Calorific Values of Grassland Plant Population and Functional Groups in the Agro-pastoral Ecotone of Inner Mongolia and Liaoning Province Border北大核心CSCD

Agro-pastoral ecotone is an important ecological barrier in China,and its ecological environment problems are becoming increasingly prominent. In this study,61 species of plants in 27 grassland plots in the agro-pastoral ecotone of Inner Mongolia and Liaoning border were collected for calorific value analysis under the random sampling condition. The changes of calorific value of plants in different types of functional groups were explored to provide scientific data and research support for energy fixation and rational use of grassland resources in the agro-pastoral ecotone. The results showed that:The average calorific value of 61 species was 17.14 KJ·g-1. Among them,Salsola collina had the lowest calorific value (12.82 KJ·g-1),the caloric value of Polygala tenuifolia was the highest (20.07 KJ·g-1),and the total calorific value was normal distribution. Comparing the caloric values of different life-type functional groups,the caloric value of annuals and biennials was significantly lower than perennial grasses and shrubs (P<0.05),which had no significant difference with sub-shrubs and perennial forbs. There was no significant difference among perennial grasses,shrubs,perennial weeds and semi-shrubs (P>0.05). There was no significant difference in caloric value between different water ecological functional groups (P>0.05). The plant caloric mean value of the Xero-mesophytes was slightly lower than other groups. There was no significant difference in calorific value among Liliaceae,Leguminosac,Gramineae,Compositae and Rosaceae,and the caloric value of Chenapodiaceae was significantly lower than other families (P<0.05). There was a significant positive correlation between plant calorific value and carbon content (P<0.05). © 2019 China Agricultural University. All rights reserved.     

The Effect of Irrigation Period and Amount on Production Performance of Alfalfa in Haihe Plain北大核心CSCD

To explore the suitable irrigation techniques for Alfalfa in Haihe Plain, six irrigation treatments were set up to study the effects of different irrigation treatments on the yield, agronomic traits and water use efficiency of one-year and two-year Alfalfa from 2015 to 2017. The results showed that alfalfa yield increased slightly with increasing irrigation amount in Haihe Plain, but had no significant difference among six treatments. Compared with the treatment without irrigation, the cumulative increment of alfalfa yield in three years was only 6. 13 t • hm~z. The water use efficiency of Alfalfa significantly decreased gradually with the increase of irrigation amount (P相似文献   

The influences of reseeding date and mowing prior to reseeding on establishment of alfalfa in Leymus chinensis meadows北大核心CSCD

This research studied the effects of sowing date and cutting prior to sowing on establishment of the leguminous forage，alfalfa（Medicago sativa），in a lightly degraded Leymus chinensis meadow and investigated the sowing date×cutting interaction. The factorial experiment comprised four sowing dates（May 1，June 1，July 1，August 1）and cutting treatment（cut or uncut）prior to sowing，and evaluated the establishment performance of alfalfa and the ecological mechanisms related to establishment. It was found that soil moisture during emergence of alfalfa was the greatest when sowing occurred on July 1，and clipping prior to sowing significantly decreased the plant height of L. chinensis during emergence and seedling growth of alfalfa. There was a significant sowing date×cutting interaction effect on alfalfa establishment. Clipping prior to sowing significantly increased the emergence percentage of alfalfa through reducing the plant height of L. chinensis and associated above-and below-ground competition，and the seasonal soil moisture change resulted in a 20% higher（P<0. 05）alfalfa emergence rate when sowing occurred on July 1. With cutting，the number of surviving alfalfa seedlings and seedling survival rate were greatest（83 plants· m−2 and 53%，respectively）when sowing occurred on July 1. For later sowing，owing to the shortened growing time，the development and overwintering survival rates of alfalfa seedlings were significantly reduced. Cutting prior to sowing significantly increased the overwintering rate of alfalfa seedlings through improving their development. In the cutting treatment，the number of overwintered alfalfa seedlings（22 plants·m−2）when sowing was on July 1 was significantly higher than for other reseeding dates. In the second year，a botanical composition measurement showed that clipping prior to reseeding significantly increased the alfalfa biomass within the meadow，and the alfalfa biomass was significantly greater than in other treatments when sowing occurred on July 1 after cutting. Cutting prior to sowing also significantly increased the crude protein content of forage. Based on these research results，normal production practice should include cutting when alfalfa is sown into L. chinensis meadow. Combined with cutting，a sowing date around July 1 is the most favorable for the establishment of alfalfa. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Analysis of Differences and Influencing Factors of Plant δ13C in Leymus chinensis Grassland in Inner-Mongolia,China北大核心CSCD

