As solar photovoltaic (PV) infrastructure expands across open landscapes, understanding its belowground effects in grassland ecosystems is important for sustainable solar development. PV panels can create spatially heterogeneous microsites by altering light availability, precipitation redistribution, and soil environmental conditions, but their effects on soil bacterial community structure remain insufficiently understood. Here, we investigated soil physicochemical properties and bacterial communities across four PV-associated microsites: undisturbed grassland outside the PV array (Control), the front edge of the panel (FE), beneath the center of the panel (BP), and the uncovered interspace between adjacent panel rows (IS). Soil bacterial communities were characterized using 16S rRNA gene sequencing. Most measured soil physicochemical properties did not differ significantly among microsites. Available potassium was the only variable showing an overall microsite effect and was significantly lower in FE and BP than in the Control. Shannon index and Chao1 richness did not differ significantly among microsites. In contrast, Bray–Curtis-based principal coordinate analysis (PCoA) showed that FE samples occupied a relatively distinct ordination position, whereas Control, BP, and IS samples partially overlapped; permutational multivariate analysis of variance (PERMANOVA) indicated a significant overall difference in bacterial community composition among microsites. At the phylum level, no dominant bacterial phylum differed significantly among microsites after false discovery rate (FDR) correction. Redundancy analysis (RDA) indicated that alkali-hydrolyzable nitrogen and available potassium were the measured soil variables most closely associated with bacterial community composition at the operational taxonomic unit level in the final model. Together, these results indicate that differences among PV-associated microsites were detected in overall bacterial community composition but not in Shannon index or Chao1 richness. Alpha-diversity and community-composition analyses therefore provide complementary information for evaluating belowground bacterial responses to PV development in grasslands.

The Songnen grassland is an important resource for livestock production in China. Due to the intensification of anthropogenic activities in recent years, vegetation degradation has worsened, and the salinization of grassland has become increasingly serious, which severely affects the sustainable development of grassland animal husbandry. In this study, organic fertilizer addition was carried out at saline-and-alkaline-degraded Songnen grassland sites with photovoltaic panels, and we investigated the effects of organic fertilizer treatments on the vegetation and soil bacteria in these areas. The results showed that both organic fertilizer treatments increased the community composition and diversity indices of plants (p < 0.05); they also had significant effects on soil electrical conductivity and rapidly available potassium (p < 0.05). In the dominant phylum of bacteria, the relative abundance of Firmicutes increased without adding organic fertilizer under the photovoltaic panel; the addition of organic fertilizer had a significant effect on the relative abundance of Firmicutes and Desulfobacterota (p < 0.05), reducing their relative abundance, respectively. There were differences in the number of bacteria at the genus level under different treatments compared to the control, with the highest enrichment of bacteria occurring at the OFE position, and a significant difference (p < 0.05) being found between the control and the other four groups at the genus level of g_norank_f_norank_o_Actinomarinales. Organic fertilizer had a significant effect on the bacterial Simpson diversity index, with the most significant increasing trend found in OFE (the front eaves of the photovoltaic panel in fertilization area). The results of a correlation analysis showed that pH, electrical conductivity, and total nitrogen were the main factors affecting the soil bacterial community.

培养优秀的草学类专业人才是草业发展的关键,而草学类专业又是实践性很强的专业类别.在专业认证背景下探索制订有效的实践教学体系是保障草学类专业教学质量的重要内容.文章通过对草学类专业和草学学科关系的梳理、对实践教学中存在问题的剖析、对实践教学人才培养模式的探讨和实践教学模式、实践教学体系的探索,为各高等农林院校的实践教学培养方案制订提供参考和借鉴,也为其他院校建立林草科技人才培养模式提供参考.

