Welcome Pratacultural Science,Today is

## 2021 Vol.38(1)

Display Mode：          |

2021, 38(1): 1-11. doi: 10.11829/j.issn.1001-0629.2020-0174
[Abstract](2153) [FullText HTML] (784) [PDF 1050KB](47)
Abstract:
Using pasture observation data in an ecological meteorological field trial observatory in Duolun County during the period from 2004−2018, model parameters were initialized, model applicability was successfully tested, and the dynamic changes in simulated above-ground net primary production (ANPP), during 1961−2018, were studied in the Hunshandake sand. Model correction and validation results showed that the R2 for the comparison of observed and simulated above-ground biomass was 0.78, slope b was 1.04, P was less than 0.01, the root mean square error was 25.23 g·m−2 and the ratio of the absolute mean error was 45.76%. The model test results indicated that the CENTURY model can simulate dynamic changes in above-ground biomass in the Hunshandake sand. The climatic variations since 1961 in this study area were analyzed in this paper. The results indicated that the annual average temperature and extreme annual maximum temperature had an obvious increasing trend; the rates of increase were 0.4 ℃·(10 a)−1 and 0.3 ℃·(10 a)−1 respectively. Annual and growing seasonal precipitation and ANPP did not show significant tendency of variation. Factor analyses showed that increasing temperature was the main characteristic of effect of climate change in sand. Pearson correlation analysis indicated that ANPP was highly significantly correlated with the main growing season precipitation and extreme annual maximum temperature, which were critical meteorological factors affecting ANPP in the Hunshandake sand.
2021, (1): 1-4.
[Abstract](1523) [FullText HTML] (612) [PDF 427KB](33)
Abstract:
2021, 38(1): 1-1.
[Abstract](160) [FullText HTML] (101) [PDF 203KB](0)
Abstract:
2021, 38(1): 11-19. doi: 10.11829/j.issn.1001-0629.2020-0115
[Abstract](2596) [FullText HTML] (952) [PDF 1751KB](66)
Abstract:
Unmanned aerial vehicles (UAVs) equipped with high-definition digital cameras have various advantages such as low cost, high mobility, and large observation range in the field of grassland resource surveys and have a developmental potential. In this study, small UAVs and mobile phone cameras were used to obtain grassland coverage data. The vegetative index (VEG), excess green index (ExG), excess green minus excess red index (ExGR), and green leaf index (GLI) were selected to extract the grassland coverage information based on the visible light vegetation index, and the applicability of each vegetation index was analyzed from the viewpoint of UAV flight height and grassland coverage level. The results showed that (1) VEG and ExG can effectively estimate grassland coverage, with an average accuracy of more than 93%. The estimation results of ExGR and GLI were poor, with an average accuracy of only 75%～80%. (2) The estimation accuracy of the four methods reduced with increasing coverage. VEG had the worst performance in terms of accuracy of grass coverage estimation, followed by ExG. ExGR and GLI were less effective in estimating high-coverage grasslands. (3) The optimal UAV heights for VEG were 100 m for the high and middle coverage levels and 40 m for the low coverage level. The optimal UAV heights for ExG and ExGR were 100 m for the high and middle coverage levels and 80 m for the low coverage level. The UAV optimum heights for GLI were 100 m for the high coverage level and 20 m for the middle and low coverage levels.
