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2020 Vol.37(1)

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2020, 37(1): 1-4.
[Abstract](925) [FullText HTML] (515) [PDF 379KB](18)
Abstract:
Distribution of shrub-herb community biomass and its relationship with soil factors in middle and low mountainous areas of northwest Hebei Province
DU Meiqi, ZHANG Hengshuo, PENG Dong, ZHA Tonggang
2020, 37(1): 1-9. doi: 10.11829/j.issn.1001-0629.2019-0227
[Abstract](1624) [FullText HTML] (969) [PDF 641KB](70)
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The distribution of aboveground and belowground biomass (Belowground / Aboveground, BA) is an important parameter associated with shrubby grassland communities. It is of great significance for estimating carbon storage and studying the growth strategy of shrubby grassland communities. The shrubby grassland communities at altitudes of 1 630 – 2 030 m in the middle and low mountainous areas of Northwest Hebei Province were chosen as the research objects. This study compared and analyzed the distribution of shrub-herb community biomass and its response to soil factors through field investigation, sampling and indoor analysis. The results showed the following: 1) the relationship between the aboveground biomass and altitude is a “single peak curve”, reaching a maximum at altitudes of 1 830 – 1 930 m, with an average value of 293.90 g·m–2, and the relationship between belowground biomass and altitude is defined by a “U-shaped curve”, with a minimum at altitudes of 1 830 – 1 930 m, and an average value of 620.07 g·m–2; 2) the belowground biomass has an “inverted pyramid” distribution, and the belowground biomass of 0 – 10 cm soil layer is more different (P < 0.1) in the 1 830 – 1 930 m and 1 930 – 2 030 m altitude gradients; 3) the biomass of shrub-herb communities is mainly distributed underground, and the belowground biomass is 6.16 times that of the aboveground biomass, and the aboveground biomass is negatively correlated with the belowground biomass of 0 – 20 and 0 – 40 cm at 0.05 level; 4) the belowground biomass is negatively correlated with soil pH and bulk density at 0.05 level, and positively correlated with available phosphorus at 0.01 level, and the aboveground biomass is negatively correlated with the pH value at 0.05 level, while the ratio of belowground biomass to aboveground biomass is positively correlated with soil organic matter at 0.01 level. Overall, there was a negative correlation between the aboveground and belowground biomass of shrub-herb communities in the study area (P < 0.05), and the belowground biomass was greater than the aboveground biomass. The results of this study provide a scientific basis for improving the ecological services and ecological restoration of shrub-herb communities in the middle and low mountainous areas of the northwest Hebei Province.
Characterization of soil bacterial communities in alpine and desert grasslands in the Qilian Mountain range
KANG Baotian, HOU Fujiang, Saman BOWATTE
2020, 37(1): 10-19. doi: 10.11829/j.issn.1001-0629.2019-0407
[Abstract](2103) [FullText HTML] (1293) [PDF 830KB](58)
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The Qilian Mountain range is an important ecological zone in western China. Grasslands account for a significant proportion of land area in this mountain range. Understanding the composition of soil microbial communities in different grassland types found in the Qilian Mountains, as well as their relationship with soil factors, is important for sustainable conservation of grassland health. In the present study, we examined the diversity of soil bacterial communities using Illumina MiSeq high-throughput sequencing and investigated the relationship between bacterial composition and soil parameters in an alpine grassland meadow on the northeastern side of the Qilian Mountains and in a desert grassland in the Pingshan Lake desert (Linze County, Hexi Corridor). The beta diversity and community composition analyses revealed a significant difference between the bacterial communities in the two investigated grasslands. The four phyla that dominated both grasslands were Actinobacteria, Proteobacteria, Chloroflexi, and Acidobacteria. These phyla accounted for 84% and 89% of the total bacterial community in the alpine and desert grassland, respectively. Actinobacteria was the most dominant phylum in both grasslands, accounting for 57% and 29% of the total bacterial community in the desert and alpine grassland, respectively. The relative abundances of Actinobacteria and Chloroflexi were significantly higher in the alpine grassland than in the desert grassland (P < 0.05). The relative abundances of Proteobacteria, Acidobacteria, Bacteroidetes, and Rokubacteria were significantly higher in the alpine grassland than in the desert grassland (P < 0.05). There was no significant difference in the relative abundances of Gemmatimonadetes, Verrucomicrobia, and Planctomycetes between the two grasslands (P > 0.05). Pearson correlation and principal component analysis showed that Actinobacteria had a significant negative correlation with soil nutrients (total nitrogen, total carbon, organic carbon, water content, and carbon:nitrogen ratio) (P < 0.01) and a significant positive correlation with soil bulk density (P < 0.01). Proteobacteria, Acidobacteria, and Rokubacteria were positively correlated with soil nutrients and negatively correlated with soil bulk density (P < 0.05). Our results indicated that total soil nitrogen, total soil carbon, soil pH, organic carbon, water content, soil bulk density, and carbon:nitrogen ratio were the key determinants of soil bacterial community distribution at the depth of 0 – 10 cm in the two investigated grassland types.
