Bioremediation for water purification· A case study at St. Coombs Lake, Talawakelle

Phytorernediation is one of the most eco friendly and innovative techniques to remove pollutants fromsoi I and water in agricu Itural areas. Th is study explored potentials ofbioremediation for water purificationat Tea Research Institute of Sri Lanka through monitoring water quality of St. Coombs lake andthrough several glasshouse and laboratory experiments for validating the resu Its during the period ofNovember 2004- February of2005.The water qual ity parameters such as pH, nitrate, phosphate, iron and total col iforrns at 35 DC / 100 rnland Escherichia coli at 44° C / 100 ml were monitored during dry and rainy periods. The possiblecauses for water pollution of the lake were also monitored. Nitrate pollution was greater during rainyperiods since higher contribution of erosion and runoff. Higher levels of total coliforms and Escherichiacoli were observed in both seasons. Five plant species traditionally known to have phytorernedialproperties i.e. Kang kong (Ipomea aquaticai, Giant reed (Arunda danax), Water hyacinthiEichhornia cracipesi, Bulrush (Scirpus lacustris) and Kurnbuk (Terminalia arjuna) wereevaluated for nutrient absorption. The histology of Kumbuk and Tea roots were assessed for theiranatomical attributes to the biorernediation properties.The differences in root anatomical traits in different plant species lead to differences in nutrient andwater absorption. Kang kong, Water hyacinth and Bulrush showed better performances in nutrientabsorption. The results supported the potentials and technical attributes to common biorernediationplant species in purification of water. These attempts would be environmentally and user friendly, costeffective as well as aesthetic advantages and long-term applicability compared to chemical treatments.

IMPORTANCE OF IMPROVING BIOLOGICAL ACTIVITY OF TEA SOILS IN SOUTHERN PROVINCE OF SRI LANKA.

The detrimental effects of soil pesticides on soil micro biota and biodiversity of the teaecosystem are poorly understood. In the current study, microbial activity in southern teasoils of Sri Lanka as affected by application of commonly used soil pesticides and certaincultural practices was evaluated by m-:asuring the soil respiration in vitro and in vivo.CO2 evolution rates in Southern tea soils were generally low as compared to soils in otherareas. Herbicide and formalin applications significantly (p=O.005) suppressed thebiological activity of Southern tea soils; the nematicide tested was less effective.Incorporation of compost and tea waste significantly (p=O.005) elevated CO2 evolution ratein tea soils than that of in undisturbed, virgin forest soils. Forking strengthened microbialbiomass through improved soil physical conditions. Soil biomass was positively correlatedwith growth of the test plants viz tea and tomatoSouthern tea soils with low organic matter contents arc exposed to repeated application ofherbicides and negligence of important agronomic practices due to labour shortage. Suchmalpractices could aggravate potential build up of pesticide residues in the soil. Thus,improvement of soil organic matter status by incorporation of various organic amendments,establishment of green manure crops, rehabilitation of old tea soils and more importantly,restricted usage of agro-chemicals etc. is essential. These practices will assure long-termsustainable productivity and quality of soils as well as help degrade accumulated chemicalresidues and elevate densities of soil microbial communities. As a consequence, increasedefficacy of bio control of nematodes and soil borne pathogens and proper administration ofnatural nutrient cycles could be envisaged.

Comparative dynamics of tea (Camellia sinensis L.) roots under organic and conventional management systems with special reference to water use

Comparative measurements were carried out in the on-going, long-term organic and conventional comparison “TRI OR-CON” trial at the Tea Research Institute of Sri Lanka. The tea was grown organically using tea waste (TW), neem oil cake (NOC), compost (COM) as soil amendments using IFOAM guidelines, which were compared with tea grown conventionally (CONV) with recommended synthetic inputs. Responses of the tea yield, root system and mass volume sap flow were studied. The tea bushes showed comparable responses between all the treatments, the differences of which were not statistically significant: They exhibited similar yield, root distribution, growth, extension rates, mortality, mass volume flow of water and water use efficiency (WUE). The organically grown (ORG) tea bushes invested more roots in deeper soil layers than the CONV bushes. The results showed that in terms of plant growth, managing tea organically is as equally feasible as managing tea in the conventional manner

Elevation of earthworm biomass by organic cultivation practices Long-term evidence from tea soils

