Grassland Science最新文献

Paspalum atratum is a tropical grass with potential to contribute to forage availability in areas dominated by waterlogged acidic soils. However, little is known of the interactive effect of N fertilization and stage of harvest on its nutritive value. Therefore, the objectives of this study were to evaluate the interactive effects of N fertilization and harvesting stage on herbage characteristics and nutritive value of P. atratum (Cv. Ubon) and to determine the optimum N fertilization rate at each stage of regrowth. P. atratum seedlings were planted in 18,631-cm³ plastic pots containing growth media amended with 0, 25, 50, and 75 kg N/ha. Forage was harvested after 6- and 12-weeks regrowth. Nitrogen fertilizer had a significant effect (p < 0.05) on herbage yield, sward height, crude protein yield, crude protein concentration, and 12- and 24-h in vitro ruminal organic matter digestibility (IVOMD). P. atratum fertilized with 50 kg N/ha produced the highest dry matter yield (1,133 kg DM/ha) at 12-week regrowth. Crude protein (CP) was highest (133 g/kg DM) in 6-week regrowth forage that received 50 kg N/ha. IVOMD at 12 and 24 h of incubation was highest in 6-week regrowth forage amended with 0 and 50 kg N/ha, respectively. Herbage characteristics and nutritive value of P. atratum showed a quadratic response to N fertilization at both regrowth stages. Response surface optimization indicated that N fertilizer application rates of 56.0 and 52.3 kg N/ha maximized P. atratum herbage yield, CP content, and 12-h IVOMD at 6- and 12-week regrowth, respectively. It was, therefore, concluded that the herbage yield and nutritive value of 6- and 12-week regrowth P. atratum is optimized with N fertilizer rates of 56.0 and 52.3 kg N/ha, respectively.

We proposed a mixture of animal husbandry and fruit tree industry: livestock grazing under an orchard layer to increase agricultural productivity per area and reduce the costs of feed, fertilizer, and weed control. Lambs were reared in-house for 1 month and then moved to a pear orchard for 1 month of grazing. We recorded the changes in body weight, blood properties (e.g., albumin, cholinesterase, and nonesterified fatty acids), and parasitic infection to compare the in-housed lambs with the grazing lambs in the orchard. Additionally, we conducted field investigations for changes in vegetation and soil properties before and after grazing. Grazing caused significant increases in body weight, helminth eggs in dung, and soil water retention, and significant decreases in plant biomass, grass digestibility, and soil hardness. In contrast, the nutritional values of the feed, blood properties, and soil chemical properties (e.g., pH, P, N, and C) were not significantly changed after grazing. These results highlighted that the fruit tree industry combined with livestock production would be an acceptable management approach for Japanese agriculture, although further case studies are required.

Lactic acid bacteria (LAB) naturally present on forage crops are responsible for the silage fermentation quality. However, there are few reports on the factors affecting the distribution of epiphytic LAB on the crops. Therefore, the influences of spraying sugars, growth temperatures and nitrogen application levels on the amounts and species of LAB on Italian ryegrass (Lolium multiflorum) were evaluated in this study. Spraying xylose, fructose, glucose, sucrose and galactose significantly increased (p < 0.05) the population sizes and species of LAB on Italian ryegrass. Spraying sucrose made Italian ryegrass epiphyte the most LAB. As for the effect of temperatures, Leuconostoc mesenteroides dominated on Italian ryegrass grown at 10 and 15°C, while Lactobacillus plantarum dominated at 20°C, and Weissella paramesenteroides dominated at 25°. The population sizes and species of LAB on Italian ryegrass were the most at 15°C. When N (0, 35, 70, 105, 140 or 175 kg/ha) was applied to Italian ryegrass, LAB population sizes and species were the most at N 35 kg/ha (p < 0.05). Lactobacillus plantarum was detected in all the treatments of Italian ryegrass except the growth temperatures of 10 and 25°C.

