Table of Content

20 October 2020, Volume 29 Issue 10

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Remote sensing diagnosis of grassland ecosystem environmental health in the Ebinur Lake Basin

LIU Si-yi, DING Jian-li, ZHANG Jun-yong, ZHANG Zhen-hua, CHEN Xiang-yue, Mayira·Raxidin

2020, 29(10):  1-13.  DOI: 10.11686/cyxb2019542

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This study analyzed the changes in grassland ecosystem health from 2001 to 2017 in the Ebinur Lake Basin. The research was based on MODIS and Landsat data, and used information entropy principles and a pressure-state-response (PSR) model to evaluate the health status of grassland in the Ebinur Lake Basin in 2017, based on the change trends and current data. It was found that: 1) From 2001 to 2017, the proportions of land area in the Ebinur Lake Basin for which environmental health of the grassland ecosystem has improved, remained unchanged or deteriorated were, respectively, 29.5%, 59.4% and 11.1% of the total grassland area. The ecological environmental health of the environment is generally stable or is improving. 2) In 2017, grassland ecosystem ecological environment health index ranged between values of 0.1097 and 0.3892, indicating that the overall health level was not high. Hence there is a need strengthen the protection and management provisions for grassland resources. 3) The results were used to devise and map three proposed grassland management categories for the grassland ecosystems in Ebinur Lake Basin: a governance area, a protection area and a prevention area. The governance area (in which management should be strengthened to ensure current health status is maintained) accounts for 39.1% of the total grassland area, mainly located in mountain foothills and desert grassland. The protection area (where effort is needed to reverse a current degradation trend) accounts for 34.2% of the total grassland area, mainly distributed in particular mountain foothill regions. The prevention area (generally with good health status but needing management of population pressures from nearby cities) accounts for 26.7% of the total grassland area, mainly in the areas with relatively concentrated towns.

Effects of grazing exclusion on community characteristics and productivity of Stellera-dominated degraded grassland in the northern Tibetan Plateau

SHUI Hong-wei, HASBAGAN Ganjurjav, WU Hong-bao, WANG Zi-xin, LÜ Cheng-wen, GAO Qing-zhu, HU Guo-zheng, YAN Jun, XIE Wen-dong, WANG You-xia

2020, 29(10):  14-21.  DOI: 10.11686/cyxb2019538

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Stellera-dominated degraded grassland is one of the more common categories of degraded grassland in the northern Tibetan Plateau. Protection by grazing exclusion (fencing) is a common measure for the restoration of degraded grasslands. We conducted observations over a three-year period (2010-2012) in both grazed and protected (fenced in 2004) habitats in a Stellera-dominated, degraded grassland, to explore how grazing exclusion impacts on plant community characteristics and productivity of degraded grasslands. It was found that: 1) Grazing exclusion significantly increased the total aboveground biomass in the Stellera-dominated degraded grassland (P<0.05), with the largest increase in 2012. Compared with grazed grassland, the total above-ground biomass in the fenced habitat was increased by 62.4%, 64.3% and 70.2%, respectively, in 2010, 2011, and 2012. 2) Grazing exclusion also increased aboveground biomass of Stellera chamaejasme (P<0.05). Aboveground biomass of S. chamaejasme in grazed plots in 2010, 2011, and 2012 was 43.8%, 55.3% and 89.3% lower, respectively, than that under grazing exclusion (P<0.05). 3) Grazing exclusion was beneficial in that it improved the community species diversity of Stellera-dominated degraded grassland. The species diversity, evenness and species richness indexes all increased significantly as grazing exclusion time increased (P<0.05). 4) The pattern of annual variation in aboveground plant biomass under grazing exclusion was similar to that in grazed plots. In summary, grazing exclusion has no obvious suppression effect on Stellera chamaejasme, so for the restoration of Stellera-dominated degraded grassland, other management measures should be combined.

Physiological-ecological responses of twelve herbaceous plant species under drought stress and evaluation of their drought resistance when planted in coal producting basis in arid windy and sandy areas

XU Ai-yun, CAO Bing, XIE Yun

2020, 29(10):  22-34.  DOI: 10.11686/cyxb2020114

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This research aimed to identify herbaceous plant species which are suitable for vegetation restoration and construction in coal producting basis in arid wind and sand areas, we studied the effects of drought stress on functional traits, photosynthetic characteristics and antioxidase activities of twelve herbaceous plant species grown in pots. The tested plant species were: Limonium bicolor, Agropyron mongolicum, Agropyron desertorum, Astragalus adsurgens, Mellilotus officinalis, Trifolium repens, Medicago sativa, Glycyrrhiza uralensis, Artemisia ordosica, Suaeda glauca, Althaea rosea, and Agriophyllum squarrosum. It was found that at low soil water content, the plant height, specific leaf area, leaf dry matter content, leaf relative water content and root:shoot ratios of all species were affected by the drought stress to some extent, and most species were significantly affected after 14 days of drought stress. Compared with the control treatment, the net photosynthetic rate, stomal conductance and transpiration rate decreased and the activities of superoxide dismutase, catalase, and malondialdehyde (MDA) concentration increased among twelve herbaceous plants after 21 days of drought stress. Re-watering after drought stress resulted in partial recovery of superoxide dismutase, and catalase activity. However, there was significant variation in the MDA content of the twelve species after re-watering, and the MDA content of A. mongolicum, A. desertorum, A. adsurgens and M. sativa displayed an upward trend. Evaluation of multiple traits by principal component analysis showed that the functional trait and antioxidase activity data could be used to evaluate the adaptation capacity of the plant species under drought stress because these traits had the largest eigenvector coefficients. The drought resistance of the twelve herbaceous plant species was then evaluated with a multivariate procedure combining principal component analysis and membership function value, and the ranking so obtained was A. ordosica>A. adsurgens>M. officinalis>A. rosea>A. mongolicum>S. glauca>T. repens>M. sativa=G. uralensis>A. desertorum>L. bicolor>A. squarrosum.