IntroductionSaline-alkali degradation in grassland significantly affects plant community composition and soil physical and chemical properties. However, it remains unclear whether different degradation gradients affect soil microbial community and the main soil driving factors. Therefore, it is important to elucidate the effects of saline-alkali degradation on soil microbial community and the soil factors affecting soil microbial community in order to develop effective solutions to restore the degraded grassland ecosystem. MethodsIn this study, Illumina high-throughput sequencing technology was used to study the effects of different saline-alkali degradation gradients on soil microbial diversity and composition. Three different gradients were qualitatively selected, which were the light degradation gradient (LD), the moderate degradation gradient (MD) and the severe degradation gradient (SD). ResultsThe results showed that salt and alkali degradation decreased the diversity of soil bacterial and fungal communities, and changed the composition of bacterial and fungal communities. Different degradation gradients had different adaptability and tolerance species. With the deterioration of salinity in grassland, the relative abundance of Actinobacteriota and Chytridiomycota showed a decreasing trend. EC, pH and AP were the main drivers of soil bacterial community composition, while EC, pH and SOC were the main drivers of soil fungal community composition. Different microorganisms are affected by different soil properties. The changes of plant community and soil environment are the main factors limiting the diversity and composition of soil microbial community. DiscussionThe results show that saline-alkali degradation of grassland has a negative effect on microbial biodiversity, so it is important to develop effective solutions to restore degraded grassland to maintain biodiversity and ecosystem function.

Grazing heavily influences the soil organic carbon pool of grassland ecosystems and therefore plays an important role in the global carbon balance. In China, various efforts aimed at alleviating grazing pressure have been promoted in the past two decades to conserve and restore degraded grassland, and improved management has shown profound effects on grassland resilience. Although many studies have explored the role of rest-grazing in arid grasslands, little is known about the effects of seasonal rest-grazing strategies on carbon storage in mesic grasslands. This study analysed the effects of rest grazing in spring, summer, and autumn on the soil nutrients and plant growth content of plots under light, medium, and heavy grazing intensities, respectively, for 3 continuous years (2010-2012) on the Deyeuxia angustifolia meadow grassland in Sanjiang Plain in Northeast China. The study contributes to the understanding of the relative effectiveness of different seasonal rest-grazing strategies on grassland sustainability in the Sanjiang Plain. The results highlight the importance of timing in the use of seasonal rest-grazing the short term for the soil carbon balance of mesic grassland: (1) under moderate and severe grazing pressure, the aboveground net primary productivity of grassland plants was significantly increased in spring and summer but not in autumn. The organic matter content in the 0-30 cm soil layer significantly increased in spring and autumn, and the organic matter content in the 0-20 cm soil layer significantly increased in summer. (3) Seasonal rest-grazing significantly decreased the content available nitrogen in the 0-30 cm soil layer, especially in the 10-20 cm soil layer. In addition to the driving power of growing season precipitation, our results suggest that seasonal rest-grazing has a great potential for the recovery of soil carbon storage in mesic grassland despite differential grazing intensity levels.

为了解盐碱化草地中土壤碳、 氮和土壤酶随盐碱化程度的变化规律,选择典型的松嫩羊草草地为研究对象,依据草地优势植物种的变化特征,定性地划分出不同盐碱退化程度的草地.通过对不同盐碱退化程度草地土壤碳、土壤氮和土壤酶活性变化规律的研究,发现随草地盐碱退化程度的增加,土壤有机碳、全氮、碱解氮、过氧化氢酶、蔗糖酶含量呈下降的趋势,特别是重度盐碱退化草地的土壤碳、土壤氮和土壤酶含量下降显著(P<0.05).土壤碳、土壤氮和土壤酶在0～10 cm土层的含量高于10～20 cm土层.

草业科学专业的"科技论文写作"课程作为一门重要的专业选修课,对大学生文献检索和科技论文写作能力提升有极大的益处,有益于科学精神和创新精神的培养.针对目前教学过程中学生对课程认知和重视程度不高、课程教材及内容与专业契合度相对较低且教学模式与考核方式相对较为单一等问题,从课程内容、教学方法和考核方式等方面进行了探索和改革,对培养符合国家需求的优秀创新型草业科学专业人才具有非常重要的意义.

