Grassification and Fast-Evolving Fire Connectivity and Risk in the Sonoran Desert, United States

In the southwestern United States, non-native grass invasions have increased wildfire occurrence in deserts and the likelihood of fire spread to and from other biomes with disparate fire regimes. The elevational transition between desertscrub and montane grasslands, woodlands, and forests generally occurs at ∼1,200 masl and has experienced fast suburbanization and an expanding wildland-urban interface (WUI). In summer 2020, the Bighorn Fire in the Santa Catalina Mountains burned 486 km2 and prompted alerts and evacuations along a 40-km stretch of WUI below 1,200 masl on the outskirts of Tucson, Arizona, a metropolitan area of >1M people. To better understand the changing nature of the WUI here and elsewhere in the region, we took a multidimensional and timely approach to assess fire dynamics along the Desertscrub-Semi-desert Grassland ecotone in the Catalina foothills, which is in various stages of non-native grass invasion. The Bighorn Fire was principally a forest fire driven by a long-history of fire suppression, accumulation of fine fuels following a wet winter and spring, and two decades of hotter droughts, culminating in the hottest and second driest summer in the 125-yr Tucson weather record. Saguaro (Carnegia gigantea), a giant columnar cactus, experienced high mortality. Resprouting by several desert shrub species may confer some post-fire resiliency in desertscrub. Buffelgrass and other non-native species played a minor role in carrying the fire due to the patchiness of infestation at the upper edge of the Desertscrub biome. Coupled state-and-transition fire-spread simulation models suggest a marked increase in both burned area and fire frequency if buffelgrass patches continue to expand and coalesce at the Desertscrub/Semi-desert Grassland interface. A survey of area residents six months after the fire showed awareness of buffelgrass was significantly higher among residents that were evacuated or lost recreation access, with higher awareness of fire risk, saguaro loss and declining property values, in that order. Sustained and timely efforts to document and assess fast-evolving fire connectivity due to grass invasions, and social awareness and perceptions, are needed to understand and motivate mitigation of an increasingly fire-prone future in the region.

Microbial Community and Fermentation Characteristics of Native Grass Prepared Without or With Isolated Lactic Acid Bacteria on the Mongolian Plateau

This study aimed to isolate and identify lactic acid bacteria (LAB) from the native grass and naturally fermented silage from the Mongolian Plateau. The effect of selected strains on bacterial community and quality of native grass silage was also studied. Strains XM2, 265, and 842 could grow normally at 15°C–30°C, pH 4.0–8.0, and NaCl 3 and 6.5%; they were identified as Lactiplantibacillus plantarum subsp. plantarum, Pediococcus acidilactici, and Latilactobacillus graminis, by sequencing 16S rRNA, respectively. The three strains (XM2, 265, and 842) and one commercial additive (L) were used as inoculants and singularly added to the native grass. Compared to the control, the dry matter content was significantly (p < 0.05) lower in L and XM2 groups. The water-soluble carbohydrate content was significantly (p < 0.05) higher in control than in other groups. Compared with the control, the crude protein and ammonia nitrogen contents were significantly (p < 0.05) higher and lower in the LAB-treated groups, and the acid and detergent fiber contents were significantly (p < 0.05) reduced in the L and XM2 groups than those in other groups. There was a significant (p < 0.05) difference in the pH value, lactic acid content, and lactic acid-to-acetic acid ratio in L and XM2 groups than in other groups. Compared with the control, the number of LAB was significantly (p < 0.05) higher in LAB-treated silages, whereas no significant (p > 0.05) differences were observed in yeast and aerobic bacteria in all groups. Compared to the control, the Shannon index was significantly (p < 0.05) reduced. Simpson and Chao1 were significantly (p < 0.05) increased. Principal coordinate analysis based on the unweighted UniFrac distance showed clear separation of the bacterial community in fresh materials and LAB-treated silages. Besides, compared to the control, the principal coordinate analysis of LAB-treated silages was also separate. After 30 days of fermentation, the relative abundance of Firmicutes increased and was the primary phylum in all silages. Compared with the control, the abundance of Firmicutes and Proteobacteriawas significantly (p < 0.05) higher and lower in L and XM2 groups. In contrast, no significant differences were observed among control, 265, and 842 groups. At the genus level, the relative abundance of Lactobacillus, Enterobacter, Pediococcus, and Weissella was increased and dominated the native grass fermentation. Compared with the control, the abundance of Lactobacillus was significantly (p < 0.05) higher in L, XM2, and 842 groups, while no significant (p > 0.05) differences were observed between the control and 265 groups. The abundance of Pediococcus was higher than that in other groups. Consequently, the results demonstrated that LAB significantly influenced silage fermentation by reconstructing microbiota, and Lactobacillus was the dominant genus in the native grass silages. Furthermore, the results showed that strain XM2 could effectively improve the silage quality, and it is considered a potential starter for the native grass silage.