Effect of climate warming on decomposition of plant litter in alpine meadow pastures in Northwestern Sichuan

YANG Yang, TIAN Li-hua, TIAN Hao-qi, SUN Huai-en, ZHAO Jing-xue, ZHOU Qing-ping

2020, 29(10):  35-46.  DOI: 10.11686/cyxb2020191

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Litter decomposition is an important part of the carbon cycle in terrestrial ecosystems, and temperature is a key determining factor of litter decomposition rate. This research explored the effects of warming on the decomposition of plant litter from alpine meadow grasslands in Northwestern Sichuan, using open-top chambers (OTCs) and the decomposition-bag method, to study the effects of warming on the litter decomposition rate of dominant species: Elymus nutans, Deschampsia caespitosa, Foeniculum vulgare, Potentilla anserine, Artemisia mongolica, Saussurea stella, and Saussurea nigrescens. The decomposition bags in this experiment contained mixed aboveground litter and community root litter from the dominant plant species. It was found that: 1) Warming did not significantly change the decomposition cycle of mixed aboveground litter, but significantly improved the decomposition efficiency of root litter. The decomposition-cycle responses of aboveground and underground litter to temperature changesdiffered. 2) Although there were significant differences in nutrient content and stoichiometric characteristics of litter from different plant species (P<0.05), compared with natural decomposition conditions, warming had no significant effect on the decomposition efficiency and the decomposition and release process of litter from individual plant species. In summary, the decomposition process of aboveground litter in the alpine meadow ecosystem in Northwestern Sichuan did not respond significantly to simulated warming, but simulated warming significantly affected the decomposition process of underground litter.

Effect of Stellera chamaejasme removal on the nutrient resorption of plants in an alpine grassland community

SONG Mei-ling, WANG Yu-qin, BAO Gen-sheng, WANG Hong-sheng

2020, 29(10):  47-57.  DOI: 10.11686/cyxb2019548

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Control of Stellera chamaejasme is one of the main methods used to promote recovery of degraded grasslands in the Qinghai-Tibetan Plateau. Limited studies have been conducted on the nutrient resorption of plants during this recovery period. This study investigated the effects of S. chamaejasme removal (SR) on the nutrient resorption efficiency (NuR) from species level, to functional group level, and to community level of the alpine grassland ecosystem. It was found that: At the species level, SR decreased NuR (Nirogen, N) of Poa alpigena and Festuca ovina; SR decreased NuR (Phosphorus, P) of P. alpigena and Stipa aliena, but increased NuR (P) of Koeleria litvinowii, Kobresia capillifolia and Kobresia humilis. At the functional group level, SR induced increased N content in green and senesced leaves of forbs, and the decline of NuR (N) in forbs. The NuR (N) and NuR (P) of Poaceae and Fabaceae all decreased after SR treatment, however, the NuR (P) of sedges increased after SR. At the community level, N content of green leaves and P content of senesced leaves were significantly lower, but the NuR (P) was significantly higher in the SR treatment, compared to CK. In conclusion, different species and functional groups have different NuR responses to SR, but SR promoted P use efficiency at the plant community level. These results may provide basic data for the study of nutrient utilization mechanisms in the recovery of degraded grassland, and provide a theoretical framework for developing effective and sustainable measures for S. chamaejasme control in the Qinghai-Tibetan Plateau.

Effects of alternative fertilization practices on components of the soil organic carbon pool and yield stability in rain-fed maize production on the Loess Plateau

WANG Xiao-jiao, QI Peng, CAI Li-qun, CHEN Xiao-long, XIE Jun-hong, GAN Hui-jiong, ZHANG Ren-zhi

