- Field Testing of Best Management Practice guidelines for sustainable management of irrigation water.
- Implications of groundwater nitrate standards for agricultural management.
- Silvicultural research in selected forest types.
- Review of trends in agricultural pesticide use in New Zealand.
7. Facilitating resource management
7.1 FRM 406
Programme Title: |
An examination of factors affecting farmers’ use of management practices to achieve sustainable agriculture: a case study approach. |
| Programme Leader: | Dr Gavin Sheath |
| Institution: | AgResearch |
Summary
This programme aimed to identify a low cost and accurate method for Policy Agencies to examine complex issues that involved misaligned organisations. An approach involving taking a professional practice viewpoint and methods from Rapid Appraisal of Agricultural Knowledge Systems (RAAKS) was applied to a case study of farm dairy effluent disposal. The results of the case study showed that the approach was very useful and should be applied and tested in a wider variety of situations.
Objective Title: Defining the people and their relationships involved in the management of effluent on dairy farms.
Research Leader: M S Paine
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Background
The goal of this project was to examine factors affecting farmers’ use of management practices to achieve sustainable agriculture: a case study on farm dairy effluent disposal. This involved developing and testing a method (based upon professional practice theory) that would allow agencies to undertake such an examination in a way that would be low cost and accurate.
Approach & Outcomes
A number of agencies were involved (AgResearch, Massey University, Landcare Research) in developing the approach that was taken. Two workshops and a survey were held to collect data about farm dairy effluent disposal and the way in which the various practices interacted.
The researchers modified and applied steps in the Rapid Appraisal of Agricultural Knowledge Systems (RAAKS) process for systems analysis and participatory learning using both quantitative and qualitative data. In addition, the researchers held their own meetings to analyse and interpret the results and to further develop their inquiry process.
- Misalignment of the interplay between practices was identified both in the initial workshops and the survey. These misalignments were limiting the adoption by farmers of the effluent disposal policies most preferred by policy makers. Examples of these misalignments were:
- all practitioners inside organisations saying that they tend to work in isolation from other practices
- farmers saying that policy makers are not justifying their rules, or providing workable alternatives
- farmers saying that advisors were not providing sufficient information about the site specific issues involved in deciding upon the best effluent disposal policy for their properties.
- In the final workshops, the participants set priorities for actions that would have benefits for all the practices involved in effluent disposal issues. These priorities involved:
- providing realistic water quality standards for farmers to achieve; the choices available for achieving them; and the penalties for not reaching them
- direct problem-solving research with farmers
- better communication and working relationships within and between practices
- more work on policies and information to reduce the risks of making changes
- use of farmer examples and mentors in education
- specialist advisers to package technical information.
- Reflections on the development of a cost effective inquiry method highlighted that:
- the practice approach enabled participants to focus on the issues quickly
- the workshop processes required experienced facilitators in both the “practice” approach as well as workshop methodologies
- a mixture of workshop methods produced multiple perspectives on the problem increasing the speed at which likely solutions were uncovered.
Publications
Paine, M.S., Parminter, T.G., Sheath, G.W., Morriss, S.D., 1998. An Evaluation of Methodologies for Analysing Change in Farming Practice. AgResearch Report
Parminter, T.G., Paine, M.S., Morriss, S.D., Sheath, G.W. and Wilkinson, R.L. 1999. A Workshop Report on Implementation of Sustainable Farming Methods in the New Zealand Dairy Industry. AgResearch Report
Parminter, T.G., Paine, M.S., Morriss, S.D., Sheath, G.W. and Wilkinson, R.L. 1999. The Second Workshop Report on Implementation of Sustainable Farming Methods in the New Zealand Dairy Industry. AgResearch Report
Parminter, T.G., Paine, M.S., Morriss, S.D., Sheath, G.W. and Wilkinson, R.L., 1999. Final Report on Implementation of Sustainable Farming Methods in the New Zealand Dairy Industry. AgResearch Report
7.2 FRM 409
Summary
This programme aimed to test Irrigation Best Management Guidelines developed in the 1996/97 year to find out if they were workable, sensible and could be used to improve the sustainability of irrigation on farms. The project is the last of a series of MAF Policy funded projects that aimed to develop procedures to achieve sustainable irrigated agriculture in New Zealand.
The work programme included a review of problems experienced in the previous years testing, installation of the remaining monitoring and data collection/analysis of equipment on three farms, monitoring farmers progress, resolving difficulties, providing on-going liaison and refinement of the system, and calculation of end of season indicators.