2021, 38(1): 20-31. doi: 10.11829/j.issn.1001-0629.2020-0372
[Abstract](2079) [FullText HTML] (742) [PDF 58099KB](16)
Abstract:
Based on the Landsat data of 2000, 2008, and 2018, the remote sensing ecological index (RSEI) was used to determine the ecological environment quality level of Hami Oasis, the 3D trend surface was used to explore the spatial change law of each level of ecological environment quality, and the moving window method was used to analyze the spatial heterogeneity of the ecological environment quality of the oasis and the change of the ecological quality pattern. The results show that: 1) From 2000 to 2018, the average RSEI of Hami Oasis increased from 0.223 to 0.396 and the overall ecological environment quality improved; however, the level was low. 2) In 2000, the regions with medium, good, and excellent ecological environment quality were more concentrated, all on the southeast-northwest axis. In 2008, the areas with extremely poor and poor grades of ecological environment were significantly reduced, and the areas with medium grade, good grade, and excellent grade increased greatly, indicating that the Hami Oasis as a whole expanded rapidly. In 2018, the areas with medium, good, and excellent ecological environment quality were intertwined with each other, mixed, and distributed in a large range, indicating that the ecological quality was not stable enough. 3) The areas where the quality of the ecological environment had improved were concentrated in the interior of the oasis and distributed in a ring-like nest from the inside to the outside. In 2008 and 2018, the ecological index performance from internal to external was determined to be low value area-high value area-low value area-high value area, which was just the opposite of that observed in 2000.
2021, 38(1): 32-43. doi: 10.11829/j.issn.1001-0629.2020-0092
[Abstract](1797) [FullText HTML] (686) [PDF 1313KB](36)
Abstract:
This study focuses on grasslands in the Gannan Prefecture, we used the measured data of aboveground grassland biomass (AGB) and the MOD13Q1 vegetation index product from 2016 to 2019, to construct a remote sensing inversion model of grassland AGB, and further analyzed the characteristics of temporal and spatial changes in the grassland AGB in the last 20 years (from 2000 to 2019). The results showed that: 1) Our moderate resolution imaging spectroradiometer enhanced vegetation index (MODIS EVI) is suitable for grassland biomass inversion (R2 = 0.524 9, RMSE = 527.9 kg·ha−1). 2) In the past 20 years, the alpine meadows and mountain meadows showed an increasing trend, while swamp AGB decreased. 3) In the past 20 years, the grasslands in Gannan Prefecture showed a trend towards partial deterioration; the overall trend for grassland vegetation in Gannan Prefecture was positive, 66.04% of the grassland showed a trend of stabilization or recovery, 33.96% of the grassland AGB decreased, and 18.08% of the grasslands showed a continuous deterioration trend. The study results provide data support for Gannan Prefecture grassland vegetation dynamic monitoring and alpine grassland degradation restoration.
2021, 38(1): 44-51. doi: 10.11829/j.issn.1001-0629.2020-0161
[Abstract](1581) [FullText HTML] (591) [PDF 627KB](10)
Abstract:
Nitraria tangutorum and Artemisia sphaerocephala are widely distributed psammophytes in arid desert areas, where the frequency and intensity of wind-sand flow are high. Investigating the physiological response of N. tangutorum and A. sphaerocephala to stress caused by wind-sand flow is significantly important to understand the mechanism of wind-sand flow resistance of plants in sandy areas. In this study, using wind tunnel simulation test, the two plants were stressed under 12 m·s−1 wind-sand flow for 0, 10, 20, and 30 min. Then, two indices—leaf membrane permeability and membrane protection—were determined. The results showed that with the increase of wind-sand flow blowing, in N. tangutorum, malonaldehyde (MDA) and soluble protein (SP) decreased, membrane permeability decreased first and then increased, superoxide dismutase (SOD) and catalase (CAT) activities increased simultaneously under 10 and 30 min stress, and Peroxidase (POD), soluble sugar (SS), and proline (Pro) contents increased, which prevented membrane lipid peroxidation in N. tangutorum. In contrast, in A. sphaerocephala, MDA content decreased first and then increased, SP was significantly reduced (P < 0.05), CAT activity significantly increased under 20 min stress (P < 0.05), membrane permeability and POD activity increased, and Pro increased slightly under the 20 and 30 min stress, which played a major role in reducing cell membrane damage.