2020, 29(10):  58-69.  DOI: 10.11686/cyxb2020187

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This research quantified and explored the sustainability status of various soil carbon fractions under different fertilization regimes in land used for rain-fed maize production on the Loess Plateau in Gansu province, China. Sustainability of crop yield and of soil carbon pools are key considerations in the selection of fertilization practices in rain-fed agricultural areas on the Loess Plateau that are both economical and environmentally friendly. A long-term experiment was set up in 2012 on maize-production farmland in the dry farming area of the Loess Plateau in central Gansu. Yield stability and sustainability, soil organic carbon (SOC), free particulate organic carbon (FPOC), occluded particulate organic carbon (OPOC), particulate organic carbon (POC), mineral-associated organic carbon (MOC) and carbon pool stability were compared for 0-5 cm, 5-10 cm and 10-30 cm soil depths under five treatments, as follows: no fertilization (CK), nitrogen fertilizer (NF), organic fertilizer (OM), straw (ST) and organic fertilizer combined with nitrogen fertilizer (OMNF). It was found that: 1) The average yield and water use efficiency from 2014 to 2018 differed significantly (P<0.05) under different fertilization practices. OMNF had the highest average yield and water use efficiency (42.75% and 108.73%, respectively, higher than CK). OMNF also had the highest yield stability index (0.34) and sustainability index (0.43), with a high potential for yield increase. 2) Compared with CK, the various fertilization treatments significantly increased the organic carbon content in the measured soil layers to 30 cm depth by between 6.80%-18.81% (P<0.05). For all three measured soil layers, all treatments (ST, OM and OMNF) significantly improved the FPOC, OPOC, POC and MOC (P<0.05). For the 0-30 cm soil depth, the increase range across fertilization treatments for FPOC, OPOC, POC and MOC was, respectively 5.24%-57.05%, 4.31%-20.69%, 4.72%-25.17% and 6.58-7.95%. With increasing soil depth, the levels of soil organic carbon, FPOC, OPOC and POC all decreased under all fertilization treatments, while MOC increased. 3) The dominant component of soil organic carbon was MOC (range across fertilization regimes 55.60%-67.51%), and the main component of POC was OPOC (range 19.14%-22.50%). In the 0-10 cm soil layer, OMNF and NF treatments conferred high stability of the soil carbon pool, while ST, OM and OMNF treatments promoted soil carbon pool activity, and patterns of variation of other soil layers were inconsistent. With increasing soil depth, the stability of carbon storage increased under ST, OM and OMNF treatments. Overall, OMNF increased crop yield, enhanced soil vitality and promoted soil carbon sequestration, making this treatment a better agricultural production scenario providing both economic benefit in terms of yield and environmentally friendly maize production in the Loess Plateau arid region.

Changes in root morphology and anatomical structure of Poa pratensis under different simulated precipitation rates

WANG Zhen-sheng, LI Yan-xue, YU Cheng-long, DI Xiao-lin, CHEN Peng, TIAN Jing-yao, WANG Jing-hong

2020, 29(10):  70-80.  DOI: 10.11686/cyxb2019563

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This research studied the root development of Poa pratensis under four different levels of simulated precipitation. The simulated precipitation treatments were: heavy rain (HR, 25-50 mm precipitation each 24 h), moderate rain (MR, 10-25 mm precipitation each 24 hours), light rain (LR, <10 mm rainfall each 24 h) and control (CK, 60% of the simulated light rain). Treatments were maintained over an experimental period of 24 days. The research aim was to explore the effect of the different simulated precipitation rates on the development of the P. pratensis root system. It was found that the CK treatment was affected by drought and the HR group by flooding, whereas roots of the MR treatment grew well throughout the experiment. In terms of root morphology, root length, root surface area, total root volume, average root diameter and the number of root functions all increased significantly, specific root length and root dry weight density were more stable. Data root system configurations of the various treatments showed that the growth status of P. pratensis in the MR treatment was better than other treatments. In terms of root anatomical structure, by the 50th day, in the CK treatment affected by drought stress, the root structure was damaged, the ratio of cortex to root diameter, diameter of vascular cylinder and xylem duct decreased. Slight drought effects on root anatomical structure were observed in the LR treatment, while the root anatomical structure of the MR and HR treatments was normal. The above results indicate that the moderate rain treatment provided the most suitable water regime for P. pratensis.

Effects of uniconazole on morphology and physiological characteristics of proso millet seedlings under salt stress

ZHANG Pan-pan, YANG Yu-ran, XUE Jia-xin, WANG Tao, LIU Han, LIU Cui-ying, FENG Bai-li, ZHANG Xiong

2020, 29(10):  81-90.  DOI: 10.11686/cyxb2020140

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The aim of this research was to investigate the effect on seedling morphology and physiological characteristics of foliar uniconazole spraying of ‘Yumi 3’ proso millet seedlings under salt stress. Leaf photosynthetic characteristics, seedling growth and seedling antioxidase systems were measured, following foliar spraying with uniconazole (50 mg·L^-1), in plants grown under 150 mmol·L^-1 NaCl stress in sand culture experiments. The results showed that foliar uniconazole spraying increased net photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO₂ concentration, maximum light energy conversion efficiency, actual photochemical efficiency and photochemical quenching of the seedlings, but decreased non-photochemical quenching coefficient. In seedlings exposed to salt stress and foliar spraying with uniconazole, seedling height decreased significantly (P<0.05), and leaf area and shoot dry weight also decreased. However, the total root length, root volume, root surface area, root average diameter and root dry weight of seedlings increased. With respect to antioxidase systems, in seedlings treated with uniconazole under salt stress, superoxide dismutase activity, peroxidase (POD) activity, catalase activity and soluble protein content were all increased, while malondialdehyde content and superoxide anion content ($\mathop{}_{A}^{B}$) were decreased. Among these parameters, POD activity and $\mathop{}_{A}^{B}$ levels showed no significant differences in leaves, but significant differences in roots (P<0.05). Therefore, foliar uniconazole (50 mg·L^-1) spraying at the three-leaf-and-one-leaflet stage of development effectively improved the salt tolerance of proso millet seedlings by regulating the seedling morphological characteristics, enhancing the protective enzyme activity and soluble protein content in the roots and leaves, and decreasing the degree of membrane lipid peroxidation.

