Presentation on theme: "Presented at Third Summit of Science Academies of South Asia and General Assembly of Association of Academies and Societies of Sciences in Asia, 14-17."— Presentation transcript:
Presented at Third Summit of Science Academies of South Asia and General Assembly of Association of Academies and Societies of Sciences in Asia, October 2014, New Delhi, India Are we wrong in conventional approach of agriculture? Gamini Seneviratne Research Professor Microbial Biotechnology Unit (MBU) Institute of Fundamental Studies (IFS) Kandy Sri Lanka
Introduction How does an ecosystem work? - Ecosystem is a food web-based network of interactions of organisms & the environment - Nutrients are conserved in undisturbed ecosystems, leading to sustainability, particularly due to their cycling in the producers-consumers- decomposers loops
Food web-based network of interactions of a forest ecosystem in USA, using Pyrosequencing Flora & fauna Microbes
In the food web-based network of interactions Interaction lines are synergistic (positive) or antagonistic (negative). As long as all the interactions are intact, the ecosystem is equilibrated and sustainable (Lupatini et al. (2014) Frontiers in Environmental Science (www.frontiersin.org)
In food web-based network of interactions of forest ecosystems Some microbes and fauna (particularly insects) contribute to structure or stratify plants, by consuming (feeding on) seedlings of the same species growing at high densities on the forest floor Thereby, they thin the seedlings, thus allowing the other species too to emerge, leading to remarkable diversity (Bagchi et al. (2014) Nature 506, 85-88). Thus, those microbes and insects play an extremely important role in forest structuring and diversifying.
Remarkable diversity in forest ecosystems
In forest conversion to agriculture Stress factors like forest clearing, tillage and chemical inputs reduce biodiversity of functional flora, fauna and microbes. Most of the disappeared biodiversity enter into an inactive or dormant phase to bypass the stress factors, by forming ‘seeds’, which are stored in soil seed bank.
Chemical inputs reduce biodiversity of microbes CF applied tea soil Forest soil
In agroecosystems (i.e. forests converted to agriculture) The natural food web is collapsed due to removal of flora, fauna & suppression of microbes. Then, remnant forest structuring and diversifying microbes and insects start feeding on our crops in the absence of other plants for them to feed on. Then, we name them as pathogens and pests attacking our crops. This is how pathogens and pests originate in agroecosystems.
In agroecosystems The reduced biodiversity due to stress factors leads to; - reduced photosynthesis and carbon accumulation due to removal of flora - depletion of soil organic matter due to reduced fungal diversity and fauna. These lead to retarded nutrient cycling, soil moisture stress, yield decline etc., thus collapsing sustainability of agroecosystems.
In conventional agriculture We address above issues by killing pests and pathogens, by increasing chemical fertilizer use with yield decline etc., which contribute to further depletion of biodiversity. As one can understand, what we should have done, was to reinstate the lost biodiversity for re-establishing ecosystem functioning and sustainability of agroecosystems. Thus, in this manner, we are wrong in the conventional approach of agriculture.
With this understanding We developed biofilm biofertilisers (BFBFs) for reinstating biodiversity of degraded agroecosystems. Their major role after field application is to increase soil biodiversity through breaking dormancy of the soil seed bank that was developed under the stress conditions. This increase of the biodiversity leads to improve ecosystem functioning, which in turn reinstates sustainability of degraded agroecosystems. In addition, the BFBFs application increases endophytic colonization of microbes, which helps improve environmental stress tolerance of plants.
BFBFs -A method to direct application of developed microbial communities in vitro, to the soil -Beneficial communities of microorganisms (bacteria, fungi & cyanobacteria) in surface-attached biofilm mode -Different from organic fertilizers and conventional biofertilizers -More effective than conventional biofertilizers Fungal-bacterial biofilm (FBB) Seneviratne et al. (2008) World J. Microbiol. Biotechnol. 24:739–743
Some highlights of BFBFs application in different crops & other benefits
Effects of BFBFs on tea In collaboration with TRI Tea nursery at Ratnapura
Young tea field trial at Ratnapura Causalities due to drought BFBFs + 50% CF 100% CF
Biocontrol of pathogens by stimulating emergence of microbes from soil microbial seed bank by BFBFs (no Fus. or Trich.)
A 250 ml bottle of Biofilm biofertiliser for tea “Biofilm-T”. Two of these bottles with 50% of recommended chemical fertilizers are adequate for 1 acre of tea cultivation
A luxuriant growth of tea cultivation with Biofilm-T application in the south of Sri Lanka (10-80% yield increase depending on soil & climatic conditions)
Comparison of tea buds of crops treated with Biofilm-T + 50% of chemical fertilizers (left) and 100% of chemical fertilizers alone (right)
Other crops studied Rubber – RRI Coconut- KPL Sugar cane- SRI Strawberry- ARS, Seetha Eliya & Growers Vegetables- SARD Tree nurseries- OUSL, Popham Arboretum, Dambulla
Investigators & collaborators IFS- Prof. S.A. Kulasooriya, L. Herath, S. Ekanayake, U.V.A. Buddhika & N. Weeraratne. Tec. Assist.- K. Karunaratne, A. Pathirana, Kosala Kumara, Volunteers……………….. TRI- A. Jayasekara & L. De Silva RRDI- S.N. Jayawardana & A. Subasinghe RRI- R. Hettiarachchi & S. Dharmakeerthi Plenty Foods (Pvt.) Ltd. & Univ. of Peradeniya – A. Gunaratne, Preethi Viraj, M. Ariyaratne, H. Ariyawansa & K. Manikdiwela NBG- C. Seneviratne SARD- L. Weerakoon, A. Indrajith Uva Wellassa Univ.- A. Priyashantha, D. Sinhalage Univ. of Colombo- S. Thirimanne, T. Perera Universities & Research Institutes……………..