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The soil organic carbon (SOC), total nitrogen (TN), particulate organic carbon (POC), light fraction organic carbon (LFOC), carbohydrate, soil organic carbon density were determined on-site under different land cover types with the similar altitude and landform in alpine grassland in Eastern Qilian Mountain. The results showed that SOC and TN changed consistently and performed differently in different land cover types. Soil organic carbon density also performed differently in different land cover types which was highest in grassland (40.42 kg·m-2), moderate in shrub land (32.42 kg·m-2) and lowest in bare land (9.33 kg·m-2) in 0-60 cm depth soil. The content of the POC, LFOC and carbohydrate performed differently in different land cover types, which were highest in grassland, moderate in shrub land and lowest in bare land. With the degrading of alpine grassland to bare land or black beach due to overgrazing, there was an obvious decrease of SOC, TN, POC, LFOC and carbohydrate which result in serious degradation of alpine soil and meadow ecosystem. Therefore, reasonable grazing and regulation of human activities were the effective ways to maintain alpine meadow and achieve sustainable development and social stability of Eastern Tibet Plateau.
In the present study, the change characteristics of soil carbon storage under different grazing systems were studied to provide suggestion for grassland reasonable usage in carbon storage perspective because grazing system is the main artificial factor of soil carbon storage. The variations of organic carbon storage in the 0－30 cm soil layers were studied from May to October with three different grazing systems which were continuous grazing (CG), rotational grazing (RG) and non-grazing (NG) in Stipa breviflora desert steppe in Inner Mongolia. The soil organic carbon storage in 0 to 30 cm soil layers of CG were significantly lower than that of RG and NG (P0.05), however, there were no significant difference between RG and NG (P0.05). There were two carbon sources progresses and one carbon sink progress in 0 to 30 cm soil layers of CG in growing season, there were one carbon sources and one carbon sink progress in that of RG and there was one carbon sources progress in that of NG. The soils from all the sampling sites were identified as carbon source with net increase carbon storage. The carbon source of CG, RG and NG were -0.75, -0.45 and -0.32 kg·m-2, respectively. The comprehensive analysis suggested that the reasonable grazing system contributed to soil carbon accumulation and could reduce carbon emission and the order was NGRGCG.
In order to quantitative analyze the climate variation characters and tendency of Inner Mongolia desert steppe at different time scales, the present research employed monthly average temperature, precipitation and average wind speed from 9 meteorological stations around desert steppe area and surrounding regions during 1961-2011 to understand the basic climate of desert steppe and diagnose the yearly and monthly variations tendency and degree of the above 3 factors. The results showed the mean annual temperature of Inner Mongolia desert steppe significantly increased in the 1990s, increased by 2.7 ℃ after 2000 in the western region, increased by 4 ℃ in February. The annual precipitation has no significant variations with the yearly 5% changes in most regions, however, the winter precipitation increased significantly in northern and south-central and the spring and autumn precipitation decreased in the west. The annual mean wind speed slowed down by 0.1~1.4 m·s-1 since the 1980s, and it slowed down more in spring and winter.
The adaptability of 32 ornamental grasses species belonged to 10 families and 20 genus and introduced to Rizhao were evaluated based on anniversary observation of phenological phase, biological characteristics and landscape characteristics. The results showed that the grasses were divided into five levels(Ⅰ～Ⅴ). Arundo donax and Cortaderia selloana were in grade Ⅰ which had high ornamental value in Rizhao and were perfectly suitable to Rizhao. Miscanthus sp., Pennisetum sp., Thalia dealbata and other 14 grasses were in grade Ⅱ which had ornamental value in Rizhao and can be extended in Rizhao. Scirpus validus, Iris tectorum and other 6 grasses were in grade Ⅲ which had high value of each index with unobvious inflorescence and lower ornamental value or short flowering-time and could be extended. Carex tristachya, Calamagrostis epigejos and Juncus effusus were in grade Ⅳ which did not have enough introduction and need more planting before a further evaluation. Ophiopogon japonicus and O. bodiniert were in grade Ⅴ which were not suitable for ornamental plants.
Arbuscular mycorrhizal fungi(AM) exist widely in agricultural system, which may be associated with the vast majority of crop to be arbuscular mycorrhiza symbiosis. AM can improve nutrient and water absorption of the crops, and increase crop yield and resistance to biotic and abiotic factors and improve soil structure. Tillage, straw mulching, crop rotation, fertilizer, pesticides and other agricultural management practices will influence the diversity of AM fungi, hyphal length and the infection status of crops which will affect the function of AM fungi in pastoral agricultural ecosystem. No tillage, straw mulching, crop rotation, organic fertilizer can promote the infection of AM fungi which have significant impacts on the diversity of AM fungi. However, tillage, monoculture, fertilizers, fungicides can reduce the infection of AM fungi which also have influence on the diversity of AM fungi. The present paper summarized and reviewed the effects of agricultural management measures on AM fungi diversity and function, aiming to improve pastoral agricultural ecosystem productivity through the application of AM fungi.
