Compatibility of root growth and tuber production of potato cultivars with dynamic and static water‐saving irrigation managements          下载免费PDF全文

S. H. Ahmadi  M. Agharezaee  A. A. Kamgar‐Haghighi  A. R. Sepaskhah 《Soil Use and Management》2017,33(1):106-119

The important root characteristics of root length density (RLD) and root mass density (RMD) generally differ among irrigation managements and potato cultivars. The objective of this study was to investigate the RLD and RMD variations and their functional relationships with gross potato tuber yield for two commercial potato cultivars, Agria and Sante, under different irrigation strategies. Full irrigation and water‐saving irrigation strategies, deficit and partial root drying irrigations, were applied statically (S) and dynamically (D) based on daily crop evapotranspiration. Results showed that SPRD had significantly greater RLD (3.64 cm/cm³) and RMD (132.7 μg/cm³) than other irrigation treatments. Between the potato cultivars, Agria had significantly larger values of RLD (3.50 cm/cm³) and RMD (138.7 μg/cm³) than Sante. The functional relationship between the root growth characteristics and tuber yield showed that under water‐saving irrigations, Agria increased root mass at the expense of gross tuber yield but Sante increased root mass to maintain larger gross tuber yields. However, Agria produced more roots and gross tuber yield than Sante, and it is concluded that Agria is a more drought‐tolerant potato cultivar, which is recommended for tuber production in regions where water might be scarce. It was shown that larger root production in potatoes was associated with improved tolerance to water stress.  相似文献   

Comparison of the microbial communities of alpacas and sheep fed diets with three different ratios of corn stalk to concentrate     

Ruimin Chao  Chengqiang Xia  Caixia Pei  Wenjie Huo  Qiang Liu  Chunxiang Zhang  Youshe Ren 《Journal of animal physiology and animal nutrition》2021,105(1):26-34

The objective of this study was to investigate the characteristics of ruminal microbial communities of alpacas (Lama pacos) and sheep (Ovis aries) fed three diets with varying ratios of roughage (corn stalk) to concentrate, 3:7 (LS), 5:5 (MS) and 7:3 (HS). Six alpacas (one-year-old and weighing 29.5 ± 7.1 kg) and six sheep (one-year-old and weighing 27.9 ± 2.7 kg) were used in this study, in a replicated 3 × 3 Latin square experiment. Total protozoa concentration was determined under the microscope; total fungi and methanogens were assessed using quantitative polymerase chain reaction and expressed as a percentage of total bacterial 16S rRNA gene copies; bacterial communities were investigated by targeted 16S rRNA gene (V3–V4 region) sequencing. The percentage of fungi was significantly higher in alpacas than in sheep under the LS diet, while the concentration of protozoa was significantly lower in alpacas under HS, MS and LS diets. The alpha diversity including Shannon, Chao l and ACE indices of bacterial communities was higher in alpacas than in sheep, under the LS diet. A total of 299 genera belonging to 22 phyla were observed in the forestomach of alpaca and sheep, with Bacteroidetes and Firmicutes dominating both animal species. Phyla Armatimonadetes and Fusobacteria, as well as 64 genera, were detected only in alpacas, whereas phyla Acidobacteria and Nitrospira, as well as 44 genera, were found only in sheep. The abundance of cellulolytic bacteria, including Butyrivibrio and Pseudobutyrivibrio, was higher in alpacas than in sheep under all three diets. These differences in the forestomach microbial communities partly explained why alpacas displayed a higher poor-quality roughage digestibility, and a lower methane production. Results also revealed that the adverse effects of high-concentrate diets (70%) were lesser in alpacas than in sheep.  相似文献   

The microbial diversity and structure in peatland forest in Indonesia     

Bing Liu  Muhamed Jamal Hosen Talukder  Eeva Terhonen  Maija Lampela  Harry Vasander  Hui Sun  Fred Asiegbu 《Soil Use and Management》2020,36(1):123-138

The microbial community structure and function under forest in tropical peatlands are poorly understood. In this study, we investigated the microbial community structure and diversity in natural peat swamp forest soil, disturbed peat soil and mineral soil in Central Kalimantan, Indonesia, using 454 pyrosequencing. The results showed that the natural peat soil had the greatest fungal species richness (Chao1), which was significantly (p < .05) larger than that in the other two soils. Community structure of both fungi and bacteria in natural peat soil differed significantly from that in the disturbed peat soil (p = .039 and p = .045, respectively). Ascomycota (40.5%) was the most abundant phylum across the three soils followed by Basidiomycota (18.8%), Zygomycota (<0.1%) and Glomeromycota (<0.1%). The linear discriminant analysis with effect size (LEfSe) showed that Ascomycota (p < .05) and genus Gliocephalotrichum (p < .05) dominated in natural peat soil. Functionally, pathotrophs were more abundant in disturbed peat soil (p < .05). Proteobacteria (43.8%) were the most abundant phylum followed by Acidobacteria (32.6%), Actinobacteria (9.8%), Planctomycetes (1.7%). Methylocystis, Telmatospirillum, Syntrophobacter, Sorangium and Opitutus were the more abundant genera in disturbed peat soil, whereas Nevskia and Schlesneria were more abundant in mineral soil and natural peat soil, respectively. The natural peat forest soil supported a more diverse microbiology; however, the land use of such a soil can change its microbial community structure. The results provide evidence that the disturbance of tropical peat land could lead to the introduction and spread of a large number of fungal diseases  相似文献   

