grew when moisture became available regardless of season. Our findings suggest that increased dry spell length and frequency in the growing season may slow down tree growth in some savannas, which together with longer growing seasons may allow grasses an advantage over C3 plants that are advantaged by rising CO2 levels.

The South African Pollen Monitoring Network: Insights from 2years of national aerospora sampling (2019-2021).

Pollen monitoring has been discontinuously undertaken in South Africa, a country with high biodiversity, a seasonal rainfall gradient, and nine biomes from arid to subtropical. The South African Pollen Monitoring Network was set up in 2019 to conduct the first long-term national aerospora monitoring across multiple biomes, providing weekly reports to allergy sufferers and healthcare providers. Daily airborne pollen concentrations were measured from August 2019 to August 2021 in seven cities across South Africa. Updated pollen calendars were created for the major pollen types (>3%), the average Annual Pollen Index over 12 months was calculated, and the results were compared to available historical data. The main pollen types were from exotic vegetation. The most abundant taxa were Poaceae, Cupressaceae, Moraceae and Buddleja. The pollen season start, peak and end varied widely according to the biome and suite of pollen taxa. The main tree season started in the last week of August, peaked in September and ended in early December. Grass seasons followed rainfall patterns: September-January and January-April for summer and winter rainfall areas, respectively. Major urban centres, for example, Johannesburg and Pretoria in the same biome with similar rainfall, showed substantive differences in pollen taxa and abundance. Some major differences in pollen spectra were detected compared with historical data. However, we are cognisant that we are describing only 2years of data that may be skewed by short-term weather patterns. Differences in pollen spectra and concentrations were noted across biomes and between geographically close urban centres. Comparison with historical data suggests pollen spectra and seasons may be changing due to anthropogenic climate change and landscaping. These data stress the importance of regional and continuous pollen monitoring for informed care of pollinosis.

Diurnal greenhouse gas emissions and substrate temperatures from blue-green roofs in north-eastern Italy during a dry-hot summer season

Covering building rooftops with vegetation [Green roofs (GRs)] holds promise for lowering building temperatures, reducing stormwater runoff, and providing other ecosystem services, but it is unclear how this will impact greenhouse gas (GHG) emissions. The latter may also be influenced by vegetation type, substrate depth, and irrigation regime and we sought to test this by comparing daytime GHG emissions (i.e., CH4, CO2, and N2O) and daily substrate temperatures in 48 GR microcosms in North-eastern Italy during a dry-hot summer season (June to September). Four vegetation types (Sedum mixture, cold season grasses, warm season grasses, or wildflowers), two substrate depths (8 cm or 14 cm), and two irrigation levels (1 or 2 mm d−1) were evaluated, for a total of 16 treatments with 3 replicates. We found that vegetation type had a significant effect on temperature [average temp. of 24.8 °C (Sedum) vs 25.5 °C (warm season grasses)] and CH4, CO2, and N2O emissions. While all vegetation types had net CO2 emissions (median values from 147 to 671 mg m−2 h−1) and net N2O uptake (median values from -0.06 to -0.28 mg m−2 h−1), CH4 flux had net negative values (capture) only in microcosms with wildflowers (-0.07 mg m−2 h−1), whereas other treatments had a median CH4 emissions of 0.09 mg m−2 h−1. Substrate depth significantly affected CO2 and N2O fluxes with deeper substrate leading to higher CO2 emission (+ 60.7%) and greater N2O uptake (+ 30.8%). Irrigation level only significantly influenced N2O fluxes with 2 mm irrigation resulting in higher fluxes (-0.20 mg m−2 h−1) than 1 mm irrigation (-0.09 mg m−2 h−1). Our study suggests that under heat induced plant-stress conditions, GRs can improve N2O and CH4 capture but might increase the emissions of CO2 fixed by plants in the previous years in the substrate and that vegetation type and substrate depth can significantly alter emissions and are thus important design parameters.