2021, 38(1): 52-62. doi: 10.11829/j.issn.1001-0629.2020-0282
[Abstract](1607) [FullText HTML] (565) [PDF 1153KB](13)
Abstract:
Exploring the effects of soil characteristics of lake wetlands on plant diversity is of great significance to understand how wetland vegetation distributes and maintains its function. We established sampling plots along a series of groundwater level gradients in the riparian zone of Shengjin Lake in the Anhui Province and measured the coverage, aboveground biomass of plants and soil moisture, soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) among other indicators. By using Pearson correlation analysis and redundancy analysis (RDA), we examined the effects of soil characteristics on plant community diversity. The results showed that as the groundwater level increased, the soil moisture and TN content increased significantly, whereas soil SOC and TP content decreased significantly. The contents of SOC, TP, and C ꞉ N were significantly and negatively correlated with soil moisture, whereas TN, N ꞉ P, and C ꞉ P were significantly and positively correlated with soil moisture. Collectively, soil moisture, TN content, C ꞉ P, and N ꞉ P were determined to be the key factors affecting plant diversity in the riparian zone, explaining 91.85% of the variation in plant diversity altogether. In conclusion, soil moisture could effectively determine plant community assemblage in the Shengjin Lake riparian zone, either directly or indirectly, by changing the cycling of N and the availability of P in the soil.
2021, 38(1): 63-69. doi: 10.11829/j.issn.1001-0629.2020-0416
[Abstract](2128) [FullText HTML] (625) [PDF 872KB](35)
Abstract:
To provide a scientific basis for the scientific returning of leguminous green manure and reasonable reduction of chemical fertilizer application in yellow soil uplands, a nylon bag net bag embedding method was utilized for the decomposition and nutrient release of leguminous green manure with different water contents and biochar addition in the yellow soil uplands experimental base of the Guizhou Academy of Agricultural Sciences. The trend of the decomposition rate was the same between the different treatments, which showed that the decomposition rate was fast at first, then slowly decomposed, and finally the decomposition stabilized and reached equilibrium. The total decomposition rate was air dried green manure + biochar > fresh green manure + biochar > air dried green manure > fresh green manure. After 180 days of decomposition, the decomposition rates of fresh green manure, air dried green manure, fresh green manure + biochar, and air dried green manure + biochar were 74.77%, 83.13%, 92.69%, and 95.83%, respectively. The decomposition rate of green manure treated with biochar was higher than that without biochar, and the decomposition rate of air dried green manure was higher than that of green manure. Similar to the decomposition rate, the decomposition rates of N and P were fast at first, then slowly decomposed, and finally the decomposition stopped and reached equilibrium. After 180 days of decomposition, the decomposition rates of N and P for fresh green manure, air dried green manure, fresh green manure + biochar, and air dried green manure + biochar were 73.55%, 83.80%, 92.00%, 95.00%, and 76.40%, 87.13%, 93.31%, 96.27%, respectively. The decomposition rate of K was higher than that of N and P, the release rate of green manure in different treatments reached more than 80% after 30 days of decomposition. The decomposition rate of the air dried green manure was higher than that of the fresh green manure, and adding biochar improved the decomposition rate of air dried and fresh green manure. In actual operation, the decomposition rate of green manure with different water content was different; leguminous green manure can be returned to the field after air drying, and biochar and other alkaline substances are added to improve the decomposition efficiency. It was indicated that after returning green manure to the field, the application rates of N and K fertilizer should be decreased and K fertilizer could be used in crop growth at a later stage, while N and P should be maintained as a usual practice at the early crop growth stage.
2021, 38(1): 70-80. doi: 10.11829/j.issn.1001-0629.2020-0186
[Abstract](2144) [FullText HTML] (708) [PDF 861KB](23)
Abstract:
Abundant native landscape cover plants exist in the green spaces of Changchun. To study the species composition and diversity of native landscape cover plants in Changchun, the species, crown density, height, density, and coverage were investigated using 595 samples, and the soil physical and chemical properties of typical samples were determined. The results showed that 95 species belonged to 40 families and 83 genera. The importance of Liliaceae was 31.93%, which was dominant among all families, followed by Cmpositae, Violaceae, and Gramineae. The diversities of native landscape cover plants among different type green spaces and communities changed obviously, and the park green spaces and coniferous and broad-leaved trees mixed communities had the highest diversity index, whereas the road green spaces and coniferous mixed communities had the highest evenness index. RDA results showed that there was a positive correlation in the Margalef index, Shannon-wiener index, and Simpson index between the soil total nitrogen and organic carbon (P < 0.05) and a native correlation between crown density and pH values. The results are expected to provide a certain reference value for the selection and application of landscape cover plants in northeast China.