Effects of alfalfa intercropping on soil carbon, nitrogen, and phosphorus and the fungal community in the rhizosphere of soils in silage maize
MA Chaoran, HE Shubin, BAI Xuechun, WANG Tao, ZHANG Junhong, FENG Kuiliang, XIA Yukang
2020, 37(1): 20-29. doi: 10.11829/j.issn.1001-0629.2019-0247
[Abstract](2739) [FullText HTML] (980) [PDF 932KB](67)
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Under the control of monoculture silage maize (Zea mays) and the intercropped alfalfa (Medicago sativa) model, we measured the index of soil C, N, P, microbial biomass C (MBC), microbial biomass N (MBN), microbial biomass P (MBP), glomalin-related soil proteins (GRSP), soil fungal diversity, and community structure characteristics in the soil rhizosphere of early-maturing and late-maturing maize. The results illustrated that the total N content in the soil rhizosphere of the two types of maize increased significantly (P < 0.05) in the first year, indicating that intercropping may enhance the activity of soil N fixing microoganism. The intercropping significantly increased the content of MBN, MBP, late-maturing soil MBC, and easily extractable glomalin (EEG) in the soil rhizosphere of early maturing maize (P < 0.05), and the characteristics of the rhizosphere soil fungal communities tended to be similar. This indicated that intercropping may improve soil nutrient supply and promote soil microbial activities, thereby improving soil fertility and promoting plant growth. Therefore, according to the analysis of results of soil physical and chemical properties and fungi in the first year, the alfalfa and silage maize intercropping in the Guanzhong area may effectively improve the efficiency of soil nutrient element utilization.
Characterization of greenhouse gas emissions from the alfalfa field in Loess Plateau during different planting years
ZHANG Yaoquan, DENG Changfang, LUO Zhuzhu, NIU Yining, LI Lingling, CAI Liqun, XIE Junhong, MA Xin
2020, 37(1): 30-40. doi: 10.11829/j.issn.1001-0629.2019-0215
[Abstract](1780) [FullText HTML] (904) [PDF 832KB](29)
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Alfalfa is the main grass species in the farmlands returned to forests in Loess Plateau, whose planting area has been expanding. The experiment relied on the alfalfa (Medicago sativa) cultivation with different planting years (14, 12, and 5 a) in Loess Plateau. The objective of this study was to determine the effects of different planting years on soil greenhouse gas (CO2, N2O, and CH4) emission of alfalfa, and we discuss the main mechanisms underlying the effects of soil temperature, soil moisture, and enzyme activities under different treatments on soil greenhouse gas emission. The results showed that all the treatments showed source effects for atmospheric CO2 and N2O, but sink effects for atmospheric CH4; the flux of CO2 peaked in June and bottomed in January, whereas the flux of N2O peaked in July and bottomed in December, and the flux of CH4 peaked in July and bottomed in March. According to the planting years, the amount of total CO2 emission showed a pattern of 5 a > 14 a > 12 a; Compared with 12 and 14 alfalfa planting years, the CO2 emission of 5 alfalfa planting years increased significantly by 16.60% and 13.01%, respectively. Total N2O emission showed a pattern of 14 a > 12 a > 5 a, but there was no difference among the treatments. CH4 absorption showed a pattern of 5 a > 12 a > 14 a, in opposite correlation with the increase in alfalfa planting years. The warming potential under 5 a was higher than those under 12 a and 14 a. Stepwise regression analysis results showed that the flux of CO2 was significantly affected by soil temperature and moisture (R2 = 0.870), that of N2O was significantly affected by soil temperature (R2 = 0.930), and the flux of CH4 was significantly affected by soil temperature and urease (R2 = 0.962).
