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2022 Vol.39(2)

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2022, 39(2): 0-0.
[Abstract](277) [PDF 26401KB](8)
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2022, 39(2): 1-4.
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Effect of sodium hypochlorite on physiological characteristics of Nitraria tangutorum open tissue culture seedlings
BIAN Hongying, SU Shiping, LI Yi, WANG Xinxin
2022, 39(2): 213-221. doi: 10.11829/j.issn.1001-0629.2021-0094
[Abstract](888) [FullText HTML] (306) [PDF 1288KB](10)
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Taking the Nitraria tangutorum tissue culture seedlings grown by traditional tissue culture technology as a control, using an open tissue culture method, different concentrations of the bacteriostatic agent sodium hypochlorite were added to N. tangutorum spur medium. According to physiological characteristics, the effects of the bacteriostatic agent were evaluated for tissue cultured N. tangutorum plants. The results showed that with the increase in the sodium hypochlorite concentration, the antibacterial effect on N. tangutorum medium gradually increased. Sodium hypochlorite at a concentration up to 50 mg·L−1 inhibited the root number and root length of N. tangutorum tissue culture seedlings. A sodium hypochlorite concentration of 15 ~ 20 mg·L−1 promotes the growth of N. tangutorum tissue culture seedlings. The addition of sodium hypochlorite in the open tissue culture enhances the autogenous metabolism of the tissue culture seedlings and significantly increases the concentration of superoxide anions (O2·) and hydrogen peroxide (H2O2). Compared with the traditional tissue culture, the accumulation of nutrients was inhibited in the tissue-cultured seedlings of N. tangutorum. Free proline (Pro), soluble sugar (SS), and soluble protein (SP) accumulate at high concentrations; when the sodium hypochlorite concentration is greater than 20 mg·L−1, the activities of antioxidant enzymes catalase (CAT), superoxide (SOD), peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) are significantly different compared with the control (P < 0.05). The comprehensive consideration of morphological indicators indicated that a sodium hypochlorite concentration of 50 mg·L−1 is extremely unfavorable for the growth of N. tangutorum tissue culture seedlings. Sodium hypochlorite at a concentration of 15 ~ 20 mg·L−1 can be used as a bacteriostatic agent for Nitraria open tissue culture.
Response of soil physical and chemical properties of zokor mounds to grazing management modes in an alpine meadow
ZHANG Qian, YAO Baohui, YANG Jing, CAI Zhiyuan, SUN Xiaomei, SU Junhu
2022, 39(2): 222-234. doi: 10.11829/j.issn.1001-0629.2021-0042
[Abstract](653) [FullText HTML] (240) [PDF 911KB](15)
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The aim of this study was to analyze zokor (Eospalax baileyi) of different mound ages [one-year (ZM1), two-year (ZM2), three-year (ZM3), and Multi-year (ZMM)] and control meadow (CM) under four grazing management modes (rotational grazing (RG), growing season grazing (GSG), continuous grazing (CG), and prohibition grazing (PG). The study was performed to evaluate the effects of grazing on soil physicochemical properties during the succession of zokor mounds and provides references for grazing management in alpine meadow. The results showed that GSG significantly increased the soil water content of ZM2 and ZM3 in 0 − 10 cm layers compared with PG. In addition, total nitrogen content of ZM3 in 0 − 10, 10 − 20, and 20 − 30 cm layers significantly increased (P < 0.05), respectively. Compared with CG, GSG significantly increased the total phosphorus content of ZM1 and ZM2 in 0 − 10 cm layers (P < 0.05), and RG significantly increased the soil C/N ratio of ZM2 in 0 − 10 cm and 10 − 20 cm layers (P < 0.05), respectively. Structural equation model analysis revealed that different management regimes had a positive effect on the soil water content, total nitrogen, and organic carbon of ZM3 and had positive effects on soil organic carbon and C/N ratio of ZMM. Therefore, GSG can better restore the soil nutrient content of zokor mounds compared with other grazing management modes.