2021, 38(1): 81-88. doi: 10.11829/j.issn.1001-0629.2020-0140
[Abstract](1545) [FullText HTML] (588) [PDF 1079KB](19)
Abstract:
This study aims to investigate the effects of Arthrobacter psychrolactophilus strain B7 on plant growth and the physiological characteristics of the perennial ryegrass under different shade stress treatments (0, 20%, 40%, 60%, and 80%). The combined effects of B7 inoculation and various levels of shade stress on plant growth and physiological characteristics were investigated via pot experiments. The results showed that shade stress significantly inhibited the perennial ryegrass seedling growth (P < 0.05), whereas B7 inoculation alleviated the growth inhibition caused by shade stress. The relative electrolyte leakage and malondialdehyde accumulations increased with increasing shade stress. B7 inoculation significantly reduced the cellular membrane damage and reactive oxygen species (ROS) levels under shade stress (P < 0.05), compared with shade treatment alone. Inoculation of B7 decreased the H2O2 and \begin{document}${\rm{O}}_2^{{\rm{\cdot}} - }$\end{document} levels by 5.88%, 24.41%, 33.60%, and 40.00%, and by 30.91%, 22.94%, 25.67%, and 49.37% when exposed to 20%, 40%, 60%, and 80% shade stresses, respectively. Additionally, shade stress resulted in an increase in the antioxidant enzyme activities and non-enzyme antioxidant contents, whereas B7 inoculation further improved the activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, glutathione reductase, and the contents of ascorbic acid (AsA) and glutathione (GSH). In conclusion, B7 inoculation could improve the antioxidant defense activities, which led to a decline in ROS, thus enhancing shade tolerance in perennial ryegrass. The present study indicates that A. psychrolactophilus strain B7 has considerable potential for improving the ability of plants to adapt to stress.
2021, 38(1): 89-98. doi: 10.11829/j.issn.1001-0629.2020-0238
[Abstract](1783) [FullText HTML] (553) [PDF 1739KB](11)
Abstract:
In order to explore the optimal approach for analyzing the root tips of Panicum repens, we compared different pre-treatment, fixation, prehypotension, and dissociation conditions during chromosome preparation. The results demonstrated that the optimal pre-treatment was a mixture of ice and water at 4 ℃ for 22 h, the optimal fixation was Cano′s fixed liquid Ⅰ at 4 ℃ for 24 h, the optimal pre-hypotension was 0.075 mol·L−1 KCl at 25 ℃ for 15～20 min, and the optimal dissociation was a mixture of 1% pectinase and 2% cellulase at 25 ℃ for 3 h. The karyotype analysis revealed the formula for P. repens to be 2n = 2x = 40 = 34m + 6sm. Furthermore, no satellite was observed. The absolute chromosome length ranged from 10.87 to 19.21 μm, which indicates P. repens contains a single large chromosome. The relative chromosome length composition was 2n = 40 = 2L + 16M2 + 22M1. The ratio of longest to shortest chromosome length was 1.77, and the arm ratio ranged from 1.04 to 2.08. The karyotype asymmetry coefficient was 58.99%, and the karyotype beingwas 2A, which may be an evolutionarily primitive type, providing a certain theoretical and technical basis for the origin, evolution, inheritance, and breeding of P. repens.
