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Snow cover is an important part and one of the most active natural elements of the earth surface as well as an important factor affecting climate. As one of seasonal snow area in China, estimating the snow cover of the Tibet Plateau accurately has a great significance on hydrology, climate and economic. The MODIS/Terra daily snow product (MOD10A1) would underestimate snow cover area because of shade during mapping snow cover in mountainous regions over the Tibetan Plateau. To achieve snow cover image in mountainous regions with higher algorithm, the present study used Landsat 30 m observations as “ground truth” and MODIS data(MOD10A1 and MOD09GA) as data sources to improve the method of snow mapping by topographic correcting based on CIVCO. The results showed that, the overall accuracy, snow classification accuracy, Kappa coefficient of the improved method were 86.46%, 73.66% and 0.61, while MOD10A1 were 85.69%、65.35% and 0.57, respectively. Therefore, the algorithm of the improved method were higher than the method of MOD10A1, meanwhile, the missed error of the improved method were much lower than MOD10A1, which indicated the improved method based on CIVCO topographic correction model were more capable of the alpine snow cover mapping and dynamic monitoring in Tibetan Plateau.
To understand the change of soil shear strength and its’ spatial distribution, two sites: Continuous Grazing (CG) and Un-grazed since 1979 (UG79) were investigated by Hand-held vane tester. In each site, a regular sampling grid which covered an area of 105 m×135 m and included 100 points was positioned by GPS. The results showed that, CG induced the reduction of porosity and the increase in bulk density which resulted in the greater shear strength than UG79 within higher litter and soil organic matter. At both UG79 and CG sites, the obvious difference in spatial distribution of shear strength from dry soil water condition to moderate soil water condition indicated that soil water content, at some extent, determined the spatial distribution of shear strength. However, such capacity was limited when soil water content increased, which suggested that soil has the ability to maintain spatial distribution of shear strength itself.
The variation of nutrient elements contents and pH value between rhizosphere and non-rhizosphere soils of 5, 10, 15, and 20-year-old Artemisia sphaerocephala were studied. The results revealed the following conclusions: 1) With the extension of growing period, N and P in rhizosphere soil increased, the highest enrichment rate of ammonium and P were 91.15% and 127.30%, respectively. 2) Cu had negative enrichment, which decreased with the extension of growing period. The contents of other micronutrients were higher in rhizosphere than that in bulk soils. For example, Mn accumulated significantly in rhizosphere with the extension of growing period, and the highest enrichment rate 85.24% which appeared in 20 year-old A.sphaerocephala growing soil. 3) There were obvious acidification in rhizosphere of 15 and 20 year-old A.sphaerocephala, however, there was no obvious change in rhizosphere of 5 and 10 year-old A.sphaerocephala. 4) There was rhizosphere effects correlated with different nutrient elements in soil.
Stylosanthes are good legume forages. The high level of polyphenol and polysaccharides in the blade make DNA extraction difficult. CTAB method for DNA extraction was improved for Stylosanthes in this study. The orthogonal design was employed to optimize SSR-PCR system of Stylosanthes. The optimal system was each 20 μL sample mixture contained 1 μL 50 ng·μL-1 template DNA, 1.6 μL 5 μmol·L-1 primers, 1.6 μL 10 mol·L-1 dNTPs, 1.2 μL 25 mol·L-1 Mg2+, 0.3 μL 5 U·μL-1 Taq DNA polymerase, 2 μL 10× PCR Buffer (Mg2+ free) and 10.7 μL ddH2O. The PCR was performed with 35 cycles with three steps . One hundred and twenty three polymorphic microsatellite loci from seven species of Stylosanthes were amplified in eight another different species of Stylosanthes with the optimization system. Forty four polymorphic microsatellite loci can be effectively amplified in these eight species of Stylosanthes. Twenty six SSR primers with high polymorphism were selected for fingerprinting, genetic diversity analysis, molecular breeding and variety identification of Stylosanthes.
The effects of different concentrations of polyethylene glycol (PEG) solution intimidated water stress on physiological property of Miscanthus sinensis were studied. The results showed that the content of malondialdohyde(MDA) and relative conductivity increased, superoxide dismutase(SOD), peroxidase(POD), catalase (CAT), ascorbate dependent peroxidase (APX), glutathione reductase(GR), ascorbate(ASA) and glutathione(GSH) increased firstly and then decreased with PEG stress extension. However, the variation of each index was different under different PEG stress conditions. Each of indices could maintain similar levels with control (CK) in low PEG concentration (10% or less). These indices were significantly different with CK in high PEG concentration (20% or higher). These results showed that M.sinensis seedlings can stand less than 20% PEG stress and had a certain degree of drought tolerance. More than 20% PEG could bring M.sinensis seedlings severe drought stress and even death.