Secondary community characteristics and interspecific associations in alpine meadow areas along the Qinghai-Tibet railway
XU Yun, LUO Jiufu, ZHOU Jinxing, WANG Lina, YANG Meixiang
2020, 37(1): 41-51. doi: 10.11829/j.issn.1001-0629.2019-0262
[Abstract](22281) [FullText HTML] (19067) [PDF 840KB](46)
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Species composition and interspecific relationships determine the characteristics and dynamics of a community. In order to explore the influence of the Qinghai-Tibet Railway route on the alpine meadow plant community in the Qinghai-Tibet Plateau–along the Tanggula Mountain to Naqu section–plots were set at 5 m and 300 m, respectively from the railway. On the basis of the community survey of plots, the variance ratio method, the χ2 test method and the Spearman rank correlation coefficient test were used to analyze the overall correlation and inter-species correlation of the vegetation community. The results show that: Compared with the non-engineered site, the species composition along the engineered site changed significantly. The number of species in the engineered site was less than that in the non-engineering site, but the number of drought-tolerant species increased in engineered site. The plants at the engineered site belonged to 17 families, 36 genera, and 46 species, whereas the plants at the non-engineered site comprised 18 families, 38 genera, and 54 species. The variance ratio test shows that the community of engineered and non-engineered site statistic W were 51.84 (χ2 0.95(36) = 23.27) and 42.09 ( χ2 0.05(36) = 51.00), indicating that the overall correlation degree of the community in the non-engineered site did not show a significant positive association, while the overall correlation degree of the communities at the engineered site showed a significant positive association. The correlation between the main species showed that compared with that in the non-engineered site, the positive correlation ratio between the species pairs at the engineered site is increased, and the degree of association among the species within the community is also increased. In general, the species composition of the secondary community in the engineered site has been dominated by drought-tolerant and barren-resistant plants in the past 10 years, and it is at a relatively stable stage in the succession process. It is difficult to restore the top alpine meadow community in either theshort- or long-term.
Nutrient characteristics of soil sowed with different combinations of alfalfa and three perennial grasses
LAI Xingliang, SHI Shangli, WU Fang, HAO Zixuan, ZHOU Tong, CHEN Jian’gang, ZHAO Yadong
2020, 37(1): 52-64. doi: 10.11829/j.issn.1001-0629.2019-0127
[Abstract](23113) [FullText HTML] (19549) [PDF 1094KB](64)
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We evaluated the nutrient characteristics of soil sowed with different combinations of alfalfa and three grasses, namely, Bromus inermis, bluegrass, and tall fescues at ratios of 1∶1, 1∶2, and 2∶1. The effects of different combinations and ratios on soil nutrients in the 0 – 20 cm and 20 – 40 cm soil layers were evaluated. The results revealed the following. 1) The combination of alfalfa and three perennial grasses can significantly promote the accumulation of soil organic matter, available potassium, soil hydrolysis nitrogen, soil available phosphorus, and total phosphorus (P < 0.05). 2) Alfalfa + B. inermis was better than the other two combinations in improving soil fertility. The combination of alfalfa + B. inermis was more conducive to the accumulation of soil organic matter, nitrogen, and phosphorus nutrients in the 0 – 40 cm soil layer, whereas the effect of alfalfa + bluegrass in improving potassium accumulation was more obvious. 3) The ratio of alfalfa and the grasses had a significant effect on available phosphorus, total phosphorus, deep soil organic matter, and hydrolysis nitrogen in the shallow soil layer (P < 0.05). The soil nutrient content increased with an increase in alfalfa proportion. Among the three ratios, the 1∶1 ratio of alfalfa + B. inermis in the 0 – 20 cm soil layer and the 2∶1 ratio of alfalfa + B. inermis in the 20 – 40 cm soil layer were more conducive to the accumulation of available nutrients. In the 0 – 20 and 20 – 40 cm soil layers sowed with alfalfa + bluegrass at a ratio of 1∶2, soil available potassium and total potassium content was the highest, and at the ratio of 2∶1, the content of soil available nitrogen, total nitrogen, and total phosphorus was the highest. The content of organic matter, total nitrogen, total phosphorus, total potassium, and available nutrients in the 0 – 20 and 20 – 40 cm layers of soil sowed with alfalfa and reed fescue at 2∶1 ratio was higher than that at the other two ratios. 4) In terms of spatial distribution, except for single sowing of bluegrass and combination alfalfa + tall fescue, under all other combinations, the shallow soil nutrient content was higher than that in deep soil, showing a phenomenon of nutrient surface cohesion.