2021, 38(1): 99-109. doi: 10.11829/j.issn.1001-0629.2020-0464
[Abstract](2233) [FullText HTML] (766) [PDF 658KB](15)
Abstract:
The aim of study was to investigate the effects of cutting number and pelletizing on vitamin content, chemical composition and Escherichia coli population of alfalfa planted in the test field of Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences. Three cuttings (first, second and third) were harvested at bud stage to make pellets. Then, samples were taken from the pellets to determine the vitamin content, chemical composition and E. coli population. The results showed that cutting number had significant influence on the amount of VB2, VB3, VB5, VB6 and Vc in alfalfa; the amount of VB2, VB3, VB5 in the second cutting alfalfa was significantly higher than in the first and the third cuttings (P < 0.05), while the B6 and Vc content was significantly higher in the first and second cuttings than in the third (P < 0.05). The cutting number had significant influence on the content of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber of alfalfa. Overall, the quality of the second cutting was better than the first and third cuttings (P < 0.05). The amounts of B3 and B5 in alfalfa were not significantly affected by pelletizing (P > 0.05), but the amounts of B2, B6, Vc and VK1 were significantly reduced (P < 0.05). The interaction effect of cutting and pelletizing had significant influence on the content of B1, B6, organic matter, and dry matter in alfalfa (P < 0.05). The population of Escherichia coli was lowest in the first cutting and highest in the third cutting; pelletizing significantly inhibited the activity of E. coli (P < 0.05).
2021, 38(1): 110-121. doi: 10.11829/j.issn.1001-0629.2020-0272
[Abstract](2390) [FullText HTML] (651) [PDF 1182KB](44)
Abstract:
Using the data of daily mean temperature, the minimum temperature from 102 meteorological stations in Xinjiang during 1961–2019, based on statistical method and ArcGIS, the fundamental spatial-temporal change characteristic of key climatic factors affecting alfalfa planting, such as ≥ 5 ℃ accumulated temperature (\begin{document}$\sum$\end{document}Tmean ≥ 5 ℃), and the minimum temperature in winter (Tmin) were analyzed. Taking 80% guarantee rate ≥ 5 ℃ accumulated temperature (\begin{document}$\sum$\end{document}Tmean ≥ 5 ℃ of 80% guarantee rate) and 90% guarantee rate minimum temperature (Tmin of 90% guarantee rate) as the index factors, the climate suitability changes of different fall dormancy grades in alfalfa planting were studied under the background of climate warming in Xinjiang. The results showed that spatial distribution of \begin{document}$\sum$\end{document}Tmean ≥ 5 ℃ of 80% guarantee rate and Tmin of 90% guarantee rate had very obvious differences from place to place in Xinjiang. Generally, they were more in the south than in the north and more in the plain than in the mountainous regions. Under their comprehensive influence, the suitable planting areas for alfalfa off all dormancy grades 4 ~ 6 was mainly in the Tarim, Turpan, and Hami Basins. The suitable areas for fall dormancy grades 2 ~ 3 was in the sloping plains around the Tarim Basin, Turpan Basin, Hami Basin, the Yili Valley, and the low plains in the west and east of the Junggar Basin. Areas for fall dormancy grades 1 ~ 2 was in the north and west of northern Xinjiang, the hinterland of Junggar Basin, and the middle and low mountain belts of Tianshan mountain and Kunlun mountains. Alfalfa was not suitable for planting in the Altai, Tianshan, and Kunlun mountains. The dominant factors affecting the distribution of suitable planting areas for alfalfa of different fall dormancy grades were different. Generally, the suitable planting areas of fall dormancy grades 4 ~ 6 and 2 ~ 3 were mainly affected by \begin{document}$\sum$\end{document}Tmean ≥ 5 ℃ of 80% guarantee rate, but the areas of suitable planting for alfalfa of fall dormancy grades 1 ~ 2 and unsuitable for alfalfa planting were mainly affected by Tmin of 90% guarantee rate. In the background of global warming, \begin{document}$\sum$\end{document}Tmean ≥ 5 ℃ and Tmin significantly (P < 0.001) increased at the rate of 65.52 (℃·d)·10 a−1 and 0.63 ℃·10 a−1 respectively, during 1961–2019 in Xinjiang. \begin{document}$\sum$\end{document}Tmean ≥ 5 ℃ of 80% guarantee rate and Tmin of 90% guarantee rate were increased too, but the changes were different in different periods during 1961–2019. During period Ⅰ (1961–1980), \begin{document}$\sum$\end{document}Tmean ≥ 5 ℃ of 80% guarantee rate and Tmin of 90% guarantee rate were the lowest in nearly 59 years. In period Ⅱ (1981–2000), the Tmin of 90% guarantee rate was 2.9 ℃ higher than that of period Ⅰ, but the \begin{document}$\sum$\end{document}Tmean ≥ 5 ℃ of 80% guarantee rate had no obvious change. In period Ⅲ (2001–2019), the Tmin of 90% guarantee rate was 0.8 ℃ lower than that of period Ⅱ while the \begin{document}$\sum$\end{document}Tmean ≥ 5 ℃ of 80% guarantee rate increased by 147.0 ℃·d. Under their influence, the suitable planting areas for 4 ~ 6 and 2 ~ 3 grades of fall dormancy alfalfa showed an expanding trend, whereas the suitable planting areas of 1 ~ 2 grades and the unsuitable planting areas of alfalfa showed a decreasing trend in Xinjiang. These results showed that climate warming was beneficial to the development of alfalfa planting in Xinjiang.