‘Lanyin Ⅲ’ Zoysiagrass (Zoysia japonica cv. Lanyin No.Ⅲ) has widely application on sports turfs in south China. However, it has been limited for further application in larger market due to lower seed yields and poor seed setting rate. This study was aimed to increase seed production of ‘Lanyin Ⅲ’ Zoysiagrass through cultivation practices, such as mowing frequency and time, fertilization and planting row-spacing. Branches density, spike density, ear length, grain number per ear, seed yield, weight of 1 000 seeds, seed setting rate and germination percentage of seed were evaluated during this experiment. The results showed that these three cultivation practices had impacts on seed production of ‘Lanyin Ⅲ’ Zoysiagrass and the effects of row-spacing were biggest among them. The optimal cultivation practices for seed production of ‘Lanyin Ⅲ’ Zoysiagrass were 50 cm row-spacing, mowing one time in May and fertilization of N fertilizer three times during the growing season. The results will provide theoretical basis for the feasibility of seed production of ‘Lanyin Ⅲ’ Zoysiagrass.
Setaria sphacelata cv. Narok is one of the most popular forages applied in grassland production and ecological environment construction in southern China. However, the low seeds production and deep dormancy restrict the popularization and utilization of this forage. Four different methods including mechanical treatment and various chemical treatments were applied to break dormancy of Narok seeds from Yunnan Province. The results showed that all of these four different treatments could break Narok seed dormancy with varied effects. The treatments of piercing skin after removing shell and soaking in 25% HCl solution for four minutes were more useful than the others. The germination potential, germination rate, germination index and the vigor index of piercing skin after removing shell was 32%, 33%, 8.85 and 0.012 0, respectively, and these four indices of soaking in 25% HCl solution for four minutes was 31%, 35%, 8.47 and 0.014 3, respectively. The indices of these two treatments were significantly higher than the corresponding index from control(P＜0.05), but there was no significant difference between each other (P＞0.05).
In order to explore the effects of vegetation on seed germination and seedling settlement during the process of ecological restoration, the allelopathy of the extracts of different plant tissue from Populus euphratica with various concentrations (0.04, 0.08, 0.12, 0.16, and 0.20 g·mL-1) on the seeds of perennial herb Alhagi sparsifolia was analyzed. The water extracts of P.euphratica have inhibition effects on the seed germination and seedling growth of A.sparsifolia. Different plant tissues and different concentrations of water extracts had different inhibition effects. The water extract of P.euphratica leaves had significantly inhibition effects on seed germination rate and seedling length of A. sparsifoliai The water extracts of stems also had significantly inhibiting effects on seed germination of A.sparsifoliai. The water extract of roots had significantly inhibiting effects on the seedling length of A.sparsifolia.
Autumn sowed oats were intercropped with common vetch at different ratios in the rain-fed Loess Plateau, so that the effects on yield, leaf area index (LAI), light interception and soil nitrate content could be evaluated. Intercropping of oats with common vetch was carried out at ratios of 1∶0, 4∶1, 2∶1, 1∶1, 1∶2, 1∶4 and 0∶1. Results indicate that the ideal cutting time is between flowering and harvesting, and that the best mixture rate is 2∶1 or 1∶1. At vetch flowering, The highest yield of 3 264 kg·ha-1 occurring at a mixture rate of 2∶1, followed by 2 828 kg·ha-1 at a mixture rate of 1∶1, producing 30% and 13% more yield than monocultured oat respectively. The highest yields at harvesting were 5 942 kg·ha-1 under mixture rate of 1∶1 and 4 980 kg·ha-1 under mixture rate of 2∶1, which respectively produced 50% and 30% more yield than monocultured vetch. The highest relative total yield at flowering was 1.39 (2∶1 mixture rate), followed by 1.24 (1∶1), which indicates that the land use efficiency under this intercropping program was improved by 24%~69% when compared with monocultured oats. There was no significant difference observed in canopy leaf area index, light interception and soil nitrate content between intercropping mixture rates, which suggests that there was no competition for light and that the nitrogen fixation ability of legumes was not demonstrated during the intercropping experiment. This result may be related to “nitrogen repression” caused by a large amount of fertilizer applied at sowing.