Breeding and feeding quality analysis of a new soybean strain deficient in Kunitz trypsin inhibitor

JIANG Yan, XUE En-yu, LU Wen-cheng, CUI Guo-wen, LI Yuan-ming, HAN Tian-fu, WANG Shao-dong

2020, 29(10):  91-98.  DOI: 10.11686/cyxb2019547

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As a source of feed protein, soybean contains rich nutritional components, but also have trypsin inhibitors that affect protein digestibility and absorption. Through conventional breeding and Native-PAGE molecular assisted breeding technology, a new soybean strain ‘HZ8009’ deficient in Kunitz type trypsin inhibitors was selected, with Hefeng50 as the female parent and Zhonghuang16 as the male parent. The new soybean strain HZ8009 is suitable for cultivation in Heilongjiang Province and has a maturity time of 120 days. The plant is tall with luxuriant foliage and an indeterminate podding habit. The protein content of the seed is 42%, and the fat content is 20%. The feed nutritional value of advanced generation strain was analyzed using feed quality testing technology. Hay yield was 21.39% greater and the dry matter crude protein content was 3.92% greater than for Mudanjiang fodder soybean. The best cutting period was from flowering to podding. The new soybean strain HZ8009 has a high protein content and high crop biomass, indicating wide potential for use as a forage resource.

Effects of pelletizing and adding Mongolia medicinal Scutellaria baicalensis on vitamin content and chemical composition of alfalfa

SUN Lin, LIU Guang-hua, ZHANG Xin-xin, XUE Yan-lin, WU Xiao-guang, XIAO Yan-zi, YIN Guo-mei, LIU Si-bo, ZHANG Fu-jin

2020, 29(10):  99-108.  DOI: 10.11686/cyxb2020115

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This study investigated the changes in nutritional quality, vitamin levels and microbial population levels in dried alfalfa herbage in storage and the extent to which vitamin content in alfalfa pellets can be stabilized by adding small amounts of the Mongolian medicinal plant Scutellaria baicalensis (hereafter abbreviated SB). Data were collected on the effects of pelletizing (by measurement before and after pelletizing) and on addition of SB at a range of concentrations (0, 0.5%, 1.0%, 1.5%) on the nutritional quality, vitamin levels and population of Escherichia coli and mold incidence. It was found that after pelletizing the contents of vitamin B₂, vitamin B₅ and vitamin B₆ decreased significantly, while the contents of vitamin K₁, vitamin C, dry matter and lipids (measured by ether extraction) increased significantly, and the population of E. coli decreased significantly. The contents of vitamin C, vitamin B₂ and vitamin B₆ in alfalfa were significantly increased by addition of 1.5% of SB, while the content of vitamin K₁ was significantly decreased by addition of 0.5%-1.0% of SB, and the content of vitamin B₁ was significantly reduced by addition of 1.5% of SB. Considering the influence of the two factors, the content of vitamin C and vitamin B₆ in dried alfalfa herbage in storage was significantly increased by adding 1.5% SB. The ether extract component of dried alfalfa herbage was significantly increased by addition of 1.5% SB and pelletizing.

Analysis of stress-resistance of CgDREB22 from Chrysanthemum×grandiflora in tabacco

HUANG Qin-mei, YANG Yi-ru, CHEN Li-fei, YIN Hang, LIU He, LIU Ying-jie, ZHOU Yun-wei, HE Miao

2020, 29(10):  109-118.  DOI: 10.11686/cyxb2019552

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DREB transcription factor is a subfamily of the AP2/ERF transcription factors, which is involved in the molecular response mechanism of plants to enviromental stresses such as drought, salinity and low temperature. The CgDREB22 gene from Chrysanthemum×grandiflora was incorporated into tobacco using an agrobacterium-mediated method. Seeds and seedlings of the T₁ generation transgenic tobacco were treated with 150 mmol·L^-1 NaCl, 150 mmol·L^-1 mannitol, and low temperature (4 ℃). It was found that under NaCl exposure, osmotically simulated drought stress, and low temperature stress, the fresh weight and root length of transgenic tobacco were lower than in untransformed comparisons. Under NaCl exposure and osmotically simulated drought stress, the resistance mechanism of transgenic tobacco was destroyed,and the proline content and antioxidant enzyme activities (superoxide dismutase, peroxidase and catalase) of transgenic tobacco were significantly lower than the untransformed comparison plants. In summary, the CgDREB22 plays a negative role in regulating environmental stresses in plants.

Effects of salt stress on the growth and physiological characteristics of Primula forbesii

JIA Yin, XIANG Yuan-fen, WANG Lin-lu, ZHAO Jian, LIU Cai-lei, PAN Yuan-zhi

2020, 29(10):  119-128.  DOI: 10.11686/cyxb2019572

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In order to investigate the resistance and adaptation mechanism of Primula forbesii to salt (NaCl) stress, a pot experiment was conducted to determine the growth and physiological characteristics of P. forbesii under NaCl concentrations of 0, 50, 100, 150, 200, and 250 mmol·L^-1. It was found that: 1) Along the concentration gradient of NaCl, the growth of P. forbesii showed low-concentration promotion and high-concentration suppression effects. At higher NaCl concentrations, plants showed stress symptoms in that plant height, crown width, leaf area, and above-ground and underground dry weight, and leaf water content were significantly decreased. Meanwhile, the relative electrical conductivity was significantly increased. 2) The leaf net photosynthetic rate, intercellular CO₂ concentration, transpiration rate, stomatal conductance, soluble protein, free proline, soluble sugar, and the activities of superoxide dismutase, peroxidase and catalase all rose with increasing NaCl concentration and then decreased at higher concentration. Malondialdehyde content displayed continuous increase across the concentration range tested, indicating that the photosynthetic system, cell osmotic regulation and antioxidant enzyme system of plants had positive response strategies to NaCl stress. 3) Higher NaCl concentrations significantly increased the Na⁺ content in leaves, petioles and roots of the plants, with the largest increase of Na⁺ content in roots. With increasing NaCl concentration, the contents of K⁺ and Ca²⁺ in plant organs other than leaves showed a trend of initial increase and later decrease while the contents of K⁺ and Ca²⁺ in leaves remained relatively high at higher NaCl concentrations. In summary, P. forbesii has moderate salt tolerance and is a potential flower species for saline soil garden applications. In this experiment a low NaCl concentration of 50 mmol·L^-1 promoted the growth of P. forbesii, but the growth and development of plants were inhibited when the concentration of NaCl was equal to or greater than 150 mmol·L^-1.

