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The deterioration of soil ecosystem and soil degradation related to overgrazing were serious and cannot be restored in short period. In order to determine the impacts of fencing on the soil enzyme activities and soil microbial communities in Damxung steppe, the activities of β-glucosidase, invertase, phenol oxidase, peroxidase, L-asparaginase, protease, urease and alkaline phosphatase were investigated, as well as the biomass of bacteria, fungi, actinomycete, gram-positive bacteria and gram-negative bacteria. Water soluble organic carbon (WSOC) and water soluble organic nitrogen (WSON) in soils with all fencing treatments were significantly higher (P＜0.05) than that in grazing soils. There were significant variations of soil moisture and pH between grazing and fencing 6 years. Invertase and L-asparaginase activities significantly increased with the fencing year extended. The biomass of bacteria, actinomycete and gram-positive bacteria in soil with 6 years fencing were significantly higher (P＜0.05) than that in soil. All of these results suggested that fencing changed not only soil physicochemical properties, but also soil enzyme activities and microbial communities. The further pearson correlation analysis showed that WSOC, WSON and moisture had significantly positive correlation with soil enzyme activities and soil microbial communities which suggested that all of tested factors could be good indicators for grassland degradation and restoration. All of these results showed that fencing helped improving soil organic matter to promote growth of microorganism and recovery of alpine grassland ecosystem.
Human activity has adversely affected global carbon(C) and nitrogen(N), and contributed to an alteration of climate that will generate discernible feedbacks to all organisms and ecosystems on earth. The purpose of this study was to provide the basis of degrading mechanisms in alpine meadow research and understanding global C reserves and quantifying the pools and changing of soil carbon under grazing intensity. The combined methods of field survey and experiment analysis were applied to detect the influence of biomass and soil carbon characteristics under different grazing intensity: enclosure (EN), light grazing (LG), moderate grazing (MG), heavy grazing(HG) and control (CK)on an alpine meadow. The experiment plots were located in the Yushu Longbao alpine meadow. The results showed that aboveground biomass and underground biomass of grassland were maximum in EN treatment. With the grazing intensity increasing, the aboveground biomass and underground biomass decreased. The soil moisture in EN and LG treatments were significantly higher(P＜0.05) than the other treatments which influenced by grazing disturbance. In the soil profile, the soil moisture decreased with soil depth increase in all treatments. Trampling of grazed not only influenced soil moisture but also impacted soil bulk density, the soil bulk density increased with the grazing intensity increasing. The soil organic carbon(SOC) and total nitrogen were also influenced by grazing, the total nitrogen decreased in the following order: LG＞EN＞MG＞CK＞HG whereas the SOC decreased in the following order LG＞EN＞MG＞HG＞CK. Optium trampling of grazing increased soil bulk density, however, but the effects on meadow vegetation and soil structure of high grazing intensity were not benefical for sustainable development of grassland ecosystem.
Soil respiration is an important index for evaluation of soil quality and fertility properties. The clarification of the variations and influence factors of soil respiration in grass-legume mixture pasture will provide evidence for accurately assessment of the effects and response of mixture pasture. In order to comprehensively evaluate the performance of mixture pasture of Bothriochloa ischaemum and Lespedeza davurica, diurnal changes of total soil respiration rate with different mixture ratio of the two species, the contribution of each species and temperature responses of each species were investigated and analyzed in June, 2011 and 2012. The diurnal variation of total soil respiration rates were asymmetric unimodal curves which peaked between 12:00 and 14:00. The daily average of total soil respiration rate decreased in the following order: B. ischaemum monocultureB. ischaemum and L. davurica intercroppingL. davurica monoculture. There were significant correlations between total soil respiration rate and air temperature (P0.05), while there was no significant correlations between soil respiration rate and soil temperature at 5, 10 or 15 cm soil layers. In monoculture, soil respiration rate of B. ischaemum was more sensitive to temperature than that of L. davurica. Q10 values ranged from 1.48 to 2.61 with the highest Q10 value of B. ischaemum monoculture. There was no significant differences between L. davurica monoculture and mixtures.