The project has clearly shown that the concept of measuring water use and soil moisture, and calculating indicators to make short-term and long-term irrigation decisions is workable and sensible. It enables irrigation performance, both in terms of profit and in terms of minimising environmental effects, to be improved. It also provides supporting information to substantiate that performance.
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Background
The goal of the project was to provide field-tested Best Management Practice guidelines for sustainable irrigation. Indicators of sustainable irrigated agriculture and Best Management Guidelines were developed in 1996/97. Field-testing began on two dairy farms in 1997/98 with the goal of determining whether the Guidelines were workable, sensible and could be adopted by farmers nationally. However, the testing was significantly restricted by unusual and extreme climatic conditions, difficulties with flow measurement and long delays in equipment supply. The goal of the 1998/99 project was to continue testing the Guidelines for a full season on three farms; the border-strip irrigated dairy farm and the spray irrigated dairy farm from the previous season, a spray irrigated cropping farm. The aim was to resolve the difficulties experienced in the previous year, hopefully under more normal climatic conditions.
Approach & Outcomes
The approach was to help farmers plan their irrigation for the season, provide the resources to monitor water use and soil moisture, and have the farmers use the information to operate their irrigation systems themselves according to best practice principles, as described in the Guidelines.
The work programme included a review of problems experienced in the previous year, installation of the remaining monitoring and data collection/analysis equipment on the farms, monitoring farmers progress, resolving difficulties, providing on-going liaison and refinement of the system, and calculation of end of season indicators.
To use the Guidelines to best effect required measurement of soil moisture, water use, and recording and analysing the information to make irrigation decisions. Technology to carry out these functions was provided to the farmers involved in the project.
All three farmers adopted the process of using soil moisture data and water use information to help manage their irrigation systems to good effect. All farmers obtained sufficient data to allow them to make good irrigation management decisions.
Key seasonal indicators such as percentage of water stored in the crop root zone, and volume of water used per unit of production were calculated. Some outstanding results were achieved. For example, the water-production indicator for the spray irrigated dairy farm improved by 36% from 7.8 m3 /kgMS in 1997/98 to 5.0 m3 /kgMS in 1998/99. The borderstrip farm production indicator improved by 8% from 25.8 m 3/kgMS to 23.8 m3 /kg MS.
All farmers see the value in the process, and wish to continue in the following season. They now have benchmark indicators that they can use to compare with future seasons.
To make the best use of the Guidelines, continuous soil moisture measurement is desirable. Sensor technology for providing this is now widely available, and was used to good effect in this project. However, the transfer of data from the sensors to farm computers needs to be made easier if it is to be widely adopted. Technology in this area is developing rapidly, and suitable equipment will almost certainly become available in the near future.
If wider use of the concept is to be adopted, flow measurement, for both spray irrigation and flood irrigation systems, needs to be improved. Again, continuous measurement is ideal, and various levels of technology are available. A prototype flow meter used on the spray irrigation systems, although conceptually sound, was not as reliable as expected. The meter requires refinement and commercialisation to provide a workable unit at reasonable cost to farmers.
The irrigation water budget spreadsheets, that were developed as part of the project and provided to the two dairy farmers, were very successfully used to record and track progress. However, a suitable spreadsheet that could be used by the cropping farmer was not available because optimal irrigation management on a cropping farm is much more complex, and insufficient time and resources were available to buy or develop one. This needs to be addressed if the Guidelines are to be adopted on multi-crop farms.
Publications
McIndoe, I. (1999): Testing of irrigation best management guidelines 1998-1999. Lincoln Environmental report number 4312/1 to MAF Policy.
7.3 FRM 419
Programme Title: |
Implications of groundwater nitrate standards for agricultural management. |
| Programme Leader: | Jacalyn Scott |
| Institution: | Eco-link Limited |
Summary
This programme aimed to assess the farm management, production and economic implications of drinking water standards for nitrate concentrations being applied to groundwater management in New Zealand.
Currently available information on the relationship between agriculture and groundwater nitrate levels in New Zealand was interpreted for three representative farm types (dairying, arable and market gardening), located on three aquifers. Improved nitrogen management strategies were suggested for each of the three farm types and the management, production and economic implications of introducing these were estimated for a typical farm.
Leaching losses for ‘typical’ farms were found to be between 39-45 kg N/ha/yr for dairy farms, 54 kg N/ha for arable farms and for vegetable enterprises 300 kg N/ha for early winter potato crops and 235 kg N/ha for onion crops. Where 100% of the landuse over an aquifer is devoted to either arable or vegetable production, it was found that nitrogen groundwater concentrations would be above the acceptable international guideline level of 11.5 g N/ m3. Nitrogen groundwater concentrations were found to be 23-34 g N/ m3 for arable farms and 24 g N/ m3 for vegetable farms. For dairy farms the concentrations at 6 g N/ m3 were within acceptable levels. A range of revised management practices aimed at reducing nitrate leaching, were proposed. The cost of the suggested revised nitrate management strategies for cropping farms and market gardens, ranged from between $161-$1337/ha. For dairy farms the cost was $4.37 per cow.