On the response of plant-soil feedback to grass endophytes
LIU Huan, CHEN Tao, XIA Chao
2020, 37(1): 65-74. doi: 10.11829/j.issn.1001-0629.2019-0015
[Abstract](2651) [FullText HTML] (922) [PDF 491KB](44)
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Plant-soil feedback refers to plant growth that can be altered by the biological and abiotic characteristics of the soil. In turn, changes in soil properties can affect plant growth, thereby altering the structure and dynamics of plant communities. Studies have shown that the endophytic fungi of grasses have essential effects on plant-soil feedback. In this study, the effects of grass endophytes on the chemical properties of rhizosphere soil, rhizosphere microorganisms, plant competition, and ecological adaptation mechanism of host plants were reviewed. It was found that the presence of endophytes would affect soil nutrients, leading to changes in the soil organic carbon and soil total nitrogen content. The microbial biomass and microbial community in rhizosphere soil were affected by grass endophytes, resulting in different changes in gram-negative bacteria, mycorrhizal fungi, and glomalin. The endophytes participated in the life cycle of host plants and affected the intra- and inter-species competition, community structure, and species richness.
Progress in research on the diseases of buckwheat
QI Yangju, CHEN Zhenjiang, LI Zhenxia, LIU Hui, WANG Lihua, LI Chunjie
2020, 37(1): 75-86. doi: 10.11829/j.issn.1001-0629.2019-0143
[Abstract](2645) [FullText HTML] (1125) [PDF 683KB](42)
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Buckwheat is an important source of coarse grains that have a high nutrient content, and is also a high-quality forage resource with potential for development. Diseases, which affect both quality and yield, are the main factors limiting buckwheat production. To date, 14 genera and 16 species of fungal pathogens causing disease in buckwheat have been identified, along with eight non-fungal diseases caused by bacteria, viruses, and nematode. Although both in China and in other countries studies have examined the effects, occurrence rates, and control strategies relating to the ring spot, downy mildew, root rot, and seedling blight diseases of buckwheat, there have been few similar studies on other leaf diseases and seed-borne fungi. In the future, we should focus to a greater extent on the etiology of the fungal diseases of buckwheat, the factors affecting buckwheat growth and associated pathogen diversity, strengthening the rule of occurrence, and developing appropriate control measures.
Study of factors affecting callus induction from mature seeds of orchardgrass
XU Lei, HAN Jiating, FENG Guangyan, LIU Ya’nan, HUANG Linkai, ZHANG Xinquan
2020, 37(1): 87-97. doi: 10.11829/j.issn.1001-0629.2019-0195
[Abstract](4156) [FullText HTML] (1001) [PDF 866KB](39)
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To establish an efficient regeneration system for orchardgrass, mature seeds were studied to determine the effects of seed pretreatment, variety selection, medium selection, and hormone ratio on the process of callus induction. The results showed a statistically significant (P < 0.05) effect of NaClO concentration on callus induction rate among the three pretreatment conditions. The cultivar ‘Anba’ had the strongest callus induction ability among the ten cultivars. Callus induction ability and morphological development were related to the medium used: Schenk & Hildebrandt medium (SH), Murashige & Skoog medium (MS), and Linsmaier & Skoog medium (LS) (all resulted in higher callus induction rates; of these, SH had the best induction effect and yellowish or yellow, dry, and crisp calli were obtained). It was thought that 2,4-D with 30 μmol·L–1 dicamba would promote callus induction; in addition, the combination of 2,4-D and a lower concentration 6-KT was also beneficial for callus induction. In conclusion, the seeds of ‘Anba’ were first placed at 4 ℃ for 24 h after soaking, then treated with 75% alcohol for 5 min, and sterilized with 1.1% NaClO for 30 min. The optimum medium for callus induction was SH + 2.0 mg·L–1 CPA + 0.1 mg·L–1 6-KT + 30 μmol·L–1 dicamba + 0.5 mg·L–1 2,4-D. With this medium and hormone combination, the callus induction efficiency was high and embryonic calli were more readily induced. Thus, an efficient and stable preliminary tissue culture and regeneration system was established for orchardgrass.
