Drought Evaluation and Driving Force Analysis of Grassland in Qinghai Province北大核心CSCD

This study was aimed to find out the drought characteristics and driving factors of grassland in Qinghai Province. The grassland coverage area in Qinghai Province was selected as the sampling site. The temporal and spatial distribution characteristics and occurrence trend of grassland drought in Qinghai Province were evaluated according to the water balance and crop water requirement and the key driving factors of drought were explored. The results showed that: during the whole growing season, the grassland in the eastern agricultural area, the peripheral area of the Qinghai Lake and the Qilian mountain area maintained light drought and no drought. The serious drought areas were mainly distributed in the southern Qinghai Pastoral Area and some low coverage grassland areas. The spatial distribution of drought was low coverage grassland > medium coverage grassland > high coverage grassland; the drought disaster type of grassland in the whole growing season was mainly light drought, followed by medium drought, the frequency of severe drought and special drought was low, and the intensity of extreme drought was increasing; precipitation and evapotranspiration played the largest driving role in the whole drought process, and they were all negative. With the aggravation of drought grade, evapotranspiration gradually replaced precipitation as the most important driving factor. On the whole, wind speed has a positive effect on drought, while temperature, sunshine hours, and water vapor pressure have little effect on drought. © 2019 Authors. All rights reserved.     

Effects of Utilization Patterns on the Spectral Characteristics of Soil Dissolved Organic Matter in Alpine Meadow of Qinghai Province北大核心CSCD

Soil dissolved organic matter is the most active component of the global carbon cycle. It plays an important role in the terrestrial ecosystem. In order to explore the effects of utilization patterns to the content and structural characteristics of soil dissolved organic matter of alpine meadow in Qinghai province,the contents of soil dissolved organic carbon,ultraviolet-visible spectroscopy,SUVA254,SUVA280,f450/500,HIX and synchronous fluorescence spectroscopy in 0 to 10 cm and 10 to 20 cm soil layers under 4 different utilization patterns,including secondary seabuckthorn forest,returning farmland to forest,farmland and natural pasture,were measured. The results showed that the variation of soil dissolved organic carbon and organic carbon contents in 0 to 10 cm layers performed a similar pattern,i.e. natural pasture > secondary seabuckthorn forest > returning farmland to forest > farmland. However,soil of returning farmland to forest and secondary seabuckthorn forest in 10 to 20 cm layers had higher dissolved organic carbon and organic carbon contents. The contents of organic carbon and dissolved organic carbon decreased with the depth of the soil layer. The same as the complexity of soil dissolved organic matter. The soil dissolved organic matter in the soil of natural grazing land had a higher degree of aromatization and humification,and had more polycyclic aromatic hydrocarbons. The results indicated that the structure of soil dissolved organic matter of natural pasture was more complicated and more stable. It could give a positive effect on maintaining the balance and ecological stability of the carbon pool in the alpine region of Qinghai province. The structure of soil dissolved organic matter in 0 to 10 cm layers was more complicated. © 2020 Ｊｏｕｒｎａｌ ｏｆ Ｒｅｆｒｉｇｅｒａｔｉｏｎ. All rights reserved.     

Study on the Characteristics and Interrelationship of Plant Community and Soil in Degraded Alpine Meadow北大核心CSCD

To explore the changes of vegetation and soil characteristics and their relationships in the alpine meadow at different stages of degradation, the plant biomass, species diversity index, soil nutrient, soil physical and chemical properties were measured by the combination of field sample survey and laboratory analysis. The results showed that vegetation coverage, above ground and below ground biomass decreased from slight to severe degradation, the species diversity index, Shannon-wiener diversity index, Evenness index and Simpson index of vegetation community all showed a decreasing trend, and the soil nutrient and physical and chemical properties tended to deteriorate, the decrease of soil moisture and the increase of soil bulk density led to the decrease of biomass. The interaction and interaction between biomass and soil properties can change plant community composition and soil properties and reduce soil nutrient loss in the moderate degradation stage, improving the stability of plant community structure and increasing the diversity of plant community will be beneficial to the restoration of degraded alpine meadow. This study will help to clarify the degradation pattern of alpine meadow in different degradation stages, and provide a scientific basis and theoretical basis for restoring degraded alpine meadow. © 2019 Authors. All rights reserved.     