Introduction Human concerns about fossil fuel depletion, energy security and environmental degradation have driven the rapid development of solar photovoltaic (PV) power generation. Most of the photovoltaic power generation plants are concentrated in desert, grassland and arable land, which means the change of land use type. However, there is still a gap in the research of the PV panel layout on grassland plant species diversity and ecological function. Methods In this study, Illumina high-throughput sequencing technology was used to investigate the effects of PV panel arrangement on grassland plant species diversity and soil microbial diversity. In view of the differences in the microclimate at different sites of the PV panels, quadrates were arranged in front edge (FE), beneath the center of each panel (BP), back edge (BE), the uncovered interspace adjacent to each panel (IS) and the undisturbed grassland around the PV panels (Control), respectively. Results PV panels (especially FE) significantly increased the total aboveground productivity (total AGB) and plant species diversity in grasslands. FE increased precipitation accumulation and plant species diversity directly and indirectly changed the diversity of soil bacterial and fungal communities. PV panels decreased the relative abundance of Actinobacteriota, while increased the relative abundance of Proteobacteria, Acidobacteriota, and Methylomirabilota. EC, Margalef’ s richness and total AGB were the main factors affecting the composition of bacterial communities, while alkaline hydrolysis nitrogen (AN) and available phosphorus (AP) were the main factors affecting the composition of fungal communities. Discussion In conclusion, the arrangement of PV panels increased the plant species diversity and soil microorganisms in grassland. This study provides important information for further understanding the impact of PV panels on grassland ecosystem function and is of great significance for maintaining grassland ecosystem function.

The Sanjiang Plain is famous for its concentrated distribution of natural wet grasslands. These wet grasslands are an important source of seasonal pasture or hay in the area. However, changes in community structure and ecosystem function have already occurred in wet grasslands because of overgrazing and climate change, resulting in severe grassland degradation. Exploring a reasonable grazing management strategy is crucial for improving grassland species diversity, increasing grassland productivity, and maintaining sustainable grassland utilization. We investigated the effects of five grazing management (GM) strategies (no grazing through the growing season (CK), spring grazing exclusion (Spr-GE), summer grazing exclusion (Sum-GE)), autumn grazing exclusion (Aut-GE), and grazing through the growing season (G)) on the productivity, community composition and structure of wet grasslands in the Sanjiang Plain under three grazing intensities (GI) (light (L), moderate (M), and heavy (H)). Results showed that Spr-GE and Sum-GE were beneficial in increasing total aboveground biomass (AGB), but decreased plant community diversity in Spr-GE due to increased intraspecies and interspecies competition. The exclusion of different seasonal grazings changed the composition of plant communities. At the level of functional groups and dominant species, Spr-GE had a significant effect on most functional groups and dominant species’ characteristics, while Aut-GE had little effect on most functional groups and dominant species’ characteristics. However, different functional groups and dominant species had different responses to seasonal grazing exclusion. In addition, under M, there were significantly improved grassland total AGB and PF AGB. The results indicated that Spr-GE with M may be an effective livestock-management strategy to protect grassland vegetation and community diversity, as well as to restore degraded grassland.

In order to explore the salt tolerance of oats and smooth bromegrass to different salt solutions, neutral salt（NaCl）, alkaline salt（Na 2 CO 3 ） and mixed salt（Na 2 CO 3 +NaHCO 3 +Na 2 SO 4 +NaCl） were used to stress the seeds of four varieties of oats（Avena sativa L.cv. Lena, A. sativa L.cv. Qingyin No.1, A. sativa L.cv. Qingyin No.2, A. sativa L.cv. Qinghai）and smooth bromegrass seeds with different harvest years. The results showed that the germination percentage of oat and smooth bromegrass decreased with the increase of salt solution concentration and storage life. Among them, neutral salt（NaCl） had the least inhibitory effect on seed germination. Generally speaking, oat（A. sativa L.cv. Lena） had relatively good adaptability to saline-alkali, and the germination rate of smooth bromegrass seeds with storage life of less than two years was higher.

Changes in land use types can significantly affect soil porperties and microbial community composition in many areas. However, the underlying mechanism of shift in bacterial communities link to soil properties is still unclear. In this study, Illumina high-throughput sequencing was used to analyze the changes of soil bacterial communities in different land use types in a forest-grassland transition zone, North China. There are two different land use types: grassland (G) and cultivated land (CL). Meanwhile, cultivated land includes cultivated of 10 years (CL10) or 20 years (CL20). Compared with G, CL decreased soil pH, SOC and TN, and significantly increased soil EC, P and K, and soil properties varied significantly with different cultivation years. Grassland reclamation increases the diversity of bacterial communities, the relative abundance of Proteobacteria, Gemmatimonadetes and Bacteroidetes increased, while that of Actinobacteria, Acidobacteria, Rokubacteria and Verrucomicrobia decreased. However, the relative abundance of Proteobacteria decreased and the relative abundance of Chloroflexi and Nitrospirae increased with the increase of cultivated land years. Mantel test and RDA analysis showed that TP, AP, SOC and EC were the main factors affecting the diversity of composition of bacterial communities. In conclusion, soil properties and bacterial communities were significantly altered after long-term cultivation. This study provides data support for land use and grassland ecological protection in this region.