In order to understand the distribution and change of stable carbon isotope13C in grassland plants and the effects of soil moisture and temperature on the stable carbon isotope13 C composition (δ13 C), w e measured the δ13 C of shoots and living roots which both had two treatments, 13 C pulse labeling treatment and control treatment, and analyzed the effect of soil moisture content, air temperature and ground temperature on the δ13 C of plants body during the fast-growing stage (July-September) of the Leymus chinensis grassland in Inner Mongolia. The results showed that the δ13C of the living roots was 1-2% higher than the δ13C of the shoots in control treatments, and the δ13C of the shoots in13C pulse labeling treatment was significantly greater than the δ13C of the living roots. The variation trends of the δ13C value of shoots and living roots in labeling and control treatments were both in good consistency with time, which showed that the value of13C in shoots and living roots decreased at first, then increased, and then decreased during the growing season of plants. The δ13 C of the shoots and living roots in control group and living roots in13 C pulse labeling treatment had a linear negative correlation with soil moisture content in the layer of 0-20 cm, but the δ13C of shoots in13C pulse labeling treatment had Quadratic function relation with the soil moisture content in the layer of 0-20 cm, which indicated that the δ13C increased with increasing soil moisture content when it had a low soil moisture content, and the δ13C decreased when there was a high soil moisture content. In13 C pulse labeling treatment and control treatment, there were significant positive correlation between temperature and the δ13C of the shoots and living roots, the δ13C of the shoots and living roots increased with increasing the temperature. © 2019 China Agricultural University. All rights reserved.     

Seasonal Changes of Grazing Grassland Nutrition and Yields and Feeding Preferences of Tibetan Cashmere Goats in Nagqu Prefecture of Tibetan Plateau北大核心CSCD

This experiment was conducted in Nima County,Nagqu region,Tibet,to investigate the effects of seasonal changes on pasture nutrients and the feeding preferences of Tibetan cashmere goats,and estimate grassland yield and livestock carrying capacity. The results showed that the nutrient content in pasture showed regular changes with the seasons. The weight of crude protein (CP) and dry matter (DM) showed an inverted "V" shape with the increase of season,neutral,but the change in the content of detergent fiber (NDF) and acid detergent fiber (ADF) was in verse. Compared with autumn,there was a significant change in the eating degree of Tibetan cashmere goats on forages such as Stipa purpurea,Potentilla bifurca, Anaphalis xylorrhiza, Cirsium souliei and Leontopodium pusillum in summer (P<0.05),which was significantly correlated with the total coverage of forage (P< 0.05). The NDVI extracted from the TM remote sensing image of alpine meadow grassland showed linear and logarithmic relationship with fresh grass biomass and biomass,and the correlation coefficients were 0.8108 and 0.7970,respectively. At the same time,it found that there was overgrazed throughout the year. © 2019 Ｊｏｕｒｎａｌ ｏｆ Ｒｅｆｒｉｇｅｒａｔｉｏｎ. All rights reserved.     

Changes of Rumen Microbiota Density and Physicochemical Properties at Different pH北大核心CSCD

The aim of this experiment was to investigate the changes of rumen microbiota density and physicochemical properties at different pH. Five Holstein cows in dry milk period were selected as rumen fluid donors. Using in vitro method, five treatments were set according to the criteria of rumen acidosis, and the pH of culture medium was 6.5, 5.8, 5.5, 5.2 and 5.0, respectively, with five replicates in each treatment. After three hours of incubation, the changes of rumen microbiota density and physicochemical properties were measured. The results showed as follows: 1) with the decrease of pH, the rumen microbiota density showed a fluctuation change of first decreasing, then increasing and then decreasing, and the microbiota density in pH 5.8 treatment was significantly lower than that in pH 6.5 treatment (P<0.05). When pH was 5.2, the rumen microbiota density was the highest, which was significantly higher than that in the other treatments (P<0.05). 2) With the decrease of pH, the intracellular H+-ATPase activity in rumen microbiota was firstly increased and then decreased, but there was no significant difference among all treatments (P>0.05). 3) The intracellular ATP content in rumen microbiota was not significantly affected by different pH treatments (P>0.05). 4) With the decrease of pH, the intracellular protein content in rumen microbiota was gradually increased (P<0.05). 5) With the decrease of pH, the intracellular pH (pHi) and cellular transmembrane pH difference (ΔpH) in rumen microbiota were firstly increased and then decreased, and the pHi and ΔpH in pH 5.5 and 5.2 treatments were significantly higher than those in the other three treatments (P<0.05). 6) With the decrease of pH, the cell membrane permeability of rumen microbiota was gradually increased, except for pH 5.8 treatment, the other treatments were significantly higher than pH 6.5 treatment (P<0.05). In conclusion, the rumen microbiota can increase the intracellular H+-ATPase activity and protein content, consume ATP, and change pHi and ΔpH in response to external pH decline. When pH decreases to 5.5, the membrane permeability and pHi of rumen microbiota increase significantly, indicating that they are running to be subjected to more serious acid stress. The density of rumen microbiota fluctuates with the decrease of pH, and when pH decreases to 5.2, the density of rumen microbiota is the highest. © 2023 Authors. All rights reserved.     