Further research would be required to confirm all the estimates made for both the ‘typical’ and revised farm management practices for each of the three representative farm types, and to support the extension of these estimates to other aquifers.
Objective 1: Nitrate leaching from three farm types
Research Leader: Dr Glyn Francis
Objective 2: Nitrate leaching impacts on groundwater
Research Leader: Vince Bidwell
Objective 3: The management, production and economic implications.
Research Leader: Peter Jarvis
Objective 4: Development and submission of final report
Research Leader: Jacalyn Scott
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Background
In late 1997 Eco-Link completed a project for MAF Policy, a scoping report on initial projects for a ‘National Nitrates in Groundwater Programme’. This report highlighted a number of urgent projects, one of which was the need for more information on the relevance and implications of widespread policy adoption of groundwater standards, at or below those of the European Union and Ministry of Health’s drinking water standards. Before any such policies are considered an indication of the likely management, production and economic implications for New Zealand’s agricultural industry would be needed. The goal of this project was to assess the farm management, production and economic implications of drinking water standards for nitrate concentrations being applied to groundwater management in New Zealand.
Approach & Outcomes
This project collated the limited information that is currently available on the relationship between agriculture and groundwater nitrate levels in New Zealand. This information was interpreted for dairying, arable and market gardening farms, located on three aquifers around New Zealand. Improved nitrogen management strategies have been suggested for each of the three farm types and the management, production and economic implications of introducing these estimated for a typical farm.
Arable
- For average amounts of winter drainage under ‘typical’ farm management practices the average winter nitrate leaching loss for the 'typical' arable farm was 54 kg N/ha
- For average amounts of winter drainage under revised farm management practices the average winter nitrate leaching loss for the farm is 25-30 kg N/ha
- The cost of revised nitrogen management was estimated as $295 per ha or $63,250 per farm. Assuming all 140 cropping farms on similar soils (29,000 ha of cropping) incurred costs similar to those calculated for the model farms, the cost over the aquifer would be around $8 million.
Vegetable
- The estimated leaching losses from early winter potatoes and onions were very high (300 kg N/ha and 235 kg N/ha, respectively).
- Applying less N fertiliser reduced the leaching loss by 60 kg N/ha for the potatoes and 45 kg N/ha for onions.
- Reducing N fertiliser application to the potato crop by 135 kg N/ha reduced the crop yield by 8 t/ha. Similarly reducing N fertiliser by 70 kg N/ha reduced the onion yield by 7 t/ha.
- Growing cover crops between the vegetable crops, instead of leaving the soil fallow, reduced nitrate leaching from the potato crop by 40 kg N/ha and 100 kg N/ha from the onion crop.
Dairy
- For average amounts of winter drainage under ‘typical’ farm management
practices:
- average annual nitrate leaching is estimated to be 45 kg N/ha/yr for well-drained soils
- average annual nitrate leaching is estimated to be 39 kg N/ha/yr for poorly-drained soils
- The elimination of early-winter nitrate fertiliser application was considered to have the greatest potential to reduce nitrate leaching and was adopted as the revised management practice, this reduced leaching losses by about 10kg N/ha/yr.
Economics
If 100% of the landuse over an aquifer is devoted to either arable or vegetable production, it was found that nitrogen groundwater concentrations would be above the acceptable international guideline level of 11.5 g N/m3. However, for dairy farms the concentrations are within acceptable levels.
Publications
Cameron, Keith et al Implications of Groundwater Nitrate Standards for Agricultural Management’ (May 1999) Project Report to MAF
7.4 FRM 421
Programme Title: |
Silvicultural research in selected forest types. |
| Programme Leader: | Rob Allen |
| Institution: | Landcare Research Ltd |
Summary
This programme aimed to provide technical information on sustainable management plans. In doing so it adds to the information about methods and criteria for sustainable forest management requirements under the Forests Act (1949). An ecological site classification is a desirable basis for indigenous forestry sustainable management plans and monitoring. To provide a technical basis for this, Landcare Research reviewed current approaches to site classification and developed an ecological site classification for a Taranaki podocarp-tawa forest. The site classification takes the form of a key, and defines the site in terms of multiple management objectives.