Agrochemicals used in conventional agriculture affect soil fauna and flora while organic managementi.e. organic matter incorporation, mulching and avoid of synthetic chemicals etc. favor natural soilinhabitants. Amongst them, earthworms are the most effective bio-indicators which signify structural,microclirnatic, nutritive properties and health of agricultural soils. Data were generated from soils ofthe on going 'TRI-ORCON' trial set up at St. Coombs estate of the Tea Research Institute of SriLanka, Talawakelle. Using standard size quadrates, the number and weight of earthworm eggs andearthworms from 0 - 15 and 15 - 30 ern soil depths were determined at 10 years after exposure toorganic and conventional systems with tea waste, neem oil cake and compost applications and syntheticagro-chernicals respectively. The earthworm biomass was significantly (p<0.05) superior in organicallymaintained soils than that of the conventional. Earthworm activity was significantly diminished due tosynthetic fertil izers and pesticide use; earthworm eggs in the 0-15 ern and 15-30 ern layers were 0 and40 x 10J per ha while compost application exhibited 64.8 x 103 and 200 x 103 per ha respectively.Amongst organic amendments, neem oil cake due to its wormicidal effects and oily and cloggy naturelowered earthworm biomass in the 0 - 15 em layer of which the effect was similar to conventional.The higher aggregate stability in the organically maintained soils with macro pores developed throughearthworm burrows showed strong relationship with the earthworm activity. Therefore, our resultsconfirm the immense potentials of organic management practices in developing biological and physicalparameters through burrowing, loosening of soil, recycling of nutrients and organic matter in deepersoil depths by earthworms and their castings. Resultantly, organic agricultural systems act as analogueforest conditions with activated and conserved native soil biodiversity components assuring long-termsustenance in crop productivity

Analytical Hierarchy Process for Comparison of Organic and Chemical Farming of Tea Small Holdings in Baddegama, Galle

Tea Small Holders in Baddegama, Galle typically use chemical fertilisers and pesticides for their tea cultivations. However, in recent years, there has been a gradual transition to organic and nonchemical practices, including a variety of soil conservation techniques such as stone hedges, live fences, lock and spill drains. Yet, no quantitative comparative studies have been carried out in Sri Lanka on these aspects for tea small holdings. The present study broadly intends to compare costs and benefits related to four categories of tea small holdings which include: Organic plots with soil conservation (ORG+SC), Organic plots without soil conservation (ORG-SC), Chemical plots with soil conservation (CHE+SC) and Chemical plots without soil conservation (CHE-SC), selecting five plots per each category. Physical, chemical and biological parameters and economic parameters were used to estimate overall soil condition and quality in a given plot. The physical and chemical parameters included soil retention capacity and the nitrogen and carbon content. The diversity and abundance of soil organisms was selected as the biological parameter. The economic indicators were the income received form tea and other plants and the cost of production. The Analytic Hierarchical Process Method (AHP), a multi criteria analysis was adopted to select the best category that provide optimal benefits under small tea holding conditions. The physicochemical parameters of soil retention and nitrogen and carbon content were more positive in the organic tea plots. The biological parameters such as earthworms, biological activity and arthropods in the soil were significantly higher in the organic plots. Benefit cost ratio of tea production for the small tea holders was higher in the organic plus soil conservation plots. AHP provided the ranking of the selected categories as ORG+SC, ORG-SC, CHE+SC and CHE-SC.The study highlights the importance of understanding environment issues holistically. In order to understand the sustainability of a system both economic parameters and non- economic parameters have to be considered.Key words: Analytic Hierarchy Method, Organic farming, Soil Conservatio

Restoration of Tsunami affected Landscape and Plant Diversity in Dharmapala Park in Galle

