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Water and fertiliser use efficiency
Improving water and fertiliser use efficiency
Swan Coastal Plain
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BY VO THE TRUYEN REGIONAL DEVELOPMENT OFFICER, VEGETABLESWA
3 UNIFORMITY assessment on water distribution in a vegetables field in North Perth in 2019 by DPIRD. T he main vegetable production region in Western Australia is the South West, including the Swan Coastal Plain from Gingin (100km north of Perth) to Myalup (100km south of Perth). Within this area, about 67 per cent of the total value 1 of the State’s vegetables are produced.
There are opportunities for vegetables growers to improve their profitability.
TABLE 1. PRACTICE GAPS IN FERTILISER APPLICATION BY TOMATO GROWERS IN NORTH PERTH AS COMPARED TO
Problem Nitrogen Phosphorous Potassium Approximate Yield The three main soil types of the Swan Growers (kg/ha/crop) (kg/ha/crop) (kg/ha/crop) cost ($/ha) (kg/plant) Coastal Plain include Spearwood sand, 1 1429 42 347 14,149 6 Karrakatta sand and Bassendean sand, which are some of the most 2 1111 234 1186 16,998 7 infertile soils in the world 2 . Adding to 3 800 544 541 9,589 - the hardships of the region, is a state 4 777 253 1000 9,443 10 government proposal of a 10 per cent reduction to groundwater allocations 5 753 78 997 8,680 6 for growers in the North Wanneroo 6 717 71 741 6,654 5 area from 2028 3 , which makes growing 7 1992 235 1552 22,275 7 conditions in this region significantly more difficult. 8 DPIRD 686 625 231 125 616 950 6,693 6,397 8 8 In addition, vegetable growers in the recommendation area showed a lack of knowledge in soil types, water and fertiliser management. TABLE 2. PRACTICE GAPS IN WATER APPLICATION AND VALUES OF FREE NITROGEN IN IRRIGATION WATER. A survey on water and fertiliser use in this growing region 4 showed high Value of free variation in water and fertiliser use Free Nitrogen Nitrogen efficiency. The water application was Nitrogen in supply to crop supply to crop from 7.8ML/ha/crop to 26.9ML/ha/ irrigation from water from water crop producing almost the same yield. Growers water (mg/l) ML/ha/crop (kg/ha/crop) ($/ha/crop) Similarly, the fertiliser cost was from $6,700/ha/crop to $22,300/ha/crop. 1 2 15.0 29.0 13.6 25.2 204 730 163.2 584.0 Opportunities 3 6.1 18.9 115 92.0 There are opportunities for vegetables 4 21.0 8.3 174 139.2 growers to improve their profitability while continuing to produce under such 5 8.1 7.8 63 50.4 a hostile growing condition. 6 4.5 11.9 54 43.2 In terms of governmental support, the 7 32.0 9.4 297 237.6 Department of Water and Environmental 8 0.1 29.6 0 0 Regulation (DWER) are working with the Department of Primary Industries and DPIRD recommendation 10.5–15 Regional Development (DPIRD) to assist RECOMMENDATION. North Wanneroo growers by piloting independent water use assessments and developing best practice irrigation demonstration sites 5 . An independent irrigation system efficiency assessment This event will be organised by DPIRD in collaboration with DWER, vegetablesWA and several private companies such as Irrigation Australia. 37% of growers have Analysing the practice gap A survey on water and fertiliser use in 2016 6 showed that compared to the $6,500 fertiliser cost per hectare for a tomato crop, suggested by DPIRD, 75 per cent of the participating growers had the ability to save from between was completed earlier this year. A workshop to present the results, in combination with best practice demonstrations and modern irrigation technology, is scheduled for October at a commercial growing property. In conjunction, the state’s peak vegetables industry body — vegetablesWA — is implementing a project to assist vegetable growers to bring down their production costs by making the most of their limited water resources the opportunity to save from 3–10ML/ha/crop $1,000 to $15,000/ha while achieving the same level of yield, if good practice was implemented (Table 1). Similarly, 37 per cent of the surveyed growers had the ability to save 3ML/ha/crop to 10ML/ha/crop. Also, earlier research showed a significant amount of nutritional content in the 2 www.agric.wa.gov.au/soil-productivity/ and increase the competency of their irrigation water, which could result in 3 vegetable-crop-nutrition-sandy-soils-swancoastal-plain?page=0%2C1 www.mediastatements.wa.gov.au/Pages/ McGowan/2019/01/Delivering-certainty-forfertiliser applications. This elementary project is a part of a larger VegNET project funded by a financial benefit to growers when included in irrigation and fertigation programs 7 (Table 2). 4 Wanneroo-growers.aspx Report on water and fertiliser use by vegetable grower in North Perth. Neil Lantzke and Truyen Vo, 2016, funded by Natural Resources Hort Innovation Australia (HIA), using national vegetables levies to support WA vegetable growers. 6 Report on water and fertiliser use by vegetable grower in North Perth. Neil Lantzke and Truyen Vo, 2016, funded by Natural Resources management. management. 7 Report on water and fertiliser use by vegetable 5 www.mediastatements.wa.gov.au/Pages/ grower in North Perth. Neil Lantzke and
McGowan/2019/01/Delivering-certainty-forTruyen Vo, 2016, funded by Natural Resources
Wanneroo-growers.aspx management.