A variety of nutrition indices including crude protein (CP), crude fat (CF), acid detergent fiber (ADF), neutral detergent fiber (NDF), calcium (Ca), phosphorus (P), crude ash and grasslands yield of 15 different mixture modes were analyzed. The grey relational degree method was applied to comprehensively evaluate nutrition. The variation of the contents of CP, CF, ADF, NDF, Ca, P and crude ash was 15%~18%, 1.5%~1.8%, 25%~30%, 30%~50%, 0.4%~1.8%, 0.1%~0.3% and nearly 10%, respectively. Three mixture modes including Leymus chinensis+Setaria italic+Medicago varia (3∶1∶1), Bromus inermis+M.varia(2∶1) and Elymus nutans+M.varia (3∶2) were the best among all of the mixture modes. Two mixture modes including perennial grasses+M.varia (1∶1) and perennial grasses+Avena sativa+M.varia (3∶1∶1) were not suitable. The other 10 mixture modes were better. These results were consistent with mixture mode applied in some regions in Hulunbeir which had the important theoretical value to the entire region.
In order to screen appropriate grass varieties and seeding rate for orchard in Shenyang area, three different forages including alfalfa (Medicago sativa cv. Zhaodong), white clover (Trifolium repens cv. Rivendel) and red clover (T. pratense cv. Renegade) were interplanted with different seeding rates in apple orchard. The winter surviving rate, grass yield, growth rate and crude protein were investigated to determine appropriate grass varieties and seeding rate. The results indicated that alfalfa with natural winter surviving rate of 100% performed better compared with white clover and red clover with highest winter surviving rate of 12% and 48%, respectively, which was appropriate in the orchard of this region. Alfalfa can be mowed three times throughout the year. The yield of hay, growth rate and the average crude protein of alfalfa were highest with the medium seeding rate (15 kg·hm-2) which were 15 783.74 kg·hm-2, 2.63 cm·d-1 and 19.79%, respectively. Alfalfa with the low seeding rate have the highest average of net assimilation rate which was 3.32 g·m-2·d-1. Alfalfa was appropriate grass variety for orchard in cool area and the appropriate seeding rate was 15 kg·hm-2 based on the yield of hay, growth rate and the average crude protein.
In order to explore the mechanism and regular pattern of precipitation on wheat yield, the impacts of precipitation from 1971 to 2005 on wheat yield during its growth period were imitated using APSIM model and quadratic polynomial stepwise regression analyzed in Dingxi City, Gansu province. The results showed that wheat production was not only affected by total annual precipitation, but also the variations of growth period precipitation. The most effective precipitation period was seedling stage and followed by jointing stage, carry flag stage, heading stage, filling stage and flowering stage. The correlation between precipitation and wheat yield during seedling stage and jointing stage showed downward opening parabola. Effects of precipitation in seedling stage and jointing stage were 6.6 and 3.7 times of precipitation in carry flag stage, respectively. Effects of precipitation in heading stage, carry flag stage, flowering stage and filling stage on wheat yield showed secondary superposition incremental trends during the studied area. The precipitation in seedling and elongation stage was one of main limit factors of wheat yield in this studied area.
Production of Poa crymophila cv. Qinghai in the alpine region of Qinghai Tibet was studied. In the alpine region without specific irrigation, P.crymophila cv. Qinghai grew very slowly in the first year of planting and faster in second and third years. The growing period was 106～110 days. P.crymophila cv. grew very fast from the flowering stage to the milky maturity stage and grew very slowly in the ripe stage. Crude protein content decreased with plant growth with the highest content in heading stage. Crude fiber content increased gradually with plant growth. Crude fat, nitrogen free extract and crude ash content have no significant change during the whole productive period.
Phragmites australis widely distributed in Songnen Prairie with long history and formed a series of biological, ecological as well as genetic characters contributing to accommodate to the specific local climatic and edaphic conditions. These characters included anatomy and ultrastructure, photosynthetic and resistance physiology, various functions of rhizome, resistance to different stresses including salinity, alkalinity, drought and cold, gene flow, genetic variation among clones and populations, phenotypic plasticity, plasticity in reproductive strategy as well as coordination of reed growth and biomass allocation strategy.
The relationship between ecological distribution of grasshopper and environmental factors is theoretical basis to reveal geographic occurrence of grasshopper. The relationship between grasshopper population composition and vegetation community was studied using field investigation and quantitative analysis in typical steppe of Yanchi in Ningxia. The results showed that there were 24 different species of grasshoppers in typical steppe of Mahuangshan Mountain and the dominant species were Calliptamus barbarus, Oedaleus asiaticus, Angaracris rhodopa, Bryodema nigroptera, Bryodemella tuberculatum, C.abbreviates, Compsorhipis davidiana, Chort hippus dubius, C.albonemus. The numbers of individuals and richness and diversity of species had positive correlation with the diversity, biomass and coverage of vegetation and had negative correlation with the evenness and height of vegetation. The numbers of individuals, and richness and diversity of species had negative correlation with the dominance of the families of Gramineae and Compositae and had positive correlation with the dominance of the families of Leguminosae and others. O.asiaticus, A.rhodopa and C.albonemus performed best in terms of selectivity for grass forages and E.coerulipes and F.beicki performed best for composite forages based on the correlation between dominant species and vegetation community. C.albonemus, F.beicki and E.coerulipes preferred to the poor vegetation conditions, while A.rhodopa preferred to the good vegetation conditions.