Effects of different levels of dietary digestible energy and crude protein on nutrient digestion and plasma physiological and biochemical parameters and hormones during early lactation of Yili mares

FANG Mei-yan, WANG Xian-dong, YU Quan-ping, CHEN Yong

2020, 29(10):  129-138.  DOI: 10.11686/cyxb2019556

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This study evaluated the effects of different levels of dietary digestible energy and crude protein on nutrient digestion and metabolism, and plasma physiological and biochemical parameters and hormones during early lactation of Yili mares, in order to provide reference information on the nutritional requirements, particularly digestible energy and crude protein, of the mares. A total of 25 Yili mares within 7 days after parturition were selected and divided into 5 groups (Groups Ⅰ-Ⅴ) using a stratified random procedure according to their body weight, with 5 animals (replicates) in each group. In the first month of lactation, dietary digestible energy and crude protein levels of the five groups were: 101.41 MJ·d^-1 and 1.38 kg·d^-1 (Group Ⅰ), 112.05 MJ·d^-1 and 1.50 kg·d^-1 (Group Ⅱ), 122.40 MJ·d^-1 and 1.63 kg·d^-1 (Group Ⅲ), 133.27 MJ·d^-1 and 1.75 kg·d^-1 (Group Ⅳ), and 143.84 MJ·d^-1 and 1.87 kg·d^-1 (Group Ⅴ). In the second month of lactation, dietary digestible energy and crude protein levels were 129.73 MJ·d^-1 and 1.82 kg·d^-1 (Group Ⅰ), 140.37 MJ·d^-1 and 1.94 kg·d^-1 (Group Ⅱ), 150.72 MJ·d^-1 and 2.07 kg·d^-1 (Group Ⅲ), 161.60 MJ·d^-1 and 2.19 kg·d^-1 (Group Ⅳ), and 172.17 MJ·d^-1 and 2.31 kg·d^-1 (Group Ⅴ). The trial lasted for 60 days, with two test cycles of 30 days. At the end of each test cycle, feces and urine were collected to determine feed digestion and metabolism of nutrients and blood was collected to determine nitrogen and lipid metabolism parameters, and concentrations of various hormones. It was found that the body weight, average daily gain, apparent digestibility values of dry matter, organic matter, gross energy, neutral detergent fiber, crude protein and phosphorus, as well as the nutrient utilization rates of digestible energy, digestible nitrogen and phosphorus, were not affected by dietary digestible energy and crude protein levels (P>0.05). The apparent digestibility of calcium in Group Ⅴ mares was 14.14%, 27.08% and 24.13% higher, respectively, than that of Group Ⅰ, Ⅲ and Ⅳ mares (P<0.05), while the apparent digestibility of calcium of Group Ⅱ mares was 21.91% and 19.09% higher than that of mares in Groups Ⅲ and Ⅳ (P<0.05). The retention rate of digestible calcium of Group Ⅴ mares was 33.56%, 54.79% and 26.46% higher than that of mares in Groups Ⅰ, Ⅲ and Ⅳ (P<0.05), and the retention rate of digestible calcium of Group Ⅱ mares was 36.02% higher than that of Group Ⅲ mares (P<0.05). The availability of digestible calcium in mares of Groups Ⅱ, Ⅳ and Ⅴ was, respectively, 23.24%, 27.67% and 34.16% higher than in mares of Group Ⅲ (P<0.05). Dietary digestive energy and crude protein levels had no significant effects on plasma GLT, AST, FFA, I-FABP, VLDL-C, TG, TP, BUN, estrone, estradiol, pituitary prolactin, progesterone, T3, GH and INS levels. The concentration of T4 in Group Ⅱ mares was, respectively, 34.83%, 26.57%, 30.36%, 34.39% higher than that of mares in Groups Ⅰ, Ⅲ, Ⅳ and Ⅴ (P<0.05). In conclusion, in the first and second month of lactation, dietary digestible energy levels of 112.05 and 140.37 MJ·d^-1, respectively, and crude protein levels of 1.50 and 1.94 kg·d^-1, respectively were able to supply the early lactation nutritional requirements of Yili mares, and promoted calcium digestion and metabolism, and levels of plasma thyroxine.