Characteristics of Forage Nutritional Quality and Digestibility in Different Types of Grassland in Qinghai Tibet Plateau and their Correlation北大核心CSCD

In order to explore the differences of forage nutritional quality and digestibility among different types of rangelands, five typical rangeland types (alpine meadow, alpine steppe, warm steppe, desert steppe and warm desert steppe) in Qinghai-Tibet Plateau were used as research objects. The characteristics of forage nutritional quality and digestibility of typical rangelands and their correlation were analyzed. The results showed that: there were significant differences in crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF) and dry matter digestibility (DMD) among different types of rangeland (P<0.01). The results of Pearson correlation analysis showed that there was a significant positive correlation between DMD and CP (P<0.05), and a significant negative correlation between DMD and NDF and ADF (P<0.05). Elevation (ELE) was positively correlated with DMD and CP (P<0.05), but negatively correlated with NDF and ADF(P<0.05). In conclusion, there were significant differences in CP, ADF, NDF and DMD among different types of grasslands in Qinghai-Tibet Plateau, and it mainly manifested that with the increase of altitude, ADF and NDF gradually decreased, while CP and DMD gradually increased, and forage quality gradually increased. © 2019 Authors. All rights reserved.     

Dynamic Characteristics of Soil Sucrase and Amylase Activities during Vegetation Degradation in Gahai Wetland北大核心CSCD

In order to study the activities and dynamic characteristics of soil invertase and amylase during the process of vegetation degradation (Non-degradation, Light degradation,Moderate degradation, and Heavy degradation),the filed experiments were conducted in marsh meadow of Gahai wetland in Gannan state,Gansu province. The main results were as following: the average activity values of invertase and amylase activities in 0~100 cm layers varied in different stages of vegetation degradation of marsh meadow, following the order of CK (Non-degradation) > SD (Light degradation) > MD (Moderate degradation) > HD (Heavy degradation). With the increasing of soil layers,the activity of invertase significantly decreased (P<0.05),while the activity of amylase decreased fluctuantly. The activities of enzymes in the surface soil (0~20 cm) accounted for more than 60% of the total activities of each enzyme. The activities of invertase and amylase showed the obvious dynamic characteristics with time in all stages of vegetation degradation. The average activity of invertase in different months was the highest in June (47.07 mg·g-1) and the lowest in August (22.69 mg·g-1). The average activity of amylase was the highest in July,85.18 mg·g-1,while the activity values in other months were low. Correlation analysis showed that soil organic carbon was significantly correlated with invertase and amylase (P<0.01),and soil water content was only significantly correlated with invertase (P<0.01). The results showed that the vegetation degradation in Gahai wetland significantly affects soil invertase and amylase activities,reduces the efficiency of enzymatic reaction,and leads to the deterioration of wetland soil environment. © 2019 Ｊｏｕｒｎａｌ ｏｆ Ｒｅｆｒｉｇｅｒａｔｉｏｎ. All rights reserved.     

Characteristics of Nutrient Contents and Evaluation of Nutritional Value of the Alpine Grassland Plants in the Source Area of the Yellow River北大核心CSCD

In order to explore the characteristics of nutrient contents and scientifically evaluate the nutritional value of the alpine grassland plants in the source area of the Yellow River, the plants of the five different alpine grasslands were selected as the research objects, and the content of crude protein (CP), ether extract (EE), crude fiber (CF), crude ash (CA), total phosphorus (TP) of the plants were determined. At the same time, the principal component analysis method was used for quantitative comprehensive evaluation of the plants nutritional value. The results showed that the CP content of the plants in all alpine grasslands was between 12.78%~15.35%, the EE content was between 2.63%~3.38%, the CF content was between 17.56%~25.16%, the CA content was between 5.52%~11.53% and the TP content was between 0.11%~0.27%. The order of nutrient value of plants in different alpine grassland from high to low was: degraded alpine meadow > native alpine meadow > swamp meadow > degraded alpine steppe> native alpine steppe;The order of yield per unit area of the total nutrients of plants in different alpine grasslands from high to low was: swamp meadow > native alpine meadow > native alpine steppe> degraded alpine steppe> degraded alpine meadow;The order of nutrient value of different plant species from high to low was: Leguminosae>Forbs >Cyperaceae>Gramineae. © 2019 Authors. All rights reserved.     