Effect of Poly-β-hydroxybutyrate on Reproductive Performance and Larval Development of Fenneropenaeus chinensis

In the present study, Fenneropenaeus chinensis individuals were assigned into six groups, and fed with a diet supplemented with 0(Con-trol), 0.5%(Group E0.5), 1.0%(Group E1.0), 2.0%(Group E2.0), 3.0%(Group E3.0) or 5.0%(Group E5.0) of poly-β-hydroxybutyrate(PHB) during their growth and spawning periods, to explore the effect of PHB on the reproductive performance of parents and the development of larvae. The experi-ment was lasted for 192 d to measure the mortality rate, relative percentage of survival(RPS), weight gain rate(WGR), specific growth rate(SGR) and cycle of gonadal development of parental shrimps, number of eggs, number of nauplii, stages of larval development and metamorphosis. The results indicated that PHB had an obvious effect on the fecundity of parental shrimps and growth performance of larva. Compared with control group, the mortality rate of broodstock in experimental groups decreased initially and increased subsequently with the increase of PHB concentration, while RPS showed an opposite pattern. The mortality rate of group E2.0 was the lowest among all groups, showing significant difference from that of other groups(P﹤0.05) except group E1.0(P﹥0.05). WGR of all experimental groups was higher than that of the control group, among which, group E2.0 and group E5.0 had significantly higher WGR than the control(P0.05). However, there was no significant difference in the cycle of gonadal development between the experimental groups and the control group(P ﹥ 0.05). The numbers of eggs and nauplii in the experimental groups were higher than those of the control group. And the numbers of eggs and nauplii in group E2.0 were significantly higher than those of the control(P ﹤ 0.05), bud showed no significant difference from those of other groups(P﹥0.05). However, there was no significant difference in the duration of larval devel-opment and metamorphosis among all the groups. In summary, PHB is capable of improving the reproductive performance of parents and the survival and development of larva in F. chinensis, and 2.0% is the optimal concentration of PHB supplemented to the diet.     

Short-term Effects of Nitrogen Deposition on Soil Enzyme Activities in Tibet Grasslands

[Objective] The paper was to study the effects of nitrogen deposition on enzyme activity in different layers of soil. [Method] With grassland located in Zhuqudeng Village, Bujiu Township, Linzhi City, the Tibet Autonomous Region, as the object, nitrogen deposition was simulated from July 2014 to August 2015. Four N addition treatments were established: control(0 kg·hm2/a), low N(LN, 25 kg·hm2/a), medium N(MN, 50 kg·hm2/a) and High N(HN, 150 kg·hm2/a), aiming at measuring enzyme activity(invertase, catalase, urease, amylase, cellulase, polyphenol oxidase and β-glucosidase) in different layers of grassland soil(0-20 cm and 20-40 cm). [Result](1) Different levels of simulated nitrogen deposition had significant impact on invertase and β-glucosidase at the soil depth of 0-20 cm(P0.05), but no significant impact on catalase, urease, amylase, cellulase and polyphenol oxidase(P0.05); invertase, polyphenol oxidase and β-glucosidase had significant response to nitrogen deposition at the soil depth of 20-40 cm(P0.05), while catalase, urease, amylase and cellulose had no significant response( P0.05).(2) The activities of invertase and polyphenol oxidase were enhanced at the soil depth of 0-20 cm, and that of β-glucosidase was inhibited.(3) With the deepening of nitrogen deposition, the ac-tivities of invertase and cellulose were enhanced at the soil depth of 20-40 cm; the activity of polyphenol oxidase was reduced in LN treatment, but increased in HN treatment; the activity of β-glucosidase was increased in LN treatment, but decreased in MN treatment.(4) With the deepening of soil layers, invertase and polyphenol oxidase responded similarly to simulated nitrogen deposition. [Conclusion] The results provide certain scientific basis and fundamental data for better understanding and evaluating the effects of nitrogen deposition on enzyme activity in grassland soil.     

