Grassland Science最新文献

In resource-limited agroclimatic environments such as the semiarid and arid regions of the world, mineral undernourishment has been a major limitation to grazing livestock productivity. A soil amendment that has the potential to increase plant mineral uptake and reduce nutrient losses in grassland systems is biochar. The objective of this study was to evaluate the effects of biochar and nitrogen application rates on forage tissue mineral concentrations, soil constituents and leachate quality in a semiarid environment. Treatments were the factorial combination (3 × 3) of three biochar application rates (0, 8.9 and 17.8 Mg/ha) and three N application rates (0, 80 and 120 kg N/ha) arranged in a randomized complete block design experiment with four replications. Treatment means were considered different p ≤ .05. Forage tissue phosphorus concentration was altered by biochar rate × year interaction and a main effect of N rate. Tissue phosphorus concentration was greater at 17.8 Mg biochar/ ha rate than the 0 and 8.9 Mg/ha rates in 2019. For the N rate effect, forage tissue phosphorus concentration was greatest at 0 kg N/ha rate and lowest at 120 kg N/ha rate. The concentration of potassium in the forage was influenced by a biochar rate × N rate interaction. At 120 kg N/ha rate, tissue potassium concentration was greater at 8.9 and 17.8 Mg biochar/ ha rates than the 0 Mg biochar/ha rate. After three years of evaluation, this study demonstrated that biochar used independently or through its interaction with nitrogen fertilizer or year, had a positive influence on the forage minerals phosphorus, potassium, sodium and manganese and the tendency to also positively influenced the forage sulfur and boron concentrations.

Grazing exclusion is a commonly used method to protect and recover herbaceous plants in grasslands, and woody expansion is a common phenomenon in grasslands. However, the effects of grazing exclusion on shrub reproduction remain poorly understood. We investigated the effects of long-term grazing exclusion (0, 8, 30 and 34 years) on reproductive effort of Caragana microphylla in the semi-arid Inner Mongolia Steppe. Our results showed that the 8-year grazing exclusion significantly increased the number of flowers, juvenile pods, mature pods and seed (seed number increased 33.5%) of C. microphylla, however, the 30- to 34-year grazing exclusion significantly decreased seed production (seed number decreased 77.9% and 88.1%) of C. microphylla. The 8-year grazing exclusion had no significant effect on the single flower weight, while the 30- to 34-year grazing exclusion significantly decreased (31.7% and 38.7%) the single flower weight. The grazing exclusion had no significant effect on the seed number per pod. The 8-year grazing exclusion significantly increased sexual allocation (31.6%), and it had no significant effect on sexual allocation efficiency; however, the 30- to 34-year grazing exclusion significantly decreased the sexual allocation (50.4% and 70.4%) and sexual allocation efficiency (55.5% and 60.1%). The 8-year grazing exclusion significantly increased seed weight and seed vigor (seed weight increased 18.7%, seed vigor index increased 28.7%), whereas the 30- to 34-year grazing exclusion decreased these indexes (seed weight decreased 14.2% and 21.0%, seed vigor index decreased 9.1% and 14.7%). These results indicated that the 8-year grazing exclusion increased reproductive effort of C. microphylla, while the 30- to 34-year grazing exclusion sharply decreased the reproductive effort of this shrub species. Our study suggests long-term grazing exclusion limited the expansion of shrubs in grassland by decreasing sexual reproduction and thus inhibiting population growth of shrubs.

This study was conducted to evaluate the physical characteristics of the biomass crop Erianthus arundinaceus as a bedding material for broiler and to compare it with existing bedding materials. Three physical characteristics were evaluated: the water absorbability, the water-holding capacity, and the cushioning property. E. arundinaceus, shredded to five different particle sizes, was compared with sawdust, which is a typical bedding material used worldwide, and three alternatives: recycled paper, rice husks, and bagasse. E. arundinaceus absorbed water 5.0 to 10.2 times its weight, and water absorbability increased with decreasing particle size. E. arundinaceus held water around twice its weight regardless of the particle size. The cushioning property of E. arundinaceus tended to improve with increasing particle size. For each physical property, the total average value of the E. arundinaceus samples was compared with the values of other bedding materials. The water absorbability of E. arundinaceus was significantly higher than that of sawdust, recycled paper, and rice husks (p < .01). The water-holding capacity of E. arundinaceus was significantly higher than those of sawdust, recycled paper, rice husks (p < .01), and bagasse (p < .05). The cushioning property of E. arundinaceus was significantly higher than those of sawdust and recycled paper (p < .01). When E. arundinaceus had an average particle size of less than 2.33 mm, it exceeded sawdust in all physical characteristics, suggesting that E. arundinaceus could replace sawdust as a favored bedding material. Our observations of surface structures revealed that the stem pith of E. arundinaceus has a spongy structure, which may contribute to its high water absorbability and water-holding capacity. Moreover, the outermost layer of the E. arundinaceus stem appears to function like a leaf spring, contributing to the high cushioning property.

