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The aim of this study was to investigate the influence of precipitation level on the characteristics of soil water-stable aggregates (WSA), fractal dimension (D), mean weight diameter (MWD), and geometric mean diameter (GMD) in steppe grasslands. More specifically, the study determined the effects of precipitation level (50%, 100%, and 150% rainfall) on soil particle size in the Yunwu Mountain of Guyuan City, Ningxia, China. 1) The proportion of > 3 mm WSA in the 0 –10 cm soil layer was greater under 100% rainfall than under either 50% or 150% rainfall (P < 0.05). However, rainfall had no significant effect on the size of particles in the 10 – 20 cm soil layer. The > 3 mm and < 0.25 mm WSA in the 20 – 30 cm soil layers under 100% rainfall were significantly different from those under 50% and 150% rainfall (P < 0.05). 2) In the 0 – 10 cm and 10 – 20 cm soil layers, the D, MWD, and GMD were lower under 100% rainfall than under 50% or 150% rainfall, and in the 20 – 30 cm soil layer, D, MWD, and GMD decreased with increasing rainfall. 3) The soil fractal dimension was positively correlated with > 3 mm WSA (r = 0.43, P < 0.01) and negatively correlated with < 0.25 mm WSA (r = 0.49, P < 0.01). These results indicate that the stability of > 3 mm and < 0.25 mm WSA was sensitive to rainfall and that changes in rainfall will elevate D, MWD, and GMD.
Wetlands is important for the carbon balance of the arid area ecosystem to clarify the characteristics and influencing factors of active organic carbon in wetland soil. In order to investigate the influence of land use type on total soil organic carbon contents, soil organic carbon (SOC), readily organic carbon (ROC), and dissolved organic carbon (DOC) contents, as well as the organic carbon density, of Chaiwopu Lake wetland soil were determined. Land use type affected SOC content, as follows: farmland reclaimed before 1983 [(22.97 ± 0.85) g·kg–1] > natural farmland [(21.83 ± 1.97) g·kg–1] > wetland farm belt [(16.74 ± 6.52) g·kg–1] > lake wetland [(11.98 ± 3.67) g·kg–1] > salinized wetland [(9.86 ± 3.31) g·kg–1].There was a significant difference in ROC content between wetland and farmland(P < 0.05).Furthermore, the DOC contents of the farmland (reclaimed after 1983) soil was highest and significantly different (P < 0.05)from that of wetland-farmland transition zone and natural farmland soils respectively. The SOC, ROC, and DOC contents decreased with increasing depth (0 – 40 cm) in the lake wetland and wetland-farmland transition zone soils, whereas the opposite trend was observed for the DOC of the salinized wetland soil. The active organic carbon contents of farmland soil did not change significantly with increasing soil depth. The organic carbon density of Chaiwopu Lake wetland soil under five different land use types was higher than the national average. Soil pH was negatively correlated with organic carbon accumulation (P < 0.01), and soil conductivity was positively correlated with both SOC and ROC contents (P < 0.01). These results revealed that the active organic carbon components of arid-area wetland soil are affected by land use type and that the active organic carbon content of farmland soil after natural or wetland transformation is higher than that of wetland soil.
The study was to determine the effects of different grazing intensities on plant community species composition, importance values, community characteristics, and diversity of mountain meadow grasslands in the middle section of the northern slope of the Tianshan Mountains. Three kinds of grazing intensity were used, including no grazing (CK), light grazing (LG), and heavy grazing (HG). The results showed that the species composition was different under different grazing intensities. With increased grazing intensity, the importance value of high-quality gramineous plants and leguminous plants decreased, whereas that of Achnatherum inebrians and forbs increased. Margalef index, Shannon-Wiener index, Simpson index, and Pielou index for the plant community increased after an initial decrease but were the highest under the HG treatment. Plant community height, community coverage, community density, and aboveground and belowground biomass were significantly reduced (P < 0.05), and plant roots were primarily distributed in the 0–10 cm soil layer. Plant community richness, diversity, and community characteristics were negatively correlated. In conclusion, the increase in grazing intensity led to changes in species composition of plant communities in mountain meadows. The HG treatment increased the advantages of A. inebrians and forbs, and the plant community richness and diversity index were the highest; however, the height of the plant community was significantly reduced, as was density, coverage, and biomass.