Approximately 6 ha. of Dharmapala Park in Galle City has traditionally been maintained as a recreation area for children and adults. Owing to significantly poor horticultural attention and maintenance for many decades and the Tsunami hit, most of the lower level trees, shrubs and landscape designs as well as a few buildings and structures have been damaged. Many large trees seemed dying due to prolonged exposure to salt concentra tions in the ground and due to age, over shading and competition, termite and wood rot damages, poor drainage facilities and dumping of city garbage etc. Sky view of the park did not appear a recreational park but looked overcrowded and not harboring a diverse and fascinating array of flora arranged or managed systematically. Therefore, rehabilitation of degraded and eroded landscape status of Dharmapala Park was recognized by the local authorities. We attempted to improve the landscape status purely on the basis of adaptability to the inherent soil and land parameters and environmental conditions by choosing compatible vegetation types, strengthening architecture in par with culture and traditions of Southern Sri Lanka and existing architectural models historic to Galle Fort and other structures. Whilst restoring, improving and enhancing biological, eco logical and esthetic values, architectural and landscaping designing was aimed at accommodating requisites for future beneficiaries i.e. demonstration of ecological and biodiversity conservation and urban forestry etc. for educational, leisure and recreational purposes. Dumping yards were completely removed and the original soil organic matter status of 0.6 – 1.1 % was improved by land filling with soil sources having more than 1.5 % organic matter. Thinning out of branches, removal of old trees, shrubs and plants in unwanted places, tree surgeries and treatments of diseased and damaged tree por tions were completed to establish the proposed landscape designs. Walk ways for jogging and pets, steps, open spaces with playing, and historic exhibition facilities were systematically arranged with improved drainage and erosion control measures while the open theatre area was renovated attractively. The dominated and over crowded vegetation by Mudilla (Barringtonia asiatica L) and exotic trees and plants of about 40 species including Pinus, Casurina and Cypres etc. with little or no ecological, aesthetic or landscaping significance were changed into a variety of different canopy architectural beauty by introducing more than 120 different species of plant and tree species and turfs to give beauty and attraction for the users with cool and peaceful satisfaction. Introduction of new species was based on assuring different colour i.e. dark and light green, yellow, pink etc., diversity, size, appearance and shade horizontally and vertically during different seasons in the year, protection of the Park from sea breeze using tolerant hedge tree species and easy and less mainte nance of vegetation. In a sample survey, the visitors expressed full satisfaction of the present developments. We propose therefore to impose strict entry requirements avoiding misuse and a nominal levy in view of sustenance of the Park status and its facilities for the beneficiaries. This would also help attract both local and foreign visitors of any ag

Fotossíntese e fotoinibição em mogno e acariquara em função da luminosidade e temperatura foliar Photosynthesis and photoinhibition in mahogany and acariquara as a function of irradiance and leaf temperature

A fotoinibição pode ser intensificada por fatores de estresse como alta temperatura. O objetivo deste trabalho foi determinar os efeitos da luminosidade e temperatura na fotossíntese e na recuperação da fotoinibição sob baixa irradiância em mogno (Swietenia macrophylla King) e acariquara (Minquartia guianensis Aubl.). As plantas cresceram sob baixa irradiância: 0,20 (acariquara) e 1,43 mol m-2 dia-1 (mogno). A fotossíntese líquida e as características da fluorescência foram avaliadas em duas irradiâncias, 1.000 e 1.700 mmol m-2 s-1 , e duas temperaturas foliares, 32 e 38ºC. A 32ºC, a fotossíntese máxima (Amáx) foi maior em mogno do que em acariquara. Em mogno, a exposição a 38ºC causou redução gradativa na fotossíntese, sendo a taxa fotossintética após 50 min similar à encontrada em acariquara. A 32ºC, o aumento na irradiância, de 1.000 para 1.700 mmol m-2 s-1 , intensificou a fotoinibição, mas Amáx não foi alterada. Em 1.700 mmol m-2 s-1, o aumento da temperatura, de 32 para 38ºC, não afetou a fotoinibição. Após 72 horas em baixa irradiância, a recuperação da fotoinibição foi de 80% em acariquara e 89% em mogno. Não houve efeito da temperatura da folha na fotoinibição.<br>Photoinhibition may be exacerbated by stress factors such as high temperature. The aim of the work was to determine the effects of temperature and irradiance on photosynthesis and photoinhibition in mahogany (Swietenia macrophylla King) and acariquara (Minquartia guianensis Aubl.). Also to assess the effect of irradiance and temperature on the recovery from photoinhibition at low irradiance. Sapling were grown at low irradiance: 0.20 mol m-2 day-1 (mahogany) and 1.43 mol m-2 day-1 (acariquara). Photosynthesis and fluorescence characteristics were assessed in plants subjected to two irradiances 1,000 and 1,700 mmol m-2 s-1 , and two temperatures, 32 e 38ºC. At 32ºC, light saturated photosynthesis (Amax) was greater in mahogany than in acariquara. Mahogany plants exposed to 38ºC showed a consistent decline in carbon uptake, and after 50 min both species showed the same photosynthetic rates. In saplings exposed to 32ºC, increase in irradiance, from 1,000 to 1,700 mmol m-2 s-1 , exacerbated photoinhibition, but without reducing Amax values. At 1,700 mmol m-2 s-1 , the rise in temperature, from 32 to 38ºC, did not increase photoinhibition. After 72 hours at low irradiance, recovery from photoinhibition was 80% in acariquara and 89% in mahogany. There was no effect of leaf temperature on photoinhibition