Soil microbial diversity of grassland is one of the important issues in grassland ecology. This paper reviewed the advances in researches on influencing factors of soil microbial diversity in grassland, including abiotic factors, human activities and biological factors, and explored the effects of variations on microbial diversity from soil temperature, soil moisture, soil pH, grazing, cultivation, fertilization, vegetation type, plant diversity, community structure, invasive plants and rhizosphere. Finally, future researches of soil microbial diversity, environmental factors and adaptation strategy were discussed which provided scientific basis for the response and adaptation mechanism of grassland.
Seeds of Elymus atratus and E. sibiricus were treated with accelerated aging at high temperature (45 ℃)and high humidity(RH100%) for 0, 1, 2, 3, 4, 5, 6 and 7 d. The results showed that germination rate, germination energy, germination index and vigor index of both E. sibiricus and E. sibiricus decreased with treatment period extended whereas E. sibiricus decreased more than E. atratus. The content of malondialdehyde slowly increased and the content of soluble sugar increased. However, the peroxidase activity, superoxide dismutase activity and the content of soluble protein decreased with treatment period extended. Resistance to accelerated aging of E. atratusis better than that of E. sibiricus
The present study evaluated the effects of shading on germination of different cultivars of Poa pratensis (Merit, NuGlade and K. B. G) and Festuca rubra (Boreal and Rubra). The shading treatments including 22%, 45%, 66% and 83% of shading and no shading as control. The results showed that shading treatments significantly increased (P＜0.05) the germination percentage, the germination power, the germination index and the vigor index which also increased with the increasing of shading. But the length of radicle decreased and the length of germ increased with the increasing of shading.
The objective of this study was to determine the content of coumarin in the aqueous extracts of yellow sweet clover (Melilotus officinalis) and evaluate its allelopathic effect on weeds. Liquid chromatography-mass spectrometry (LC/MS) was employed to determine the content of coumarin in the aqueous extract of yellow sweet clover. Laboratory bioassay was conducted to evaluate the effects of different concentrations of coumarin on seed germination and seedling growth of Italian ryegrass (Lolium multiflorum), grainamaranth (Amaranthus hypochondriacus), barnyardgrass (Echinochloa crus-galli), common knotgrass (Polygonum aviculare), alfalfa (Medicago sativa “Victoria”), red clover (Trifolium pratense) and yellow sweet clover. The results showed that content of coumarin in the aqueous extracts of yellow sweet clover was 46.7 μg·mL-1, accounting for 1.152% of total dry matter of the aqueous extract. At the concentration of 40 μg·mL-1, coumarin significantly inhibited (P0.05) seed germination and seedling growth of Italian ryegrass, common knotgrass, red clover and alfalfa. At the concentration of 80 μg·mL-1, coumarin significantly inhibited (P0.05) both the seed germination and seedling growth of all the tested plants except with a promotion on the seed germination of grainamaranth, and completely inhibited seed germination and seedling growth of ryegrass seed, common knotgrass and red clover. These results suggested that there were high content of coumarin in aqueous extract of yellow sweet clover which had different allelopathic effects varied with weeds species.
The phenotypic and reproductive characteristics of Kobresia setchwanensis were investigated and analyzed in order to understand the clonal phenotypic variation and reproductive strategies of this species along altitude in Northern Tibet. For the clonal phenotypic parameters, there were significant differences among populations from different altitudes. The most suitable altitude for K. setchwanensis was about 4400m above sea level in Northern Tibet. With the increase of the altitudes, the plant height, ramet number and biomass accumulation of K. setchwanensis decreased. The number of reproductive branches and grains per spike, the germination rate and biomass allocation also decreased with the increase of altitude which suggested that there was a trade-off relationship between the sexual reproduction and the clonal reproduction of K. setchwanensis. The results suggested that K. setchwanensis gradually reduced input of the sexual reproduction while increased input of the clonal reproduction to maintain and expand the population with the increase of the altitude.
In Qinwangchuan saline soil region of Gansu Province, the phenological phase, growing rate, leaf area and tiller number of 4 domesticated lines of Pennisetum longissimum var. intermedium were comparatively investigated in field trials and their production performance were comprehensively evaluated with grey system theory. The result showed that line 1, 2 and 3 germinated quickly, matured early and had growth period of 147 d, in contrast, line 4 germinated slowly, matured lately and had growth period of 160 d. Line 1 was the fastest growing with significantly higher (P0.05) plant heights than the other three lines in each growth period and reached the maximum (187.94 cm) at blooming stage. Line 3 grew slowly with the lowest height of 150.51 cm at ripe stage. During the early and middle of growth stage, leaf area and stem diameter of all lines gradually increased and then stabilized or declined after heading stage. Line 1, 2 and 4 performed consistently and significantly better than the line 3. Line 2 also has the strongest tiller ability. Line 1 and 2 had fast growing rate, strong tiller ability, high hay yield and early maturity after comprehensive evaluation which were suitable for widely planting in the Qinwangchuan saline soil region.