In recent years, heavy metal contamination of soils has worsened. For example, the release of chromium into the environment by the chemical industry is accelerating, and as such, Cr has become one of the main heavy metal ions causing environmental pollution. The contamination of soils by heavy metals is one of the main abiotic stressors that affects plant growth and development, and severe cases of heavy metal stress can even kill plants entirely. In addition, such pollution also represents a potential threat to human food safety. The effects of Cr depends on ionic charge, and Cr pollution mainly affects plant processes by inhibiting seed germination, blocking plant growth and development, and damaging cell structure. In this review, the effects of Cr stress on plant growth, physiology, biochemistry, and molecular regulation are summarized, thereby providing valuable insight into the selection of plants for remediating chromium-polluted soil, breeding of low-toxicity Cr-tolerant crops, and analyzing the mechanism of plant resistance to heavy metal stress.
Disease is one of the primary factors limiting the production of Vicia faba. This paper reviews recent progress in studies of major fungal diseases in broad bean, including investigations of varieties, distribution, effects on plant growth, physiology and biochemistry, genetic disease resistance, disease epidemiology, and prevention and control technologies. It also discusses research prospects in the occurrence, prevention, and control of broad bean diseases, in order to establish a theoretical basis for disease control. Fungal diseases affect plants in a variety of ways, including elevation of transpiration, intracellular Na+ levels, and phenol and amino acid contents, which negatively affect chloroplast membranes and produce toxins. Faba bean varieties differ in their disease resistance, and disease occurrence is closely related to levels of tannins, amino acids, and the expression of disease resistance-related genes, such as members of the Af family. Seeds, diseased plants were the initial sources of infestation; conditions such as highly moist and warm soil or air promote disease occurrence and epidemic. Therefore, controlling the field environment is also very important to prevent diseases. It is possible to effectively prevent and control diseases through valuable agricultural practices, such as the cultivation of disease-resistant varieties, crop rotation, intercropping, biological control measures (e.g., application of Pseudomonas fluorescens), red light treatment, and the application of chemical pesticides (e.g., zineb and triadimefon).
Most plants of the genus Hordeum form excellent pastures and are important food crops. It is well known that endophytic fungi live inside the plant. In this paper, all endophytic fungi belonging to the genus Epichloë were investigated. Endophytes inhabit above-ground plant tissues without causing disease symptoms. They can improve the host's ability to deal with biotic stress and abiotic stress. It is of great ecological and economic value to study the endophytic fungi symbionts of Hordeum. This article reviews the research progress in the study of the symbiotic endophytic fungi in Hordeum plants in China and abroad. It is believed that the reasons affecting the content of alkaloids and rate of infection are not clear, and the utilization of symbiosis is not sufficient. This paper aims to provide guidance for the research and utilization of the symbiosis for the future.
This study focused on 8-year old plantings in the coal gangue at Dahe Coal Mine in Liupanshui, Guizhou Province. We analyzed the dynamic changes in nutrient elements (N, P, and K) in the roots, stems, and leaves of Vetiveria zizanioides (May to October) and the relationship between Pearson’s correlation and allometric growth. Based on the annual mean value, the N and P content in the organs of V. zizanioides was leaf > stem > root, whereas the K content was stem > leaf > root. The N and K content in the roots and stems first increased and then decreased, whereas the N, P, and K content in the leaves decreased and the P content in the roots increased with the growth period. Pearson’s correlation analysis showed a significant positive correlation between N and K in the roots , P and K , and N and K in the stems (P < 0.05), and the correlation coefficients were 0.585, 0.590, and 0.692, respectively. Significant positive correlations were observed among N, P, and K content in the leaves (P < 0.01) and the correlation coefficients were 0.712, 0.899, and 0.849, respectively. The allometric relationship of nutrient elements in the different organs showed no significant difference among N, P, and K content in the roots. However, the N, P, and K content in the stems and leaves showed highly significant allometric relationships. This study may have partly revealed the regulation of nutrient use by V. zizanioides in the gangue matrix and the regulatory mechanism in the nutrient-poor habitat at different growth stages by the dynamic changes in N, P, and K in different organs of V. zizanioides. Our results provide a theoretical basis for the utilization of V. zizanioides for vegetation restoration of coal gangue.