社会林业与五指山的自然保护   总被引：1，自引：0，他引：1  

周燕华  包焱 《热带林业》2001,29(2):73-80

五指山自然保护区是世界上现存地势最高的原始热带雨林之一，是我省目前面积最大的自然保护区，也是海南三大河流的发源地。但由于保护区横跨琼中、通什、保亭三县、市，紧邻保护区还生存着众多贫困的黎、苗族村民。因此，保护区与周边社区的联系是十分紧密的，社区的发展也直接影响到五指山热带天然林的保护。海南省林业局中德海南热带林保护和恢复项目在社会林业与五指山森林的保护上做出了有益的尝试，就在全省来说，也是首次对社会林业与森林保护上进行的探索。五指山地区社会林业的研究，对保护海南热带雨林也有着积极的意义。特对社会林业与五指山的森林保护进行了阐述、分析和设想。  相似文献   

数量化理论Ⅲ在土地质量综合评价中的应用   总被引：2，自引：0，他引：2  

王久丽  李亚光 《北京林业大学学报》1992,(2)

木文对土地质量综合评价的方法进行了探讨,首次提出将数量化理论Ⅲ应用于土地质量分级。与目前使用的系统聚类、动态聚类方法相比,数量化理论Ⅲ更适合于变量类型为定性变量的土地资源调查资料的分类。它弥补了系统聚类方法和动态聚类方法在土地资源评价中应用的局限性,数量化理论Ⅲ是一种可用于土地质量分级的理想方法。  相似文献   

关中地区几种苜蓿地上生物量初步研究   总被引：6，自引：0，他引：6  

郑红梅  李明胜  呼天明 《草业科学》2005,22(7):19-22

对5个苜蓿Medicago sativa品种的地上生物量形成规律进行了初步研究.结果表明:苜蓿生物量的增长速率不仅与本身生理特性有关,而且与环境密切相关;株高在分枝末期现蕾初期增长速度快.绝对生长速率与相对生长速率在分枝末期现蕾期都较大,此时的水分管理具有重要意义;不同苜蓿品种的群落结构大多为菱形;同化系统与非同化系统的比值随高度的增加而减少.  相似文献   

施肥对红三叶群落营养元素含量和积累量的影响   总被引：1，自引：0，他引：1  

杜占池  钟华平 《四川草原》2001,(4):14-16

本文研究了施肥对红三叶群落地上部和地下部 1 0种营养元素的影响 ,结果如下 :( 1 )从含量看 ,施氮肥后 ,地上部B明显降低 ,地下部B明显升高 ;施磷肥后 ,地上部N、B显著下降 ,地下部K、P、N上升幅度较大。 ( 2 )就积累量而言 ,施氮肥后 ,地上部大多数元素增高 ,地下部多数元素降低或无变化 ;施磷肥后 ,无论地上部还是地下部 ,大多数元素均有所增高  相似文献   

潜江小城镇景观规划     

彭凤 《湖北农学院学报》2001,21(2):188-191

潜江小城镇的水资源丰富但开发落后，绿系统不完善，街景缺乏工艺性。在对现状调查分析的基础上，提出了对过境公路、水体、街景进行动感空间、情感空间规划的建议，对乡土化设计、恢复性设计进行了探讨。  相似文献   

科尔沁沙地差巴嘎蒿——杂类草群落结构、功能的沙漠化演变特征   总被引：3，自引：0，他引：3  

赵哈林  周瑞莲 《草业学报》1993,2(1):21-27

研究结果表明：在沙漠化发展过程中，差巴嘎蒿－－杂类草群落（1）首先是植物种组成数量和密度大幅度减少，继而植被盖度和地上生物量急剧下降，四项指标受沙漠化影响的强弱顺序是密度＞植物种数量＞工＞地上生物量；（2）结构趋于简单，功能逐渐消退，优势种或亚优势种发生更替，群落最终变性；（3）沙漠化演变既有连续性又有间断性，随着沙漠化的加剧，其连续性变弱，间断性增强，变幅增大；（4）轻度沙漠化时群落稳定性最高，严重沙漠化可导致其稳定性迅速破坏；（5）对沙漠化的危害，表现出一定的时滞效应和自我适应调节能力，这两个问题有等于进一步研究。  相似文献   

CVT起步离合器模糊控制算法研究     

张飞铁  周云山  薛殿伦 《湖南农业大学学报(自然科学版)》2006,33(5)

探讨了汽车无级变速器控制的关键技术之一———汽车起步离合器的控制技术,并针对汽车起步时条件的多样性以及驾驶员意图的不确定性,研究了适用于复杂条件的模糊控制算法.在离合器的滑磨阶段,把动态跟踪发动机转速的油压作为控制目标,离合器结合的控制便转化为一闭环控制.结果表明汽车能在任意工况下平顺快速起步.因此,本研究为控制CVT(Continuously Variable Transmission)起步离合器这种时变、非线性系统提出了一种简单可行的解决方法.  相似文献