Wyoming Big Sagebrush Transplant Survival and Growth Affected by Age, Season of Planting, and Competition

Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis [Beetle & A. Young] S. L. Welsh) has decreased from its historic prevalence across the sagebrush steppe in part because of its interaction with invasive annual grasses and the increased wildfire frequency. Restoration of this species is vital to the ecosystem; however, traditional seeding methods such as broadcast or drill seeding have low success rates. Seedling mortality is associated with harsh weather conditions such as freezing temperatures in the winter and extreme temperature and soil moisture conditions during the summer drought. Transplanting sagebrush has greater success by overcoming the bottleneck of early seedling mortality. We tested how sagebrush transplant survival and size (canopy volume) are affected by age at the time of planting (10 classes, 6−24 wk), planting season (fall versus spring), and invasive annual grass competition (low/high) with a randomized factorial design over 2 yr. Survival was lower for age classes under 10 or 12 wk (in yr 1 and 2, respectively) but relatively similar from 12 to 24 wk. Fall-planted transplants had lower survival but increased canopy volume compared with spring-planted transplants. Survival and canopy volume decreased with competition with annual grasses. Our results suggest that land managers should consider planting younger transplants than previously thought and controlling invasive annual grasses before planting sagebrush transplants to increase long-term survival and canopy volume.

Pristine wild sugarcane (Saccharum spontaneum) as a biosorbent for removal of methylene blue from wastewater: isotherm, kinetics and regeneration studies

Saccharum spontaneum, popularly known as Kashful (KF) is a seasonal perennial grass with thin culms, mostly an abundantly growing shrub during the autumn season in southern Asia. It is used as no-cost scavenger to convincingly arrest methylene blue, a recalcitrant dye from colored effluent. FTIR, FESEM-EDX, and BET surface area characterize the material well whereas the surface activity was evaluated from zero-point charge (pHZPC = 6.720). FTIR highlights the presence of polyphenolic and carboxylate moieties. The surface texture is rod-like with intermittent non-homogeneous pores with occasional fractures. The equilibrium reaches within 60 min with the maximum adsorption capacity of 20.917 mg/g. The fibrous powder of kashful stalk (KFS) follows pseudo-second-order (R 2 = 0.999 for linear and R 2 = 0.985 for non-linear) kinetics and both Langmuir and Freundlich isotherm model (for linear, Langmuir R2=0.995; for non-linear, R 2 = 0.994 for both Langmuir and Freundlich model). The uptake process was spontaneous (ΔG= −3.077 kJ/mol) and endothermic (ΔH = 17.815 kJ/mol). 1:1 methanol could regenerate the dye-loaded material in up to 55% and onward efficiency was conducive for three consecutive cycles. Industrial effluent analysis suggests a real-time removal of ∼55% in the first cycle. Saccharum spontaneum could be exercised to solve environmental problems related to colored water.

Investigation on the forage utilization of indica and japonica weedy rice with strong ratooning ability

AbstractThere was few research on the utilization and development of weedy rice. Some weedy rice has remarkable good characteristics as forage in some soil which is difficult to plant crops and pastures. In this study, two weedy rice lines of japonica and indica subspecies with high ratooning ability (Xijing, japonica; Gaoxian, indica) were used to study the possibility of their forage utilization and related suitable cultivation methods. Three different stubble heights of first season were set in 2018 and 2019, and three cutting times of first season (heading stage, milk stage, and waxy ripening stage) were set in 2019. The ratoon grass was harvested 40 days after the first season harvest. For japonica weedy rice line Xijing, its grass yield was significantly lower than that of indica weedy rice line Gaoxian. The dry matter yield of first season grass plus ratoon grass of Gaoxian with the first season harvested at milk stage was the highest of all. The total digestible dry matter yield (first season grass plus ratoon grass) of Gaoxian with 15 cm cutting stubble of first season was higher than those of stubble 30 and 45 cm treatments (p &lt; .05). In conclusions, indica weedy rice line Gaoxian, with high biomass of first season and good ratooning ability, had the good potential for forage development by harvesting first season at milk stage with 15 cm stubble height.

Seasonal grass production and carrying capacity of buffalo grazing area in Paminggir, South Kalimantan

The population and performance of Kalimantan swamp buffalo are declining. Diminishing grazing area and pasture biomass availability, especially in the rainy season, contribute to inadequate buffalo feed consumption. This study was conducted to investigate the seasonal productivity of palatable native grasses and to estimate the carrying capacity of the swamp grazing area. One year of observation indicated that kumpai banta and sumpilang had higher dry matter production in the deep-water season, whereas kumpai minyak was in the shallow-water season, and padi hiyang had similar production in both seasons. Dry matter production in the deep-water season was higher than in the shallow-water season (1.29 vs 1.15 ton DM/ha/month) as well as for the carrying capacity of swamp grazing area (0.044 vs 0.029 AU/year). It is concluded that the swamp grazing area in the Paminggir sub-district could not carry the existing buffalo population.