Species diversity is an important index of forest community structure, composition and spatial feature. In the present study, the influence factors of species diversity of Picea crassifolia forest in Dongdahe forest area were analyzed with vegetation survey, species diversity analysis and correlation analysis. There were total 6 factors influence species diversity of P. crassifolia forest and their importance decreased in the following order: aspect, bryophyte coverage, soil bulk density and soil porosity, community types, canopy coverage. These factors had different ways to influence species diversity, for examples, the community characteristic directly affected the species diversity whereas the aspect indirectly affected species diversity by affecting the forest environment, soil type and characters. Bryophyte- P. crassifolia forest, higher canopy coverage, bryophyte coverage, soil porosity were not favor to increase species diversity. P. crassifolia forest had higher species diversity with 0.73~0.77 g·cm-3 soil bulk density, 68%~70% soil porosity, 0.6~0.7 canopy coverage and 14%～40% bryophyte coverage. For the different forest community types, species diversity of herb-P. creassifolia forest was higher than shrub-P. creassifolia forest and bryophyte-P. creassifolia forest. The multivariable regression model has been established for preliminary calculation of species diversity and the influence factor.
In order to determine if exogenous oxalic acid (OA) can induce alfalfa resistance to downy mildew, different OA concentrations including 10, 20, 30, 40 mmol·L-1 were sprayed on alfalfa seeding at 10-leaf stage. Disease index of alfalfa downy mildew was surveyed after treatment 7 days, activities of peroxidase (POD), phenylalanine ammonialyase (PAL) and superoxide dismutase (SOD) were analyzed after treatment 1 days, 3 days, 5 days, 7 days and 9 days. The results indicated that the 10~40 mmol·L-1 OA solution can reduce alfalfa downy mildew disease index and the disease index decreased with the OA concentration increased. The relative induced resistance increased with the maximum value of 50.8%. The POD, PAL and SOD activities in alfalfa leaf increased.
As the “Ball of Hainan Island”, golf sports is developing rapidly relying on the advantages of Hainan’s climate and environment in recent years. In order to design proper golf landscape to adapt to the development of the international tourist island, we have selected four golf course as the research region, there were East Hill, Moon Bay, Mission Hill and Three Kilometer respectively, according to time gradient and geographic span of the course construction. Then we used AHP method to build a comprehensive evaluation system to measure the landscape quality from multiple perspectives. Finally, we summarized the merits of the landscape quality of golf course, according to the quality ranking, Mission Hills, Moon Bay, Three Kilometers and East Hill respectively. All courses landscape quality grades were excellent and each courses had its unique landscape style. There were no significant difference of landscape although comprehensive scores existed.
Effects of aqueous extract from different parts of Conyza canadensis on weeds Digitaria sanguinalis, Echinochloa crusgalli, Abutilon theophrasti and Amaranthus retroflexus were tested in Petri dishes. The results showed that aqueous extract from root, stem, leaf, flower and whole plant had inhibated effect on the seed germination and seedling growth of the 4 tested weeds. The aqueous extract from flower, leaf and stem, especially flower had higher inhibiting on the seed germination and seedling growth of all tested weeds than the extract from root and whole plant. At 100 g·L-1 concentration, the synthetic effect(SE) of the aqueous extract from C. canadensis flower, leaf, stem, root and whole plant were 87.64%, 80.65%, 72.19%, 48.24% and 64.08%, respectively. At 100 g·L-1 concentration, the inhibition of the aqueous extract from C. canadensis leaf on D. sanguinalis, A. retroflexus, A. theophrast and E. crusgalli germination were 100.00%, 100.00%, 75.00% and 16.67%, respectively, which suggested that A. retroflexus, A. theophrast and D. sanguinalis were more sensitive to the extract than E. crusgalli. These results showed the aboveground parts of C. canadensis had strong inhibition effects on weeds.