Effects of degradation degree on plant communities and soil water holding capacity of Maqin alpine meadow
ZHANG Yuheng, ZHANG Li, ZHANG Xiujuan, YANG Yongsheng, WANG Junbang, XU Xingliang, HUANG Yuru, ZHAO Qiudong, LI Yingnian, ZHOU Huakun
2022, 39(2): 235-246. doi: 10.11829/j.issn.1001-0629.2021-0388
[Abstract](1057) [FullText HTML] (346) [PDF 1112KB](28)
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To explore the influence of the degree of degradation on the success of plant communities and the water conservation capacity of alpine meadows in the Three Rivers Source Region, this study selected Maqin alpine meadow sample land with different degradation degrees in the source area of the Three Rivers on the Qinghai-Tibet Plateau. Through a combination of field monitoring and indoor tests, this study analyzed the effects of different degradation degrees on plant coverage, height, species number, biomass, soil bulk density, soil saturated hydraulic conductivity, and water holding capacity. The results showed the following: 1) The alpine meadow is in the process of continuous degradation, and the average height and coverage of plants in the Maqin alpine meadow decreased significantly by 41.1% and 58.5%, respectively (P < 0.05); the species number, richness, diversity index, and evenness index of vegetation decreased gradually, and the dominance index was the highest (0.18) in mildly degraded plots. 2) The aboveground, belowground, and total biomass decreased significantly with an increase in the degree of degradation (P < 0.05). Compared with the original vegetation sample plot, the aboveground, underground, and total biomass decreased by 49.8%, 71.1%, and 70.0%, respectively. 3) The effect of the degree of degradation on the soil water holding capacity and saturated water conductivity of alpine meadows decreased with increasing depth, and the effect on soil water holding capacity and saturated water conductivity of the surface layer (0 − 5 cm) was the most significant. Compared with the native vegetation, the 0 − 5 cm soil water capacity, field water capacity, capillary water capacity, and saturated water conductivity of the severely degraded alpine meadow decreased by 41.7%, 42.9%, 41.4%, and 84.4%, respectively. With an increase in the degree of degradation, the soil bulk density of the 0 − 5 cm soil layer of alpine meadow increased significantly (P < 0.05). In conclusion, as the degree of degradation increased, the species richness, diversity, evenness, and dominance of alpine meadow vegetation communities decreased. At the same time, the influence of the degree of degradation on the soil water holding capacity of alpine meadows is primarily concentrated in the 0 − 5 cm layer, and the surface matting of alpine meadows is the key to maintaining the water conservation function of this region.
Weed-control effectiveness of different post-emergence stem and leaf herbicides in first-established turf of buffalograss and their safety evaluations
ZHANG Jiayu, JIAO Yuejia, ZOU Bokun, WANG Xinming, CHU Zhangshan, QIAN Yongqiang
2022, 39(2): 247-253. doi: 10.11829/j.issn.1001-0629.2021-0369
[Abstract](714) [FullText HTML] (215) [PDF 785KB](4)
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In order to effectively control weeds and improve the turf-building quality of buffalograss (Buchloe dactyloides), based on an investigation of weed spectrum composition and biological characteristics, the weed control effect and safety of different post-emergence stem herbicides after seedling were compared and analyzed.The results showed that on the 15th day after application, the highest effectiveness of bentazone and fluoroglycofen-ethyl on broadleaf weeds was 88.76% and 88.30%, respectively, and the highest efficacy of topramezone on gramineous weeds was 90.02%. On the 30th day, the highest effectiveness of topramezone on broadleaf and gramineous weeds was 97.89% and 89.51%, respectively. Clopyralid had the smallest effect on the growth of buffalograss, with 7.11% inhibition of plant height and 1.6 new stolons, whereas fluroxypr-mepthyl and fenoxaprop-P-ethyl had the largest effect on the growth of buffalograss, with more than 50% inhibition of plant height, and fenoxaprop-P-ethyl severely inhibited the formation of new stolons. Weed control effectiveness and safety for buffalograss were considered, and the topramezone was the most appropriate herbicide for buffalograss.
Assessment of suitable Potentilla anserina habitat and its response to climate change in the source region of the Yellow River based on ensemble species distribution modeling
ZHANG Xinyu, ZHU Zequn, YUAN Yaxin, JI Wenxiang, SONG Cenyu, LU Hongwei, ZHAO Xilei, BIAN Qingyao, SUN Zimo, YI Shuhua, SUN Yi
2022, 39(2): 254-267. doi: 10.11829/j.issn.1001-0629.2021-0480
[Abstract](271) [FullText HTML] (169) [PDF 1630KB](18)
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Potentilla anserina is a herbaceous perennial plant within the family Rosaceae that is widely distributed in the source region of the Yellow River (SRYR), and is one of the main economically important wild plants growing on the Qinghai–Tibet Plateau. To date, however, the spatial distribution of P. anserina has yet to be determined, which is primarily attributable to a lack of high-precision survey data and effective methods that are applicable at a regional scale. In this study, we propose a sampling method based on fragmentation monitoring and analysis with aerial photography (FragMAP) to obtain basic sampling data for species distribution models (BIOMODs). During the period between 2018 and 2020, we obtained > 3000 observation samples (aerial photographs) in the SRYR, and manually identified whether P. anserina appears or not (i.e., a 0,1 dataset) as the basic driving data. Combined with data obtained for the climate, terrain, and soil, we predicted the potential and future distributions (in the 2050s and 2070s) of P. anserina against a background of climate change. The findings are as followings: 1) Use of an ensemble model can reduce the uncertainty of spatial distribution predictions for P. anserina in the SRYR. 2) P. anserina is distributed primarily in the central and southeast regions of the SRYR, and the environmental factors having the most pronounced influence on P. anserina spatial distribution are annual precipitation and elevation. 3) In the projected future climate scenarios, the proportion of extremely suitable P. anserina habitat in the SRYR initially increased, although subsequently underwent a reduction. In this study, we succeeded in modeling the potential distribution characteristics of P. anserina at a regional scale. These findings can provide the theoretical and practical bases necessary for the rational management and utilization of economically important crops in alpine grassland, the ecological restoration of the source area of the Yellow River, and the ecological reconstruction of alpine regions.
