| Biochar, in recent years, frequently used as soil carbon basal and modifier in agricul-ture, as adsorbent and carbon storage carrier in pollutant removal and carbon emission reduction as well, was made of biomass by pyrolysis carbonization in anoxic condition.In order to deeply explore the impact on highland barley growth,soil property and the community structure of soil microorganism had by yak dung biochar, the biochar, highland barley, topsoil was selected as the research objects in this study.After the inputs of biochar into sample farmland spots as a percentage of (0,1/16,1/8,1/4), laboratory analysis in situ-observation was applied.It also studies the trends and characteristics of highland barley yield, aboveground biomass, soil physical and chemical property, as well as a variety of elements content of 5 parts of highland barley.At the same time, a comp-arative analysis of yak dung biochar and yak dung biomass was prepared to study the differences in physical and chemical properties between them, summarizing the changes of all the indexes in the study to make a comprehensive analysis of responses of differe-nt biochar input quantity as well, which the highland barley and soil environment made.The main results of this study were as follows:1、The yak dung biochar, with large specific surface area and high adsorption perfor-mance, had rough surface and the porous texture; Biochar was rich in functional groups, mainly includingO-H, C≡C, C=O, nitrocellulose, aromaticC=C,basicgroups like ketone structure containing C=O on the surface of the biochar lead to the biochar’s alkaline property which can improve soil acidification and soil pH; and a variety of polar functio-nal groups on the surface of biochar were good for the soil amelioration;The Yak dung biomass and yak dung biochar contained abundant element types, suchas C, N, H, O, playing the main role;Contents of C, N, H,O in biomass accounted for 32.15%,2.31%,4.09%,32.15% and 33.0%,1.96%,2.69%,16.48% in yak dung respectively; H/C value of biochar was 0.08, declaring a low aromatization degree; (O + N)/C value of biochar was 0.56, to explain a strong surface polarity hydrophilic of the biochar; Contents of 10 kinds of metal elements such as Cu, Fe, Mn et al in the yak dung was lower than that in the biochar; Contents of polluted heavy metal ions in the yak dung and biochar were low relatively.Higher TOC in Yak dung biochar can improve soil fertility after puting into soil; Therefore, yak dung biochar can be used as a soil conditioner application; Contents of the polluted heavy metal ions in the yak dung and biochar was low, explaining biochar input will not result in soil heavy metal polluti-on;2、Biochar had a promoting effect on highland barley growth and crop yield which can be increased by 16% at most, while can not shorten the development period of the highland barley growth obviously; Sample spot B (1/16 percentage input) in the study showed an advantage on 3 indicators of plant height, leaf length and leaf width to; TN of highland barley plants and N contents of root, stem and leaf dropped off, and showe-d a sharply drop along with the increasing the biochar input;P in root, stem and leaf of highland barley were premier at sample spot B and reached the lowest point at sample s pot C, rebounded again at sample D; Most of the metal elements were tested in the st udy showing that easily enriched in the root under the action of biochar.3、Biochar input can improve the properties of Napa Lake upland soil, like increase-ng the pH value and TOC value of soil and lowering the CNSP content in the soil; 10 kinds of metal elements content in soil such as As, Cu, Ni, Ti, Mn, Fe etal, decreased more than 5% after biochar input; Biochar can change the soil properties, improve soil quality and also be one of the cause of increase in Highland barley yield.Dominant population of soil microorganisms surrounding Napa Lake wetlands farmla-nd was Proteobacteria, Actinobacteria, Chloroflexi, Planctomycetes, Acidobacteria, Bacte-roidetes and Gemmatimonadetes, of which the total percentage was over 89.8%. Proteob-acteriawas the most preponderant at a percentage of 29.4%.The community diversity sho-wed high and richness of the structure of soil microbes indicated a downward trend wit-h the biochar input increased; Overall, soil microbial surrounding NapaLake wetlands far-mland was abundant at community diversity and tructure.The results of this study had opened up a feasible path for yak dung biomass of utilization, biochar soil input is meaningful for the farmland soil improvement and proteti-on of Napa Lake plateau wetland area,and can also promote the development of the plateau agricultural science and the rational use of biochar, providing theoretical data for ecological security. |
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