Participatory Land Rehabilitation Strategies in Angacha District, Kembata Zone, Central Ethiopia Region

Community participation has become widely incorporated into policies of many soil and water conservation organizations. The purpose of this study was to assess the community participation in the rehabilitation of degraded land. In order to achieve the objective of the study, both primary and secondary data were generated by employing qualitative and quantitative data. Purposive sampling was employed to select three study kebeles (the smallest administrative structure of the country) from 16 rural kebeles in Angecha District. Simple random sampling technique was used to select 183 household heads from the lists of farmers in the selected kebeles for detailed household survey. In addition to household survey, field observation and key informant interview were also conducted to collect the necessary data. The data were presented using descriptive statistic such as percentage, frequency, tables and figure. The data collected through the use of household survey questionnaires were analyzed using logit regression while data collected through field observation and key informant interview were analyzed and interpreted using qualitative description. The findings of the present study revealed that population pressure, soil erosion, deforestation, overgrazing, and over cultivation were the major causes for land degradation. Moreover, the results of this study indicated that the main causes of the low productivity of farmland were farmers’ involvement in off-farm activities, increase in size of human population, lack of full cooperation of family members to involve in land rehabilitation practices. Households participated in rehabilitation practices at different levels, with 43.7% respondents showing intermediate participation. However, 22.4% of the farm households clarified that there is low experience sharing and motivation to participate in the process of implementation of rehabilitation programs. It is recommended that, continuous training and experience sharing program, immediate action to increase the number of literate persons, to practicing compatible practices for the agro climatic zone such as soil bund, Fanyaaju, stone bunds, and tree planting, extending effective practices, create opportunities for alternative means of livelihood and promoting NGOs effort to involve in land rehabilitation practices in the highly degraded area.

Effects of sediment dredging on water quality and zooplankton community structure in a shallow of eutrophic lake

Effects of suction dredging on water quality and zooplankton community structure in a shallow of eutrophic lake, were evaluated. The results showed that a decreasing trend for levels of phosphorus, organic matter, total suspended solids, Chlorophyll a and Secchi transparency in the water column was found, while levels of water depth, electrical conductivity, total dissolved solids and NO3^--N concentration increased markedly post-dredging. The effects of dredging on dissolved oxygen, pH value and temperature were almost negligible. The zooplankton community structure responded rapidly to the environmental changes caused mainly by dredging. As a result, the abundance of rotifers decreased, while the density of zooplanktonic crustaceans increased markedly. The representative taxa were Brachionus angularis, B. budapestinensis, B. diversicornis, Synchaeta spp. and Neodiaptomus schmackeri. A distinct relationship between zooplankton taxa composition and their environment, unraveled by a redundancy analysis, indicating that the measured environment contributed to the variations in the zooplankton community structure to some extent. The first four synthetic environmental variables explained 51.7% of the taxonomic structure. Therefore, with the reduction of internal nutrient load and a shift in dominance by less eutrophic species, it inferred that dredging might be one of effective measures for environmental improvements of such lakes.

Microbial community variation in phytoremediation of triazophos by Canna indica Linn. in a hydroponic system

Phytoremediation of triazophos （O,O-diethyl-O-（1-phenyl-1,2,4-triazole-3-base） sulfur phosphate, TAP） pollution by Canna indica Linn. in a hydroponic system has been well studied, whereas the microbial mechanism on TAP degradation is still unknown. The variation in microbial community compositions was investigated by analyzing phospholipid fatty acids （PLFAs） profiles in microbes under TAP exposure. The TAP exposure resulted in an increase in proportions of fatty acid 16：0 and decrease in fatty acid 18：2ω9,12c, indicating that TAP may stimulate the reproduction of microorganisms and inhibit the growth of fungi to some degree. Significant correlation was found between the ratio of fungi to bacteria and TAP removal （r 2 = 0.840, p 0.01）. In addition, the microbial community in the phytoremediation system with C. indica was dominated by Gram negative bacteria, which possibly contributed to the degradation of TAP. These results indicated that TAP might induce the colonization of bacteria in the hydroponic system planted with C. indica, and lead to a discrimination of microbial community, which might be one of the mechanisms on TAP dissipation in phytoremediation system.

A comparison on the phytoremediation ability of triazophos by different macrophytes

The strategy of choosing suitable plants should receive great performance in phytoremediation of surface water polluted by triazophos （O,O-diethyl-O-（1-phenyl- 1,2,4-triazol-3-base） sulfur phosphate, TAP）, which is an organophosphorus pesticide widespread applied for agriculture in China and moderately toxic to higher animal and fish. The tolerance, uptake, transformation and removal of TAP by twelve species of macrophytes were examined in a hydroponic system and a comprehensive score （CS） of five parameters （relative growth rate （RGR）, biomass, root/shoot ratio, removal capacity （RC）, and bio-concentration factor （BCF）） by factor analysis was employed to screen the potential macrophyte species for TAP phytoremediation. The results showed that Thalia dealbata, Cyperus alternifolius, Canna indica and Acorus calamus had higher RGR values, indicating these four species having stronger growth capacity under TAP stress. The higher RC loading in Iris pseudacorus and Cyperus rotundus were 42.11 and 24.63μg/（g fw.day）, respectively. The highest values of BCF occurred in A. calamus （1.17）, and TF occurred in Eichhornia crassipes （2.14）. Biomass and root/shoot ratio of plant showed significant positive correlation with first-order kinetic constant of TAP removal in the hydroponic system, indicating that plant biomass and root system play important roles in remediation of TAP. Five plant species including C. alternifolius, A. calamus, T. dealbata, C. indica and Typha orientalis, which owned higher CS, would be potential species for TAP phytoremediation of contaminated water bodies.

Freshwater algae chemotaxonomy by high-performance liquid chromatographic(HPLC)analysis

The study of community composition of algae is essential for understanding the structure and dynamics of the aquatic ecosystem and for evaluating the eutrophic level of the water body.A high-performance liquid chromatographic(HPLC)method based on a reversephase C_(18) nonpolar column was developed for the main algal taxa,which includes cyanophytes,bacillariophytes,euglenophytes,dinophytes,and chlorophytes.Based on the elution order using HPLC,19 pigments were identified,and they were chlorophyllide a,19′-butanoyloxyfucoxanthin,chlorophyll c_(1)+c_(2),phephorbides a,peridinin,methyl-chlorophyllide a,fucoxanthin,neoxanthin,violaxanthin,myxoxanthophyll,diadinoxanthin,diatoxanthin,lutein,zeaxanthin,chlorophyll b allomer,chlorophyll b,chlorophyll a allomer,chlorophyll a,andβ,β-carotene.A comparison study of cell microscopic counts and accessory pigment analysis indicated that HPLC analysis could be a useful tool for monitoring phytoplankton communities and their abundance.