Effects of total mixed rations with different concentrate∶roughage ratios on meat quality, serum indexes and organ development in Nubian goats

ZHAN Jin-shun, HUO Jun-hong, HU Yao, ZHONG Xiao-jun, WU Yan-ping

2020, 29(10):  139-148.  DOI: 10.11686/cyxb2019544

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To study the effects of total mixed ration with different concentrate∶roughage ratios on meat quality, serum indices and organ development of goats, thirty six two-month old healthy Nubian goats with similar body weights were chosen and divided into three groups with 12 goats per group. The groups of goats were then fed total mixed rations with low (L, 40∶60), medium (M, 50∶50 M) and high (H, 60∶40) concentrate∶roughage ratios. The experimental period was 70 days, with a diet adaptation period of 14 days and a formal experiment period of 56 days. The results were as follows: 1) The diets with different concentrate∶roughage ratios had no significant effect on body measurement traits of the goats over the whole experimental period (P>0.05). 2) The activities of aspartate aminotransferase, alanine aminotransferase and creatine kinase were significantly lower in serum of diet H goats than in diet L goats on day 14 of the formal experiment (P<0.05). The ratio of aspartate aminotransferase to alanine aminotransferase was significantly higher in group H goats than in group L goats on day 56 of formal experiment (P<0.05), but the activity of alkaline phosphatase showed the opposite pattern. 3) Rate of water loss was significant lower in diet H goats than the other two groups (P<0.05), but pH value showed the opposite result. The redness of meat was significantly lower in diet M goats than the other two groups (P<0.05). There were no significant differences between dietary groups in other indices (P>0.05). Rumen weight, liver weight and liver index were significantly higher in diet L goats than in diet H goats (P<0.05), but the opposite pattern was observed for lung index. Reticulum and omasum weights, reticulum and omasum indices, and abomasum index were significantly higher in diet M goats than in diet L goats (P<0.05), but the opposite pattern was observed for spleen weight and spleen index. Villus height and villus height∶crypt depth of duodenum, and villus height∶crypt depth of jejuna were significantly higher in diet L goats than in diet H goats, but crypt depth of jejuna showed the opposite result. Villus height and villus height∶crypt depth of the ileum were significantly higher in diet M goats than in diet H goats. In conclusion, total mixed rations with low concentrate∶roughage ratio promoted gastrointestinal development of Nubian goats, and high concentrate∶roughage ratio improved meat quality. For conditions in this experiment, feeding Nubian goats a total mixed ration diet with low concentrate∶roughage ratio is recommended.

Effects of dual-mulching of furrow and ridge with plastic film and straw on temporal and spatial changes of soil moisture and potato yield in dry-farming areas of southern Ningxia

PU Xue-ke, WU Chun-hua, ZHOU Yong-jin, MIAN You-ming, MIAO Fang-fang, HOU Xian-qing, LI Rong

2020, 29(10):  149-160.  DOI: 10.11686/cyxb2019534

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The work was conducted over two consecutive years (2015-2016), in dry-farming areas of southern Ningxia for two consecutive years. The potato variety Longshu 3 was used and the research aim was to study the effect of different mulching patterns on soil water temporal and spatial variation patterns, and on potato yield. Three mulching patterns were set up: full mulching of furrow and ridge with plastic film (ridge covered with plastic film, furrow covered with plastic film, DD), dual-mulching of ridge and furrow with plastic film and straw (ridge covered with plastic film, furrow covered with straw, DJ), and traditional flat(CK) was used as control. It was found that compared with CK, the soil water content of the 0-200 cm soil layer was significantly improved in the DJ and DD treatments by 18.4% and 9.1%, respectively, in 2015 and 38.1% and 15.7%, respectively, in 2016, averaged over different potato growth stages. Differences were especially important during the period from 70 to 90 d (days after sowing). During that critical growth period (70-90 d), the soil water coefficient of variation in the 0-60 cm layer was decreased significantly under the DJ and DD treatments by 63.4% and 49.7%, respectively, in 2015 and 56.1% and 25.8%, respectively, in 2016, compared with CK. The DJ treatment increased the water infiltration from the upper soil layer (0-100 cm) to the lower layer (100-200 cm), and the soil water content in the lower layer of the DJ treatment was increased significantly compared with CK treatment (by 10.9% and 37.9%, respectively, in 2015 and 2016). The variation amplitude (K_a) and coefficient of variation (C_v) for soil water in the 0-200 cm soil layer of the different treatments was greater in the upper layer than in the lower layer. K_a and C_v averaged over the DJ and DD treatments had significantly lower values than in the CK treatment and were, respectively, 19.6%, and 14.5% lower than CK in 2015, and 20.8% and 19.0% lower in 2016. In this study, the different mulching treatments altered the duration of the rapid growth period of tubers, and improved potato yield and harvest index. The average duration of the tuber rapid growth period was significantly prolonged (by 12.3 and 8.2 d in 2015 and 2016, respectively); the average tuber yield was increased by 50.8% and 38.5% in 2015 and 2016, respectively, and the average harvest index was improved by 33.6% and 18.1% in 2015 and 2016, respectively. Correlation analysis showed that at the seedling stage (30 d), the correlation between soil water and soil water coefficient of variation and yield was mainly related to the 0-40 cm soil layer, while in the bud, tuber formation and expansion stages (50-90 d), this correlation mainly related to the 0-120 cm soil layer. In summary, the dual-mulching of ridges and furrows with plastic film and straw (DJ) significantly improved the soil water environment during the critical crop growth for potatoes, prolonging the rapid growth period of tuber, and increasing the potato yield and harvest index in dry-farming areas of southern Ningxia.