2021, 38(1): 122-135. doi: 10.11829/j.issn.1001-0629.2020-0301
[Abstract](3615) [FullText HTML] (721) [PDF 723KB](65)
Abstract:
In this study, single sown of forage maize (Zea mays) (Z), mixed sowing of forage maize and forage beans (Glycine max) (ZG) and forage maize dolichos lablab mixture (ZD) were planted in Hexi region in 2019. Six irrigation modes were set under each planting mode to study the effects of different planting and irrigation modes on the yield, quality and water use efficiency of forage grass. The results showed that: 1) the fresh and hay yield of ZG and ZD treatments was significantly higher (P < 0.05) than Z, the fresh grass yield increased by 19.1% and 16.4%, and the hay yield increased by 12.7% and 9.0%, respectively. Under the same planting method, the fresh and hay yield of water deficit in later stage (I4), mild water deficit in early stage (I5) and full irrigation (I6) was significantly higher (P < 0.05) than that of severe water deficit (I1). Compared with I1 treatment, their average fresh grass yield increased by 39.1%, 45.9% and 46.6%, respectively, and the average hay yield increased by 35.8%, 44.2% and 43.8%, respectively. 2) The results showed that mixed sowing treatments increased crude protein content, reduced starch, acid and neutral washing fiber, and further increased relative feeding value (RFV), and ZG treatment significantly (P < 0.05) increased crude protein, crude fat and crude ash yield compared with Z. The average crude protein, crude fat content and RFV of I5 treatment were significantly higher (P < 0.05) than that of I1. The yield of crude protein, starch, crude fat and crude ash of I5 treatment were the highest among the six irrigation modes. 3) The data showed that ZG and ZD treatments significantly improved (P < 0.05) the water use efficiency (WUE) compared with that under Z. The soil water storage and evapotranspiration of I5 and I6 treatments were significantly higher (P < 0.05) than I1, and the WUE of I5 was significantly higher (P < 0.05) than that under I4 and I6. The WUE, crude protein, crude fat and starch of ZG-I5 treatment were the highest in all treatments, and the fresh hay yield of ZG-I5 was just below that of ZG-I6. This treatment was the best suitable cultivation mode for green forage corn production in Hexi region.
2021, 38(1): 136-146. doi: 10.11829/j.issn.1001-0629.2020-0221
[Abstract](1598) [FullText HTML] (619) [PDF 787KB](17)
Abstract:
Planting density is an important factor affecting the yield potential of intercropping systems. To determine the suitable planting densities for different maize plant types intercropped with soybean, a field experiment was conducted on four planting densities (45 000, 52 500, 60 000, and 67 500 plant·ha–1) of maize in the intercropping system at same fertilization level, using the pact-type “Denghai 605” (DH605) and flat-type variety “Chuandan 428” (CD428) and fresh soybean as materials. The effects of different plant types and planting densities of maize on aboveground dry matter accumulation, yield, yield components, nutrient uptake, and utilization of soybean were studied. The results showed that both the aboveground dry matter accumulation of different growth periods, yield, number of pods per plant, 100-grain weight, nutrient accumulation, and the partial fertilizer productivity of intercropped soybean were significantly reduced with increasing maize planting density. The effects of CD428 on intercropped soybean were higher than those of DH605 at the same planting density. A combination of yields of the maize-soybean complex population could be given better consideration with the cultivar DH605 at 60 000 plant·ha–1 planting density intercropped with soybean, and the cultivar CD428 at 52 500 plant·ha–1 planting density intercropped with soybean.
