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Growth and yield of two grain crops on sites former covered with eucalypt plantations in Koga Watershed, northwestern Ethiopia

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Journal of Forestry Research 2014年第4期25卷 935-940页

作者： desalegn tadele Demel Teketay Bahir Dar University P. O. Box 1817 Bahir Dar Ethiopia Botswana College of Agriculture Department of Crop Sciences and Production Private Bag 0027 Gaborone Botswana

Farmers in the highlands of Ethiopia often plant Eucalyptus on their farmlands. However, growing Eucalyptus, especially on farm- lands suitable for crop production has become a great concern due to its alleged long-term site effects. Our study was conducted at Koga water- shed, Mecha District, northwestern Ethiopia to investigate whether crop- lands afforested with Eucalyptus camaldulensis Dehnh. can be restored for annual crop production after tree harvest. We compared growth and yield of two agricultural crops, barley （Hordeum vulgate L.） and finger millet （Eleusine coracana （L.） Gaertn.）, grown in clear-felled stands of E. camaldulensis and continuously cultivated croplands at twelve paired farmlands under a conventional farming system. Plant height and dry matter production were evaluated as indices of crop growth, while grain weight was evaluated as an index of crop yield. Crop growth and yield measurements averaged over all farmlands differed between land-use types. For both crops, plants grown on clear-felled stands were taller than on croplands. Dry matter production and yield were also significantly greater in crops cultivated on clear-felled stands. Cropland aboveground and belowground dry matter productions were lower by 31.8 and 25.4% for barley and 32.8% and 37% for finger millet, respectively. Clear-felled stands gave an average yield of 2.91 ***-1 for barley and 3.27 ***-1 for finger millet while cropland gave a yield of 1.97 and 2.31 ***-1 for barley and finger millet, respectively. Farmers also responded that farm plots on former eucalypt plantations showed greater crop growth and yield thandid continuously cultivated croplands. Farmers perceived that Eucalyptus plantations improved soil fertility and they preferred clear-felled stands for crop production and wished to plant Eucalyptus on their farmlands. Our results suggest that conversion of agricultural lands to Eucalyptus plantations can increase post-felling yields of cereal crops.

关键词： barley finger millet land-use change reclamation

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Growth and ecophysiology of seedlings of Podocarpus falcatus in plantations of exotic species and in a natural montane forest in Ethiopia

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Journal of Forestry Research 2013年第1期24卷 29-35页

作者： desalegn tadele Masresha Fetene Bahir Dar University College of ScienceDepartment of BiologyP.O. Box 1817Bahir DarEthiopia. Addis Ababa University Faculty of ScienceDepartment of BiologyP.O. Box 1176Addis AbabaEthiopia.

The potential role of exotic tree plantations in facilitating successional processes on degraded areas was evaluated in southern Ethiopia by comparing seedling characteristics, transpiration and photosynthetic performance of Podocarpus falcatus seedlings in Eucalyptus plantation, Pinus plantation, adjacent natural forest and clear-felled plantation site. P. falcatus seedlings exhibited differences in architecture between Eucalyptus and Pinus plantations. They had higher leaf area, shorter internode length and greater number of lateral branches in Eucalyptus plantation. At similar vapor pressure deficit （VPD）, P. falcatus transpired much less than E. saligna, especially at higher VPDs. Analysis of fluorescence parameters in the leaves showed no significant differences in the level of dark-adapted and light-adapted fluorescence yield （Fv/Fm and ΔF/Fm′, respectively）, electron transport rate （ETR） and nonphotochemical quenching （NPQ） among seedlings grown inside plantations and adjacent natural forest, indicating similar photosynthetic performance. Nevertheless, there was evidence of photoinhibition in P. falcatus in the clear-felled site which had low fluorescence yield but high values of NPQ as protection from photoamage. The light response curves of ETR, NPQ and ΔF/Fm′ showed similar light saturation behavior among the seedlings grown inside plantations and natural forest and suggested a sequence of light-adapted to shade-adapted behavior in Natural forest 〉 Eucalyptus plantation 〉 Pinus plantation. The results show the structural flexibility, better water-use and adaptability of P. falcatus in its use of the understory environment of plantation species.

关键词： chlorophyll fluorescence height growth lateral growth light response curves transpiration

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Floristic diversity and regeneration status of woody plants in Zengena Forest, a remnant montane forest patch in northwestern Ethiopia

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Journal of Forestry Research 2014年第2期25卷 329-336页

作者： desalegn tadele Ermias Lulekal Destaw Damtie Adane Assefa Bahir Dar University College of ScienceDepartment of Biology Ghent University Department of Plant Production

The study was conducted at Zengena forest, a fragmented remnant montane forest in northwestern Ethiopia, which surrounds Lake Zengena. The purpose was to assess the species composition, diversity and the regeneration status of woody plants. A total of 27 plots of 20 m - 20 m were sampled along the line transects laid down the altitudinal gradient from the edge of the forest encompassing the lake to the edge of the lake in eight aspects. In each plot, woody species were counted and the diameter at breast height and the height of trees and shrubs were measured. A total of 50 woody species belonging to 31 families were found, of which 17 （34%） were trees, 7 （14%） trees or shrubs, 23 （46%） shrubs and 3 （6%） lianas. The overall Shannon-Wiener diversity and evenness indices of woody species were 2.74 and 0.7, respectively. Clausena anisata had the highest relative density （23.5%）, Rapanea rhododendroides the highest relative frequency （6.5%） and Prunus afri- cana the highest relative dominance （45%） and importance value index （IVI, 51.6）. The total basal area and density of woody plants were 22.3 ***-1 and 2,202 ***1, respectively. The population structure showed variations among woody plants and revealed varied regeneration patterns of different species. The importance value index and population structure revealed that some species are threatened and need prioritization for conservation measures. The results suggest that remnant forest patches in the highlands of northern Ethiopia host several woody plant species that are almost disappearing in other areas due to deforestation.

关键词： conservation density dominance frequency IVI LakeZengena population structure

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