Gaps in Sustainable Land Management Research and Options for Land use Change in Relation to the Nutrient Load on the Rotorua lakes

Transcription

1 Gaps in Sustainable Land Management Research and Options for Land use Change in Relation to the Nutrient Load on the Rotorua lakes Sustainable Management Fund, Project Number: 2238 Addressing Land/Water Issues Through partnerships in Rotorua Melinda Dresser, New Zealand Landcare Trust Milestone 3 - March

2 Acknowledgement Financial support has been received from the Minister for the Environment s Sustainable Management Fund, which is administered by the Ministry for the Environment. Disclaimer The Ministry for the Environment does not necessarily endorse or support the content of the publication in any way. Copyright Reproduction, adaptation, or issuing of this publication for educational or other non-commercial purpose is authorised without prior permission of the copyright holder(s). Reproduction, adaptation, or issuing of this publication for resale or other commercial purpose is prohibited without the prior permission of the copyright holder(s). 2

3 Contents Introduction 4 Research Gaps 5 Land Use Change 7 Rural Residential Subdivision... 7 Organics... 8 Truffles... 9 Short Rotation Coppice Willow for Biofuels Grow Otago Taupo Land Use Study

4 Introduction This report includes a summary of the future opportunities listed in Helen Ritchie s report: Review of research on practices to reduce N and P loss from farms in the Rotorua Lakes catchments November 2008, commissioned by the Land Use Futures Board. These oportunities give a good idea of the gaps in research into the nutrient load issues in the Rotorua Lakes. The second part of the report focuses on potential options for land use change in the Rotorua Lakes catchments in order to reduce the nutrient load on the lakes. 4

5 Research Gaps According to the report by Helen Ritchie (2008) the suggested high priority projects to gain more knowledge in order to reduce the loss of nutrients due to current land use practices to the Rotorua lakes are: Continue nitrification inhibitor (DCD) work for free-draining soils, including more high rainfall studies, long-term trials to assess variability, use of DCD on winter-grazed crops. Continue field testing of internal DCD use and animal health research. Ongoing research into high-performing dry stock systems with different cattle: sheep ratios and better genetics and pasture utilisation to get the most out of the system for the same N loss (optimised scenarios for different conditions, with economic analysis including sensitivity analysis for price changes). Research any limits to ongoing wintering outside the catchment to determine long-term viability of this option. Also determine how much stock is imported into the catchment for wintering. Research production gains from animals on a range of pad types (e.g. Birchalls Herd Home monitoring project) expand to a range of lower-cost pad options. Further research on effectiveness of different stand-off scenarios, linked to cow grazing/ feed intake and excretion behavior. Identify current Olsen P levels on Rotorua farms. More research into the high proportions of dissolved P in pumice soils and possibility of P leaching, and how Olsen P relates to this circumstance. Research into forage legumes with low P requirements. Identify Critical Source Areas (CSAs) for a number of farms in Rotorua catchments and compare results. Effects of filters, sediment traps and P-socks are well proven, but structures and materials are likely to be location-specific. Continue current trials and experiment further on a range of sites and with different reactive materials and practical designs for maintenance. Establish the longevity of different P-sorbing materials, and any contaminant effects. 5

6 Establish long-term loss of dissolved P from filter/ settling areas including riparian filters, sediment traps and grass filter strips; and, where P-sorbing materials are used that are not removable, establish ultimate fate of sorbed or locked P. Ritchie, H., (2008) Review of research on practices to reduce N and P loss from farms in the Rotorua Lakes catchments - A report for the Land Use Futures Board 6

7 Land Use Change A number of different land uses have been identified which could be adopted in the Rotorua area which would reduce the amount of nutrients being leached into the lakes. The following section summarises these options. For more detailed information on each option the original report has been referenced. Rural Residential Subdivision The Rotorua District Council is planning a potential new rural subdivision on 2400 ha. One of the applicants applying for a change in the plan is Ngati Whakaue The Private Plan Change application deals with the first stage of the Ngati Whakaue Master Plan, Ngati Whakaue s long term vision for their land. The project has been born out of Ngati Whakaue s concerns at the amount of nitrates and phosphates released into the streams and lakes from farming practices carried out on their land. As well as this, Ngati Whakaue want to achieve a higher use of their land and provide employment and housing for their people. The first stage of development (the area subject to this Plan Change) is known as the Wharenui Road Area (WRA) which includes 125 ha or 7.7% of the Ngati Whakaue Master Plan Area (1,500ha). In addition to this RDC is also considering plan changes in the Eastern and Western structure plan to allow a rural cluster zone and rural living zone to be established on what is currently farm land. According to Park (2009) in a presentation to the Land Use Futures Board the conversion of farm land to residential could lead to a relatively large reduction in N loss to Lake Rotorua. Looking at the Western Structure plan rural living 655 ha will be converted which is made up of four dairy farms plus dry stock. The following predictions can be made as to the N loss reductions by converting farm land to rural residential: current 2051 kgn/ha/yr Area ha tn/yr Area ha tn/yr Dairy Drystock Rural res Total Net N reduction 21 Assuming dairy produces 56kgN/ha/yr (Smeaton 2008); dry stock produces 19kgN/ha/yr (R-R Action Plan Table 7) and rural residence produce 8kgN/ha/yr (Park 2009) 7

8 Simon, P, (2009), Finding 170 Tonnes of N: The Lake Rotorua Land Target - Presentation to Land Use Futures Board 11 th March 2009 Environment Bay of Plenty, Rotorua District Council, Te Arawa Lakes Trust, (2007), Proposed Lakes Rotorua and Rotoiti Action Plan. Proposed Lake Rotorua Rotoiti Action Plan.pdf Organics In a report by Smeaton and Longhurst (2008) it was found that organic dairying leaches far less N than regular dairying methods and also does not reduce the profitability of the farm by as much as some of the other management changes looked at. It was found that converting the base farm in the study to organics appears to reduce the N loss by 35%. It appears that as the milk payout goes lower the profitability of the organics option increases dramatically. The graph below clearly shows that the Gross Margins per kg N leached is highest with the organic conversion option. Nitrate leached (kg/ha, black line) and Gross Margins at three milk payout levels ($5, $6, and $7 kg MS), expressed relative to base farm scenario for Case Study Farm B. NB, base farm model (87 ha) = 100%, at top of chart. 8

9 Conversion to organics deserves serious consideration as it might achieve the win-win situation of both increasing profit and significantly reducing N leaching. Further research on the costs and level of production for organic farming is required to confirm this outcome. Longhurst, R D., Smeaton D C., (2008), Improving Nutrient Efficiency Through Intergrated Catchment Management in the Little Waipa and Waipapa, Environment Waikato Technical Report. Truffles Ngati Whakaue Tribal Lands Incorporated was formed in 1960 with the amalgamation of some 34 individual parcels of land owned by approximately 4,500 maori owners. These blocks of land were amalgamated into three large farms. Wharenui Station has a land area of ha, (Ngati Whakaue website) and it is on this farm that a number of initiatives are taking place to promote sustainable land management. The most recent development is the move away from dairy farming and setting aside 10 hectares of land for growing truffles evergreen oak trees inoculated with the truffle fungus were planted in September 2007 with a local team of forestry people, with an automated computer controlled irrigation system added in December. (Rick Vallance, Personal coms). According to Southern Cross Truffles Nursery Ltd. production of truffles can be projected from an initial 2-4 kg/ha to 40-60kg/Ha over a subsequent 5 year period. Thus, after say 10 years, ongoing production should be at least 40kg/Ha/year. In New Zealand there have been instances of yields in excess of 90kg/ha, and one plantation in the Bay of Plenty is apparently achieving yields in excess of 200kg/Ha. Assuming that correct inoculation and then appropriate on-going husbandry has taken place and that each tree is producing, some estimates can be made regarding yield. Basing on the Tasmanian situation, about 70% of the truffles produced are graded as premium quality, which currently sell for A$3000/kg. The rest sell at a discount of about 35% and are usually converted into other value added products. Thus, currently, possible returns/ha can be around $161,100/Ha/year (Southern Cross Truffle Nurseries Limited, Brochure) By using the land in this way rather than pastoral farming the potential reduction in nutrient loss to the lake is hugely significant. Ngati Whakaue Tribal Lands Website: 9

10 Southern Cross Truffles Nursery Ltd, Brochure: Short Rotation Coppice Willow for Biofuels Short Rotation Coppice (SRC) willow provides landowners with a new land use opportunity. There are many potential market routes for willow to contribute to farm returns, either directly as market products or indirectly as co-products. It is envisaged that the primary uses of willow in New Zealand will be: Ethanol for fuel Lignin for the production of biopolymers Xylose for food sweetening With secondary uses: Fuel in cogeneration plants (heat and electricity generation) Stock fodder The most value will be obtained from the production of Lignin rather than the production of Ethanol at the moment however a rise in oil prices will create a higher value for ethanol in the future. Willow plantations could also provide increased biodiversity, shelter, nitrate management, waste water treatment (in the form of a place to dispose of effluent) and carbon sequestration. The development of a vibrant willow biomass enterprise has the potential to play an important role in bolstering a regions rural sector, increasing energy independence, strengthening the protection of the environment, and mitigating polluting problems such as the nitrogen impact of current land use practices and thereby protecting Lake Taupo. (Snowdon et al, 2008) Seven hectares of trials were established on three sites on land around Lake Taupo and Rotorua during Evaluation over three years has allowed a handbook to be produced. Trials will also be available for demonstration of the concept to land owners. Snowdon, K. McIvor, I. Nicolas, N. (2008), Energy Farming with Willow in New Zealand. Handbook. Energy Farming to Protect Lake Taupo, Sustainable Farming Fund Project Summary # 05/058, SFF website: 10

11 Grow Otago An example of what could be done in Rotorua to determine what alternative crops would be successful can be seen in the growotago project. The growotago project comprehensively maps the Otago region's climate and soils. It provides information that can be used to improve existing land uses, develop new high value land-based activities and foster regional economic development, through optimising the use of Otago's varied climate and soils. (Otago Regional Council Website) The growotago project was undertaken by the Otago Regional Council to comprehensively map climate and soils across the Otago region. It provides information for improving existing land uses, developing new high value, land-based activities and fostering regional economic development, through the optimum use of Otago s varied climate and soils. growotago utilised scientific skills from several New Zealand research organizations. Existing climate and soil data, satellite observations, temporary climate station measurements and additional soil measurements were merged through innovative approaches using the latest computer mapping techniques. (GrowOtago Companion booklet) Otago Regional Council, Otago Regional Council, GrowOtago Companion Booklet, Taupo Land Use Study A study carried out by the Lake Taupo Development Company in 2003 researched all the potential land use options for farmers in the Taupo area. As the Rotorua area is not dissimilar to Taupo some of the options suggested in the report my also be viable in Rotorua. Below is a summary of the land uses investigated for the report. Forage grown for sale off farm: Lucerne, Maize and cereal silage. The main effect of this option is to replace livestock therefore removing urine patches which are the main source of leached nitrogen. 11

12 Horticulture Significant scale: Blueberries and Lucerne Alternative Uses Beekeeping. The Central North Island is one of the stronger regions for honey production in the North Island. In recent years the health properties of manuka honey have been discovered, yielding added value to the industry. Boutique Crops Ginseng Wasabi Saffron Lavender Chestnuts Floriculture Essential oils Olives New Horizons Geothermal Opportunities. Geothermal heat opens up horticultural opportunities during winter and during seasons where climate would otherwise limit production. Control of the climate allows consistent production. Aquaculture. Freshwater aquaculture not only provides resources for human consumption and recreation but also provides the opportunity to add value by integrating these types of systems with effluent and waste treatment. Nutraceuticals / Pharmaceuticals. New Zealand is experiencing a real growth in this area, as we discover the potential of our indigenous plants to bring health benefits to the world. One viable option for the Taupo / Rotorua area is Taxus or Yew which contains a chemical which has been proven to treat solid tumour cancers such as breast and uterine cancers. Snowdon, K., (2003), Taupo Land Use Study, Lake Taupo Development Company. 12