Among the cereal crops, whole-crop wheat (Triticum aestivum L.) has become a common silage material in many countries of the world. However, there was little information about its planting methods. In order to obtain a optimum planting and utilization methods, this research investigated the effects of wheat-legume cultures on the fermentation quality and protein degradation of silage. In the present research, wheat, alfalfa (Medicago sativa L.), common vetch (Vicia sativa L.), milk vetch (Astragalus sinicus L.) and smooth vetch (Vicia villosa L.) were planted by monoculture and mixture of wheat with other one, and they were ensiled. There were no significant differences in pH value, lactic acid, acetic acid and butyric acid contents among all silages with wheat, either monoculture or mixture with legume (p > .05). The wheat-legume silages had higher lactic acid and lower butyric acid contents than their corresponding legume silages (p < .05). The non-protein nitrogen and peptide-N contents of wheat silage were significantly lower than those of wheat-legume silages (p < .05). Aminopeptidase and acid proteinase activities of monoculture legume and wheat-legume silages were significantly higher than those of wheat silage (p < .05). Overall, the chemical composition of forage has a greater influence on the fermentation quality and protease activity of silage compared to epiphytic microbes. The wheat-legume cultures could effectively improve the fermentation quality of silage compared to monoculture legumes and wheat.

Elytrigia elongata, a rhizomatous and sparse-type perennial herb of the Triticeae tribe, with stronger drought and salt tolerance, is an important wild genetic resource for wheat variety improvement. However, no precise information about seed germination and biochemical responses of this species to drought, salinity and mixed saline–alkaline stresses is available. Hence, this experiment was conducted to investigate the effects of three abiotic stresses on seed germination and physiological characteristics of two E. elongata accessions. The results showed that drought and mixed saline–alkaline stresses impair seed germination and bud seedling growth of E. elongata. However, seed germination and bud seedling growth were promoted by 50 mmol/L, but inhibited by 100–200 mmol/L salinity treatments. The malondialdehyde (MDA) content was increased and the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in the bud seedlings were significantly increased (p <.05) with increasing osmotic stress from 0 to −0.4 MPa, and salinity and mixed saline–alkaline from 0 to 150 mmol/L, but reduced at −0.75 MPa osmotic stress and 200 mmol/L salinity and mixed saline–alkaline stresses. Under the same salinity and mixed saline–alkaline treatment, the activities of SOD and CAT of EE030 were higher than those of EE024 except in 200 mmol/L salinity treatment; however, the MDA content of EE030 was lower than that of EE024, except in 150 mmol/L salinity treatment. In conclusion, the results of this study demonstrated that E. elongata seeds are more tolerant to salinity stress than to drought and mixed saline–alkaline stresses, and EE030 seed are more tolerant to three abiotic stresses than are the seeds of EE024.

The growth responses of alfalfa (Medicago sativa L.) to azomite, a natural composite earth mineral, were assessed in a greenhouse experiment at Virginia State University, Chesterfield, VA. Alfalfa plants were raised on lime-amended Bojac, Bourne, Emporia and Cullen soils that received 224 kg K/ha in 14 × 16 cm pots. Azomite, a natural composite micronutrients fertilizer, was applied at 0, 200, 400, 600 kg/ha and experiment replicated three times. Over 29 weeks, plant heights and forage biomass were recorded and growth rates calculated at four different cuts. The data were analyzed using the PROC GLIMMIX procedure in SAS 9.3 to test for effects of soil type and azomite rates on the performance of alfalfa. Results indicate that, compared to the control, azomite application increased plant heights, forage biomass and growth rates of alfalfa and more so on Bojac and Bourne than Emporia and Cullen soils. This was most likely due to good water permeability and high nutrient activity in the semi-active Bojac and Bourne compared to the sub-active Emporia and Cullen soils. Plant heights, biomass and growth rates were greatest for plants receiving 200 kg azomite/ha while those on the 600 kg/ha rate performed worse than the control. Alfalfa on lime-amended and K-sufficient soils responded positively to 200 kg azomite/ha, but was impacted negatively at the higher rates.