Effects of different enclosure methods on early community vegetation structure and stability of alpine meadows in northwest Sichuan
HE Li, HUANG Chao, CHEN Dechao, DENG Dongzhou, YAN Wuxian, WU Shilei, LI Honglin, LIU Yuping, ZHANG Li
2022, 39(2): 268-277. doi: 10.11829/j.issn.1001-0629.2021-0158
[Abstract](738) [FullText HTML] (290) [PDF 1065KB](11)
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This research explores suitable management measures for alpine meadows in northwestern Sichuan. In this study, grazing prohibition and grazing restrictions (grazing prohibition in growing season + grazing in non-growing season) and typical alpine meadow plots under the management of forage and animal husbandry were used as the research object for this research. Degraded grassland vegetation outside the fence was used to create a control group. Using a combination of field surveys and lab-based analyses, species diversity and stability of the alpine meadow plant community in Northwest Sichuan was examined. This research explored the relationship between species diversity and plant community stability immediately following enclosure of research plots to determine preliminary recommendations for an appropriate grassland management model. The results showed the following: 1) In the initial stage of implementation of the three enclosure management methods, grasses such as Elymus nutans are the dominant species in the plant community, with important values of 9.14, 13.52, and 8.17, respectively. No absolute dominant species were recorded in the degraded grassland community, with Potentilla anserina, Anemone rivularis, and Anaphalis flavescens being the main plant species observed. 2) Provision of fencing increased community species diversity. Sites where prohibition of grazing had been implemented had the highest species diversity. The lowest species diversity was recorded for the forage-livestock balance plant community. Simpson’s diversity index and Pielou evenness index of were slightly higher in the degraded grassland communities in comparison to grasslands where grazing was restricted. 3) The stability of the community in each plot is expressed as grazing restriction > forage-livestock balance > grazing prohibition > degeneration. Reasonable grazing can therefore improve grassland stability. 4) The relationship between community species diversity and stability was found to be negative. Species diversity is mainly affected by the type and quantity distribution of species, while community stability is closely related to the stability of dominant species. Therefore, taking into account the structure and stability of the plant community, grazing prohibition and grazing restriction management are effective measures for the ecological restoration of alpine meadow vegetation in northwest Sichuan.
Comprehensive evaluation and evolutionary characteristics of eco-environment quality in Qilian Mountain National Park
YANG Lei, SHAN Shuyao, SANG Chen, LIU Yue, XU Haojie
2022, 39(2): 278-289. doi: 10.11829/j.issn.1001-0629.2021-0392
[Abstract](931) [FullText HTML] (338) [PDF 2097KB](29)
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Qilian Mountain National Park serves as a vital ecological security barrier in Western China, but mining, hydroelectric development, and overgrazing have resulted in serious ecological and environmental damage. Using remote sensing as well as meteorological and socio-economic statistical datasets of 14 counties in Qilian Mountain National Park from 2000 to 2018, this study established an assessment indicator system for eco-environmental quality. We also employed the principal component analysis method to determine the contribution of each indicator, which was then used to develop a new eco-environmental quality index (EQI). The spatiotemporal variations in the EQI and its influencing factors were examined. The results showed that the spatial distribution of mean annual EQI was characterized by low values in the west and high values in the east of Qilian Mountain National Park. The EQI varied significantly for the different counties. During the study period, the EQI of the national park showed a significant increasing trend (P < 0.01). The smaller the average EQI, the slower the rate of increase. Natural factors were the major driving force for the temporal variation of eco-environmental quality, followed by economic and social factors, showing a contribution of 52%, 28%, and 20%, respectively. The mean annual temperature and precipitation, annual average radiation, vegetation coverage, enhanced vegetation index, leaf area index, net primary productivity, gross output value of forestry, amount of livestock raised, grain planting area, value-added index of primary industry, per capita GDP added value index, natural population growth rate, the number of educated people, urban and rural household savings, per capita net income of rural residents, and non-agricultural population played a positive role. Value added index of secondary industry, value-added index of tertiary industry, agricultural population, and other indicators played a negative role. Our findings suggest the need for further implementation of natural forest protection, returning farmland to forest, and forbidden grazing programs in the future. Decision-makers need to improve the ecological compensation mechanism and eco-environment supervision. Strict limits on the intensity of human activities in the central and western parts of the national park should be set to promote the restoration of a fragile ecological environment.
