Browsing by Author "Premarathna, M."

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    Effect of Biofilm Biofertilizer on Tea Cultivation
    (Uva Wellassa University of Sri Lanka, 2020) Chandralal, R.P.V.T.; Jayasekara, A.P.D.A.; Seneviratne, G.; Herath, H.M.S.K.; Silva, P.D.P.M.; Abeysinghe, D.C.; Premarathna, M.
    In tea cultivation, decreased soil quality can be seen in places where tea has been grown for a long period. Although chemical fertilizers (CFs) release nutrients quickly, they are leached to the deeper layers of soil polluting water bodies. Also, CFs deplete beneficial microbes and insects, thus decreasing plant immunity and soil fertility, causing huge damage to the ecosystem. Biofilm is an assemblage of microbes adherent to each other and/or biotic/abiotic surfaces and embedded in a self-produced extracellular matrix of polymers. In-vitro developed biofilms can be used as biofilm biofertilizers (BFBFs). BFBFs can break the dormancy of microbial forms in the soil, thus enhancing biodiversity, nutrient cycling, plant immunity, and crop production. This study focused on analysing the effects of the BFBF on soil, plant, and microbial parameters. The study consisted of two uniformly managed tea lands in Badulla. The fields were applied with two treatments separately; (a) 100% CF of Tea Research Institute (TRI) recommendation of VPUva 925, and (b) 75% CF of TRI recommendation of VPUva 925 + BFBF 2.5 L ha–1 . All quantitative data were analysed with a two-sample t-test. An increasing trend was observed in endophytic diazotrophs (p=0.08) in BFBF treatment over the growers’ 100% CF practice. Significantly (p≤0.05) higher soil pH, moisture, labile carbon, organic carbon, total nitrogen, leaf total polyphenols (SPAD), made tea production and the amount of soil carbon sequestered was observed in the BFBF practice over the growers’ practice. However, a significant (p>0.05) difference could not be observed for soil available potassium and soil total phosphorous contents. Application of BFBF improved the nutrient utilization efficiency of plants and led to an increase in tea yield over the growers’ practice of CF alone application while cutting down CF usage by 25%. Therefore, it is concluded that the BFBF is an eco-friendly and economically viable method to replace the growers’ current practice of CF alone application. Keywords: Biofilm, Biofilm biofertilizers, Nutrient cycling, Soil fertility
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    Potential of Biofilm Biofertilizer Application in Paddy Soil Carbon Sequestration in Sri Lanka: An Economic Feasibility Analysis
    (Uva Wellassa University of Sri Lanka, 2020) Ekanayake, S.N.B.; Seneviratne, G.; Premarathna, M.; Gunathilaka, R.P.D.; Banagala, C.H.M.; Hearth, H.M.S.K.
    Anthropogenic emissions of carbon (C) to the atmosphere at higher rates have led to global warming and climate change. Soil carbon sequestration (SCS) has been recognized as the process that stores atmospheric C for a long period without escaping back to the atmosphere. Globally, expanding agricultural lands has come to play a major role in SCS in the phase of degradation of natural ecosystems like forests by deforestation, fire, etc. The objective of this study was to evaluate the potential of Biofilm biofertilizer (BFBF) application in SCS under rice cultivation. Soil stable C was estimated as sequestered soil C by using organic carbon (Walkley-Black) and oxidizable carbon in the BFBF application and the farmers’ chemical fertilizer (CF) alone application. Soil samples were collected from paddy fields in 25 representative locations in several districts of Sri Lanka in three consecutive seasons: Yala 2018, Maha 2018/19, and Yala 2019. The results showed that the SCS was significantly (p<0.05) higher in the BFBF practice in every season. This is due to increased microbial C assimilation in the root zone of soil. The BFBF practice sequestered 19 t C ha-1 year–1 over farmers’ CF practice, showing an enormous potential to gain income through soil C trading. There was also an increasing trend in the paddy grain yield up to ca. 30% under the same practice. Thus, during the next five years, if the BFBF practice would be implemented island wide, the potential income from trading C will be ca. 190 billion rupees. In conclusion, the BFBF practice can be considered as an eco-friendly and economically viable method to replace the farmers’ current practice of CF alone application. Keywords: Biofilm biofertilizer, Carbon trading, Rice cultivation, Soil carbon sequestration