Grassland ecosystem functions are affected to a large extent by grazing activities. However, owing to the associated spatial heterogeneity, the influence of grazing intensity on grassland ecosystem biomass and the underlying mechanisms remains unclear. In this study, we analyzed data from 335 field data to clarify the response of grassland ecosystem biomass to grazing activities in China. We established that the size of the priming effect of grazing activities on total biomass, aboveground biomass and belowground biomass is −0.25 ± 0.09 (95% confidence interval [CI]: −0.42 to −0.07), −0.47 ± 0.05 (−0.57 to −0.37) and −0.18 ± 0.04 (−0.29 to −0.10), respectively. Grazing was found to significantly reduce both the biomass of grassland ecosystems (p < 0.01) and the average effect value of temperate, meadow and desert steppes with respect to vegetation type (p < 0.05). The descending order of the effects of grazing intensity on biomass was heavy, light and moderate, with light and heavy grazing significantly reducing grassland biomass (p < 0.01), whereas moderate grazing made a comparatively smaller contribution. Furthermore, explained heterogeneity analysis revealed that soil water content was positively associated with the effect size, and path analysis indicated that soil bulk density, precipitation and average annual temperature have a significant direct influence on the effect value (p < 0.05). Given the minimal impact of moderate grazing on biomass, we suggest that stocking at moderate densities could represent an effective approach for restoring degraded grasslands. Moreover, increasing soil water content could contribute to effectively reducing grazing-related damage to the biomass of grassland ecosystems.

The present study was aimed to investigate the protective role of silicon (Si) from salt-induced damages in alfalfa. Seedlings were treated with 200 mM NaCl plus three silicon levels (0, 0.75 and 1.5 mM) for 1 week. We observed that salt stress impacted plant growth remarkably, including height, root length, stem and leave weight, aboveground biomass and total biomass, chlorophyll a (chl a), chlorophyll b (chl b), total chlorophyll (total chl), chlorophyll fluorescence, K concentration and K/Na ratio. Consequently, electrolyte leakage (EL), superoxide dismutase (SOD) activity, Na concentration, proline, malondialdehyde (MDA), soluble sugar (SS) and soluble protein (SP) content were found to be raised significantly. After exogenously applying Si under salt stress, the EL, MDA, proline and Na content, except SOD activity, were observed to be dropped. Meanwhile, the chl a, chl b, and total chl and SS content, and chlorophyll fluorescence were found to be elevated. In terms of Si concentration, we found that the protective effects of Si were considerably better at lower concentration (0.75 mM) than higher (1.5 mM) one. Collectively, our results suggested that Si alleviate salt-induced damage and promote alfalfa growth by changing physiological characteristics.

Elymus nutans is an important forage and ecological restoration herbage in the Qinghai-Tibet Plateau, which is an allohexaploid species with the StStYYHH genomes. Previous studies suggested that Pseudoroegneria is the maternal genome donor to E. nutans, but exactly which Pseudoroegneria species is still unknown. Here, we report the complete chloroplast (cp) genome sequence of two E. nutans from the Qinghai-Tibet and five Pseudoroegneria species. The cp genomes of the seven samples ranged narrowly from 134,924 bp to 135,142 bp in size, comprising inverted repeats of 20,808–20,814 bp, single-copy regions of 80,536–80,754 bp (LSC) and 12,762–12,772 bp (SSC). It encoded 111 total genes, of which 78 protein-coding genes, 29 tRNA genes, and four rRNA genes. A comparative cp genome analysis and characteristic junctions of St-containing species revealed that the gene content and organization were conserved, but differences were still found in sequence variation and border regions. Further, the Bayesian inference (BI) phylogenetic tree using the whole chloroplast genome sequence demonstrated that P. cognata might be the most likely St genome donor of E. nutans in the Qinghai-Tibet Plateau, followed by P. strigosa. However, whether E. nutans has other maternal genomes still needs further research.

This study was conducted to assess the effect of different additives on the fermentation characteristics, in vitro digestibility and aerobic stability of fermented total mixed ration (FTMR) prepared with local feed resources in Tibet, China. Additives added to FTMR were Lactobacillus buchneri (1 × 10⁶ cfu/g fresh weight (FW)), acetic acid (0.3% FW), propionic acid (0.4% FW), 1,2-propanediol and 1-propanol (0.5% FW). FTMR were opened after 90 days and subjected to a 14-d aerobic stability test. The results showed that L. buchneri, 1,2-propanediol and 1-propanol increased (P < 0.05) pH values and acetic acid concentrations and decreased (P < 0.05) lactic acid concentrations in FTMR. Adding acetic acid decreased (P < 0.05) lactic/acetic acid ratio. FTMR treated with propionic acid had higher (P < 0.05) lactic acid, propionic acid and DM recovery compared with the other treatments. Treating FTMR with acetic acid, 1,2-propanediol and 1-propanol decreased (P < 0.05) yeast counts. The in vitro potential gas production tended to be lower in L. buchneri-treated silage than other silages. During aerobic exposure, FTMR treated with propionic acid spoiled first, with marked pH increase and lactic acid decrease from days 9 to 14. Treatment with L. buchneri, acetic acid, 1,2-propanediol and 1-propanol markedly improved the aerobic stability, as indicated by nearly unchanged pH and lactic acid concentrations. The results suggest that L. buchneri, acetic acid, 1,2-propanediol and 1-propanol did not adversely affect the in vitro digestibility and could be effective additives for enhancing the aerobic stability of FTMR prepared on Tibetan plateau.