Analysis of phenophase and morphological traits of perennial ryegrass germplasm
ZHANG Chenchen, ZENG Lingshuang, ZHANG Jing, XU Bin
2022, 39(2): 290-299. doi: 10.11829/j.issn.1001-0629.2021-0365
[Abstract](766) [FullText HTML] (302) [PDF 971KB](11)
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To evaluate and screen the germplasm resources of perennial ryegrass (Lolium perenne) for excellent characteristics, 99 perennial ryegrass germplasm resources were selected to observe and analyze their phenological periods and eight morphological traits, and principal component analysis and cluster analysis were performed based on the morphological indicators. The results showed that the whole growth period of the tested germplasm was 252.0 ~ 310.0 days, their morphological characteristics showed abundant variation with a coefficient of variation of 22.63% ~ 44.11%. The cluster analysis of eight morphological characteristics, perennial ryegrass germplasms were extracted into four groups withobvious morphological differences. The germplasms of groups Ⅰ and Ⅳ can be further investigated as parent breeding materials or released as new varieties for forage- or turf-type breeding objectives. In summary, there are rich variations in the morphological characteristics of the perennial ryegrass germplasms used in this study, among which, germplasms of groups Ⅰand Ⅳ can be used as elite parental materials to breed new forage and turf-type varieties.
Histochemical characteristics and differentiation of the belowground buds of Medicago archiducis-nicolai during overwintering
YANG Xiaoxia, WEI Jiake, XIA Jianqiang, FANG Qiang’en, ZHANG Bo
2022, 39(2): 300-308. doi: 10.11829/j.issn.1001-0629.2021-0074
[Abstract](639) [FullText HTML] (229) [PDF 1351KB](10)
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To determine the mechanisms underlying belowground bud overwintering in Medicago archiducis-nicolai, we examined the histochemical characteristics and differentiation of buds during the period of overwintering, based on the histochemical staining of paraffin sections. Observations revealed that the starch content in overwintering buds is stored primarily in the cortex, pith, the peripheral young leaves and basal tissue of bud tips, and in the basal part of the leaf primordium, whereas protein is mainly stored in the growth cone of bud tips, apical leaf primordia, and cambium of the bud body. At the cold-adaptation stage in late autumn, the bud body was observed to undergo rapid elongation and starch in the buds began to undergo degradation, although total starch contents remained at a high level during this stage. At the beginning of winter, there was a retardation in both bud differentiation and elongation, concomitant with a reduction in temperatures. At the freezing-stress stage in winter, there was a cessation of growth in both the bud cone and bud body, and at this stage, the starch content of buds had been almost completely degraded. Thereafter, in response to gradually increasing temperatures, the bud body slowly began to resume growth, although meristematic growth of the bud cone did not recover fully until the growing stage in spring. In conclusion, our findings indicated that in belowground buds of M. archiducis-nicolai, the transition to a dormant state is characterized by growth stagnation and a reduction in the starch contents of buds, and that dormant buds can withstand cold stress during the period of overwintering on the Qinghai-Tibet Plateau. This cold tolerance can be attributed to the degradation of starch in buds, which, by increasing the concentration of soluble sugars in cells, contributes to reducing their freezing point.
Growth responses of Stylosanthes guianensis ‘Reyan No. 2’ to root exudates from different relatives
WANG Liyuan, WANG Jian, ZHAO Yuanchen, XU Zhao, LI Xuefeng
2022, 39(2): 309-317. doi: 10.11829/j.issn.1001-0629.2021-0331
[Abstract](795) [FullText HTML] (312) [PDF 1224KB](13)
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Plants communicate with each other and cooperate or compete with their relatives through identity recognition. The aim of this study was to clarify the identification differences of Stylosanthes guianensis ‘Reyan No. 2’ on root exudates of different plant relatives. In this study, the effects of root exudates from S. guianensis ‘Reyan No. 2’ itself and its close and distant relatives on seedling growth of this taxa were studied. This was undertaken by culturing them in seven nutrient solutions containing root exudates of different relatives of Stylosanthes. Results showed that the average values of lateral root number, total biomass, stem leaf biomass, and root biomass (fresh weight) in the close relative treatment group were significantly higher than those in the self root exudate treatment group (P < 0.05). For the self-treatment group, the average values of lateral root number and root biomass increased by 250.00% and 41.85%, respectively. Meanwhile, the average values of plant height, root length, and root-shoot ratio were not significantly different (P > 0.05). Compared with the self-treatment group, the average values of root length, lateral root number, root biomass, and root-shoot ratio in the distant treatment group significantly increased (P < 0.05). In this group, plant height significantly decreased by 10.52% (P < 0.05). There were differences in the specific response results for each species/variety in the close relative and distant relative treatment groups. Grey correlation analysis showed that the response of S. guianensis ‘Reyan No. 2’ to the root exudates of seven Stylosanthes species was ranked as follows: S. hamata > S. guianensis ‘Reyan No. 24’ > S. gracilis > S. scabra ‘Seca’ > S. grandifolia > S. guianensis ‘Reyan No. 5’ > S. guianensis ‘Reyan No. 21’. It is suggested that kin recognition is an important mechanism for the competition and interaction between Stylosanthes and neighboring plants. In production, it is possible to develop new technologies for forage mixed sowing and increase forage yield per unit area by mixing Stylosanthes species with close relatives, such as mixed planting S. guianensis ‘Reyan No. 2’, S. guianensis ‘Reyan No. 5’, and S. guianensis ‘Reyan No. 21’.