For revealing the effects of NaCl and NaHCO₃ stress at different pH levels on the absorption and accumulation of main ions in roots, stems and leaves, alfalfa (Medicago sativa L.) plants were cultivated in a nutrient solution system. After NaCl and Na₂HCO₃ imposition, the contents of main ions in roots, stems, leaves and xylem bleeding sap were determined. Under NaCl and Na₂HCO₃ stresses with the same Na⁺ concentration, Na₂HCO₃ stress showed severer inhibitory effects on alfalfa growth in contrast to NaCl stress at different pH levels. Under NaCl stresses at different pH levels, alfalfa plants showed much lower Na⁺ accumulation and Na⁺ delivery rate in root bleeding sap than that under NaHCO₃ stress. The plants of NaHCO₃ stress showed a severer inhibition in K⁺ accumulation, lower K⁺ delivery rate, but higher Na⁺/K⁺ ratios than the plants of NaCl stress. NaHCO₃ stress increased Ca²⁺ and Mg²⁺ accumulation in alfalfa roots, decreased Ca²⁺ and Mg²⁺ delivery rates and increased leaf Na⁺/Ca²⁺ ratio and Na⁺/Mg²⁺ ratio. Both NaCl and NaHCO₃ stresses decreased the contents of Fe³⁺ and Mn²⁺ in roots, but increased the contents of Cu²⁺ in roots, stems and leaves, the content of Mn²⁺ in stems and leaf Zn²⁺ content in alfalfa plants. However, the contents of Fe³⁺ and Mn²⁺ in roots and stem Mn²⁺ content in the NaHCO₃ treatments were much lower than those in the NaCl treatments. In conclusion, NaHCO₃ stress produced severer injury and induced severer Na⁺ toxicity to alfalfa plants than NaCl stress. The effects of NaHCO₃ stress and NaCl stress on the absorption and accumulation of trophic ions were different. Under NaCl stress, the increased pH did not alter Na⁺ absorption and accumulation in plants, but altered the distribution of some nutrient ions in roots, stems and leaves.

Algeria is a country rich in phytogenetic resources, especially those of pastoral and forage interest. Unfortunately, few studies have been conducted to characterize Algerian local ecotypes. Recently, advances in next-generation sequencing technologies have allowed for robust genotyping by sequencing (GBS) for single nucleotide polymorphism (SNP) discovery, making the characterization of plant relationships with complex and unsequenced genomes more feasible. In the present study, we investigate the genetic diversity of cocksfoot and tall fescue ecotypes from different regions in Algeria, using the SNP variation supplied by a GBS analysis. We compared ecotypes to two common cultivars of both species. A total of 787 SNP markers for cocksfoot and 743 for tall fescue were obtained, and the diversity analysis revealed that 88% and 86% of overall variation in cocksfoot and tall fescue, respectively, were within populations rather than among them. Genetic structure analysis revealed a moderate genetic differentiation among accessions with a mean F_st value of 0.127 for cocksfoot and 0.140 for tall fescue, with high gene flow (Nm_Orchardgrass = 1.723, Nm_{Tall fescue} = 1.535) and no significant isolation-by-distance pattern. A unweighted pair group method with arithmetic mean tree (UPGMA) and principal component analysis revealed the genetic distinctness of populations from cultivars for each species. The flow cytometry analysis confirmed the tetraploid level of cocksfoot and the hexaploid level of all tall fescue entries but one. Although the cocksfoot populations were distinct from the cultivars, the Ruines de djemila population had the broadest base and showed the closest relative relationship to the two cultivars. Similarly, the FE5729 tall fescue population showed the closest relationship to the two tall fescue cultivars.

This paper demonstrates a non-destructive method for measuring the moisture content of silage in wrapped round bales (WRBs) via microwave signals using a microstrip transmission line (MSTL) sensor and vector network analyzer under outdoor conditions. We analyzed the relationships between the amplitude changes (Δα) and phase shifts (Δφ) of the microwave-transmitted signals from the WRB surfaces without tearing their films. The press MSTL method was strongly suggested over the touch MSTL method for the non-destructive measurement of WRB qualities. We also obtained strongly negative and significant correlations between the slopes of the linear regression lines (Δφ–Δα ratios) and moisture contents for frequencies in the range of 3.6–6.2 GHz. Thus, in this frequency zone, the press MSTL method can be effectively used to determine the moisture content of silage in WRBs.

In southwestern Japan, palisadegrass (Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster) is used as annual summer grass with fertilizer application. In this system, the risk of a poisonous nitrate nitrogen concentration in grass is high. Nevertheless, no report describes a study of nitrate nitrogen in palisadegrass as annual summer grass. Therefore, we clarified the effects of chemical fertilizer to nitrate nitrogen concentration in palisadegrass cultivated as annual summer grass for two years. Treatments were factorial combinations of three basal fertilizer applications (0, 100 or 200 kg N, P₂O₅, K₂O/ha) and two additional fertilizer applications (0 or 100 kg N, P₂O₅, K₂O/ha) in a randomized complete block design with five replicates. Results well demonstrated that nitrate nitrogen concentrations in palisadegrass increase with fertilizer application, especially with fertilizer added after decreased growth of palisadegrass caused by lower temperatures. Harvest of palisadegrass after additional fertilizer application requires awareness of its nitrate nitrogen content.