Effects of soil moisture content on morpho-physiological of four Potentilla
YAN Shangbo, QIAN Yongqiang, ZHANG Yan, YAN Li, DONG Li
2020, 37(1): 98-105. doi: 10.11829/j.issn.1001-0629.2019-0512
[Abstract](1580) [FullText HTML] (916) [PDF 630KB](46)
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In north China, Potentilla are potentially important indigenous plants recognized for their ornamental value along with strong stress resistance characteristics. To provide a reference for the sustainable development of these plants,we studied the response mechanisms of four Potentilla species (P. reptans var. sericophylla, P. reptans , P. flagellaris, and P.anserina ) to changes in soil moisture content, and their ability to retain their visual appeal under these conditions. Three water treatments conditions were investigated: 25%, 50% and 75% of the field water capacity. At the end of the study period, the leaves were harvested for physiological analysis and their growth index monitored. These 4 Potentillawere growing well at both 75% and 50% field capacity. P. reptans var. sericophylla grew well at 25% field capacity. However, biomass decreased, and superoxide dismutase activity and carotenoid content increased in P. anserine, P. reptans and P. flagellaris was through increase in superoxide dismutase and catalase activity to relieve the decline of plant height, respectively. These results suggest that P. reptans var. sericophylla is a drought tolerant species due to its higher leaf-water content. High antioxidant capacity under water stress plays a crucial role in resisting oxidative damage, and helps to relieve water stress in P. anserina, P. reptans and P. flagellaris.
Sowing rates and row spacing of Avena sativa ‘Heyan No.1’ influence agronomic characters and yield
WU Huijuan, ZHANG Rong, ZHANG Shaoping, GENG Xiaoli, LI Deming, LIU Qian
2020, 37(1): 106-116. doi: 10.11829/j.issn.1001-0629.2019-0161
[Abstract](1174) [FullText HTML] (742) [PDF 480KB](37)
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An experiment was conducted in Hezheng County of Gansu Province to study the effects of different sowing rates and row spacing of Avena sativa ‘Heyan No.1’ on agronomic characters, hay yield, and seed yield. Results show that sowing rate and row spacing significantly affected A. sativa ‘Heyan No.1’ agronomic characters, hay yield, and seed yield. Hay yield was highest (9 059.73 kg·ha–1) with a row spacing of 30 cm and seeding rate of 300 kg·ha–1, while seed yield was highest (2 728.40 kg·ha–1) with a row spacing of 20 cm and sowing rate of 300 kg·ha–1. Correlation and path analyses showed that plant height, tiller number, hay yield, and seed yield were positively correlated with row spacing (P < 0.01), while stem diameter, leaf length, and effective tiller number were positively correlated with row spacing (P < 0.05). Seed yield was positively correlated with sowing rate (P < 0.05), while tiller number, stem diameter, and leaf width were negatively correlated with sowing rate (P < 0.05) and seed yield was negatively correlated withspike length (P < 0.01). Seed yield was significant positively correlated with plant height and hay yield (P < 0.01). The direct effect of plant height on hay yield was the greatest. In production, yield potential of A. sativa ‘Heyan No.1’ could be excavated by altering plant height, effective tiller number, leaf length, stem diameter, and so on, to maximize economic benefits.
Effects of cutting frequencies on the yield and quality of Longdong alfalfa in the Loess Plateau
YANG Liye, YANG Tianhui, CHANG Shenghua, LIU Yongjie, JIA Qianmin, HOU Fujiang
2020, 37(1): 117-125. doi: 10.11829/j.issn.1001-0629.2019-0384
[Abstract](1496) [FullText HTML] (877) [PDF 781KB](40)
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A unicast experiment was conducted in the Loess Plateau from 2012 to 2013 in order to explore the rational utilization of Longdong alfalfa (Medicago sativa ‘Longdong’) grassland. This experiment was divided into two utilization modes, i.e., multiple mowing and one mowing. The results showed that plant height accumulation, branch number accumulation, total yield, crude protein (CP), crude fat (EE) and crude ash (Ash) yields of Longdong alfalfa under multiple cutting condition were significantly higher than those under one cutting condition after two years experiment. However, the content of neutral detergent fiber (NDF) and acid detergent fiber (ADF) under multiple cutting condition were significantly lower than those under one cutting conditions The correlation analysis showed that the yield was positively correlated with plant height, number of branches, CP, Ash, NDF and ADF content under one cutting condition (P < 0.05). Under multiple cutting condition, the yield was positively correlated with plant height, branch number, CP, and EE content (P < 0.01) and negatively correlated with NDF and ADF content (P < 0.01). In conclusion, multiple cutting can increase alfalfa hay yield and yield more nutrients than that by one cutting, which is a suitable management measure for Longdong alfalfa grassland in the Loess Plateau.