Common ragweed (Ambrosia artemisiifolia) is widely recognized as a noxious invasive alien weed species. It is a source of highly allergenic pollen that threatens human health. It also seriously affects agricultural production and biodiversity, when it invades farmland and natural ecosystem. The wide distribution and high invasiveness of the plant have aroused wide attention of scientists. Numerous studies on invasion mechanisms of common ragweed have been found worldwide. We reviewed studies and found that the invasion of the plant was closely related to its invasiveness, habitat invasibility and human disturbance. On the invasion mechanisms of common ragweed, the general conclusions included that common ragweed had high invasiveness because it had high propagule pressure, high utilization efficiency of water and fertilizer, phenotypic plasticity and genetic diversity. The habitat invasibility can be explained by suitable climatic conditions, rich available resource, weak competition of native species, low biodiversity, lack of natural enemies or competitive species in new areas. International trade, cultivation practice and global change were likely to promote the invasiveness of common ragweed and habitat invasibility. We suggest that more controlled experiments should be developed to better understand the underground invasion processes and the relationships between the invader’s biological characteristics, phenotypic plasticity, genetic diversity, native plants diversity and a successful invasion.
As one of the most serious soil erosion areas in China, grassland vegetation is priority for vegetation construction in the Loess Plateau area by its unique geographical conditions and limited water. Grassland vegetation has already contributed a lot to control soil water erosion. Based on the relationships between different parts of grassland vegetation and soil erosion, the present paper drew a conclusion that grassland aboveground parts can weaken rainfall energy and runoff erosion power, and grass roots were able to enhance soil penetrability and soil anti-erodibility by improving soil properties and winding soil mass. In order to provide references for vegetation preventing and controlling soil erosion in Loess Plateau, two aspects of current research progress were summarized including the grassland aboveground part controlling soil erosion power and grass roots enhancing soil anti-erodibility and the exiting problem were discussed.
Mutants have been used widely to analyze genes function and construct functional genomics study. Many genes were isolated and identified from different mutants of plants. In the present study, the seeds of Medicago truncatula cultivar A17 were treated by EMS and 2 085 of M1 generation and 388 of M2 generation mutants were selected. The mutations with leaf color traits included pigmentation, dark green, variegation, red violet, chloric and albino which count for 5.37% in the mutation populations. The mutations with leaf shape traits included wrinkle, narrow lamina, curly and mixed foliate which count for 3.12% in the mutation populations. The mutations with plant shape traits included taller, dwarf, spreading, sydspor, multi-branch and subramose which count for 9.11% in the mutation populations. The mutations with flowering stage traits included early flower and late flower which count for 1.01%. The total mutant frequency was 18.61% in the M2 population. These mutations provided more germplasm resources for functional genomics study of M. truncatula.
Effects of hormones 6-BA and 2,4-D and different explants on callus induction of Stylosanthes guianensis cv. Reyan No.5 were studied by orthogonal design statistic analysis. The results indicated that the main factor which influenced callus induction was 6-BA and the optimal medium for callus induction was MS medium with 2.0 mg·L-1 6-BA and 0.2~0.5 mg·L-1 2,4-D. All the explants using in the study included cotyledon, euphylla, hypocotyl, the growing point tissue, epicotyl, root, respectively could induce callus. The callus inducing rate of the explants were 95% except with that root was 80%. The budding rate of the callus from the upper hypocotyl was significantly higher than the callus from the other explants.