Climate change may make semiarid grasslands increasingly prone to wildfire. We studied fire seasonality and growing season condition effects on a semiarid grassland in Southern Alberta, Canada. Plots were hand-torched in either fall or spring. Response variables estimated included plant composition and diversity, plant height, aboveground net primary production (ANPP), and forage nitrogen quality. The experiment was replicated over three consecutive growing seasons, and each replicate was monitored for 3 yr thereafter. Drought conditions occurred during two of the six growing seasons. Fall fires appeared to be hotter than spring fires based on a greater fuel mass (standing litter) and exposed the soil surface to a longer period without the benefit of standing litter over winter. Although this grassland is resilient to fire, compared with spring-burned grasslands, the species composition, ANPP, and leaf length of grasses of fall burned communities took a longer time to recover to preburn conditions. Our results suggest that spring-burned grasslands should not be grazed for 1 year post burn to allow time for recovery of ANPP and litter. However, given that ANPP of fall-burned communities also exhibited higher nitrogen concentration that may make the forage more palatable to livestock, and that these communities were more severely impacted, it seems prudent to delay their grazing for more than 1 year to prevent overgrazing. The negative impacts of fire on ANPP may be ameliorated with above-average precipitation in June, which may be forecast during an El Nino year. (C) 2021 The Author(s). Published by Elsevier Inc. on behalf of The Society for Range Management.

本科教学是高等院校的基础工作,而实验教学是本科教学中重要的环节,实验教学考核又是提升实验教学质量的重要保障.通过总结当前实验教学考核中普遍存在的问题,借鉴和分析已有实验教学改革的成果和经验,探索利用局域网和数据库相结合的实验教学考核方式,实践证明该考核方式能更加客观地评价教师的教学效果和学生的实验成绩,促进学生创新能力提升,为提高本科实验教学质量提供参考借鉴.

为了解5种引进燕麦[林纳(Avena sativa Lena)、青海444(A.sativa Qinghai No.444)、青引1号(A.sativa Qingyin No.1)、青引2号(A.sativa Qingyin No.2)、甜燕麦(A.sativa Qinghai)]异地自繁后种子对盐胁迫的适应性,采用不同浓度的单盐(NaCl、Na2CO3)和混盐(NaCl、Na2 SO4、Na2CO3、NaiHCO3)溶液对5个燕麦品种进行盐胁迫处理,通过培养皿纸上发芽法测定种子发芽率,再根据发芽率的变化得出燕麦品种耐盐适宜范围、耐盐半致死浓度和耐盐极限浓度.结果表明:最耐NaCl盐胁迫的是青引2号和青引1号,极限浓度分别是1.29％、1.18％;最耐Na2CO3盐胁迫的是青引1号和青引2号,极限浓度为0.49％;最耐混盐胁迫的是青引2号,极限浓度为1.05％.说明5种燕麦中的青引2号燕麦对轻度盐碱有较强的适应能力.

Salt stress is becoming an increasing threat to global agriculture. In this study, physiological and proteomics analysis were performed using a salt-tolerant grass species, Leymus chinensis (L. chinensis). The aim of this study is to understand the potential mechanism of salt tolerance in L. chinensis that used for crop molecular breeding. A series of short-term (<48 h) NaCl treatments (0 ~ 700 mM) were conducted. Physiological data indicated that the root and leaves growth were inhibited, chlorophyll contents decreased, while hydraulic conductivity, proline, sugar and sucrose were accumulated under salt stress. For proteomic analysis, we obtained 274 differentially expressed proteins in response to NaCl treatments. GO analysis revealed that 44 out of 274 proteins are involved in the biosynthesis of amino acids and carbon metabolism. Our findings suggested that L. chinensis copes with salt stress by stimulating the activities of POD, SOD and CAT enzymes, speeding up the reactions of later steps of citrate cycle, and synthesis of proline and sugar. In agreement with our physiological data, proteomic analysis also showed that salt stress depress the expression of photosystem relevant proteins, Calvin cycle, and chloroplast biosynthesis.