Screening and Identification of Laccase Fungi in Alpine Meadow北大核心CSCD

Nine strains of fungi that isolated from alpine meadow were used as research objects. The laccase-producing strains were identified by rDNA-ITS method. According to the strains, guaiacol, anthrone, catechol and neighbors were identified. Growth on selective medium of toluidine, o-toluidine, crnaphthol, benzidine, gallic acid as substrate, colony size, size of the color circle produced by laccase-catalyzed redox reaction, and the degree of color depth, the laccase-producing fungus is firstly screened, and the laccase activity is determined by the liquid-producing enzyme fermentation method using ABTS as a substrate for re-screening. The results showed that strain 1. 9 was Uncultured fungus clone. 2. la was Scytalidium, 310b was Marasmius tricolor, 2.1c was Saccharicola, 2. 3a was fungal sp, 2. 4d was Saccharicola. 10a was Marasmiusrotalis, 3. 7c was Alternaria. WB was Verticilliumlongisporum. The screening results showed that except for strain 3. 7c, the other 8 strains basically produced oxidative bands on the culture medium with guaiacol, anthrone, ortho-toluidine and benzidine as substrates, and cultured in gallic acid substrate. No oxidative bands were produced on the culture medium; strains 1. 9, 2. la, 310b, 2. 4d, 10a, 2. lc, and 2. 3a all had laccase activity, and strain 310b had stronger laccase activity than the other strains. © 2019 China Agricultural University. All rights reserved.     

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.     

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 Litter Addition on Soil Organic Carbon Mineralization in the Degraded Alpine Meadow in the Three-River Headwaters Region北大核心CSCD

To explore the effects of plant community structure changes on soil organic carbon mineralization in the different degraded alpine meadows in the Three-River Headwaters Region, we collected topsoil from different degraded alpine meadows, and then added three kinds of litters from different functional groups (grasses, sedges, and forbs) incubated in the laboratory for 203 days. The results showed that the cumulative mineralization of soil organic carbon first increased and then decreased as the degree of soil degradation increased. Litter addition significantly increased the cumulative mineralization of soil organic carbon of non-degraded, slightly degraded, moderately degraded, and severely degraded meadow by 102.04%, 58.71%, 70.68%, and 181.32%, respectively. However, there was no significant difference among the positive effects of different functional groups. Regression analysis showed that soil organic carbon, total nitrogen, and pH of different degraded alpine meadows could better explain the changes in the cumulative mineralization of soil organic carbon. The cumulative mineralization of soil organic carbon first increased and then decreased with soil organic carbon, total nitrogen and pH increased, while the influence degree and direction were altered by litter addition. In general, the plant community structure changes in the different degraded alpine meadows in the Three-River Headwaters Region significantly influenced soil organic carbon mineralization. © 2019 Authors. All rights reserved.     

Climate and land-use change jointly determine the spatial-temporal changes of ecosystem services in Hainan and Haibei Tibetan Autonomous Prefectures，Qinghai Province北大核心CSCD

Evaluating the spatial-temporal dynamics and driving factors of ecosystem services is fundamental to the understanding of how to maintain and improve those ecosystem services. Alpine regions are both a hotspot of ecosystem service supply，and sensitive and vulnerable to climate change. However，there are few systematic studies investigating the joint role of land-use change and climate change in shaping the spatial-temporal dynamics of alpine ecosystem services. Here，we first used models of ecosystem services to quantify changes in seven ecosystem services and in ecosystem multiserviceability from 2000 to 2015 in Haibei and Hainan Tibetan Autonomous Prefectures on the northeastern Qinghai-Tibetan Plateau. Next，we investigated the relative importance of climate change，population density change，land-use change and the interactions between climate change and land-use change effects on ecosystem services using generalized linear models. We found that ecosystem services increased in the south while decreased in the north from 2000 to 2015. Land use change（relative contribution was 34%）was the major factor affecting food supply. Net ecosystem productivity（NEP）was affected by temperature change（relative contribution was 77%）. Water purification（nitrogen and phosphorus retention），soil retention，water yield and water retention were affected by precipitation change （relative contributions were 63%，48%，74%，86% and 75%，respectively）. Ecosystem multiserviceability was also affected by precipitation. In addition to the service of soil retention，the effects of climate change（i. e. precipitation and temperature）on other ecosystem services and ecosystem multiserviceability varied with land-use change （interaction，P<0. 001）. Our study highlights that realizing the sustainable development of ecosystem services needs to pay attention to both land-use change and the interactions between climate change and land-use change and optimizing the spatial-temporal allocation of ecosystem services to improve ecosystem multiserviceability in alpine regions. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Grassland quality response to climate change in Xinjiang and predicted future trends北大核心CSCD