The genetic diversity of 30 Sorghum sudanense accessions were conducted with 19 agronomic traits by principal component and clustering analysis. The results showed that the different accessions exhibited various degree of diversity for these available 19 traits in which generalized heritability of thousand seed weights was the highest with 90.93%. The generalized heritability of ear level rachis length, stem diameter and other 5 traits were 40%~70% whereas that of all of the others were below 30%. Principal component analysis showed that the cumulative proportion of former 3 principal components reached 84.32% with the yield as the first component, growth period as the second component and leaf type as the third component. The 30 S. sudanense accessions were divided into 4 groups. The group Ⅰ was early matyurity with short stem, small leaves, short-loose spikes and multi-tillers. The group Ⅱ was high stem, broad leaves, short-close spikes, multi-tillers with long growing duration. The group Ⅲ was proper maturity, with medium stem, broad leaves, long-loose spikes, medium-tillers. The group Ⅳ was similar with the second group but with long-loose spike and fewer-tillers.
In order to understand the response of turfgrass seedlings to silicon fertilizer (Si) and improve turfgrass germination for turf management, the effects of different concentrations of K2SiO3 on seedling growth of Kentucky bluegrass (Poa pratensis cv. ‘Midnight’) was investigated under well watered conditions. Four Si amendment treatments (1, 1.5, 2 and 2.5 mmol·L-1) and one control treatment (no Si) were conducted in the growth chamber. Silicon fertilizer significantly improved(P＜0.05) seed germination rate, germination energy and germination index. The length and fresh weight of seedlings significantly increased after 35 d treatment which increased with the increasing concentration of silicon fertilizer. The root length, total surface areas of roots and average root diameter increased although only the indices with 2.5 mmol·L-1 Si treatment were significantly higher (P0.05) than the control. These improvement suggested that the appropriate amount of silicon fertilizer was benefit for seed germination and growth of Kentucky bluegrass.
Five saline tolerance rhizobial strains (Sinorhizobium meliloti, ACCC17537,ACCC17558,ACCC17617,ACCC17631 and ACCC17676) were inoculated on Medicago sativa cv. Zhongmu No.1 by two inoculation methods in field to screen high efficient rhizobia and inoculation method in coastland. Seed coating and liquid inoculant without rhizobial strains were also included as controls. The results showed that seed coating method was better compared with liquid inoculants if Zhongmu No.1 grew in soil with serious salinization and lack of rhizobia. There were significant difference between the effects of five rhizobial strains on Zhongmu No.1 by seed coating. Dry weight, crude protein, the numbers of total nodules and effective nodules of alfalfa plant inoculating with 5 rhizobial strains significantly increased (P＜0.05) compared with the controls. The effects of ACCC17558 and ACCC17617 on alfalfa were highest. Dry weight, total nodules, effective nodules and crude protein of per alfalfa inoculating with ACCC17558 and ACCC17617 increased 91.4% and 164.4%, 91.8% and 99.6%, 99.8% and 100.7%, 8.6% and 12.3% compared with the control, respectively. The strains of ACCC17558 and ACCC17617 were selected as good inoculants for Zhongmu No.1 alfalfa in saline soil.
In order to study the influence of different sowing rate and stubble height on the yield and quality of Elymus sibiricus, this experiment analyzed the regeneration performance, yield and quality traits including crude protein, acid detergent fiber (ADF) and neutral detergent fiber (NDF) of E. sibiricus under different treatments with 3 different sowing rates and 5 different stubble heights. The results showed that the sowing rate had very significant effects (P0.01) on regrowth performance, biomass, yield of crude protein, content of ADF and NDF, and had no significant influence on content of crude protein. The plants performed best in the S2(45 kg·hm-2) treatment based on these indices. The stubble height had very significant effects (P0.01) on the tested indices which performed best in the H6(6 cm). The interactions between different sowing rate and stubble height had very significant effects (P0.01) on regrowth intensity, biomass and ADF content. In conclusion, the best cultivate method of E. sibiricus in Sunan was sowing rate with 45 kg·ha-1 and stubble height at 6 cm.