2021, 38(1): 147-159. doi: 10.11829/j.issn.1001-0629.2020-0131
[Abstract](1873) [FullText HTML] (566) [PDF 1208KB](21)
Abstract:
In this study, we aimed to guide the sustainable and healthy development of artificial grasslands and herbivorous animal husbandry in hilly and gully regions of the Loess Plateau. In this study, alfalfa and sainfoin were selected as experimental materials to treat the forage productivity for alfalfa mixed with sainfoin at ratios of 1 ꞉ 0 (H1), 7 ꞉ 3 (H2), 5 ꞉ 5 (H3), 3 ꞉ 7 (H4), and 0 ꞉ 1 (H5) at the Golden Village of Lijiabao Town in Dingxi City, Gansu Province, between 2016 and 2018. The following results were obtained: (1) In the second year, the aboveground biomasses after H2, H3, and H4 treatment were 46.0%, 34.0%, and 12.0% higher than that after H1 treatment, respectively, but all were lower than that after H5 treatment. In the third year, the aboveground biomasses after H2, H3, and H4 treatment were higher by 36.5%, 40.0%, and 23.5% than those after H1 treatment, respectively, and higher by 34.9%, 38.4%, and 22.1% than that after H5 treatment, respectively. (2) When the proportion of alfalfa was reduced in the mixed sowing combination, the interspecific competitiveness of alfalfa relative to sainfoin decreased. (3) The crude protein content of alfalfa and sainfoin was the highest, and the relative feeding value of alfalfa was higher than that of sainfoin. In conclusion, under the mixed sowing ratio of alfalfa and sainfoin of 7 ꞉ 3 and 5 ꞉ 5, a relatively high aboveground biomass and nutrient yield can be obtained in the second and third years of growth, and these proportions can be employed during production.
2021, 38(1): 160-170. doi: 10.11829/j.issn.1001-0629.2020-0305
[Abstract](1839) [FullText HTML] (587) [PDF 1071KB](36)
Abstract:
Alfalfa (Medicago sativa) is an important forage crop for livestock feed that contributes nitrogen to succeeding crops in crop-rotation systems. A meta-analysis was conducted to determine how fertilization strategies affected forage yield and soil fertility of alfalfa fields in China. Non-fertilizer was used as control treatments in this research. Based on the published data of relevant location test and the meta-analysis, the quantitative effects on fertilizer application on alfalfa with respect to soil water content, nutrients, yield, and WUE were studied. The results showed that fertilization could improve soil nutrients and alfalfa yield, whereas an increase in alfalfa biomass resulted in a decrease in soil water content. Fertilization increased soil organic matter and nitrogen by 3.1% ~ 33.3% and 4.5% ~ 30.9%, respectively. Similar trends were observed with respect to soil available phosphorus and available potassium, which increased by 3.6% ~ 144.4% and 4.4% ~ 24.8%, respectively. However, owing to the increase in alfalfa biomass, the soil water content decreased by 4.4% ~ 11.8%. As a result, the alfalfa yield and WUE improved by 15.4% ~ 198.2% and 5.9% ~ 169.6%, respectively. Correlation analysis showed that the alfalfa yield was positively correlated with soil water content at 0 – 200 cm, organic matter and available phosphorus; the WUE of alfalfa was positively correlated with soil available phosphorus. In conclusion, fertilization could improve soil nutrients as well as alfalfa yields. The combined application of organic and inorganic fertilizers is an optimum strategy for increasing alfalfa yields, while the combined application of N, P, and K fertilizers is better for WUE. These findings can provide a strategy for farmers to enhance the sustainability of the alfalfa system through fertilization management.