The objective of this research was to investigate the physiological characteristics and cold resistance of wild Poa during the overwintering period, and to analyze the physiological adaptability of Poa under chilling stress in alpine regions in northern Tibet. The experimental materials included wild Poa litwinowiana, P. attenuata, P. crymophila, and a cultivated variety (Poa crymophila ‘Qinghai’). The soluble sugar (SS), soluble protein (SP), malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) activities were measured in the field at an altitude of 4 512 m. The results showed that the overwintering rate of the 4 tested materials all reached 80%, and the overwintering rate of wild Poa was significantly higher (P < 0.05) than that of the cultivated variety. The contents of SS and MDA and the relative activities of SOD and CAT increased overall at first and then decreased from late autumn (September) until turning green the following year (May), reaching its maximum during the coldest month (January). The SP contents increased during the entire overwintering period. SOD and CAT of P. litwinowiana and P. attenuata in the coldest month were significantly higher (P < 0.05) than that of the others. Through the membership function analysis, it was found that the order of cold-resistance of the Poa tested was as follows: P. litwinowiana > P. attenuata > P. crymophila (wild varieties) > Poa crymophila ‘Qinghai’ (cultivated variety).
Kentucky bluegrass (Poa pratensis) is an important cool-season turf grass, which can remain green in wet and cool areas year-round. However, it is difficult for it to survive in summer in Shanghai. In this study, eight Kentucky bluegrass cultivars with different summer stress tolerance were processed in the field under four stress treatments: drought / bright light, drought / shade, water / bright light, and water / shade. The results showed that leaf water content declined with the decrease in soil water content. When the leaf water content was less than 70%, the plants displayed obvious injuries. Drought caused more damage to plants than did intense light / UV, and intense light / UV exposure in dry conditions aggravated the damage to plants. There was no significant difference in drought and intense light / UV tolerance among the grass types, and these types could be maintained in good condition if given sufficient supply of water. Therefore, it was speculated that drought was the main abiotic stress factor that caused the difficulty in growing Kentucky bluegrass over the summer in Shanghai, and the reason for the difference in summer tolerance among the types might have been caused by biological stress (such as rust).
To study the turf quality characteristics and popularization value of Huanan centipede grass (Eremochloa ophiuroides ‘Huanan’) with wild centipede grass and American Common centipede grass as controls, the turf characteristics (coverage, density, uniformity, color, and texture), adaptability (turf-establishment time, green period, resistance, and overwintering and over-summering rate), and comprehensive quality of the three centipede grasses were observed and evaluated during the 3 experimental years. The results showed that all three centipede grasses grew normally in Guangzhou. Compared with the wild centipede grass and the American Common centipede grass, ‘Huanan’ centipede grass displayed advantages in terms of texture and green period. The leaf width of Huanan centipede grass was 3.24 mm, which was 17.97% and 21.36% narrower than the 3.95 mm of the wild centipede grass and 4.12 mm of the American Common centipede grass, respectively. The green period was 336 days, which was 29 and 32 days longer than that of the wild centipede grass and American Common centipede grass, respectively. The turf quality was evaluated and ranked as Huanan > Wild > American Common, indicating that Huanan centipede grass could be used as a good turf grass in South China and similar climatic regions.
In this study, we systematically analyzed seed germination, seedling growth, and chlorophyll fluorescence parameters of Cleistogenes songorica under different doses of 12C6+ heavy ion irradiation and space mutation. The results showed that 12C6+ heavy ion irradiation inhibited the seed germination and seedling growth of C. songorica. The germination percentage, germination index, radicle length, and biomass were the lowest under the 300 Gy irradiation dose. Space mutation inhibited the seed germination of C. songorica but increased the biomass and plant height of the seedlings. 12C6+ heavy ion irradiation and space mutation affected the maximum photosynthesis ability of seedlings and reduced the rate of electron transfer. The present study provided a basis for the effective application of 12C6+ heavy ion irradiation and space technology to the mutagenesis breeding of C. songorica.
The effect of exogenous melatonin on the germination and the morphological and physiological characteristics of the seedling stage of Bromus catharticus ‘Chuanxi’ (rescuegrass) under salt stress was investigated in the current study, providing a theoretical basis for improving the salt-resistance of ‘Chuanxi’. The experimental results indicated that the highest germination rate and salt resistance were obtained when 100 μmol·L–1 melatonin was added. In this case, the germination rate, germination energy, soluble protein, free proline (Pro) content, and peroxidase (POD) activity of ‘Chuanxi’ seedlings increased by 22.39%, 58.83%, 21.78%, 121.44%, and 81.02%, respectively. The malondialdehyde (MDA) content decreased by 45.43% compared to the salt stress treatment. The results suggested that exogenous melatonin (MT) can improve the antioxidant enzyme activity and decrease the membrane peroxidation, thereby improving the adaptability of ‘Chuanxi’ under salt stress. The research results provided technical improvements for the cultivation and utilization of the ‘Chuanxi’ in the saline area.
To investigate the relationship between forage yield, nutritional quality of clover, growth time, and ≥ 0 ℃ accumulated temperature, Trifolium repens ‘Kopu Ⅱ’ and Trifolium pretense ‘Sensation’ were used. The correlation between growth time and ≥ 0 ℃ accumulated temperature, and forage yield, neutral detergent fiber,, acid detergent fiber, crude protein, ether extract, water soluble carbohydrate, and ash content through simulated rational grazing field experiments were analyzed. The results showed that growth time and ≥ 0 ℃ accumulated temperature of clover were significantly correlated with forage yield and each nutrient index (P < 0.05). Accordingly, forage yield and nutritional quality of clover were predicted based on the growth time and ≥ 0 ℃ accumulated temperature. The accuracy of these prediction models was high and they could provide a scientific basis for the cultivation, management, and harvest of clover in the Loess Plateau.
This study aimed to determine the effect of alfalfa mosaic disease on the photosynthetic performance, growth, and forage quality of alfalfa and to evaluate the losses caused by the disease. In comparison to healthy plants, the chlorophyll content, net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) of leaves from infected plants were reduced by 35.16%, 93.3%, 65.4%, and 40%, respectively, whereas intercellular CO2 concentration (Ci) was increased by 42.52%. Plant biomass, height, leaf width, and leaf length were also reduced by infection (P < 0.01), by 29.50%, 28.74%, 39.84%, 26.27%, respectively, and the correlation coefficients of disease severity with them were –0.85, 0.953, –0.98, –0.87, respectively. Alfalfa mosaic disease also reduced crude protein and crude fat contents (by 42.70% and 70.82%, respectively) and increased acid detergent fiber and neutral detergent fiber contents (by 49.29% and 23.99%, respectively). Growth, forage quality, and photosynthesis indicators exhibited significant or significant correlations with disease severity. Growth, quality indicators exhibited significant or significant correlations with photosynthesis indicators (chlorophyll content, Pn, Tr, Ci). This indicates that alfalfa mosaic disease affects photosynthesis, which in turn affects alfalfa growth and forage quality.
Spring common vetch (Vicia sativa) is a forage legume and green manure crop with high yield and quality. Nitrogen, phosphorus, and potassium fertilizers have important effects on its yield and quality. Therefore, understanding the relationship between fertilization and the growth and development of common vetch is critical for the establishment and sustainable development of alpine meadow in this region. This paper summarizes the responses of spring common vetch to nitrogen, phosphorus, and potassium fertilizers over the past 30 years worldwide. According to the analyses, application of nitrogen, phosphorus, and potassium fertilizer separately or in combination reduced respiration by 24.5%～69.5%, increased the content of N, P, and K in plants by 1.7%～69.7%, promoted nodule growth, and increased biological nitrogen fixation. Therefore, the yield of the product increased by 4.7%～110.3% and the content of crude protein, crude fat, and soluble sugar increased by 0.9%～51.5%. Fertilization plays an important role in improving the performance and quality of spring common vetch. Future research should focus on clarifying the physiological and biochemical mechanisms of various fertilizer elements and optimizing management of different fertilizers to improve the yield and quality of spring common vetch.
To determine the most appropriate nitrogen application time and harvest time for Leymus chinensis seed production in Heilongjiang Province, we studied the effects of different nitrogen application times (fertilized in the preceding autumn, current spring, or fertilized both in the preceding autumn and current spring) and harvest times (21, 24, 27, 30, 33, 36, 39, 42, or 45 days after the full flowering stage) on seed yield, impact factors (heading rate and seed setting), and seed quality (germination rate and thousand seed weight) of L. chinensis ‘Nongjing No. 4’. The results showed that nitrogen could significantly increase seed yield (P < 0.05) of L. chinensis. Additionally, nitrogen application, except fertilization during the current spring, could significantly increase heading rate and seed setting rate (P < 0.05). The heading rate, seed setting rate, and seed yield were the highest when nitrogen was applied during the preceding autumn and current spring compared to the other treatments. With the delay in harvest time, the seed yield, germination rate, and thousand seed weight first increased and then decreased. The seed yield, germination rate, and thousand seed weight harvested 33 days after the full flowering stage were all close to the maximum value. We suggest that the most appropriate nitrogen application time for L. chinensis was the preceding autumn and current spring and the optimal harvest time was 33 days after the full flowering stage in Heilongjiang Province.
Appropriate irrigation volume and density are the key factors for managing pasture. A pot experiment was carried out to determine the effect of three irrigation volumes (35%～40%, 60%～65%, and 75%～80% of saturated soil moisture) and three densities (20, 35, and 50 plants per pot) on growth performance and above/underground biomass of Elymus nutans. The results of this study showed that there was an increasing trend in the aboveground and underground biomass, tillers per plant, and root volume with increasing irrigation volume. The plant height and the ratio of aboveground biomass to underground biomass first increased and then decreased as irrigation volume increased. With the increase of plant density, tillers per plant and aboveground biomass per plant decreased, but the density had no significant effect on aboveground and underground biomass, plant height, root volume, and the ratio of aboveground biomass to underground biomass. The interaction of irrigation volume and plant density only had a significant (P < 0.05) effect on the biomass of individual plants but had no significant effect on the biomass of the plant population. These results will provide useful information for the establishment and management of E. nutans pastures in alpine pastoral areas of China.
To clarify the relationshiops of water and phosphorus with root growth and morphology could provide the basis for water and fertilizer management during the grassland construction of switchgrass (Panicum virgatum) in dry region. A pot experiment was conducted using split-plot design, and the main plot was soil water regimes [high water: 80% FC (field capacity) and low water: 40% FC], while the subplot was phosphorus (P) treatments (0, 0.05 and 0.1 g P2O5 per kg dry soil). The shoot and root biomass production, and root morphology of switchgrass under different treatments were measured at the end of the growth period. Results showed that regardless of P application, switchgrass had significantly (P < 0.05) higher shoot and root biomass, total root length (TRL), root surface area (RSA) and root average diameter, but lower water use efficiency and specific root length under high soil water regime than under low soil water regime. Under high soil water regime, P application significantly increased shoot and root biomass production, and TRL and RSA. Under low soil water regime, P application significantly increased water use efficiency of switchgrass, and 0.1 g P2O5 per kg dry soil application significantly promoted TRL, RSA and root growth in 0～0.5 mm diameter. All these indicated that under low soil water conditions, rational P application could improve the root absorptive capacity and drought adaptability of switchgrass in the establishment year.
The study was to clarify the changes in seed moisture content, thousand-seed weight, seed germination, and conductivity of Bromus catharticus at different harvest times (8, 13, 19, 25, 32, 36, and 42 d after the onset of the flowering period). Jiangxia and Qiannan varieties were studied as test materials. The results showed that the seed moisture content of the two varieties decreased gradually with seed maturation; however, the change in thousand-seed weight showed the opposite trend and tended to stabilize at 32 d after flowering in the Wuhan area. Germination rate, germination potential, germination index, and vigor index of the seeds harvested at different stages showed a gradual increasing trend, except on day 42 after flowering, when the values decreased slightly. However, no significant differences were observed for any index from 32 to 42 d after flowering (P > 0.05). During the seed maturation process, the conductivity of the two varieties decreased continuously from 379.45 μs·(cm·g)–1 and from 340.90 μs·(cm·g)–1, respectively, at day 8 after early flowering to more than 84% by day 42. The differences were significant at 8 – 42 d (P < 0.05). Taking this into consideration, the best harvest time for B. catharticus was between days 32 and 36 after flowering, and the seed water content of Jiangxia and Qiannan was 26%～45% and 32%～49%, respectively.
China is one of the largest animal husbandry countries in the world and produces a large amount of animal manure every year; thus, organic fertilizer resources are abundant in China. To reuse animal manure, it is necessary to explore the potential of using manure as fertilizer for crop cultivation. Therefore, the current study was conducted to determine the effect of animal manure on the nutrient content and fermentation value of corn silage. A randomized complete block design was used in this study with four blocks. Each block contained four treatments, namely, the control group (CK) without fertilization, cow manure group (Cow) with 500 g·m–2 (dry matter basis) cow manure, fowl manure group (Fowl) with 500 g·m–2 (dry matter based) fowl manure, and hog manure group (Hog) with 500 g·m–2 (dry matter based) hog manure, and corn plants were fertilized accordingly. The corn plans were harvested at the 2/3 milk line of the corn kernels and silage was prepared. The nutrient content of the corn plant and silage (120 days) were measured. Furthermore, fermentation parameters of corn silage were determined. The results showed that application of 500 g·m–2 (dry matter based) fowl manure increased the crude protein and NDF content of whole corn plant but had no effect on the fermentation quality. Application of 500 g·m–2 (dry matter based) hog manure or cow manure did not affect the nutrient content or the fermentation quality of silage corn.
The production performance and nutritional value of 10 silage corn varieties were investigated to screen the number of high yield, good quality, and adaptable silage corn varieties suitable for cultivation in the Three Gorges Reservoir area. The results showed that the highest hay yield was from Yuqingyu 3 at 30 636.16 kg·ha–1. The highest plant height was for Chonggen 166 and Yuqingyu No. 3 at 311.93 cm and 310.67 cm, respectively. Spike height ranged from 99.04 cm to 123.05 cm, with the maximum value for Da’ai 111 and the lowest dry-fresh ratio for Quchen 9. The best performance for leaf length and width were for Da’ai 111 and Yuqingyu 3, respectively. The best performance for stem diameter was for Yuqingyu 3 and Quchen 9. The highest content of crude protein was silage corn 318, being up to 10.4%, and the lowest content of medium acid detergent fiber also occurred for silage maize 318. Grey correlation analysis showed that the top three equal weight correlation degrees and weighted correlation degrees were Yuqingyu 3, silage maize 318, and Da’ai 111. These varieties are suitable for planting in the Three Gorges Reservoir area.
To select the best multiple model of the autumn-sown triticale and silage maize in the drought area of the eastern Gansu Province, three triticale lines (C16, C27, and C35) and one rye variety, Heisimai, were used as the previous crops, and silage maize varieties (lines) (Fengzhu No. 1, Fengzhu No. 2, and Dunqingzhu No. 28) were used as the multiple crops. The multiple cropping effects were studied in the drought area of the eastern Gansu Province. The results showed that among the previous crops, the triticale line C16 obtained the highest fresh weight (45.20 t·ha–1), the CP content of C27 was the highest (13.32%) and the ADF content (30.93%) was the lowest. The lowest NDF content (46.64%) was observed in C35. For the multiple crops, silage maize line Fengzhu No. 2 obtained the highest fresh weight (51.16 t·ha–1). The CP content was significantly higher than that of Dunqingzhu No. 28, and contents of the NDF and ADF were significantly lower than that of this variety. From the interaction of the previous and multiple crops, the highest fresh weight and CP yield were obtained for the treatment of triticale line C16 multiplied with the silage maize line Fengzhu No. 2. This planting model would allow the harvest of extra crops using autumn fallow fields. Furthermore, it would achieve pasture rotation and increase the ground coverage during winter and autumn, and thus, it has important ecological value.