Effect of Duodenal Soybean Small Peptides Infusion on Mammary Uptake of Amino Acid and Expression of APN in Lactating Goat

<正>The aim of this study was to investigate the effect of duodenal infusion of soybean small peptides(SSP) on mammary uptake of amino acids(AA).Eight Chinese Saanen goats with duodenal fistulae and catheters were used in a crossover design trial.Goats were infused with 0,60,120,180 g/d SSP.The experimental period lasted for 14 d.The results showed:1) milk protein yield and content were increased,with the increment in milk protein yield being significant(P0.05).Milk fat yield and content were decreased with the increased amount of SSP infused(P0.05).2) Mammary plasma flow was not changed(P0.05) by SSP infusion though the average was slightly higher.Mammary plasma flow/milk yield was decreased by SSP infusion and there was significant difference between the 120 g/d treatment and the control(P0.05).3) Compared with the control treatment,uptakes of most free amino acids were increased in the 60 and 120 g/d treatments,but decreased by the 180 g/d treatment.The uptakes of all peptide-bound essential amino acids(PB-EAA) were increased except for PB-Ile.Uptake of PB-Val,PB-Leu, PB-Phe,PB-Thr,PB-Met and PB-Lys was highest in the 120 g/d treatment.Among the peptide-bound nonessential amino acids(PB-NEAA),uptake of PB-Ser,PB-Tyr,and PB-Pro was increased(P0.05) while that of PB-Gly was decreased(P0.05).4) With the exception of Lys,secretion of all essential AA(EAA) was increased by SSP infusion from 0-120 g/d(P0.05),while in the 180 g/d treatment the increase was not significant and was lower than that in the 120 g/d treatment.5) The expression of APN was increased by SSP;in the 60,120,180 g/d treatments expression was 13.55-,18.69-,and 10.01-fold over that of the controls.Conclusion:SSP might be used as substrates for milk protein synthesis by mammary gland,and can increase synthesis and secretion of milk protein.There was reason to believe that uptake and use of AA was either saturated or inhibited at high levels of infusion of SSP.Increased APN expression with infusion of SSP related to mammary uptake of PBAA by mammary gland,which suggested that APN was one of the peptidases regulating use of AA from small peptides in mammary tissue.     

Effects on Growth Performance and Feed Digestibility of Hainan Black Pigs by Adding Lysine in Low Protein Diet

[Objective] The paper was to study the effects on growth performance and feed digestibility of Hainan black pigs by adding lysine in low protein diet.[Method] A total of 36 Hainan black pigs with the body weight of(46.34 ±3.06) kg were randomly divided into three groups:control group(protein level 15%,lysine level 0.83%),experimental group I(protein level 13%,0.83%),and experimental group II(protein level 13%,lysine level 1.03),each group had three replicates of four pigs.The trial lasted 35 d.[Result] The growth performance of Hainan black pig in group II had no significant difference with that in control group(P0.05).The apparent digestibility of crude protein and phosphorus of Hainan black pigs in Group II increased significantly(P0.05),which were increased by 10.08% and 11.85% respectively compared to the control group;the apparent digestibility of calcium was increased,but the difference was not significant(P0.05).[Conclusion] It will not reduce the growth performance of Hainan black pig when the protein level of diet is reduced by 2% and the lysine level is increased to 1.03%.It is recommended that the diet can be used in the production of Hainan black pig.     

Effects of Lactic Acid Bacteria and Fructooligosaccharides on Growth Performance,Nutrient Digestibility and Serum Biochemical Indices of Arctic Foxes (Alopex lagopus) during Early Growth Period北大核心CSCD