2021, 38(1): 171-182. doi: 10.11829/j.issn.1001-0629.2020-0333
[Abstract](1546) [FullText HTML] (505) [PDF 771KB](15)
Abstract:
The purpose of this study was to optimize the forage nutritional combination of yak diet with the grading index (GI). Five combinations of alfalfa hay and wheat straw with different GI (7.03, 6.21, 5.38, 4.55, and 3.72) were selected to study yak rumen fermentation in vitro. The fermentation time was 48 h and 3 replicates were performed for each sample. At 3 ~ 48 h of fermentation, the gas production (GP) of the GI = 6.21 combination was significantly higher than that using the other GI values (P < 0.05). At 3 h and 48 h of fermentation, the dry matter degradation in vitro (IVDMD) showed a decreasing trend with a decrease in GI. At 3, 12, and 48 h of fermentation, the difference between the neutral detergent fiber in vitro (IVNDFD) of GI = 7.03 and GI = 6.21 is not significant, but they were higher than other GI combinations (P < 0.05). At 3 ~ 48 h of fermentation, the concentration of ammonia nitrogen (NH3-N) showed an initial increasing trend followed by a decrease as the GI decreased. At 48 h of fermentation, the microbial protein (MCP) showed a trend of an initial increase followed by a decrease as the GI decreased. At 48 h of fermentation, the concentrations of acetic acid, propionic acid, and total volatile fatty acids (TVFAs) showed an initial trend of increase followed by a decrease as the GI decreased. At 3 ~ 24 h of fermentation, the concentration of CH4 and DE showed an initial trend of increase followed by a decrease as the GI decreased. The GIs of 7.03, 6.21, 5.38 showed a positive combination effect from 3 ~ 48 h of fermentation, whereas GI = 4.55 and 3.72 showed a positive combination effect beyond 48 h of fermentation. The results of multiple factor associative effects index (MFAEI) were first increased and then showed a decreasing trend as the GI decreased. The GI = 6.21 combination of MFAEI was higher than other GI combinations. Overall, in vitro fermentation of yak rumen with GI = 6.21 alfalfa hay and wheat straw combination were found to be optimal.
2021, 38(1): 183-191. doi: 10.11829/j.issn.1001-0629.2020-0069
[Abstract](2266) [FullText HTML] (723) [PDF 759KB](19)
Abstract:
Predator odors are natural stressors of high ethological impact that induce a broad range of anti-predator responses, which aim to maximize the fitness of individuals through avoidance of dangerous confrontations. To analyze the response of the plateau zokors (Eospalax baileyi) to predator odors and the trade-offs between anti-predator responses and foraging, we tested the anti-predator behavioral responses of plateau zokors to the scent of weasel (Mustela sibirica) feces using distilled water as the control group. Plateau zokors were live-captured from the Qinghai-Tibetan Plateau, and individual behavior was tested in a defensive withdrawal apparatus consisting of a hideaway tunnel and a testing arena for 30 min. Results indicated that feeding time and food intake were significantly reduced in males when exposed to weasel feces (P < 0.05). Food intake was also significantly reduced in females (P < 0.05), and there was no significant difference in feeding time (P > 0.05). When exposed to weasel feces, we detected a significant increase in the cumulative time and frequency of freezing, rearing, locomotion, and avoidance behaviors in both males and females (P < 0.05). However, there was no significant change in the cumulative time and frequency of hiding and heading out (P > 0.05). In summary, the odor of weasel feces significantly affects food intake and triggers the expression of various anti-predator behaviors in plateau zokors. These behavioral adaptations to predation threats might support the functional significance of the predation risk time-allocation hypothesis.
2021, 38(1): 192-201. doi: 10.11829/j.issn.1001-0629.2020-0114
[Abstract](2997) [FullText HTML] (719) [PDF 990KB](27)
Abstract: