Báo cáo khoa học nông nghiệp: Replacing fertiliser N with rhizobial inoculants for legumes in Vietnam for greater farm profitability and environmental benefits (MS6)

Ministry of Agriculture & Rural Development Collaboration for Agriculture & Rural Development 013/06VIE Replacing fertiliser N with rhizobial inoculants for legumes in Vietnam for greater farm profitability and environmental benefits MS6: High Quality Inoculants Technical Report September 2009 1 Table of Contents 1. Institute Information 2 2. Contact Officers 2 3. Project Abstract 2 4. Executive Summary 3 5. Technical Report 5 5.1. Introduction of two Australian strains into Vietnam 6 5.2. Protocols for inoculant production, QA and use 16 5.3. Results and evaluation of on-farm demonstration trials 32 1 1. Institute Information Project Name Vietnamese Institution Vietnamese Project Team Leader Australian Organisation Australian Personnel Date commenced Completion date (original) Completion date (revised) Reporting period Replacing fertiliser N with rhizobial inoculants for legumes in Vietnam for greater farm profitability and environmental benefits Oil Plants Institute (OPI) Ms Tran Yen Thao NSW Industry & Investment University of New England University of Sydney Dr David Herridge Dr Roz Deaker Ms Elizabeth Hartley, Mr Greg Gemell March 2007 March 2009 November 2009 December 2008 – September 2009 2. Contact Officer(s) In Australia: Team Leader Name: Position: Organisation Dr David Herridge Professor, Soil Productivity University of New England -PIIC Telephone: Fax: Email: 02 67631143 02 67631222 david.herridge@dpi.nsw.gov.au In Australia: Administrative contact Name: Position: Organisation In Vietnam Name: Position: Organisation Mr Graham Denney Manager External Funding Industry & Investment NSW Ms Tran Yen Thao Researcher Oil Plants Institute (OPI) Telephone: Fax: Email: Telephone: Fax: Email: 02 63913219 02 63913327 graham.denney@dpi.nsw.gov.au 08 9143024 – 8297336 08 8243528 yenthao@opi.org.vn yenthao@hcm.fpt.vn yenthao9@yahoo.com 2 3. Project Abstract Farmers in Vietnam currently fertilise legumes such as soybean and groundnut with N, rather than inoculate with rhizobia. Replacing fertiliser N with rhizobial inoculants would save Vietnamese farmers A$50-60 million annually in input costs and, at the same time, help facilitate the desired expansion in legume production. There would also be positive environmental outcomes. This project aims to increase production of high-quality legume inoculants in Vietnam through enhanced production capacity, implementation of a national quality assurance (QA) program and increased inoculant R&D. Participating in the project in Vietnam are the Oil Plants Institute (OPI), the Institute of Agricultural Science (IAS) and the National Institute for Soils and Fertilisers (NISF), now known as the Soils & Fertilisers Institute (SFI). Institutions in Australia are NSW Department of Primary Industries and the University of Sydney. Legume inoculant use by farmers in Vietnam will be increased through the development and implementation of an effective extension and training program for researchers, MARD extension officers and farmers. The benefits of inoculants and legume nitrogen fixation will be demonstrated in the field and communicated through workshops, meetings and publications. To ensure sustainability of inoculant production and use, the project will engage the private sector in marketing and ‘pilot production’ of legume inoculants, with the aim that they may scale-up production and progressively take over supply as the technology and markets are developed. 4. Executive Summary Impact of two Australian strains in Vietnam on legume production and productivity and comparative analysis between local and introduced strains Part of this project was to evaluate elite international strains across the country and to compare them with national strains. Included were local and imported strains from Vietnamese institutes, from NifTAL (USA), ALIRU (Australia), DOA (Thailand), Korea and Argentina. Several of these strains are currently used in commercial inoculants in Australia such as CB1809 (soybean) and NC92 (groundnut). We conducted two experimental sets; the first was in a potted field soil and the second in field trials. In the potted field soil trial, there were 13 treatments for groundnut (11 groundnut strains, a +N control without inoculation and –N uninoculated control) and 18 treatments for soybean (17 soybean strains, a +N control without inoculation and –N uninoculated control). All strains increased groundnut and soybean nodulation and yield compared to the control treatments. There were close correlations between nodule number, nodule weight and plant biomass while correlations between nodulation and plant height were poor. The best strains were NC92 (Australian commercial strain), GL1 and GL2 (local strains) for groundnut and CB1809 (Australian commercial strain), SL2, SL1, CJ2 and U110 (old US commercial strain) for soybean. The total number of field experiments during 2007–09 was 36 in the 10 provinces. The experiments were conducted in the main legume-growing areas in Vietnam, from the highlands in the North, to the Central Coast area to the highlands in the South and Mekong Delta. The provinces involved were Son La, Nghe An, Binh Dinh, Binh Thuan, DakLak, 3 DakNong, Tay Ninh, Dong Thap, An Giang and Tra Vinh. There were at least 5 treatments in each experiment: 1. Farmer’s practice without N fertiliser 2. Farmer’s practice with N fertiliser 3. Inoculation with Australian strains CB1809 (soybean) or NC92 (groundnut), -N fertiliser 4. Inoculation with local strain: SL1 (for soybean) or GL1 (groundnut), -N fertiliser 5. Inoculation with local strain: SL2 (for soybean) or GL2 (groundnut), -N fertiliser The Australian strains were the most effective in terms of nodulation, biomass yield and grain yield. Compared with the uninoculated control, CB1809 and NC92 increased nodulation of soybean and groundnut, respectively, by an average of 58%, biomass yield by 30% and grain yield by 29%. Compared to the local Vietnamese strains, CB1809 and NC92, increased soybean and groundnut nodulation by an overall average of 22%. Biomass yields were increased by an average of 10% and grains yields increased by an average of 13%. Protocols for production of high quality inoculants including QA, packaging, storage, distribution and on-farm application of inoculants During the two years of the project, technology for inoculant production at the three institutes (SFI, OPI and IAS) was developed. The principal aim was production of high quality of inoculants containing >5 x 108 rhizobia/g and a maximum 1 x 108 contaminants/g. Some details of the technologies are different between the collaborating institutes depending on facilities and expertise. To some extent, the inoculant technologies have been adapted from those used in countries with existing successful inoculant industries, e.g. Australia, US. The project team has decided that CB1809 and NC92 will be used for inoculant production in Vietnam as multi-field trials throughout the country showed these strains are the best for soybean and groundnut. They increased nodule weight, crop biomass and grain yield compared to local strains tested. In the future, more strain evaluation will likely be done to try to develop even more effective inoculant strains. It is also proposed that cultures of these strains will be supplied annually from the independent QA laboratory to private and public sector laboratories producing inoculants together with protocols for strain maintenance and production of broth cultures. Details are provided in Section 5.2. It is likely that peat will be the major inoculant carrier for Vietnam. Details are provided (Section 5.2) on different peats in Vietnam, their efficacy as an inoculant carrier and the usefulness of various additives in improving efficacy. Guidelines are also provided on optimum pH and water content. An experiment was done to compare different methods of sterilization of peat. After peat samples were sterilized, some samples were used for direct determinations of contamination. Other peat samples were cultured in Glucose Peptone broth and then the broths were assessed for contamination after 3 hrs, 24 hrs, 36 hrs and 72 hrs. Samples were also assessed for rhizobial numbers. The best treatments in terms of highest numbers of rhizobia and lowest numbers of contaminants were the autoclaved treatments with autoclaving for 60 min and the irradiated treatments with 30 kGy the best overall. 4 ... - tailieumienphi.vn