The photosynthetic characteristics and seed yields of sudangrass response to different topdressing nitrogen fertilizer including six different nitrogen application rates of 0, 150, 300, 450, 600 and 750 kg·ha-1 and the fixed proportion (3∶4∶3) were studied by single factor randomized trials using Sorghum sudanense ‘Xinsu No.2’. The results showed that photosynthesis rate (Pn), stomatal conductance (GS), transpiration rate (Tr) significantly increased with increasing of nitrogen fertilization application rate in a certain range. The values of Pn, Tr, GS in heading stage were significantly greater than that in grain filling stage and heading stage. Excessive nitrogen fertilizer could inhibit the photosynthetic during growth period. The results confirmed that SPAD value can fully reflect the chlorophyll contents. The SPAD value significantly increased with increasing of nitrogen fertilization application rate if the nitrogen fertilizer rate was less than 450 kg·ha-1. Nitrogen fertilizer could effectively improved thousand seeds weight, grains per spike, and also significantly increased sudangrass seed yield in a certain range. However, the seed yield significantly decreased with the increasing of fertilizer. The seed yield was maximized (3 815 kg·ha-1) at the level of 600 kg·ha-1 nitrogen application. In combination with photosynthetic characteristics and seed yield of sudangrass, the best nitrogen application rate was 600 kg·ha-1.
The community productivity, species richness and their interaction response to grazing and fertilization were analyzed in eastern alpine meadow of Tibetan Plateau with four nitrogen fertilizer levels and two grazing levels. Fertilization significantly reduced (P0.001) the species richness and inhibited the growth of forbs group but increased the aboveground biomass and promoted the growth of grasses group, while grazing significantly increased (P0.001) the species richness and promoted the growth of forbs group but decreased the aboveground biomass and inhibited the growth of grasses group. In the plots with both fertilized and grazed, there was no significant changes for species richness, whereas there were significant reductions (P0.001) in the fertilized plots without grazing. These results suggested that grazing was the main factor and the effects of fertilization was covered up by the grazing. There was a negative relationship between species richness and community biomass in the plots two only with grazing or fertilization. The moderate nitrogen fertilization can increase community productivity and the ratio of forage without effects on species richness. This management was optimal for loading more stocks to achieve more profits without degradation of grassland which can be applied in the local grassland.ested that moderate fertilization in the grassland of the study site would increase community productivity and have little effect on species richness. The reasonable solution is suitable for generalization in the local pasture.
Grazing is an important way for grassland utilization. Livestock has direct and indirect impacts on soil seed bank through feeding, excretion and trampling during the grazing process which change the relationship between soil seed bank and plant community. In the present paper, we summarized the effects of grazing on size, species composition, spatial distribution pattern of soil seed bank and its relationship with plant community to provide a theoretical basis for sustainable utilization and management of grassland, and promote the further researches of grazing impacts on grassland.
Melilotus, an excellent pasture and green manure crop, not only has high yield and outstanding quality, but also shows very strong tolerance or resistance to the adverse environment. Scientific research progress at home and abroad on Melilotus was summarized in terms of forage value, high yield and quality forage and seed production, as well as the impacts of Melilotus on soil and following crop. Some unsolved problems in Melilotus research in China were presented and discussed based on comprehensive analysis of existing research achievement.
Animal production is the traditional agricultural industry in northwest China, and has an very important strategic significance on agricultural structure adjustment and grassland agriculture development. This aryicle choose Maqu, Huanxian and Minqin County as examples, thinking that the serious natural grassland degradation and the shrinking area, insufficient cultivated grassland area, single varieties and lower production, the mismanagement of herds et al that hindered the natural connection of grass and livestock production system, and also the main reasons to restrict the animal production. So this research present that, the in house cattle breeding+winter feeding, family joint household, short term fattening and coupling of grassland and livestock systems are the main livestock production development mode coupling in northwest of China.