Analysis of species composition and attribute characteristics of related traits of lianas growing in the karst areas of south China
WANG Yeshe, CHEN Lijun, LI Yinghui, HE Lixia, LI Zhezhi, QING Rubing, YANG Xianjun
2020, 37(1): 126-138. doi: 10.11829/j.issn.1001-0629.2019-0269
[Abstract](1926) [FullText HTML] (756) [PDF 563KB](16)
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We systematically studied the species composition and attribute characteristics of related traits of lianas in the karst areas of south China by means of field surveys and laboratory studies. The results showed that there were 1 463 species of lianas in this area, belonging to 241 genera in 67 families. Among these were the gymnosperms, which belonged to 7 species in 1 family, 1 genera, and the angiosperms, which could be traced to to 1 456 species in 240 genera spread across 66 families. Among the angiosperms, dicotyledonous lianas were more abundant than the monocotyledonous ones. With respect to the constitution of families and genera, the monotypic families and monotypic genera are the most important constructive species in this area, but the family composition was relatively centralized and the genera composition was relatively dispersed. The flora exhibited marked tropical characteristics; however, the temperate components also played an important role. With respect to the climbing mode, the winding type was the most common, followed by the curling, sorption and attachment types. Compared with other areas, the sorption type was more prevalent than the winding type. With respect to the life cycle, high buds possessed absolute advantage, while the ground buds, underground buds, and annual species had fewer advantages. With respect to the leaf characteristics, the small, single, leathery, and incomplete leaves were dominant. In the sexual breeding system, hermaphrodite flowers were the most common, followed by unisexual flowers, while the least common were the hybrid flowers. The flowering and fruiting stages showed certain seasonality, but the flowering stage was attained mainly between May to July, with June being the peak, while the fruiting stage was attained between August and October, with September being the peak. The peak of flowering and fruiting stages did not occur in July, which has the highest precipitation, and in July and August, which have the highest temperature. In conclusion, the diversity and ecological characteristics of lianas in the karst areas of South China were the result of long-term adaptation of lianas to their complex habitats.
Advances in alfalfa improvement using genetic engineering
BIAN Jiahui, LIU Ziyang, LI Zongying, ZHAO Yuanyuan, TANG Yixiong, SUN Zhanmin, LYU Jiawei, ZHANG Jinlin, WU Yanmin
2020, 37(1): 139-155. doi: 10.11829/j.issn.1001-0629.2019-0107
[Abstract](2954) [FullText HTML] (877) [PDF 604KB](34)
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Alfalfa (Medicago sativa) has the characteristics of strong adaptability, high protein content, good palatability, and rich nutritional value, and has the largest cultivation area among forage species in the world. With the rapid development of biotechnology, improvement in alfalfa using genetic engineering has become a current topic in China and abroad. In this paper, we mainly summarize and review the progress in three methods used in the genetic transformation of alfalfa, including vector-mediation, direct DNA insertion, and germplasm system mediation, and five utility aspects of alfalfa improvement using genetic engineering, including improvement in antibiotic stress, antibiotic resistance, herbicide resistance, quality, and bioreactor development. The application potential of genetic engineering in improvement in alfalfa and safety were explored to provide a reference for such technology.