Effects of seasonal grazing on spatial distribution characteristics of forage biomass in an alpine meadow on the Qinghai-Tibet Plateau
ZHANG Qianyu, ZENG Yifeng, LI Wenjie, SHEN Jie, WANG Shuohua, WANG Shulin, ADE Luji, LI Lan, HOU Fujiang
2022, 39(2): 318-327. doi: 10.11829/j.issn.1001-0629.2021-0490
[Abstract](374) [FullText HTML] (230) [PDF 1609KB](39)
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Alpine meadow are one of the main grassland types on the Qinghai-Tibet Plateau, and are of great significance to local peoples’ lives as a national ecological barrier. Four seasonal yak pastures in an alpine meadow of Maqu County, Gansu Province, were selected as research objects, and the effect of seasonal grazing on the spatial distribution of forage biomass was explored. The results showed that the coefficient of variation of aboveground biomass of plant communities in non-grazing plots and continuous grazing plots was higher than that in other seasonal pastures (29.06% and 29.02%, respectively). The coefficient of variation of root to shoot ratio and belowground biomass of plant communities in non-grazing plots was the highest, at 34.46% and 35.73%, respectively. Moreover, it was the lowest for pasture in spring, at 9.16% and 13.12% respectively. The aboveground biomass of summer pasture and continuous grazing plots was significantly lower than that of the pasture in the other three seasons, at 194.52 and 167.94 g·m−2, respectively, but the root to shoot ratio showed the opposite trend. Grazing reduced the belowground biomass of the summer, winter, and four-season continuous grazing plots, but the effect was not significant. The contribution of the aboveground biomass of Leguminosae to the belowground biomass was the lowest. The aboveground biomass of others, Cyperaceae, and Compositae accounted for 40%, 31%, and 30% of the belowground biomass, respectively. The aboveground biomass of Ranunculaceae and Gramineae could explain the variation in the root to shoot ratio by 42% and 41%, respectively. Therefore, the aboveground biomass of Compositae and others can suitably predict the alpine meadow plant community’s belowground biomass on the Qinghai-Tibet Plateau, and the aboveground biomass of Gramineae and Ranunculaceae can predict the root to shoot ratio of plant communities in the region. These results provide a theoretical and technical basis for alpine meadow utilization and grazing management.
Comprehensive analysis of production performance and nutritional value of 14 alfalfa varieties in the Ningxia Yellow River diversion irrigation area
MA Xiaoxia, BI Yixian, CHEN Hongliang, ZHANG Long, YAN Ya, QU Hailong, LANG Fenghong
2022, 39(2): 328-342. doi: 10.11829/j.issn.1001-0629.2021-0343
[Abstract](1118) [FullText HTML] (322) [PDF 963KB](18)
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A comparative experiment on filed performance and nutritional value of 14 alfalfa varieties was conducted in 2017–2019 to select Medicago sativa varieties suitable for cultivation in the Ningxia Yellow River diversion irrigation area. In this study, the filed performance parameters (plant height, number of stems per plant, hay yield, fresh to dry ratio, and stem to leaf ratio) and nutritional indicators (content of crude protein, neutral detergent fiber, acid detergent fiber, ether extract, and crude ash) of alfalfa at early bloom were measured for three consecutive years. The dataset was then analyzed using the grey correlative system to assess varieties comprehensively. Results showed that the hay yield of AmeriStand 407 was the highest of 16.68 t·ha−1 in three years, and the average hay yield of 4020MF, BR4010, Magnum Ⅶ and 55V12 were 16.47 ~ 16.63 t·ha−1. The crude protein content of 54V09 was the highest of 19.46%. The neutral and acid detergent fiber content of WL316HQ were the lowest at 35.12% and 28.85%, respectively. The comprehensive analysis results show that 4020MF, Phabulous, WL363HQ, and BR4010 perform excellently in the Ningxia Yellow River irrigation area, with potential for more extensive use as a pasture crop in the region.