This experiment was conducted to study the effects of dietary lactic acid bacteria (LAB) and fructooligosaccharides (FOS) on growth performance, nutrient digestibility and serum biochemical indices of Arctic foxes (Alopex lagopus) during early growth period. Sixty male post-litter Arctic foxes with the average body weight of (1.16±0.15) kg and at the age of (45±3) days were randomly assigned to 4 groups with 3 replicates per group and 5 foxes per replicate. The foxes were fed the following diets, respectively: basal diet (control group), basal diet+3×109 CFU / kg LAB (LAB group), basal diet+5 g / kg FOS (FOS group) and basal diet+3×109 CFU / kg LAB+5 g / kg FOS (LAB+FOS group). The experiment lasted for 30 days. The results showed as follows: 1) on the days 1 to 15, the diarrhea rate of foxes in the LAB group and LAB+FOS group was significantly lower than that in the control group and FOS group (P<0.05). On the days 16 to 30, the average daily gain of foxes in the LAB+FOS group was significantly higher than that in the control group and FOS group (P<0.05), but had no significant difference with LAB group (P>0.05); the diarrhea rate of foxes in the LAB+FOS group was significantly lower than that in the control group and FOS group (P<0.05), but had no significant difference with LAB group (P>0.05); compared with the FOS group, the feed to gain ratio of foxes in the LAB+FOS group was significantly decreased (P<0.05). 2) The dry matter digestibility of foxes in the LAB + FOS group was significantly higher than that in the control group and FOS group (P < 0.05), but had no significant difference with LAB group (P>0.05). There were no significant differences in nitrogen intake, fecal nitrogen, urine nitrogen, nitrogen deposition, net protein utilization and protein biological value among all groups (P>0.05). 3) Serum total protein (TP) content of foxes in the LAB+FOS group was significantly higher than that in the FOS group (P<0.05), but had no significant difference with control group and LAB group (P>0.05). Serum albumin (ALB) content of foxes in the LAB group was significantly higher than that in the control group and FOS group (P<0.05), but had no significant difference with LAB+ FOS group (P>0.05). Serum urea nitrogen (UN) content of foxes in the LAB+FOS group was significantly decreased compared with the control group (P < 0. 05). In conclusion, the combined supplementation of 3 × 109 CFU / kg LAB and 5 g / kg FOS in the diet is beneficial to reduce diarrhea rate, improve dry matter digestibility, improve body immune level, and promote the growth of Arctic foxes during early growth period. © 2023 Chinese Journal of Urology. All rights reserved.     

Plant Hormone Regulated Tillering in Switchgrass北大核心CSCD

Switchgrass is a perennial gramineous plant.It is studied widely and applied as an energy crop because of its huge biomass to produce fuel ethanol. Tillering is the main factor that directly affects the biomass of gramineous plants. The production of tillers is determined by the development of tiller buds,which is regulated by many factors including plant hormones and external environment. A tiller-deficient mutant lt induced by EMS was studied in physiological,biochemical and molecular mechanisms. The results showed that the number of tillers and elongation rate of axillary buds of mutant lt decreased. And the shoot of lt responded to gravity weakly,the contents of auxin,abscisic acid and strigolactones in lt increased. At the same time,the expression level of genes involved in strigolactones pathway in lt mutant increased. These results indicated that the tillering development of switchgrass mutant lt was regulated by auxin,abscisic acid and strigolactones. These results could provide theoretical direction for increasing biomass yield of switchgrass. © 2019 Ｊｏｕｒｎａｌ ｏｆ Ｒｅｆｒｉｇｅｒａｔｉｏｎ. All rights reserved.     

Harmful and economic thresholds for rodent pests in the Alxa desert area under different grassland utilization patterns北大核心CSCD

The rodent damage threshold and the rodent economic threshold are indicators that must be clearly defined in the practice of grassland rodent prevention and control. Different grassland types or different utilization methods of the same grassland type have completely different values for these two indicators. The damage threshold is the population density of pests at which the grassland is obviously compromised, and the economic threshold is the population density at which further pest population increases will cause economic losses. The Alxa desert region is ecologically fragile, and rodents are endemic. This study selected continuous grazing areas and prohibited grazing areas in the desert area of Alxa Left Banner and from 2015 to 2019 to investigated the species and density of pests using the ‘mark and recapture’ method, together with sampling to investigate the aboveground plant biomass in the sample area in August. The measured rodent unit densities and their daily food intakes were used to estimate the amount of forage loss, and a regression equation was used to obtain a fitted relationship between the rodent density and the ratio of forage loss. It was found that: 1) The fitted curves for the ratio of pest density and forage loss in the continuous and prohibited grazing areas took the form of logistic three-parameter, S-shaped curves. 2) According to the regression equation, the damage threshold in continuous grazing areas was 26 standard rodent units·ha-1 and the economic threshold was 39.3 standard rodent units·ha-1. In prohibited grazing areas, the damage threshold was 33.2 standard rodent units·ha-1 and the economic threshold was 30.2 standard rodent units·ha-1. Thus, the economic threshold pest density of continuous grazing areas was slightly higher than that of prohibiting grazing areas. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Physiological effects of different Cd concentrations on maize root architecture and classification北大核心CSCD