Progress in asymmetric light competition research
LIU Tao, JI Mingfei, DENG Yan, SU Xu
2020, 37(1): 156-167. doi: 10.11829/j.issn.1001-0629.2019-0129
[Abstract](1562) [FullText HTML] (863) [PDF 669KB](48)
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Light is one of the most basic requirements during plant growth, playing an important role in limiting plant development. This paper stay on topics which are critical problems about plant functional traits, the population size, species structure of plant community, biodiversity under the light competition, and emphasize on the effect of light competition on plant height trait strategies, neighborhood effects, zones of influence of plant populations, and dominant species change in communities by viewing recent progress in studies on of light competition. We conclude that light resource distribution models of asymmetric competition mechanisms between small and large individuals clarify that intra and interspecific light competition not only cause variation in functional traits of different plant species, but is the most important factor driving community species loss in areas of high productivity, as supported by grassland community researches. Therefore, for future research, in the context of global climate change, focusing on the relationship between plant functional traits and light asymmetric competition could provide new perspectives on species coexistence in ecological communities, ecological and hydrological processes that affect vegetation growth in response to warming, and the theoretical basis for future research on building stable community structures.
Effects of starters containing different types of neutral detergent fiber on the growth performance, nutrient digestion and metabolism of Hu lambs
LI Yanzhen, LIU Ting, DUAN Pengwei, ZHENG Chen
2020, 37(1): 168-177. doi: 10.11829/j.issn.1001-0629.2019-0139
[Abstract](1761) [FullText HTML] (1053) [PDF 524KB](22)
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In this study, by adopting a controlled experimental design, we aimed to compare the differences in growth performance, nutrient digestion, and metabolism of Hu lambs, fed starters containing two types of neutral detergent fiber (NDF). As experimental subjects, we selected 28 male Hu lambs with similar birth weight (3.5 ± 0.7 kg), which had been breastfed from 0 to 2 days of age. At 3 days of age, the lambs were separated from ewes, and were fed a milk replacer until a weaning age of 28 days. At 7 days of age (prior to being fed starters), the lambs were divided into two treatment groups according to the principle of homogeneity. Each group comprised of 14 lambs, one of which was fed a total mixed ration containing alfalfa hay (AH) as the main source of NDF and the other was fed a total mixed ration containing beet pulp (BP). Digestive and metabolic tests were carried out on lambs from between 54 and 60 days of age. The feeding test was continued for 63 days. The results showed that from 7 to 28 days of age, the average daily gain, intake of nutrients, and metabolizable energy of lambs fed a starter containing AH were significantly higher than those in the BP group (P < 0.05). In contrast, from 29 to 70 days of age, there were no significant differences in these indices (P > 0.05). The apparent digestibility of dry matter (DM), NDF, and acid detergent fiber (ADF) of the lambs fed the starter containing AH were significantly lower than those of the BP group (P < 0.05). In summary, the starter containing alfalfa hay as a NDF source significantly improved the performance and intake of Hu lambs during the pre-weaning period, whereas the starter containing beet pulp as a NDF source significantly improved the apparent digestibility of DM, NDF, and ADF in Hu lambs during post-weaning.
Predicting fecal composition of grazing beef cattle by near infrared spectroscopy
XU Jinqian, HOU Lulu, JIANG Mengyu, YAN Ruirui, WANG Yajun, XIN Xiaoping, SUN Haixia
2020, 37(1): 178-184. doi: 10.11829/j.issn.1001-0629.2019-0148
[Abstract](1210) [FullText HTML] (747) [PDF 733KB](20)
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The study evaluated the feasibility of near infrared spectroscopy (NIRS) to predict the feces composition of grazing beef cattle. The experiment was conducted in the long-term grazing experimental platform of the National Field Observation and Research Station of the Hulun Buir Grassland Ecosystem in the Chinese Academy of Agricultural Sciences. The feces samples of 72 grazing beef cattle were collected using the whole fecal collection method and analyzed using the partial least squares (PLS) method, combined with different spectral processing and software analyses. A calibration model for near infrared analysis of fecal components was established and evaluated by the predicting parameters of C, N, OM, ADF and NDF. The coefficient of determination (R2) of C, N, OM, ADF and NDF was 0.90, 0.96, 0.91, 0.23, and 0.49, and the relative analysis error (RPD) was 2.45, 2.81, 1.94, 1.00, and 1.09, respectively. The model could be used to predict the fecal content of C and N in grazing beef cattle, but the prediction accuracy needs further improvement. For OM, ADF and NDF need further study and analysis.