To evaluate the fermentation performance of different wrapped silage forage in mutton sheep rumen by using the in vitro fermentation gas production method, three kinds of wrapped silage were selected as experimental material from the hill and gully region of the Loess Plateau. The results showed no significant differences in cumulative gas production between corn (Zea mays) silage and oat (Avena sativa) silage (P > 0.05); however, the cumulative gas production of both silages was significantly higher than that for alfalfa (Medicago sativa silage) (P < 0.05). There was no significant difference in gas production rate (c) among the three kinds of wrapped silage (P > 0.05). There was no significant difference in partial gas production (b), potential gas production (a + b), and 48 h cumulative gas production (GP) between corn silage and oat silage (P > 0.05); however, these were significantly higher than that for alfalfa silage (P < 0.05). Ammonia nitrogen (NH3-N) concentration and metabolic energy (ME) were not significantly different between corn silage and oat silage (P > 0.05). The NH3-N concentration of corn silage and oat silage was significantly higher than that for alfalfa silage (P < 0.05); however, the ME was significantly lower than that for alfalfa silage (P < 0.05). There was no significant difference in the pH and in vitro dry matter disappearance rate (IVDMD) of the three kinds of wrapped silage forage (P > 0.05). Furthermore, there was no significant difference in total volatile fatty acid (TVFA) concentration and the butyric acid ratio between the three kinds of silage forage after 48 h fermentation in vitro (P > 0.05). The ratio of acetic acid and acetic/propionic (A/P) of alfalfa silage were significantly higher than that of corn and oat silage (P < 0.05); however, the propionic acid ratio of alfalfa silage (15.95%) was significantly lower than that of corn (23.98%) and oat (24.43%) (P < 0.05) silage. In summary, GP, dry matter digestibility, and ME in vitro of gramineous forage (corn and oat wrapped-silage) were higher than that of leguminous forage (alfalfa wrapped silage). However, the NH3-N and TVFA concentration of alfalfa wrapped silage was higher than that of gramineous (corn and oat wrapped-silage) forage.
Subacute rumen acidosis (SARA) is a relatively common nutritional, metabolic disease in high-yield ruminants. Although the feeding level corresponds to the feeding management conditions, the risk of SARA in individual animals is high. Therefore, the analysis of the rumen variability mechanism of ruminants and the screening of corresponding biomarkers play an important role in ensuring the efficient production of animals and increasing their useful lifespan. This article mainly explains the causes of SARA and the differences in severity through animal chewing behavior, sorting behavior, and the rumen epithelial absorption capacity. The article also reviews the current research progress on SARA risk markers, in order to identify SARA risks and corresponding mining markers in production.
To understand the condition and hot spots of yak research in China, we selected yak-related articles in the CNKI (China National Knowledge Infrastructure) published from 1998 to 2018 for bibliometric analysis. The results showed that the number of publications increased linearly from 1998 to 2018. The research direction of this paper mainly focused on animal husbandry and veterinary care. The Chinese Qinghai Journal of Animal and Veterinary Sciences had the largest number of papers. The main research institutions for yak were the Gansu Agricultural University, Southwest Minzu University, and Qinghai University. These institutions were primarily distributed in northwestern and southwestern China, which are the main yak-producing areas. The most cited paper was from Gansu Agricultural University and was titled " Analysis and evaluation of the components and flavouring substances in white yak’s meat.” These results provide important information for researchers and demonstrate the research situation and knowledge structure for yaks in China.
To investigate the best conditions of Fermentation liquid biomass of Bacillus amyloliquefaciens strain JNC2 and increase the antagonistic substance productivity against Colletotrichum gloeosporioides, the single factor experiments and orthogonal experiments were adopted to optimize the liquid fermentation medium and fermentation conditions. The results showed that the best optimize for JNC2 strain was 2% xylose, 0.4% peptone, 0.8% yeast powder, 0.6% ammonium chloride, and 0.2% magnesium sulfate. The optimum fermentation conditions were initial pH 6.0, medium capacity 60 mL in 250 mL triangular flask, 7% inoculum rate, fermentation temperature in 34 ℃, rotation speed in 200 r·min–1 and fermentation time of 72 h. Inhibitory activity of strain JNC2 fermentation solution increased 32.61% under the optimum fermentation medium and culture conditions.
The goal of this study was to develop a seed coating formula that can promote alfalfa (Medicago sativa) seed germination and seedling growth. In this experiment, fulvic acid, micronutrients, and diethyl aminoethyl hexanoate (DA-6) were used as active ingredients to determine the germination and seedling growth of alfalfa seed at different concentrations and combinations. The results showed that seeds coated with 0.2% fulvic acid, 0.02% DA-6, and 0.15% micronutrients exhibited increased germination potential, germination index, germination rate, and more alfalfa branches. The results of the chemical to seed ratios showed that using the 1∶20 ratio resulted in the highest (P < 0.05) alfalfa plant height, crown diameter, and dry weight, being 25.2%, 11.4%, and 30.6% greater, respectively. Thus, 1∶20 was confirmed as the appropriate chemical to seed ratio.