In this research, a hydroponics experiment was conducted to apply different concentrations of cadmium (Cd) (0, 5, 10, 25, 50, 100, 200 μmol·L-1) to maize seedlings with two leaves and one new leaf, in order to explore the effects of the different Cd concentrations on the maize seedling growth, Cd absorption kinetics and root morphology and classification. After 5 days of Cd stress, the maize seedings were sampled, the plant height, main root length, aboveground and underground biomass, root architecture, Cd content and photosynthesis and related parameters were measured. It was found that with increasing Cd stress, the plant height, main root length, biomass and tolerance index of shoots and roots, total root length, root surface area, root volume, root forks and root tips all decreased significantly; Root average diameter and root:shoot increased significantly (P<0.05). Meanwhile root parameters (root length, root surface area and root volume) of root diameter classes designated Ⅰ-Ⅲ (0-1.5 mm) showed a decreasing trend, which had a significant (P<0.05) negative correlation with root Cd concentration. The proportion of root length, root surface area and root volume with diameter between 0-0.5 mm showed a downward trend under Cd stress. Under Cd stress, Cd concentration and accumulation in underground and aboveground parts of maize seedlings increased significantly, chlorophyll content decreased, and photosynthesis was inhibited. This study has shown that Cd affected root development mainly by inhibiting the growth and morphology of fine roots, and inhibited photosynthesis, elongation and biomass accumulation of the aboveground and underground parts of the maize seedings. © 2022, Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Dietary supplementation of Rosmarinus officinalis L.leaves in sheep affects the abundance of rumen methanogens and other microbial populations

Background: Rumen microbiome has a great influence on ruminant health and productivity. Different plant extracts have been tested for their ability to modulate the rumen microbiome to improve feed digestion and fermentation. Among the evaluated plant extracts, essential oils, tannins, and saponins appeared to have positive effects on rumen protein metabolism, volatile fatty acids production, and methane and ammonia production.Methods: The objective of this study was to evaluate the effect of rosemary(Rosmarinus officinalis L.) leaves and essential oils on rumen microbial populations. Four ruminally cannulated sheep were used in a 4×4 Latin square design fed(21 d/period): 1) a control diet composed of alfalfa hay and concentrate pellet(CTR), 2) CTR supplemented with 7 g/d/sheep of rosemary essential oil adsorbed on an inert support(EO), 3) CTR with 10 g/d/sheep of dried and ground rosemary leaves(RL), and 4) CTR with 10 g/d of dried and ground rosemary leaves pelleted into concentrate(RL pellet). Abundance of total bacteria, archaea, protozoa, and some select bacterial species or groups was quantified using q PCR, while the community of bacteria and archaea was profiled using denaturing gradient gel electrophoresis.Results: No difference in abundance was noted for total bacteria, protozoa, or Ruminococcus flavefaciens between the control and the treatments, but the rosemary leaves, either in loose form or in pellet, decreased the abundance of archaea and the genus Prevotella(P 0.001). The rosemary leaves in loose form also decreased(P 0.001) the abundance of Ruminococcus albus and Clostridium aminophilum, while the EO increased(P 0.001) the abundance of Fibrobacter succinogenes. The community of bacteria and archaea was not affected by any of the supplements.Conclusions: Being able to affect the abundance of several groups of rumen microbes that are known to be involved in degradation of protein and fiber and production of methane and ammonia, rosemary leaves may be used to modulate rumen microbiome and its function.     

Effects of plateau pika on the relationship between plant species diversity and functional diversity in alpine meadow北大核心CSCD

The relationship between plant species diversity and functional diversity in grassland will change with environmental changes. The plateau pika （Ochotona curzoniae） has an effect on the hydrothermal process of alpine meadow in its nesting area. However,it is not clear whether the disturbance of plateau pika effects the relationship between plant species diversity and functional diversity in alpine meadow. A random stratified and paired design was used to select plots in Luqu county in Gansu Province,and Qilian and Gonghe Counties in Qinghai Province and a field survey was conducted to investigate the effects of plateau pika disturbance on the relationship between plant species diversity and functional diversity of the alpine meadow. It was found that plateau pika disturbance significantly increased the plant species richness index and the species diversity index but did not significantly affect the species evenness index. Plateau pika disturbance significantly increased plant functional richness index （P< 0.05） but had no significant effect on the plant functional evenness index or the functional divergence index. With plateau pika disturbance effects,the relationship between plant functional richness index and species richness index changed from a logarithmic function to a quadratic function,and the relationship between plant functional evenness index and species evenness index changed from non-significant to significantly positive. In addition, positive correlations between functional richness index and species richness index,and functional richness index and species diversity index were significantly decreased,as were negative correlations between functional divergence index and species richness index,and functional divergence index and species diversity index were significantly decreased. The findings of this study provide basic information for understanding the mechanism of species coexistence of plant communities under plateau pika disturbance and help understanding of how plant diversity effects in an alpine meadow ecosystem function under plateau pika disturbance. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Herbaceous Cultivation Test of Mulberry in Sichuan Sericultural Area