Evaluation of the safety of imazapic for alfalfa crops
SU Wangcang, LI Huilong, LEI Haixia, FENG Changsong, SUN Lanlan, XU Hongle, WU Renhai
2022, 39(2): 343-351. doi: 10.11829/j.issn.1001-0629.2021-0231
[Abstract](804) [FullText HTML] (308) [PDF 1302KB](5)
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This research aims to determine the safety, quality, and weed control effects of imazapic on alfalfa (Medicago sativa). Alfalfa crops that had been planted for 4 years and 10 months were used for the study. The safety level, quality index, and weed control effects of these alfalfa crops were surveyed by spraying different doses of imazapic 10 days after mowing them. Results showed that 7 and 14 days after treatment, treatment with imazapic at the doses of 100.8 and 129.6 g·ha−1 significantly reduced the plant height and fresh weight of the alfalfa (P < 0.05). Inhibitory effects on alfalfa plant height and fresh weight were significantly reduced 28 days after application of 100.8 g·ha−1 of imazapic (P < 0.05). Treatment with imazapic at the doses of 129.6 g·ha−1 still had a significant effect on the plant height, fresh weight, and number of nodules present on the alfalfa plants (P < 0.05). The number of nodules on old alfalfa plants was less than those present on young alfalfa plants. After 28 days, the plant control effect and fresh weight control effect of imazapic at the doses of 86.4, 100.8, and 129.6 g·ha−1 were both higher than 80%. Treatment with imazapic at the doses of 129.6 g·ha−1 significantly affected the yield. The crude protein content was found to have decreased significantly (P < 0.05). The experimental results showed that imazapic had a good control effect on weeds in the dose range of 86.4~100.8 g·ha−1. Use of this dosage had no adverse effect on the growth and quality of alfalfa and significantly increased the yield. It therefore has good promotion value in the context of agricultural production.
Estimation of genetic parameters and breeding value of body weight at different stages of Hu sheep growth and development and genetic correlations with key feed efficiency indices
ZHAO Yuan, ZHANG Deyin, ZHANG Yukun, ZHANG Xiaoxue, LI Xiaolong, SONG Qizhi, ZHOU Bubo, LIN Changchun, ZHAO Liming, WANG Jianghui, XU Dan, CHENG Jiangbo, LI Wenxin, WANG Weimin
2022, 39(2): 352-361. doi: 10.11829/j.issn.1001-0629.2021-0116
[Abstract](755) [FullText HTML] (226) [PDF 1036KB](7)
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In this study, we sought to determine variance components and genetic parameters for the body weight traits of Hu sheep at different stages of growth and development, thereby providing a reference for Hu sheep breeding. In 2018 and 2019, we selected new-born male Hu lambs with complete pedigree records, and used the birth weight, weaning weight, and 100- and 180-day body weights to determine the feed intake from 100 to 180 days of age. Variance components were estimated based on a restricted maximum likelihood algorithm using ASREML-R, and body weight breeding values were estimated based on the best linear unbiased prediction at each test period. The results revealed that the variance of maternal permanent environmental effects was significant at different body weight stages (P < 0.05). The estimated heritabilities of birth weight, weaning weight, and body weight at 100 and 180 days of age were 0.43, 0.27, 0.46, and 0.41, respectively. The genetic and phenotypic correlations between different body weights ranged from 0.38 to 0.97 and from 0.25 to 0.84, respectively. The genetic and phenotypic correlations between feed conversion rate and body weight were 0.09 ~ 0.74 and 0.05 ~ 0.51, respectively, whereas the genetic and phenotypic correlations between residual feed intake and body weight ranged from −0.04 to 0.26 and from −0.15 to 0.039, respectively. We concluded that in Hu sheep, maternal effects have an important influence on the growth rate of lambs. Medium and high body weight heritability were identified at different growth stages, whereas we detected large differences among the genetic and phenotypes correlations between selected feed efficiency traits and body weight at different growth stages. Accordingly, careful selection at an early stage is necessary to reduce potential losses in economic benefits. If selection is practiced at an age of 100 days, improvement would be seen at an age of 180 days.