Leymus chinensis (Trin.) Tzvel. and Stipa grandis P. Smirn. are dominant species in grassland on the typical steppe of Inner Mongolia. Long-term overgrazing, which is considered to represent multiple stresses, reduces the growth of L. chinensis and S. grandis. To gain an understanding of the molecular mechanisms underlying the responses of these plants to overgrazing, we explored the gene expression profiles of L. chinensis and S. grandis to discover the common features of these dominant plants in response to overgrazing. Using the Illumina RNA-Seq platform, two sequencing libraries prepared from non-grazed (Lc-NG) and overgrazed samples (Lc-OG) of L. chinensis were sequenced. Using Trinity software assembly, 129,087 unigenes with a mean length of 693 bp and an N50 of 1,093 bp were obtained by combining the Lc-NG and Lc-OG data. By comparing differentially expressed genes (DEGs) of L. chinensis with those of S. grandis, we identified 16 Kyoto Encyclopedia of Genes and Genomes pathways and 15 Gene Ontology terms that were significantly enriched with DEGs in both species. Most of these DEG-enriched pathways, for example, phenylpropanoid biosynthesis and flavonoid biosynthesis, were related to stress responses. The results suggest that stress plays an important role in plants’ responsiveness to long-term overgrazing and associated reductions in plant growth. The DEGs shared by these two species will be valuable for further research on key genes and molecular mechanisms involved in plants’ adaptation to overgrazing and associated stresses.

DNA markers for the genes for flowering time (Ma1/SbPRR37, Ma2/SbEHD1, Ma3/SbPhyB, Ma4/SbCO, Ma5/SbPhyC, and Ma6/SbGHD7), semi-dwarfism (dw1 and dw2), fertility restorers (Rf1, Rf2, Rf5, and partial A1 mitochondrial sequence) and cytoplasmic–nuclear male sterile (CMS), and brown midrib (bmr-2, bmr-6, and bmr-18) were developed in this study. These markers and previously published DNA markers for dw3 were used to analyze sorghum cultivars used in breeding programs in Japan and traditional landraces from the National Institute of Agricultural Sciences (NIAS) sorghum core collection. Agronomically useful mutations were effectively detected in the cultivars by the DNA markers. Most of the mutation types for flowering and semi-dwarfism were detected in sorghum cultivars, but only the dominant-type allele of SbEHD1 and SbPhyB for flowering was detected in the NIAS collection. Fertility restorers and CMS were rarely detected in NIAS collection. Agronomically useful traits such as early flowering and semi-dwarfism became combined in the modern cultivars by phenotypic evaluation for the adaptation of harvesting to the temperate zones. Fertility restorers and CMS were introduced for F₁ hybrid breeding. These phenotypes are often recessive, so information on the alleles responsible would be helpful for sorghum breeding. We expect these DNA markers to facilitate and improve the efficiency of F₁ sorghum breeding programs.

The objective of this study was to quantify the economic potential of grass-based milk production strategies with limited use of concentrated feed in the pre-alpine region. We monitored 36 family dairy farms from the pre-alpine region of Switzerland divided in three study groups following one of three defined, voluntarily adopted production strategies: Partial grazing and barn feeding with freshly cut forages, supplementing <500 kg (GBF) and 1,200 kg (GBFplus) of concentrated feed, respectively, and practicing full grazing (FG), supplementing <100 kg of concentrated feed per cow per year. For three years (2014–2016), data were collected on the farms, and experience and ideas were exchanged and evaluated in a participatory process together with local extension services and researchers. Economic success indicators such as cost price and return to labor from each study group were compared with structurally similar control groups derived from the Swiss Farm Accountancy Data Network after completing an interactive standardization process, which largely balanced farm-specific features in the study groups. Compared with the control groups, the cost price (Swiss francs [CHF] per 100 kg milk) of GBF, GBFplus, and FG was significantly reduced by 20%, 20%, and 26%, respectively. Return to labor (CHF per hour) was significantly higher than in the control group for GBF (20.60 versus. 13.80), GBFplus (19.70 versus. 10.20), and FG (29.30 versus. 19.20). The comparison between the study groups also showed that lower milk revenues due to a lower use of concentrate could be economically compensated by a better input efficiency. A consistent implementation of the production strategy as well as personal qualities in terms of cost management seems to play a decisive role.