With Guiteyou 2 as the test mulberry variety, mulberry herbaceous cultivation field was established at the planting densities of 60 000,90 000 and 120 000 plants/hm~2, respectively. Hybrid mulberry herbaceous cultivation test was conducted, with Tongxiangqing mulberry field of mid-fist-form at conventional planting density of 4 995 plants/hm~2 as the control. The results showed that the leaf yield of herbaceous cultivation mulberry was closely related to the planting density. With the increasing planting density, the leaf yield per plant was decreasing, but the leaf yield per unit area of mulberry field was increasing. The annual leaf yield per unit area in the mulberry field with the average planting density of 120 000 plants/hm~2 was 37 560 kg/hm~2, 2.14 times of that of the control field. The moisture content of mulberry leaf in herbaceous cultivation field was 4.74% higher than the control; the contents of crude protein, crude fat, crude fiber and crude ash were 1.264%, 0.014%, 0.744% and 0.002%lower than the control, respectively. Comparison of leaf rearing with herbaceous cultivation mulberry and control mulberry showed that there was no significant difference in growth status of silkworm. The cocoon weight, cocoon shell weight, cocoon yield per 10 000 larvae, cocoon filament length and non-broken filament length of Chuanshan × Shushui were 12.81%, 14.29%, 13.85%, 5.95% and 7.68% lower than the control, respectively; but the percentage of common cocoons was 0.16% higher than the control; the cleanness and neatness were 0.2 and 1.25 points higher than the control;the filament size was 0.196 dtex lower than the control. The cocoon weight, cocoon shell weight, cocoon yield per 10 000 larvae, cocoon filament length and non-broken filament length of Jingsong × Haoyue were 11.06%, 10.20%, 11.53%, 9.46% and 9.03% lower than the control, respectively;but the percentage of common cocoons was 1.77% higher than the control; the cleanness and neatness were 0.12 and 2.50 points higher the control;and the filament size was 0.196 dtex lower than the control.     

Characteristics of Evapotranspiration and Water Consumption of Typical Alpine Desert in the Tibetan Plateau During the Growing Season北大核心CSCD

To explore the law of water consumption in the underlying surface of a typical alpine desert on the Qinghai-Tibet Plateau, we analyzed the characteristics of ET change and water consumption on different time scales based on the raw eddy-covariance data and meteorological data measured in April to August 2019 from the observation tower on Tuotuohe weather station. The maximum hourly average ET appears at 2-3 p. m, reaching 0.46 mm·h-1; The maximum value of daily ET was 8.58 mm·d-1 on July 7, and the minimum value was 0.30 mm·d-1 on April 2; The ET increased first and then decreased during the growing season, the monthly ETmax was 120.68 mm in July and the ETmin was 64.80 mm in April; The total ET in 2019 growth season was 581.15 mm and the daily average was 4.01 mm. The total precipitation of the whole growing season was 235.70 mm, according to the difference between ET and precipitation(Pr) from April to August, water vapor exchange during the plant growth season was mainly characterized by water consumption on the land surface in 2019. © 2019 Authors. All rights reserved.     

Effects of Dietary Sodium Acetate on Lactation Performance and Rumen Microbiota of Dairy Goats北大核心CSCD

This experiment was conducted to investigate the effects of dietary sodium acetate on lactation performance and rumen microbiota of dairy goats. Fifteen healthy Xinong Saanen dairy goat ewes with similar body weight of (53.54±3.07) kg, the same parity (2 parities) and in mid-lactation [(60±5) d] were randomly divided into 3 groups with 5 replicates in each group. Dairy goats in the control group were fed a basal diet, and those in the experimental groups were fed the basal diet supplemented with 30 (experimental group I) and 60 g/ (d.head) (experimental group II) sodium acetate, respectively. The pre-trial period lasted for 7 days and the experimental period lasted for 21 days. The milk yield of dairy goats was recorded during the experiment. At the end of the experiment, milk samples were collected to analyze the changes in milk composition, and rumen contents of dairy goats were collected from two groups (control group and experimental group II) with significant differences in milk fat percentage. Gas chromatography and 16S rDNA sequencing technology were used to analyze the rumen fermentation parameters and rumen microbial composition and structure of dairy goats. The results showed as follows: 1) compared with the control group, dietary sodium acetate extremely significantly increased the daily milk yield of dairy goats (P<0.01), and the daily milk yield in experimental groups I and II was increased by 0.29 and 0.22 kg, respectively (P<0.01); in experimental group II, the milk fat percentage was significantly increased by 1.30 percentage points (P<0.01), and the non-fat solid content in milk was increased by 3.10% (P>0.05). 2) Compared with the control group, the rumen butyric acid content of dairy goats in experimental group II was significantly decreased (P<0.01), and there was no significant difference in rumen pH, the other volatile fatty acid content and acetic acid to propionic acid ratio (P>0.05). 3) Compared with the control group, the Sobs index, Chao1 index and Ace index of rumen microbiota in experimental group II were significantly increased (P<0.05); the results of similarity analysis (ANOSIM) also showed that there were significant differences in the structure of rumen microbiota between the two groups (P<0.05). 16S rDNA sequencing results showed that at the phylum level, Bacteroidetes and Firmicutes were the dominant phyla in the rumen of the two groups of dairy goats; at the genus level, Prevotella_1 was the dominant genus in the rumen. Compared with the control group, the relative abundances of Ruminococcus_1, Ruminococcaceae_UCG-005, Prevotellaceae_UCG-004 and Lachnoclostridium_12 in rumen of dairy goats in experimental group II were significantly increased (P<0.05), while the relative abundances of Succiniclasticum and Methanobrevibacter in rumen was significantly decreased (P<0.05). 4) The results of correlation analysis showed that rumen microbiota was correlated with daily milk yield, milk fat percentage, milk protein percentage and non-fat solid content of dairy goats. In conclusion, dietary 60 g/ (d.head) sodium acetate can significantly increase the daily milk yield and milk fat percentage, significantly reduce rumen butyrate content, and improve the lactation performance of dairy goats by improving rumen microbial composition and structure. © 2023 Authors. All rights reserved.     