The feed intake of dairy Yili horse under grazing conditions was tested in Zhaosu meadow steppe by simulating feed method, herd difference method as well as internal and external indicator method from August to October in 2013. There was no significant difference between different months of the feed intakes of dairy Yili horse determined by the same method. The dry mass intakes measured by simulating feed method, herd difference method and internal and external indicator method was 12.79 kg·15 h-1·horse-1, 16.39 kg·d-1·horse-1 and 13.28 kg·d-1·horse-1, respectively. The difference between the dry mass intakes measured by herd difference method and internal and external indicator method was not significant (P＞0.05) and the dry matter intake was initially identified as 14.83 kg·d-1·horse-1.
An experiment was conducted to examine the effects of fattening yak and yak-cattle crossbreed fed in the sheds in agro-pastoral zone, Linxia Prefecture of Gansu Province. The results indicated that the best time for fattening the yak and yak-cattle crossbreed in Linxia was from Dctober to March, when the livestock show high adaptation to local environments. The daily body weight gain and the body weight rate of the yaks fed with diet Ⅰ were significantly (P0.05) improved by 32.43% and 5.04%, respectively, in comparison with those of the control. The daily body weight gain and the body weight rate of the yaks fed with diet Ⅱ were significantly (P0.05) improved by 26.98% and 3.81%, respectively, in contrast to those of control. The daily body weight gain and the body weight rate of the yak-cattle crossbreeds fed with diet Ⅰ were significantly (P0.05) improved by 29.26% and 6.94%, respectively, in comparison with those of the control. The daily body weight gain and the body weight rate of the yak-cattle crossbreeds fed with diet Ⅱ were significantly (P0.05) improved by 28.82% and 6.21%, respectively, in contrast to those of control. It can be concluded that, fattening the yak and yak-cattle crossbreed with concentrates in shed is a good integrated economic-ecological system, which can not only promote the economic incomes for the livestock-fattening farmers in agro-pastoral zone of Linxia, but also increase the off-stock rates of grazing livestock and reduce the grazing pressures in the pastoral areas.
The extraction process of fresh leaf protein concentrate (LPC) of Helianthus tuberosus was studied. Four kinds of extraction agents were evaluated based on the extraction rate of LPC, protein content of LPC and extraction rate of crude protein and the result suggested that sodium metabisulfite was optimal for protein extraction. In order to optimize the extraction process of LPC, the solid-liquid proportion, dosage of salt, temperature and pH were optimized by single factor and orthogonal test. The optimal LPC extraction process conditions were solid-liquid proportion of 1∶7, salt dosage of 0.5%, temperature at 90 ℃ and pH 2.0. The amino acid content analysis suggested the LPC was rich in all kinds of amino acid with harmonious proportion. The total content of amino acid was 42.07%, the ratio of essential amino acids and total amino acids (E/T) was 40.55% and the ratio of essential amino acids and non-essential amino (E/N) was 0.68.
The vegetation, disease and pest were investigated and community and population characteristics were analyzed to evaluate the different management measures(enclosed, rotational grazing and non-enclosed) in Haloxylon ammodendron forest in Ulan Buh desert. The results showed that the growth of H. ammodendron in the enclosed area was better than those in rotational grazing area which was better than those in non-enclosed area. The community diversity index and evenness index decreased with were following order: enclosed areathe rotational grazing areathe non-enclosed area whereas the ecological dominance reversed in this order. Age structures of the enclosed and rotational grazing area were growth type and that of the non-enclosed area was stable type. Enclosed and rotational grazing management can promote growth of H. ammodendron which were reasonable management types.
The grassland is one of important agriculture natural resources. However, the grassland degraded seriously in China because of overgrazing. At the beginning of 21st century, enclosure was praised highly as a primary mean for grassland ecological restoration in west China. Effects of enclosure on the vegetation, soil and grassland ecosystem restoration were reviewed in this paper. It was concluded that the moderate grazing is necessary to restore degraded grassland and long-term enclosure is not as good as expected. According to the degree of grassland degradation in different regions, the enclosure should be flexibly combined with reasonable rotation grazing intensity and time to restore degraded grassland and get animal products simultaneously. It was suggested that the grassland ecological system will be sustainable and in good balance when grassland and animals are in win-win.