Effects of vertical rotary sub-soiling tillage on water use and yield of forage maize on semiarid land

FANG Yan-jie, ZHANG Xu-cheng, YU Xian-feng, HOU Hui-zhi, WANG Hong-li, MA Yi-fan, ZHANG Guo-ping, LEI Kang-ning

2020, 29(10):  161-171.  DOI: 10.11686/cyxb2020139

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This research was aimed at the development of high-yield and high-efficiency tillage techniques for the production of rain-fed forage maize in semi-arid areas of China. A long-term (2017-2019) field experiment consisting of three treatments: traditional tillage (TT), deep tillage (DT), and vertical rotary sub-soiling tillage (VRT), was carried out in the Loess Plateau, Northwest China. VRT is a recently developed tillage technique designed to break up the compacted soil layer formed just beneath the cultivated layer after repeated cycles of annual rotary tillage. We had investigated the effects of VRT on soil water storage (SWS), crop evapotranspiration (ETc) before and after anthesis, fresh and dry weights per plant, grain yields as well as water use efficiency (WUE). It was found that VRT significantly improved the infiltration of soil moisture to deeper layers, especially in dry years. At the anthesis stage, VRT decreased SWS by 7.6%-10.0% in 60-180 cm layer, and by 17.6%-18.5% in the 180-300 cm layer, compared to DT and TT in the dry year. Prior to the anthesis, SWS of VRT was increased by 13.8%-14.6% in the 0-300 cm layer, and the total ETc of VRT was increased by 6.1%-9.2%, respectively. Compared with DT and TT, VRT increased total ETc by 2.0%-7.9% in 2018, and by 10.1%-14.9% in 2019. At harvest, VRT increased fresh weights per plant by 2.4%-16.2%, dry weights per plant by 1.0%-7.8%, grain yields by 2.4%-38.6%, and population biomass by 3.4%-16.2%. It can be concluded that VRT is a drought-resistant and yield-enhancing tillage technique that is suitable for rain-fed forage maize production in semi-arid areas of the Loess Plateau. The data indicate VRT, improves the soil environment and enhances crop growth, development and yield. The benefits of VRT are more pronounced in dry years.

Effects of lactic acid bacteria inoculant level and ensiling time on nutritional value and fermentation quality of whole-crop maize silage

MAO Cui, LIU Fang-yuan, SONG En-liang, WANG Ya-fang, WANG Yong-jun, ZHAN Xiang, LI Yuan, CHENG Hai-jian, JIANG Fu-gui

2020, 29(10):  172-181.  DOI: 10.11686/cyxb2019569

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This experiment was conducted to evaluate the effects of lactic acid bacteria (LAB) inoculant level and fermentation time on nutritional value and fermentation quality of whole-crop maize silage. Maize variety Deng Hai 605 was chosen for the research. The crop was harvested at the 2/3 milk line development stage and four treatments (0, 10, 20 and 30 mg·kg^-1 of LAB preparation added) with four replicates were set up. Samples were ensiled for 45 or 90 days and then analyzed for nutrient composition, fermentation quality and ruminal degradability. It was found that the dry matter (DM) content was not affected by LAB inoculant level and fermentation time (P>0.05). With increase in LAB addition, the neutral detergent fiber (NDF) content of silage fermented for 90 days linearly decreased (P=0.018), while the relative feeding value (RFV) linearly increased (P=0.006). The acid detergent fiber (ADF) content and pH value after 90 days of fermentation were lower than that after 45 days of fermentation (P<0.01), while the content of lactic acid and acetic acid were higher at 90 days than after 45 days of fermentation (P<0.05). The content of lactic increased linearly with increase in LAB (P<0.05). The 24 h ruminal degradability of DM and NDF were unaffected by LAB addition level and fermentation time (P>0.05). With increase in LAB, the 48 h ruminal degradability of silage fermented 90 days linearly increased (P=0.034). The 48 h ruminal degradability of NDF of silage fermented 90 days was higher than that ensiled for 45 days (P=0.022). The RFV, total digestible nutrients and organic acid content were highest and the pH value was lowest in the 20 mg·kg^-1 group after 90 days of fermentation. In conclusion, the whole-crop maize silage with 20 mg·kg^-1 LAB preparation added, and fermented 90 days, had the optimal nutritional value and fermentation quality.

Effects of different plastic film mulching cultivation models on yield, water use efficiency and quality of maize

LI Shang-zhong, FAN Ting-lu, ZHAO Hui, LI Cheng-de, ZHAO Gui-bin, ZHAO Gang, DANG Yi, WANG Lei, ZHANG Jian-jun, TANG Xiao-ming, WANG Shu-ying, CHENG Wan-li

2020, 29(10):  182-191.  DOI: 10.11686/cyxb2020073

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The objective of this experiment was to study the effects of different plastic film mulching cultivation models on maize yield, water use efficiency (WUE) and quality, in order to provide reference data for cultivation of dryland maize with good quality and high-yield. Four planting systems were tested in this study: a control with no plastic film mulching (NM), and three configurations of plastic film mulching; narrow plastic film mulching (NF), wide plastic film mulching (WF), and full plastic film mulching on double ridges with planting in catchment furrows (FFDRF). These various systems have been developed in the northwest dryland region from the 1970s to the present. The four planting systems were compared for soil moisture in the 0-2 m depth before sowing and harvest, dry matter accumulation, grain yield, water use efficiency and crop quality index. It was found that for the NF, WF and FFDRF treatments, respectively, average dry matter accumulation increased by 5.5%, 11.2% and 21.9% compared with NM; yield increased by 12.1%, 18.6% and 31.3% compared with NM; WUE increased by 17.0%, 24.1% and 36.0% compared with NM; test weight increased by 2.7%, 1.9% and 1.8% compared with NM and protein content decreased by 0.17, 0.14 and 0.22 percent, compared with NM. The effects of different cultivation systems on content of the fat and starch were not significant. The data show that with the evolution of cultivation practice in the use of plastic film for dryland maize cropping, the moisture conservation for crop use and crop yield have increased with successive methodology developments, but the protein content of grain has decreased.