Effects of slope on soil properties and post construction desertification of highway embankments in an Alpine Meadow region北大核心CSCD

This research investigated effect of slope on the performance of highway embankment soil properties post construction, as there is a demand for technical data of this nature to underpin the design of highway revetment work in alpine meadow regions of China. A section of national road G248 in Northwest Sichuan Alpine Grassland, built 10 years ago, was identified as a study site and plots were marked out for sampling on five slope classes: gentle slope, 6°-15° (GS); moderate slope, 16°-25° (MS); steep slope, 26°-35° (SS); very steep slope, 36°-45° (VS); extreme slope, >45° (ES). Undisturbed flat natural grassland >10 m distant from the roadbed was used as the control (CK). Measurements conducted included determination of particle size composition, physical and chemical parameters of the soils, vegetation cover and the proportion of the plot area exhibiting degradation or desertification. The relative reduction rate of organic matter and total nitrogen was also determined, and differences in soil water content and fertilizer retention capacity were assessed. It was anticipated these data would provide a basis for the construction of ecologically sound slope protection structures in alpine regions. It was found that: 1) Increased slope significantly decreased the proportion of clay and silt particles and increased the proportion of coarse sand and small stones (P<0.05). The greater the slope, the greater the soil bulk density and pH value, and the lower the soil water content. 2) Slope facilitated leaching of soil carbon fractions with the leaching intensity of the fractions ranking soil organic matter (SOM)>total carbon (TC)>inorganic carbon (IC)>dissolved organic carbon (DOC). For example, SOM levels were, respectively, 115, 92, 72, 30, 9 and 3 mg·kg−1 for CK, GS, MS, SS, VS, and ES slope classes while DOC levels ranged from 35.4 mg·kg−1 in CK to 9.2 mg·kg−1 in ES. 3) The ranking for the effects of slope on various soil fertility measures was: effective N>alkali-hydrolysable N>total N>available K> available P>total K>total P. Thus, available N was more easily lost than total N and alkali-hydrolysable N. Available N levels declined progressively across slope classes from 236 mg·kg−1 in CK to 6.3 mg·kg−1 in ES, while total N and alkali-hydrolysable N showed marked loss between GS and VS slope classes. A slope threshold for sharp increase in loss of total P and available P was observed between GS and MS slope classes. With increase in slope gradient, the total K increased, while the available K content decreased. 4) With respect to the influence of slope on the degree of desertification: for CK and GS >90% of the plot area was classed as non-desertified; for GS 79% of the plot area was moderately or severely desertified; for SS, VS and ES, 79, 86 and 94%, respectively, of the plot area was severely or extremely severely desertified. The proportion of severe desertification increased markedly at > 15° slope (i. e. MS) and the proportion of extremely severe desertification increased markedly at >25° slope (i. e. SS). 5) When the slope effects were expressed in relative terms, the relative increase in desertification was high and changed little at slopes >15°, while the relative decreases in organic matter and total nitrogen were high and changed little once slope exceeded 25°. As slope angle increased, relatively low rate of total coverage percentage and powder particles <0.02 mm and the relative increase rate of sand particles >0.05 mm increase significantly. In summary, as slope of the study plots increased, fine sand, silt and clay particles were progressively lost, soil fertility progressively declined, and the degree of desertification increased markedly. Therefore, the technical plan for ecologically sound slope protection in highway construction should be formulated according to the steepness of the slope. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.