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Background
Landcare Research developed an approach to ecological site classification that allows management to retain as full a range of forest values as possible. The goal of this project was to provide technical information to government and stakeholders by demonstrating how the successful implementation of approved sustainable management plans can be achieved to assist MAF’s policy advice and standards setting for indigenous forest management.
Approach & Outcomes
A review was made of the environmental factors relevant to forest management for six objectives, covering a range of forest values. This formed the framework for developing an ecological site classification. As well, a review was made of approaches currently being used, with existing permanent plot data, to model individual tree growth.
A 770-ha Taranaki property, containing 528 ha of podocarp-tawa forest was selected. Thirty-four plots randomly located throughout the forested area showed that soil pH, tree diameter, altitude, and landform index commonly related to regeneration, growth, stand structure, and composition objectives. The forested area was mapped and physical features determined from a GIS system based on orthophotography and a digital terrain model.
The Taranaki property proved a useful study site to demonstrate an approach to ecological site classification. The property is topographically dissected, with a range of relief and soils, and these, along with varying stand histories, provided the opportunity to test for a complexity of relationships with the range of forest values being managed for, and for specified objectives. The site classification takes the form of a key – and works in a similar way to taxonomic keys. In an operational sense, the forest manager would arrive at a point on the property and, based on this key, define the site in terms of management objectives.
Publications
Svavarsdottir, K.; Allen, R.B.; Burrows, L.E.; Coomes, D.A.; Wiser, S.K.; Smale, M. and Benecke, U. 1999. Silvicultural research in selected forest types: a podocarp-tawa forest in Taranaki. Landcare Research contract report LC9899/119 for the Ministry of Agriculture and Forestry. 55 pp.
7.5 FRM 422
Programme Title: |
East Coast validation of the canopy closure model. |
| Programme Leader: | Leith Knowles |
| Institution: | Forest Research |
Summary
This programme aimed to validate an existing canopy closure model for radiata pine derived from the Bay of Plenty, where canopy images were digitised and assessed from 30 plots in four forests on the East Coast of the North Island.
The resulting model provided relatively unbiased estimates of canopy closure in the East Coast plots. However, the variance of the residuals was larger than the variance of the residuals from the original data set of 79 plots. The model was re-estimated to include the new data, resulting in only minor changes to the coefficients in the model. The residuals were relatively unbiased for both the Bay of Plenty and the East Coast data sets; therefore it was concluded that a separate model for the East Coast was not necessary.
The fit of the new model is quite good (approximation of an r2 = 0.90), although slightly poorer than the old model (approximation of an r2 = 0.92). As a result of an analysis of the confidence intervals around the estimates of canopy closure for each plot, amendments to the existing sampling methodology were recommended. These guidelines include a greater number of canopy images to be captured for stands of less than 75% canopy Closure, and the use of a variable distance between images, depending on the mean height of the stand.
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Background
Canopy closure can be used to describe rainfall interception losses from a forest and is therefore useful as a surrogate for water use, and an indicator of the contribution of trees to soil stability. Canopy closure is also directly related to understorey pasture production, and can therefore be used to predict changes in livestock carrying capacity of pastoral farmland planted into forestry. The goal of this project was to validate an existing canopy closure model for radiata pine derived from the Bay of Plenty, using canopy images from 30 plots in four forests on the East Coast of the North Island.
Approach & Outcomes
A total of 30 permanent sample plots (PSP) were selected to cover a wide range of stand characteristics, and growth parameters for all plots were obtained from the PSP database. The methodology for determining the degree of canopy closure was based on previous research undertaken by Forest Research and the Forest & Farm Plantation Management Cooperative. Individual images were taken in a circular format, converted from colour to a greyscale and assessed by electronically counting the number of canopy and sky pixels, thus giving a measure of percentage canopy closure.
The original radiata pine canopy closure model provided relatively unbiased estimates of canopy closure in 30 plots, from four forests on the East Coast of the North Island. However, the variance of the residuals was larger than the variance of the residuals from the original data set of 79 plots. The model was re-estimated to include the new data, resulting in only minor changes to the coefficients in the model. The fit of the new model is quite good (approximation of an r2 = 0.90), although slightly poorer than the old model (approximation of an r2 = 0.92).
As a result of an analysis of the confidence intervals around the estimates of canopy closure for each plot, amendments to the existing sampling methodology are recommended. These guidelines include a greater number of canopy images to be captured for stands of less than 75% canopy closure, and the use of a variable distance between images, depending on the mean height of the stand.