vegetablesWA project on improving water and fertiliser use efficiency There is a great source of available knowledge that can be introduced to vegetable growers to induce practice changes in terms of improving water and fertiliser use efficiency. This knowledge could enhance grower understanding of soil characteristics, the regional soil map, how water filters through the soil profile, nutritional demands of different crop types and growth stages and irrigation techniques. While high initial investment costs of irrigation systems hardware or technology may place barriers on adoption of irrigation innovations, the assessment of irrigation system efficiency carried out by DPIRD, in collaboration with vegetablesWA and a private consultant in 2019, showed all participating farm properties achieved acceptable to good levels of efficiency. It’s believed that the improvement of irrigation and fertiliser application practices and technology could bring significantly positive outcomes, including higher yield and elevated profitability, to growers. In line with the enhanced focus on productivity improvement, environmental sustainability and business profitability, the central objective of the project is ‘more profitable and productive use of water and fertiliser’. The key indicator of success is a 10 per cent reduction in net fertiliser costs and a 10–25 per cent reduction in irrigation volumes for participating growers.
Benefits of bridging the practice gap The three-year benchmarking report, produced by vegetablesWA in partnership with PlanFarm, shows average fertiliser, irrigation and power costs are $3,999, $218 and $1,530 respectively; with a large portion being used for irrigation pumping. A 10 per cent reduction of fertiliser and irrigation costs would result in a benefit of $570/ha/crop. This is a significant improvement to grower profits, since the average profit before tax for the WA vegetables industry is $6,200/ha/year.
3 IRRIGATION system efficiency assessment in Carabooda in 2019 by Truyen Vo.
Project strategy
The project is designed to help grower participants go through a 5-stage process that includes: 1. Knowledge (expose growers to water and fertiliser use efficiency concepts and assist them in understanding the benefits). 2. Persuasion (the forming of a favourable attitude to it). 3. Decision (commitment to its adoption). 4. Implementation (putting it to use). 5. Confirmation (reinforcement based on positive outcomes from it).
Enhancing grower decision making in relation to water and fertiliser application practices
Over a series of workshops the project will introduce growers to knowledge and information relative to soil types, water demand pattern of crops and soil water movement by using tools as local soil maps, soil dye test images, content of ‘free fertiliser’ in bore water analysis and crop nutrition demands etc. A core group of four to six growers will then be encouraged to try changes in water and fertiliser application using this recently introduced knowledge.
Improved irrigation scheduling and management
Trials will be conducted with a 10 per cent reduction in fertiliser and water applications, based on soil type, crop type and growth stage in anticipation of providing benefit cost analysis case studies for growers. Information sessions on the aspects of improving scheduling and management of irrigation, including the benefits from the trials, will be discussed with growers in regard to the advantages and disadvantages, with the aim of gaining ‘lessons learned’ in support of wider adoption of on farm best practice.
Benchmarking the benefit of practice change
Grower participants will be assisted in fine tuning any changed practices to see the relative advantages (the degree to which it is perceived to be better than what it supersedes); compatibility (consistency with existing values, past experiences and needs) and; observability (the visibility of results) that have resulted. Work that will support Growers in this stage will include: • Developing hand-out materials to visually illustrate the established knowledge, such as posters of root zones growing over time and the dynamics of water movement in soil over time in drip irrigation etc. • Continue assessing data on yield and/or return improvements and working with growers to highlight the
‘relative advantage’ by comparing old and new data. • Disseminating results from demonstrations and organising field days to encourage growers to learn from results of research. • Workshops to inform growers about the achievements.
Evaluation and success
This strategy is designed to capture the learnings and impacts of intensive practice-change in relation to new and improved irrigation/fertigation systems choices and improved scheduling of irrigation/fertigation management to optimise water and fertiliser use and general business profitability.
MORE INFORMATION
For more information or to offer your assistance with this project, please contact vegetablesWA Regional Development Officer, Vo The Truyen on 0457 457 559 or email