Effect of feeding fermented Pueraria lobata on pork meat
DENG Suyuan, YI Xianfeng, PANG Tiande, SHI Jing, QIU Jinhua, HUANG Zhichao
2020, 37(1): 185-193. doi: 10.11829/j.issn.1001-0629.2019-0157
[Abstract](1799) [FullText HTML] (854) [PDF 502KB](12)
Abstract:
This study investigated the effect of the addition of different levels of fermented Pueraria lobata on growth performance, slaughter performance, and meat quality of Guike black pigs to provide a reference for the development of Pueraria lobata feed for the pig industry. We randomly assigned 32 pigs one of four groups: the control group, fed only a basic diet; and three experimental groups, fed diets supplemented with 5% (Group I), 10% (Group II), and 15% (Group III) fermented Pueraria lobata respectively. The advanced experimental period had 10 days, and the formal experimental period was 90 days. The results showed that experimental group I had the highest average daily feed intake (ADFI) and fastest growth rate, and average daily gain (ADG) reached 746.73 g. The slaughter performance of experimental group I (supplemented with 5% Pueraria lobata) was best; all the slaughter indices, such as slaughter weight, carcass weight, slaughter percentage, eye muscle area, were highest; and there was no obvious difference in meat quality compared with control group, such as meat color, water-holding capacity, shear force and pH. The blood physiological and biochemical indicators, the content of alanine aminotransferase in blood of group I was the lowest, which to some extent reflected that liver function of Guike black pigs in group I were improved compared with the other treatment groups. Thus, when fermented Pueraria lobata is used as a feed additive for Guike black pigs, a level of 5% is recommend.
Forage quality of mixed silage containing citrus flesh and wheat husk
TIAN Jing, TANG Guojian, LI Guodong, ZHANG Jianguo
2020, 37(1): 194-200. doi: 10.11829/j.issn.1001-0629.2019-0219
[Abstract](1328) [FullText HTML] (719) [PDF 675KB](46)
Abstract:
In order to utilize byproducts of orange peel and increase food resources for breeding, we examined the ensiling of citrus (Citrus reticulata) flesh and wheat (Triticum aestivum) husks at different ratios. The ensiling experiment contained six different treatment groups: three different mixing ratios (citrus: wheat 7∶3, 6∶4, and 5∶5) with and without the addition of Lactobacillus plantarum. The results showed that citrus flesh was rich in nutrients and had a high utilization value. The ether extract from the citrus flesh was 3.23 times more abundant than that of the wheat husks. By contrast, the contents of water-soluble carbohydrates contents in the citrus flesh were comparable with that of the wheat husks. The levels of crude ash, crude fibers, neutral detergent fibers, and acid detergent fibers were lower in the citrus flesh compared to the wheat husks. The optimal fermentation quality of the citrus flesh and wheat husks was obtained at a ratio of 7∶3. Furthermore, the addition of L. plantarum further enhanced the fermentation quality by reducing the pH to 3.56 and increased the lactic acid content to 5.92%. The addition of L. plantarum also reduced the contents of acetic acid, propionic acid, and ammonia nitrogen.
Implementation effects of the grazing withdrawal project in national key ecological function zones: A case study of Yanchi County in Ningxia Hui Autonomous Region
ZHOU Shengqiang, SUN Pengfei, ZHAO Kai, WANG Feng, ZUO Xiangdong
2020, 37(1): 201-212. doi: 10.11829/j.issn.1001-0629.2019-0233
[Abstract](22727) [FullText HTML] (19157) [PDF 486KB](59)
Abstract:
In this study, we selected the national key ecological function zones, Yanchi County in Ningxia Hui Autonomous Region, as the research area. Based on the sampling survey data of 221 farmers in 16 villages of 4 towns, we established a comprehensive evaluation index system, which included 18 indices such as the characteristics of the project, ecological, social, and economic benefits, as well as sustainability of the grazing withdrawal project. Analytic hierarchy process (AHP), R-type clustering analysis, and variation coefficient were used to evaluate the comprehensive implementation effects of the grazing withdrawal project. The results showed that the comprehensive implementation effect of the grazing withdrawal project is generally good, with a score of 0.627. In terms of the specific effects ranked from high to low, these are the ecological, economic, and social benefits, as well as the sustainability and characteristics of the grazing withdrawal project. This indicates that the implementation of the grazing withdrawal project has resulted in good ecological, economic, and social benefits, but the sustainability of the project is still at a low level. Owing to the fact that farmers pay less attention to the characteristics of the grazing withdrawal project, the evaluation result of the characteristics is also at a low level.