Use of Agriculture Byproduct and Swamp Grass as Matterial for Ammoniation of Total Mixed Fiber in Ration on Ballinese Cattle Performance

ABSTRACT. This study was design to evaluated about the using of total mixed fiber ammoniation (TMFA) in ration on Ballinese beef performance. This study used an experimental method with Completely Randomized Design (CRD) consisting of 4 types of treatmentt ration based on TMFA usage level and 3 replications. The treatmentts were R1 = 60% native grass (Control), R2 = 20% TMFA + 40% native grass, R3 = 40% TMFA + 20% native grass, R4 = 60% TMFA. The ration is added with a 40% concentrate to obtain 100% ration. The comparison between forage and concentrate is 60:40. Parameters measured in vivo are performance (ration intake, dry matter intake, crude protein intake, daily body weight gain and ration efficiency). The results showed that treatmentt significantly influenced (P <0.05) on ration intake, dry matter intake, daily body weight gain and ration efficiency, but the treatmentt unsignificantly influenced (P>0.05) on crude protein intake. It can be concluded that the use of 60% TMF ammoniation in the ration shows the best result, that is ration intake 6.89 kg/head/day, dry matter intake 6.25 kg / head / day, daily weight gain 0.47 kg / head / day and efficiency of ration 7.42%.Pemanfaatan Hasil Samping Pertanian dan Rumput Rawa sebagai Bahan Amoniasi Total Mixed Fiber (TMF) dalam Ransum Terhadap Performa Sapi BaliABSTRAK. Penelitian ini mengevaluasi pemanfaatan amoniasi Total Mixed Fiber (TMFA) dalam ransum terhadap performa sapi Bali. Penelitian menggunakan Rancangan Acak Lengkap (RAL) dengan 4 perlakuan dan 3 ulangan. Perlakuan terdiri dari R1= 60% rumput Raja (control), R2 = 20% TMFA + 40% rumput Raja, R3 = 40% TMFA + 20% Rumput Raja, R4 = 60% TMFA. Ransum ditambah 40% konsentrat untuk memperoleh 100% ransum. Perbandingan hijauan dan konsentrat adalah 60:40. Parameter yang diukur adalah konsumsi ransum, konsumsi bahan kering, konsumsi protein kasar, pertambahan bobot badan dan efisiensi ransum. Hasil penelitian menunjukkan bahwa perlakuan memberikan pengaruh yang nyata (P<0.05) terhadap konsumsi ransum, konsumsi bahan kering, pertambahan bobot badan dan efisiensi ransum, namun perlakuan tidak memberi pengaruh yang nyata (P>0.05) terhadap konsumsi protein. Kesimpulan dari penelitian adalah pemakaian amoniasi TMF 60% dalam ransum memberikan hasil terbaik dengan konsumsi ransum 6.89kg/ekor/hari, konsumsi bahan kering 6.25/kg/ekor/hari, pertambahan berat badan 0.47kg/ekor/hari dan efisiensi ransum 7.42%.

Influence of Crested Wheatgrass on Soil Water Repellency in Comparison to Native Grass Mix and Annual Spring Wheat Cropping

Crested wheatgrass (Agropyron cristatum (L.) Gaertn.) is a common introduced grass in the Canadian prairies, but concerns remain about its possible long-term effects on soil quality, and its influence on soil water repellency (SWR) has not been determined. The long-term (24 yr) effects of crested wheatgrass on soil water repellency (SWR) in comparison to seeded native grasses and annual cropping were determined for a clay loam soil in southern Alberta, Canada by measuring SOC concentration and SWR using soil hydrophobicity (SH) and soil water repellency index (RI) methods. The cropping treatments were crested wheat grass, seeded native grass mix, continuous wheat, and wheat-fallow rotation, each with fertilized (nitrogen) and non-fertilized sub-plots, replicated four times. Mean SOC concentration, SH, and RI in samples of surface soil were similar (P > 0.05) for crested wheatgrass and seeded native grass mix; and did not support our hypothesis (seeded native grass mix>crested wheatgrass). Mean SOC was significantly greater for seeded perennial grasses than annual crops by 1.7 to 2 times and SH by 2.1-2.5 times, which supported our hypothesis, but RI was similar among treatments. As expected, nitrogen fertilization significantly increased SOC concentrations, but the effects on SH and RI were undetectable. A strong positive correlation occurred between SOC concentration and SH (r=0.92), but not for RI (r=0.10). Our findings suggested that SWR was similar for crested wheatgrasses and seeded native grass mix. The SWR as measured using SH was greater for seeded perennial grasses than annual cropping, but was similar using RI.