Publications
Forest and Farm Plantation Management Cooperative Report No. 62 NZJForSc. (pending further data from Otago/Southland)
7.6 FRM 423
Programme Title: |
Review of trends in agricultural pesticide use in New Zealand. |
| Programme Leader: | Patrick Holland |
| Institution: | Hort+Research Ltd |
Summary
This programme aimed to develop robust information on pesticide usage at the regional level to support national and regional decision-making. The research contracted a systematic study of pesticide use patterns; its comparison with previous reviews and usage data; changes in patterns of use and the products used within various primary production sectors; and consideration as to how the information could be reliably collected and used in the future.
Changes in the use of the major pesticide classes (as categorised by FAO) were tracked over the last 10 years. Detailed end use data was gathered for different sectors, for 4 or 5 specific and important regions of New Zealand, from sales information and from intensive discussions and co-ordination with the organisations involved.
The overall conclusions were that total pesticide use (excluding mineral oil) grew between 1984 and 1994 reaching a peak of about 3700 tonnes of active ingredient per annum. This has since declined to the 1998 total of 3300 tonnes. Herbicides continue to dominate pesticide use (68%) followed by fungicides (24%) and insecticides (8%). About two thirds of total use is concentrated in four classes of pesticides (phenoxy hormones, phosphonyls, inorganic fungicides, dithiocarbamates) which have excellent records of very low human and environmental risks when used as directed.
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Background
Pesticide use statistics are important for policy making in many areas, and are also useful in establishing trends. Changes in the patterns of pesticide use are important indicators of changes in land use shifts, in pest status, and in the cost-effectiveness and registration status of particular pesticides. The goal of this project was to develop robust information on pesticide usage at the regional level to support national and regional decision-making.
Approach & Outcomes
Current usage of pesticides in New Zealand has been established on a tonnage basis with division of pesticides into categories and classes according to FAO. Further sub-classes have been generated for some pesticides of current or growing importance in New Zealand. A comparison was undertaken between the current usage and data gathered in previous surveys. The overall conclusions were that total pesticide use (excluding mineral oil) grew between 1984 and 1994 reaching a peak of about 3700 tonnes of active ingredient per annum and has declined to the 1998 total of 3300 tonnes. Herbicides continue to dominate pesticide use (68%) followed by fungicides (24%) and insecticides (8%). About two thirds of total use is concentrated in four classes of pesticides (phenoxy hormones, phosphonyls, inorganic fungicides, dithiocarbamates) which have excellent records of very low human and environmental risks when used as directed.
Changes in use of the major pesticide classes were tracked over the past decade. There were significant declines in ‘other’ hormone herbicides, organophosphorus insecticides and dicarboximide fungicides, while phosphonyl herbicides (mainly glyphosate), triazine herbicides, sulfonylurea herbicides and pyrethroid insecticides all increased. These changes reflect trends in land use (more forestry), cost-effectiveness (more glyphosate and sulfonylureas) and adoption of IPM (more biologicals, less organophosphates, less dicarboximides).
Detailed end-user data were also gathered at the sector level. This unique data set serves as a baseline to measure future trends and has provided insights on specific plant protection issues and strategies within each sector. Pesticide use in pastoral agriculture is static or declining and focuses almost solely on herbicides for broadleaf and brush weed control. Cereals and other arable crops also mainly use herbicides, with resistant cultivars and IPM techniques contributing to reduced insecticide and fungicide inputs. Overall, orchard crops still have relatively high uses of pesticides despite increased adoption of IFP strategies. However the Kiwigreen (IFP) and organic production systems used by all the kiwifruit industry are notable successes for more biologically oriented insect and disease control.
Pesticide use in process vegetables such as asparagus, green peas and sweetcorn is relatively low and is mainly concentrated on early season weed control. In contrast, fresh vegetables such as lettuce, brassicas and potatoes tend to have intensive spray programmes throughout the growing season. Onions receive very frequent pesticide applications, and there are concerns over the sustainability of current plant protection strategies in this crop. Pesticide use in plantation forestry is concentrated on weed control during the first 1-2 years establishment phase of the crop rotation. Consequently the overall impacts of pesticide use in the timber production cycle are minimal.
Overall, control of weeds is often the main priority with herbicides continuing to be the most cost-effective technology. IPM techniques are making significant contributions to reductions in use of insecticides in most areas of agriculture. However fungal diseases continue to provide many challenges for more sustainable plant protection in horticultural and cropping sectors. Although no detailed risk analysis was undertaken, some key drivers for change in the area of pesticide use have been highlighted for enhancing the sustainability of agricultural production systems.
Publications
Holland, P.T. and Rahman, A. 1999. Review of trends in agricultural pesticide use in New Zealand. Report to MAF Policy, Wellington, New Zealand, Project FRM423, 54 pp.
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