Grassland is a major vegetation type in Xinjiang Province,and is an important component of carbon source-sink calculations. It is therefore important to ecological management decisions to understand the factors driving changes in grassland quality and likely future trends in those changes. We used geographic information maps to eliminate the interference of human activities and determine changes in grassland status and areas of stable grassland from 1980 to 2020,and analyzed changes in grassland quality and its response to climate change using data such as normalized vegetation index（NDVI）,vegetation net primary productivity（NPP）,and meteorological data,among others. We here estimate changes in grassland quality in Xinjiang and predict grassland quality changes from 2021 to 2040 using the Thornthwaite Memorial model and other models. We found that：1） The grassland quality in Xinjiang was generally increasing,with a statistically significant rate of ongoing increase. The grassland cover and quality in mountainous areas of Xinjiang was high,while that at the desert edge was low. 2）The main driving forces for grassland quality changes in Xinjiang are temperature and precipitation. The correlation between grassland quality and precipitation was positive. Temperatures exceeding a certain limit were found to inhibit grassland quality. Sensitivity to temperature and precipitation decline was found to be greater when vegetation cover was lower. 3）The grassland quality and its temporal and spatial changes in Xinjiang can be reflected by climatic productivity. The lower the grassland cover,the stronger was the link between grassland quality and climate factors. 4）Under currently predicted climate change scenarios,the quality of low-cover grassland will be improved in the future,while the quality of other categories will tend to decrease. This information on grassland quality in Xinjiang and its predicted future trends can assist in formulating ecological protection measures and in other ways,such as compilation of carbon stock inventories. © 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.     

Effects of Long-term and Short-term Warming on Arbuscular Mycorrhizal Fungal Community in Alpine Meadow Ecosystem北大核心CSCD

To explore whether the effect of experimental warming on the Arbuscular mycorrhizal (AM) fungal community depends on the duration of treatment, this study measured the response of AM fungal community to long-term (17a) and short-term (3a) warming with Open-top Trade Chambers (OTCs) in alpine meadow ecosystem on the Qinghai-Tibet Plateau, and inferred the main ecological processes that drive the assemblage of AM community. Results showed that long-term warming reduced the AM fungal species richness by 45.7%, while short-term warming reduced it by 80%. The negative effect of long-term warming on AM fungal species richness was mediated by the decrease in root biomass, while the negative effect of short-term warming was mediated by soil nitrogen limitation. In addition, both long-term and short-term warming not only changed the species and phylogenetic composition of AM fungal community, but also led to the transformation of the ecological process from environmental filtration to the neutralization of habitat filtration and competitive exclusion. Our results suggest that the intensity and mechanism of the effect of warming on AM fungal community depend on the duration of treatment. This illustrates that the addition of exogenous nitrogen to promote the growth of plant roots is an effective method to alleviate the negative effects of climate warming on AM fungal diversity in the alpine meadow ecosystem. © 2019 Authors. 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.     

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.     