The rodent community were sampled by a trap-day method in four different disturbance habitats in April, July and October (spring, summer, autumn) from 2009 to 2011 in Alashan desert. The habitats were farmland, rotational-grazing, over-grazing and prohibited-grazing areas, and the relationships between rodent community and plant factors were analyzed by Redundancy Analysis (RDA). The results showed that rodent community diversity indices (H) between different disturbance habitats were significant difference (P＜0.05) in three seasons. The highest diversity index of rodent community was found in rotational-grazing area (1.42) and the lowest was the over-grazing area (0.91) in spring; in the same way, the highest index was found in farmland area (1.45) and the lowest was the grazing-exclusion area (1.06) in summer; the highest index was found in over-grazing area (1.23) and the lowest was the grazing-exclusion area (0.65) in autumn. The RDA with forward selection showed that variations of rodent community were significantly related to coverage of suffruticosa plant and density of herbaceous plant in spring and summer, density and coverage of herbaceous plant in autumn. We suggest that coverage and density of plants are the most important factors influencing the structures of rodent community in Alashan desert.
In order to reveal the response of vegetation and arthropods community to simulating precipitation, the soil properties, vegetation and arthropods characteristics of sandy grassland in desert steppe of Ningxia were evaluated under different treatments including natural precipitation (control), 20% more simulating precipitation, 40% more simulating precipitation, 60% more simulating precipitation and 100% more simulating precipitation. There was no significant difference in soil, vegetation, and arthropods properties between the different treatment plots and prior experiment, which suggested the similarity of experiment plots and practicability of experimental design. After treatments, simulating precipitation had little effects on plant species richness. However, in the autumn, plant density with 40% more simulating precipitation was significantly (P0.05) lower than that with control, and plant height with 20% and 40% more simulating precipitation was significantly (P0.05) lower than that with control. Meanwhile, simulating precipitation also had little effects on arthropod abundance. In the autumn, the arthropod species richness with 20%, 60% and 100% more simulating precipitation were significantly (P0.05) higher than that with control. The present results suggested that the comprehensive consideration of all the factors including soil, vegetation and arthropods was necessary for experimental design. The plant abundance and height and arthropod species richness were relatively sensitive to the precipitation although there was time delay.
In recent years, high density grasshopper disaster within larger area occurred periodically in hilly meadow steppe of Horqin which bring severe damages and threat to the development of local animal husbandry. The plant community, grasshopper community and the correlation between them in four typical grassland plots (plotⅠ: Stipa baicalensis+Achnatherum sibiricum community; plotⅡ: Cleistogenes chinensis+Lespedeza daurica community; plotⅢ: Artemisia pectinatal community; plotⅣ: C. squarrosa community) were investigated in hilly meadow steppe of Horqin. The results showed that there were significant different (P＜0.05) for the richness index, diversity index and evenness index of plant community in four grassland plots, however, there was no significant difference for these 3 indices of grasshopper community. The correlation between different indices from plant community and grasshopper community performed differently in four grassland plots. Grasshopper community diversity and plant community diversity negatively correlated (P0.05) with each other in plot Ⅱ, however, they positively correlated (P0.05) with each other in plot Ⅰ and Ⅲ, and significantly positively correlated (P0.05) with each other in plot Ⅳ. The occurrence and distribution of grasshopper were affected or determined by the habitat condition consists of plant community and the biological characteristics of grasshopper. Habitat selection diversity of grasshopper reflected strong adaption of grasshopper and synergy between grasshopper and plant.
The conditions of 125 settled herdsmen households in Ashili County, Changji City in North Xinjiang region were investigated by questionnaire, on-site interview and key figure interview. The results showed that the production and management modes of these families were mainly divided 7 types after herdsmen settlement and the most popular mode was “Grazing+crows farming+cultivating+casual labour” which accounting for 39% of the total herdsman. The highest income per capita (11 320.47 CNY·a-1) came from the mode of “Grazing+cows farming+cultivating+casual labour”; the medium per capita income (9 488.1 CNY·a-1) came from the mode of “Grazing+cows farming+cultivating”; the lowest per capita income (2 674.75 CNY·a-1) came from the mode of “cows farming+cultivating”. There was significant correlation between per capita income of herdsman and production and management mode and the higher per capita income achieved if there was more diversified production and management mode. The correlations and stepwise regression analysis indicated that there was a significant positive correlation between per capita income of herdsman and sheep livestock units, grazing investment of per capita, cow investment of per capita and livestock sheep units was the key factor. The correlation analysis was consistent with stepwise regression analysis which fully explained the herds’ production investment was an important factor for the herds’ income.
There are significant effects of field post harvest managements on forage seed yield in the next year, especially in the areas with longer vegetative growth after fruiting. For post harvest managements, straw and stubble treatments usually were neglected which lead to negative influence on the branch and tiller formation, overwinter, regrowth in spring and utilization period. The stubble removing can reduce the shading, improve the development of new tillers, reduce temperature for vernalization, and increase the reproductive tillers. The existing problems of postharvest management were summarized by introduction of methods, roles, technical points and research status. The objective of this study was to introduce the effects of different postharvest management practices, and provide a theoretical basis and technical support for forage seed production.