草学是一门实践性很强的专业,鉴于草业、草牧业已作为大农业结构调整的重要内容,草学专业的实践教学应适应时代发展需求,培养符合我国农业改革所需的综合人才.文章力图找出实验教学中的不足,探讨和创新实验教学模式,增强实验教学质量,为草学专业实验教学改革提供参考.

为了增加高寒地区放牧家畜的优质饲草供应,于2013年在海拔4600 m的西藏羊八井牧区对5种一年生牧草进行了引种试验,采用随机区组设计测定了牧草生长高度、产草量、营养成分.结果表明:小黑麦(×Triticosecale Wittmack)和青引2号燕麦(Avena sativaL.cv.Qingyin No.2)的牧草高度和产量显著高于其他牧草(P＜0.05),青稞昆仑13(Hordeum vulgare L.cv.Kunlun No.13)和青海甜燕麦(Avena sativa L.cv.Qinghai)的牧草产量显著高于青稞北青3(Hordeum vulgare L.cv.BeiqingNo.3)(P＜0.05);小黑麦的粗蛋白含量显著低于其他牧草(P＜0.05),而中性洗涤纤维含量显著高于其他牧草(P＜0.05).根据牧草产量和品质性状的聚类分析,在西藏羊八井适宜种植小黑麦、青引2号燕麦、青稞昆仑13和青海甜燕麦(A.sativa).

本试验旨在探求玉米秸秆不同部位蛋白质营养价值与其分子结构是否存在相关关系.采用常规化学分析方法并结合美国康奈尔大学净碳水化合物和净蛋白质体系(CNCPS)对玉米秸秆不同部位(苞叶、叶片、叶鞘、茎皮和茎髓)的蛋白质化学成分(粗蛋白(CP)、中性洗涤不溶蛋白(NDICP)、酸性洗涤不溶蛋白(ADICP)、非蛋白氮(NPN)、可溶性蛋白(SCP))及CNCPS中的蛋白组分(瞬时降解含氮部分(PA)、快速降解蛋白(P B1)、中速降解蛋白(PB2)、慢速降解蛋白(PB3)和不可降解蛋白(PC))进行测定,同时利用傅里叶变换红外光谱分析技术(FTIR)分析样本的蛋白质分子结构(酰胺Ⅰ带、酰胺Ⅱ带、α-螺旋、β-折叠),进而探求两者之间的相关关系.试验结果表明,玉米秸秆不同部位的蛋白质营养价值存在显著差异(P＜0.05),其中叶片的CP和NDICP最高(分别为8.78％和3.11％),而CNCPS中的PA、PB3及PC组分在不同部位也存在明显的不同(P＜0.05).通过FTIR光谱扫描后,发现玉米秸秆5个部位的蛋白分子结构之间同样存在显著差异(P＜0.05),并且光谱参数与蛋白质营养价值存在明显的相关关系(P＜0.05),利用酰胺Ⅰ带与酰胺Ⅱ带峰高比以及α-螺旋与β-折叠峰高比、酰胺Ⅱ带峰值可以有效地预测CP含量(R2 =0.804 7)、NDICP含量(R2 =0.949 4)、ADICP含量(R2=0.600 9)以及蛋白组分中PC部分的含量(R2 =0.647 1).综上所述,玉米秸秆不同部位的蛋白质营养价值及分子结构都存在明显的差异,并且二者存在显著的相关关系.

Tibet is one of the five major pastoral areas in China,its animal husbandry has long been dependent on natural grassland. Faced with the severe problem of lack of forage supply in winter and spring,developing artificial grasslands is an important measure to solve the seasonal imbalance between livestock and grass and alleviate grazing pressure in grassland. This paper describes the status quo of the development of artificial grasslands in the Tibetan areas,as well as the five aspects of problems existed in the process of developing artificial grasslands,including cultivar selection,multiple cropping of forage grasses,soil compaction after sowing,mixture sowing of oat( Avena sativa L.) and common vetch( Vicia sativa L.),and seed production. It also puts forward the corresponding solutions.