Comparison and Correlation of Agronomic Characteristics and Fermentation Quality of Different Types of Hybrid Corn北大核心CSCD

In order to select the silage corn (Zea mays L.) hybrids suitable for planting in the northern part of Shanxi Province, the agronomic characteristics of 16 hybrid corn and the fermentation quality of silage prepared after castration were measured. The results showed that in agronomic characteristics, DJJ 26 had the highest plant height and ear height, but its stem diameter was the thinner. The green-leaf number ranked in the top three is TY168, QS 30 and GK516. For yields, DF26 had the highest yield. For ensiling characteristics, except for DH679, TY511, all hybrids were below 4. 20 for pH values. The significantly positive correlation was found between fresh grass yield and stem diameter, green-leaf number, stem weight, ear weight, leaf weight. The Lactic acid content of whole plant corn silage was positively correlated with green-leaf number. Therefore, the corn hybrids with thick stems, more green leaves and good panicle traits should be selected for silage use. The JD65 and TY168, GK516 and QS30 have good growth and fermentation performance, thereby, could be selected for silage corn in the northern part of Shanxi Province. © 2019 China Agricultural University. All rights reserved.     

Application Progress of Selenium and Selenoprotein in Aquaculture北大核心CSCD

随着水产养殖产业的高速发展,水产养殖集约化规模扩大,养殖动物密度增大,容易造成氧化应激反应,这迫使水产养殖从业者亟需寻找无毒无害且高效的饲料添加剂以提高水产动物的抗应激能力。硒(Se)是一种人体和动物生长繁育必需的微量元素,其生物学功能主要通过硒蛋白表达,饲料中添加适量的硒能够增强水产动物的抵抗力。本文综述了硒和硒蛋白的种类以及硒对水产动物的生理机制,同时对硒在水产养殖中的应用进行综述,旨在总结不同硒源作为水产饲料添加剂在改善水产动物生长、免疫与肉质等方面的作用,为其在水产养殖中的高效应用提供科学参考。     

Effects of Grazing on Vegetation Characteristics and Forage Nutrientional Quality in a Temperate Desert Steppe北大核心CSCD

Grazing and fencing field were sampled to explore their effects on vegetation characteristics and forage nutritional quality by the combined analytical method in the temperate desert steppe. The results showed that, grazing significantly decreased the height, coverage and biomass of the plant community, and significantly increased the species richness index (P<0.01). Moreover, grazing significantly increased the Crude protein (CP), Crude fat (CF), Dry matter digestibility (DMD) and Metabolic energy (ME), and significantly decreased the Neutral detergent fibers (NDF) and Acid detergent fibers (ADF) (P<0.01). The species richness index was positively correlated with CP, CF, DMD and ME, but negatively correlated with NDF and ADF (P<0.01). CP, CF, DMD and ME were negatively correlated with NDF and ADF (P<0.01). In summary, grazing significantly increased species richness index and forage nutritional quality. Therefore, it is recommended to carry out appropriate grazing on the fencing temperate desert steppe to make full use of grassland resources and protect species diversity. © 2019 Authors. All rights reserved.     

Biodiversity Characteristics and Biomass of Artificial Transplanting Leymus chinensis grassland in Soda Saline-Alkali land of Songnen Plain北大核心CSCD

In order to explore the effect of Leymus chinensis transplanting on the biodiversity and productivity of saline alkali grassland in Songnen Plain,a comparative experiment was conducted in the transplanting Leymus chinensis grassland. The results showed that the transplanting of Leymus chinensis enhanced plant species and the density of the grassland community. The total plant density under the transplanting of Leymus chinensis was 566.20 plant·m-2,6.85 times as much as that in the control (82.60 plant·m-2),and the difference between the treatments was significant (P<0.05),and the transplanting of Leymus chinensis increased the diversity index of Shannon-Wiener,the evenness index of Pielou and the richness of Margalf species. The total biomass of the community was higher than that in the control. In addition,the total biomass of the transplanting of Leymus chinensis was 357.77 g· m-2,2.14 times as much as that in the control (167.34 g·m-2),and the difference between the treatments was significant (P<0.05),which indicated that the transplanting Leymus chinensis increased the productivity of the plant community,and greatly increased the grassland output benefit, The total income was 3938.00 yuan·hm-2 for the transplanting of Leymus chinensis,7.37 times higher than that in the control (534.40 yuan·hm-2),and the difference between treatments was very significant (P<0.01).Transplanting technology of Leymus chinensis not only improved the biodiversity of the system,but also doubly increased the biomass and economic benefits,So it was a technical model which was worth of popularizing and applying in the saline alkali area of the Western Songnen Plain. © 2019 China Agricultural University. All rights reserved.