Research status and development prospects for forage wheat production and utilization

XU Liu-xing, TANG Guo-jian, HU Ya-qin, ZHANG Jian-guo

2020, 29(10):  192-199.  DOI: 10.11686/cyxb2019553

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The demand for animal proteins is growing rapidly with the improvement of living standards and the associated change in food consumption patterns. However, expansion of animal husbandry enterprises is greatly limited by a shortage of high-quality forage. Forage wheat has high yield and nutritive value. Therefore, research on forage wheat has high relevance. In this paper, the current status and development trends in domestic and foreign research on forage wheat are reviewed. The findings on production and utilization of forage are summarized under four headings: 1) Variety breeding: Germplasm creation technology, molecular breeding for stress tolerance and screening of conventional forage wheat varieties. 2) Cultivation management: Conventional field, grazing utilization and dual-purpose wheat managements. 3) Suitability for silage production: cultivation management, growth period, additives and other factors. 4) Animal feed considerations: Feed intake, digestibility, yield and quality of livestock products. Furthermore, the problems and shortcomings in various research fields relating to forage wheat are summarized, and the emerging development trends and research foci in the present context are explored. This review provides guidance and ideas for future studies on the production and popularization of forage wheat in China. At present, the ongoing development of forage wheat as a crop mainly revolves around problems such as grain surplus, contradiction between forage supply and animal feed requirement, and animal production performance. Forage wheat has high feeding value. In winter, when forage is scarce, wheat has potential to alleviate the industry forage supply issues, and provide a reliable feed supply to foster expansion of animal husbandry. However, grain wheat varieties generally have a low plant height and their whole-plant yield is limited. In order to better utilize the feeding value of forage wheat, it is imperative to cultivate varieties of wheat specifically designed for forage use.

Effects of alfalfa saponins on the blood and hematopoietic system of mice

LIU Jian-yu, YU Ying, ZHANG Ming, GUO Yu-xia, YAN Xue-bing

2020, 29(10):  200-205.  DOI: 10.11686/cyxb2019457

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In order to explore whether the intake of alfalfa saponins can cause intravascular hemolysis. A total of 180 mice were selected and divided into 6 treatment groups according to their body weight and sex, with 3 replicates in each treatment, and with 10 mice in each replicate. A 1 mL gavage containing 0.0125, 0.025, 0.05, 0.1, and 0.2 g·mL^-1 saponin, respectively was given to the mice of Groups Ⅰ, Ⅱ, Ⅲ, Ⅳ, and Ⅴ, and the remaining group (Control) was given 1 mL normal saline. The test period was 30 days. On the final day of the experiment, red blood cell (RBC), hematocrit (HCT), erythrocyte mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), free hemoglobin (FHb), reticulocyte count (RET), maximum osmotic fragility of red blood cells (OF_max) and minimum osmotic fragility of red blood cells (OF_min) were measured. Blood and bone marrow were collected to observe blood smear and bone marrow smear while heart and liver slices were made. The results show: 1) After intragastric administration of alfalfa saponins, RBC and HCT were decreased with values for Group Ⅴ being significantly lower than those of the control group (P<0.05). MCV was elevated compared with the control group, with Groups Ⅳ and Ⅴ being significantly different from the control group (P<0.05). 2) FHb values in Groups Ⅳ and Ⅴ and RET in Group Ⅳ were significantly higher than those in the control group (P<0.01). 3) With increase in the intragastric dose, the red blood cell appearance gradually changed, becoming slightly different in size, darker in color, and abnormal in shape. 4) OF_max was significantly increased (P<0.05) and OF_min sshowed a trend towards increase. 5) The proportion of granulocytes was reduced to varying degrees after gavage, and the erythrocyte proportion was increased. Thus, Granulocyte: erythrocyte ratio decreased markedly and in Groups Ⅳ and Ⅴ became significantly lower than in the control group (P<0.05). Compared with the control group, both OF_max and OF_min in Group Ⅴ differed significantly from the Control mice (P<0.05). 6) Parenchymal organs were not effected after gavage but were easily broken. In summary, a high dose of alfalfa saponins can cause intravascular hemolysis.

Summer grazing of red deer effects on plant diversity of alpine grassland on Qilian Mountain

HOU Shuai-jun, WANG Ying-xin

2020, 29(10):  206-210.  DOI: 10.11686/cyxb2019248

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The Qilian Mountains are an important ecological security shield, known as the “plateau reservoir” and “the stream of life”. They are the main water source in the Hexi Corridor, and even in the northwest China. The alpine shrub meadow on the north slope of Qilian mountains has contributed to the development of regional animal agriculture. Red deer (Cervus elaphus kansuensis) is an important and special grazing animal species in the region. At present, there is a lack of research on the influence of grazing by red deer on the community dynamics of alpine shrub rangeland. Therefore, a study both of topographic effects and the effects of red deer grazing on plant community diversity in grazing systems in alpine shrub rangeland at the northern foot of the central Qilian Mountains was conducted. It was found that: 1) In the shaded slope and valley aspects, β diversity was significantly different under different grazing intensities; in the valley topographic category, diversity nesting was evident; 2) γ diversity was the highest under moderate grazing intensity and there were no significant differences between different aspects. In general, moderate grazing by red deer significantly improved theβ diversities of alpine shrub meadow. Our study aimed to clarify the influence of red deer grazing on community diversity of alpine shrub rangeland and has provided a scientific and theoretical basis for sustainable grazing management on Qilian Mountain rangeland.