Effects of dietary protein levels on growth, nutrient apparent digestibility, nitrogen emission and serum biochemical indices of small-tailed lambs of Han sheep
YAO Xixi, LIU Haodong
2022, 39(2): 362-370. doi: 10.11829/j.issn.1001-0629.2021-0249
[Abstract](438) [FullText HTML] (185) [PDF 817KB](12)
Abstract:
This experiment was conducted to investigate the effects of different dietary protein levels on growth, apparent digestibility, nitrogen emission and serum biochemical indices of male lambs of small-tailed Han sheep to a provide theoretical basis for low protein scientific feeding of small-tailed Han lambs. Thirty-six 3-month-old male lambs with similar body weight [(18.05 ± 1.36) kg] and good health were randomly divided into three groups with 12 lambs in each group. Group Ⅰ was fed a diet with a low level of protein (12.00%), group II was fed a diet with a medium level of protein (13.40%), group Ⅲ was fed a diet with a high level of protein (14.80%), and the dietary metabolizable energy level of each experimental group was the same (10.50 MJ·kg−1). The pre-trial period lasted for 14 days, and the trial period lasted for 90 days. The results demonstrated that: 1) dietary protein intake had significant effects on organic matter (OMI) and crude protein intake (CPI), average daily gain (ADG) and feed to gain (F/G) of fattening lambs (P < 0.05). The OMI of fattening lambs in group Ⅰ was significantly higher than that in group Ⅲ (P < 0.05). CPI, ADG and F/G of fattening lambs in group Ⅲ were significantly higher than those in groups Ⅰ and Ⅱ (P < 0.05). 2) dietary protein intake had significant effects on the apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of fattening lambs (P < 0.05). Apparent digestibility of DM, OM and ADF of fattening lambs in groups Ⅱ and Ⅲ were significantly higher than those in group Ⅰ (P < 0.05). The apparent digestibility of CP and NDF in groups Ⅱ and Ⅲ was significantly higher than that in group Ⅰ (P < 0.05). 3) dietary protein intake had significant effects on nitrogen intake, excretion of fecal nitrogen, urinary nitrogen and total nitrogen, and nitrogen retention of fattening lambs (P < 0.05). Nitrogen intake, urinary nitrogen excretion and total nitrogen excretion of faltering lambs in group Ⅲ were significantly higher than those in groups Ⅰ and Ⅱ (P < 0.05). Fecal nitrogen excretion in group Ⅲ was significantly higher than that in group Ⅰ (P < 0.05). Nitrogen retention in groups Ⅱ and Ⅲ was significantly higher than that in group Ⅰ (P < 0.05). 4) dietary protein intake had significant effects on the contents of urinary nitrogen, glucose, alanine aminotransferase, total bilirubin, creatinine, low density lipoprotein and non-esterified fatty acid in serum of fattening lambs (P < 0.05). The content of blood and urine nitrogen in group Ⅲ was significantly higher than that in groups Ⅰ and Ⅱ (P < 0.05). The glucose content in group Ⅲ was significantly higher than that in group Ⅰ (P < 0.05). The contents of alanine aminotransferase and total bilirubin in fattening lambs in group Ⅰ was significantly higher than those in group Ⅲ (P < 0.05). The contents of creatinine and low density lipoprotein in groups Ⅰ and Ⅱ were significantly higher than those in group Ⅲ (P < 0.05). The content of non-esterified fatty acids in group Ⅰ was significantly higher than that in group Ⅱ (P < 0.05), and in group Ⅱ was significantly higher than that in group Ⅲ (P < 0.05). In conclusion, the experimental results demonstrated that reducing the protein content of feed can improve the utilization rate of protein and reduce nitrogen emissions. The optimal dietary protein content of feed for fattening male lambs of 3-month-old small-tailed Han lambs is 12.00%.
Research progress on rumen microbiota and their regulation
GUO Hong, YANG Huichao, GAO Qiaoxian, XIN Guosheng
2022, 39(2): 371-380. doi: 10.11829/j.issn.1001-0629.2021-0242
[Abstract](613) [FullText HTML] (206) [PDF 830KB](8)
Abstract:
Microorganisms are affected by aspects of the host environment, nutrition, and management, and play an important role in the life and production of ruminants. This review summarizes the establishment and mechanism of four different microflora, as well as their effects on animal metabolism. This review also lists the mechanisms of rumen regulation, which provides a reference for the application of rumen regulation technology, production performance, health improvement, and environmental emission reduction.
Exploration of the stereo development mode of ecological grass-based livestock husbandry in Yunnan-Guizhou Plateau: An example from the Yongshan County, Yunnan Province
SUN Jiamei, LIU Zhiquan, ZHONG Jin, WANG Tianwei, WANG Xiangquan, SUN Changrong, GAO Shuqin, PAN Qingmin
2022, 39(2): 381-390. doi: 10.11829/j.issn.1001-0629.2021-0371
[Abstract](1028) [FullText HTML] (299) [PDF 1356KB](12)
Abstract:
The development of ecological grass-based livestock husbandry is an important part of the structural adjustment of agriculture in the new era. There are 4.7 × 105 km2 hill grasslands in southern China, with abundant light, heat, water, and soil resources. Grass has a long growing season, high productivity, and huge potential for the development of ecological grass-based livestock husbandry. Moreover, vegetation and climate show obvious vertical differences due to complex terrain conditions. However, grass-based livestock husbandry development in hill grasslands in southern China has rarely been reported. Therefore, we conducted technology demonstrations in Yongshan County, Zhaotong City, Yunnan Province. Accordingly, three modes were explored based on climate and vegetation characteristics at different elevations. At high elevations (above 2 500 m), the mode centered on grazing; at middle elevations (1 500 ~ 2 500 m), the mode centered on both grazing and house feeding; and at low elevations (below 1 500 m), the mode centered on house feeding. This stereo development mode system has been formed in the region. Therefore, we made suggestions for the development of ecological grass-based livestock husbandry in southern China and can provide a basis for future decision-making.