In order to determinate the associative effects of different diet on rumen fermentation, 9 healthy and half sib Chengdu Ma goats with similar weighs (41.3±1.2) kg and fitted with permanent ruminal cannulas were randomly divided into three groups and fed with the different diets which was rice straw (RS) supplemented with 25%(MSL25), 50%(MSL50) and 75%(MSL75) alfalfa hay (Medicago sativa, MSL), respectively. pH of these three mixed forages fluctuated between 6.53 and 6.93. The concentration of NH3-N, total volatile fatty acids(VFAs), rumen microbial protein (MCP) were 73.56～132.23 mg·dL-1, 9.42～43.27 mg·dL-1 and 69.45～107.28 mmol·L-1, respectively, which nonlinearly increased with increasing levels of MSL. Compared with MSL25, the multiple-factors associative effects index (MFAEI) of MSL75 and MSL50 were 1.21 and 1.03, respectively, which indicated that 50% was the optimal proportion of alfalfa hay supplemented to the rice straw in this trail. There was no significant improvement on fiber usage when MSL supplementary proportion was over 50%.
Melilotus albus and corn straw were mixed and silaged at ratio of 10∶0, 8∶2, 6∶4, 4∶6, 2∶8 and 0∶10, respectively. The nutrition composition, fermentation quality, coumarin and dicoumarol content were measured after 30, 45 and 60 d ensilage. The aims of this study were to seek optimal mixed silage radio and ensiling days of M.albus and corn straw, improve the fermentation quality and nutrition composition, and reduce the content of coumarin and dicoumarol. The result showed that, with the increase of the proportion of M.albus, pH, ammonia/total nitrogen, crude protein and lactic acid increased while the neutral detergent fiber and acid detergent fiber decreased. The coumarin and dicoumarol contents of all mixed silage were significantly lower (P0.05) than raw material of M.albus. The mixed silage with M.albus and corn straw at ratio of 2∶8 was best as the pH value reduced to 3.87~4.03, the content of crude protein increased by 38.34%~46.47% compared with single corn straw silage and the coumarin and dicoumarol content decreased by 80.99%~81.82% and 90.52%~91.00% compared to raw material of M.albus. Ensiling days had no significant effect on the fermentation quality and content of coumarin and dicoumarol.
This article reviewed the progress of lactic acid bacteria silage technology around the world. The methods, application and effects of lactic acid bacteria silage technology and the effects of lactic acid bacteria on fermentation quality and aerobic stability of silage were summarized. The screening and identification of different bacteria strains and their impact on animal performance were also mentioned. Throughout these review, the comments about the prospects and future directions, especially the widely application of molecular biology in lactic acid bacteria silage technology were presented.
In order to improve the management of rangeland resource and achieve digitization and information management of rangeland in Liaoning Province, the rangeland geographic information database of the whole Liaoning Province has been established by taking the digital map of 1∶1 000 000, 1∶250 000 and 1∶50 000 scale of Liaoning Province as basement combining with field surveyed GPS data and rangeland attribute data. Through integrated application of geographic information, database and network information technology combined with B/S and C/S structure, Liaoning rangeland resource management system has been constructed which comprised resource, attribute, engineering, disaster, monitoring, knowledge, documents, statements and other information. This system will provide network information interaction platform with systematic, efficient, convenient and intuitive characteristics for rangeland management in Liaoning Province.
A research was conducted to study the total triterpenes distribution among different ages and different parts of sea buckthorn (Hippophae rhamnoides) from Datong County, Qinghai Province. The total triterpenes were extracted by ultrasonic extraction process and determined by spectrophotometry, ursolic acid used as control sample. The results showed that, the content of total triterpenes in sea buckthorn seedling leaf was highest among all of the samples. Furthermore, plant age and parts played important role in accumulation of plant secondary metabolites. It indicated that, sea buckthorn leaf was more valuable for the exploitation and development of total triterpenes. Key words:sea buckthorn; total triterpenes; spectrophotometry