| Fine roots are Multi-branched structure and functional unit, it affect the formation of the forest ecosystem productivity. Plant fine root architecture not only determines the size of the plant anchoring capacity, but also largely determine the spatial distribution of the plant roots in the soil and soil volume size that the plant can come into contact. Fine roots is the most sensitive part of the plant roots, and its growth has a high degree of plasticity, fine root architecture may change with the changes of the external environment, while fine root configuration changes directly affect the absorption of nutrients and water use efficiency. Study soil nutrient changes in the configuration of the fine roots, which can help in-depth understanding of the relationship between Root Architecture and nutrient supply, and benefit explaning the effect of fine root structure on the different fertilization, contribute to a correct understanding of plant nutrients and water absorption, the use of the mechanism for the growth and development of trees, the productivity of the entire stand and forest ecosystems material and energy flow is important. Therefore, this study as the research object in a hilly area of4-year-old1-107poplar young forest, through application of N+P+Manure processing, study of fertilization on1-107poplar root sequence-level fine root biomass distribution pattern, branching characteristics, shape and configuration. The results were showed as follows:(1)1-107poplar fine root biomass is mainly distributed in the0-20cm soil layer (77.34-84.07%), fertilization significantly reduces the1-107poplar1-5Fine root biomass (p<0.05), but0-20cm soil layer1-107poplar1-5fine root biomass accounted for the proportion of0-40cm soil layer of fine root biomass, the largest increase of4.13%.1-107poplar young forest fine root biomass distribution pattern in1-5fine roots, lower fine root biomass is far below the fine roots, five fine root contribution to the total biomass of31.90-36.99%. Fertilization increased the0-20cm soil layer1-107poplar1-2grade fine root biomass, reducing the level3-5fine root biomass, but only a fine root change was significant (p<0.05); fertilization reduced20-40cm soil layer1-5level fine root biomass, the difference was not significant (p>0.05) increase.(2) The plant roots are buried underground and multi-branch structure unit, unit soil volume, with increasing root order, the number of1-107poplar fine roots are drastically reduced, the number of0-20cm soil layer of fine roots isl.74-4.93times to the which is in20-40cm soil layer, fertilization significantly increased the number of1-4fine roots of1-107poplar that in the0-20cm soil layer, while it significantly reduced the number of1-3fine roots(p<0.05) of1-107poplar, which is on20-40cm soil. The main reason may be that the fertilization affected plant fine branching ratios and branching density.Compared with the control,0-20cm soil to5from1fine root branching ratios from1:2.76:22.00:122.89:453.32increase to1:3.02:24.18:137.51:508.50, and a significant increase in two, three, five branch density of fine roots;20-40cm soil branches from1:2.59:17.74:93.53:301.16reduced to1:2.28:14.89:77.08:237.39. the difference of root sequence branching density did not reach a significant level (p>0.05).(3) Plant fine root according to the position of Health and the growth of the development of the order of the formation of different root orders, with the increase of the root sequence significantly increase the1-107poplar fine root diameter and root length, lower than the root length and root length density (p<0.05). Compared with the control, fertilization on fine root diameter, root length, specific root length, root length density. According to the position of Health and the growth and development order of the formation,Plant fine root form different root orders, with the increase of the root sequence, the1-107poplar fine root increase diameter and root length significantly, but the root length and root length density lower (p<0.05). Compared with the contrast, fertilization have a different impact on fine root diameter, root length, specific root length, root length density. In the0-20cm soil, fertilization significantly reduce the1-107poplar to1-2grade fine root diameter (p<0.05), while the3-5Fine root diameter change difference is not significant;20-40cm soil layer, fertilization reduces the1-107poplar1-4Fine root diameter, an increase of5fine roots straight, but the difference was not significant (p>0.05), the Change only1.82%. Fertilization significantly increased1-5fine roots of the1-107poplar in0-20cm soil layer and The coefficient of variation of the diameter of2-5fine roots, in20-40cm soil layer. Fertilization on poplar1-5Fine root length was not significant (p>0.05). With contrast compared to,in0-20cm soil layer, fertilizing the1-107Poplar Level1-5, respectively, an increase of9.35%,11.23%,18.28%,19.20%,4.74%;in20-40cm soil layer, it changed by10.34%,3.77%,12.21%,0.74%,-4.86%. Fertilization on1-107poplar Specific root length of different root orders’ fine roots is mainly reflected in the lower root, compared with the contrast, fertilization, in the0-20cm soil layer, a significant increase on1-2grade fine roots and a fine root specific root length in20-40cm soil (p<0.05); the Specific root length of each orders’fine roots was not significant different (p>0.05), in0-20cm soil layer, Fertilization on1-107poplar make1-5Fine root length density, respectively, an increase of35.42%,37.40%,43.54%,44.04%,15.63%, analysis of variance showed a fertilization come to a significant increase in1-4level fine root length density (p<0.05),but the difference of fifth grade fine roots is not significant (p>0.05); in the20-40cm soil, fertilization on1-5grade fine root, reduced root length density by27.52%,,28.74%,21.50%,26.19%,20.72%, but the difference did not reach the level of significance (p>0.05).Comprehensive analysis show that:fertilization significantly reduce total biological amount of the1-107poplar fine root, but a significant increase in the0-20cm soil layer of fine root biomass proportion. that fertilization make1-107poplar fine root trends in distribution to the soil surface, by increasing the surface number of fine roots at all levels, branching ratio and density of branches. Fertilization on fine root morphological characteristics mainly in the lower root (1-2fine roots), root (4-5fine roots) had no significant effect.it is particularly evident in the0-20cm soil layer. These results have great significance. On the correct understanding of soil nutrient dynamics of fine root morphological configurations, in-depth understanding for response of each root order fine roots to soil nutrient, promoting the study of forest productivity and sustainable operation and management of the fast growing plantations. |
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