Current situation, implementation methods, and technical bottlenecks in forage seed quality certification in China
GAO Yuan, ZHANG Zuxin, ZHANG Rong, HU Xiaowen
2022, 39(2): 391-398. doi: 10.11829/j.issn.1001-0629.2021-0114
[Abstract](593) [FullText HTML] (271) [PDF 852KB](17)
Abstract:
Seed quality certification is a seed quality control system that ensures the authenticity and purity of seeds. This paper reviews and analyzes the development process and current status of the forage seed quality control system in China. Implementing forage seed quality certification is an effective way of solving problems in the seed market, such as poor awareness of varieties available, significant variation in seed quality, and unclear seed provenance. However, due to land fragmentation, the lack of technology to authenticate seed varieties, lack of seed certification organizations, and poor acceptance levels from seed users, implementation of forage seed quality certification has been restricted to some extent. Based on this, this paper proposes a four-step framework for forage seed quality certification in China. This framework will be implemented as follows: 1) Set up a special organization for forage seed quality certification and establish a management system for forage seed quality certification according to international standards and that reflects the status of forage seed production in China. 2) Establish a standard sample bank of forage seed varieties and compile authentication standards for the relevant seed varieties. This should be undertaken in cooperation with scientific research institutes and forage variety validation committees at various levels. 3) Conduct pilot forage seed quality certification and strengthen publicity about the program and effectiveness of certifying forage seeds. 4) Improve the management system of forage seed quality certification based on pilot work and implement these findings nationwide.
Meta-analysis of the effects of nitrogen and water input gradients on maize yield, nitrogen fertilizer productivity, and water use efficiency in northern China
MO Qishun, QIN Wangfei, ZHANG Qingping, LI Zhou
2022, 39(2): 399-411. doi: 10.11829/j.issn.1001-0629.2021-0535
[Abstract](958) [FullText HTML] (344) [PDF 7576KB](21)
Abstract:
This study was conducted to determine the overall performance of the effects of water, nitrogen, other environmental factors, and agronomic measures on maize (Zea mays) yield, nitrogen productivity (NP), and water use efficiency (WUE) under different environmental and climatic conditions. This study is based on 35 studies on the effects of nitrogen application and water input gradients on maize yield, NP, and WUE, using meta-analysis to explore the relevant factors affecting maize yield, NP, and WUE in northern China, and to quantitatively analyze the relationship between each influencing factor and maize yield, NP, and WUE. The results showed that the average maize yield was 9.19 t·ha−1, and the average of NP and WUE were 55.66 kg·kg−1 and 1.83 kg·m−3, respectively. Water and nitrogen had a significant interaction effect on maize yield. Compared with the control, water input and nitrogen application increased the overall maize yield by 13.43% (P < 0.01) and 10.69% (P < 0.01), respectively. As the input volume increased, water and nitrogen gradually became the main limiting factors for the increase in NP and WUE. In the regression analysis, the effects of water and nitrogen factors, soil organic carbon (SOC), planting density (PD), and available potassium (AK) on maize yield were positive, while that of the mean annual temperature (MAT) was negative. In the structural equation model (SEM), there was a strong positive correlation between SOC and maize yield, and its standardized path coefficient was 0.73. In summary, there is still room for improvement in the water use efficiency and nitrogen productivity of maize in northern China. Based on optimizing water and fertilizer measures, appropriate soil nutrient inputs could increase SOC and AK levels in the soil. Simultaneously, planting density can be increased appropriately, to achieve a win-win situation between high maize yield, water-use efficiency , and environmental protection.
Study on the role of weeds in the productivity improvement of “raising geese in corn field” system
YU Haoran, GUAN Fachun, MIAO Yanjun, GUO Yonggang, XIE Jiao
2022, 39(2): 412-419. doi: 10.11829/j.issn.1001-0629.2021-0412
[Abstract](954) [FullText HTML] (281) [PDF 908KB](16)
Abstract:
In this study, the effects and status of weeds in the improvement of farmland productivity in the “raising geese in corn field” system were determined by analyzing and comparing the “raising geese in corn field” (GCF) treatment and conventional herbicide treatment (CK). The results showed that the weed diversity under GCF treatment was better than that under CK, and the weed yield was significantly higher than that under CK (P < 0.05). However, the presence of weeds seriously affected the growth of maize (Zea mays), and the leaf area of maize treated with GCF was significantly lower than that under CK before and after grazing (P < 0.01), directly leading to a maize yield reduction of 40.64%. The correlation analysis results showed that both weed yield and diversity were key factors that led to maize yield reduction; the R2 values were −0.689 and −0.881, respectively, but as the number of geese eating weeds under GCF treatment reached 60.24 t·ha−1, the comprehensive income under GCF treatment was still 137.11% higher than that under CK as the geese ate weeds and turned them into an economically viable product. Therefore, weeds play a vital role in the economic benefits from “raising geese in corn fields,” which indicates a new way for treating weeds in the future.