Grow North Island 04 06 16 - Autumn 2020 - Ballance | Agri-Nutrients
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Grow North Island Autumn 2020 04 SurePhos loses less phosphorus 06 Regenerative farming for NZ? 16 Post drought recovery
03 12 19 Contents Detainment for good S products: side-by-side MitAgator at work 04 13 20 Win more, lose less with Finish fast with legumes Mo gets its mojo back SurePhos 14 Valuable but variable 16 Recovering from drought 17 06 Sustainability snaphot 21 A regenerative future? 18 Rock for New Zealand 08 A vehicle for action 22 N for pre-tupping feed Clippings 09 23 Fodder beet findings Science-based submission 10 Spread more accurately Ballance Agri-Nutrients is one of Since its inception in the SealesWinslow is a recognised New Zealand’s leading fertiliser 1980s, Super Air has evolved leader in the production of manufacturers. A 100 percent into one of New Zealand’s high-performance compound farmer-owned co-operative, leading agricultural aviation feeds and feed additives. the company has over 19,000 companies. In addition to aerial A fully owned subsidiary of shareholders and sells around fertiliser application, Super Ballance, SealesWinslow has 1.7 million tonnes of product Air has developed a world- manufacturing sites located each year, representing a class reputation for aircraft in Morrinsville, Ashburton turnover close to $900 million. engineering and innovation. and Wanganui, and supplies Its products include imported Wholly owned by Ballance, custom-blended pelletised and locally manufactured Super Air services most of the feed to farmers throughout fertilisers, the majority of which North Island. New Zealand. It also provides attract a rebate for shareholders. molasses feed blocks, feed supplements and additives. ballance.co.nz superair.co.nz sealeswinslow.co.nz 0800 222 090 0800 787 372 0800 287 325 02 / ballance.co.nz
Animal Effluent Plant Soil Detainment for good Detainment bunds can help events were responsible for most In addition, by capturing and slowing farmers in their quest for runoff water, and thus sediment and down the force of storm water, bunds phosphorus losses. can help to moderate floods and protect environmental sustainability and communities, and reduce stream bank improved water quality. Multiple benefits erosion and damage to infrastructure Detainment bunds are most effective such as fences, tracks and lanes. Final results from three years of trials show detainments bunds’ success at for smaller flows from catchments less “Achieving the full potential of intercepting and treating storm water than 50 ha in size, where they have the detainment bunds depends on the before it leaves the farm. potential to provide multiple benefits willingness of farmers, as they own the beyond phosphorus and sediment land that’s suitable for them,” says John. The recently completed three year capture. The project also recorded Phosphorus Mitigation Project has a nitrogen capture and further trials The project was funded by the Ministry governance group made up entirely of will focus on validating the capture of Primary Industries Sustainable farmers, who arranged a collaboration of of E. coli and nitrogen. Recharging of Farming Fund, and eight co-funders nine industry co-funders to support this groundwater aquifers via soil infiltration including regional councils, industry and comprehensive applied science work. from the ponding areas is another co- Ballance Agri-Nutrients. benefit of detainment bunds. Rotorua deer farmer and Bay of Plenty Regional Council sustainable farming advisor John Paterson, who kickstarted and managed the project says: “With Detainment bunds, low earth embankments across valley floors where an increasing spotlight on farmers and storm water flows, temporarily detain stormwater runoff in a large ponding the impact farming has on waterways, area for up to three days, during which time its volume decreases due to this is a project developed and led by infiltration into the soil. The suspended sediment particles, and attached farmers.” phosphorus, cannot infiltrate and settle out before the water is released. Exciting results Interim results (as reported in Grow Spring 2019) showed an average load reduction of 50 to 60 per cent, but the latest results are even higher, indicating detainment bunds capture around 60 per cent of the annual phosphorus load 1. Stormwater runoff arrival and ponding and 80 per cent of the annual suspended sediment load of storm water, depending on soil drainage conditions. The project has demonstrated that well planned and built detainments bunds have a high success rate and 2. Pond full and overtopping riser their installation does not compromise pastoral productivity. Their size needs to be matched to the catchment size, so they can store at least 120 m³ of storm water per hectare of contributing catchment. Over 20 detainment bunds have been built in recent years and 3. Settling and infiltration (up to three days) the host farmers agree that storm water should only be stored for up to three days, so that pasture growth in the ponding area is not unduly compromised. Often the ponded water has largely soaked away before the three day limit is reached. This is 4. Release of residual pond important because often the prime places for creating the bunds and their large ponding areas are on some of the best pasture areas of the farm. An interesting finding of the project was that a small number of large storm 5. Return to production Grow North Island / 03
Animal Effluent Plant Soil Win more, lose less with SurePhos A game-changing new fertiliser, years in the making, is huge news for sustainable farming. A maximum of 23% of the P Farmers can now get more wins from constraining P application. So, with in SurePhos is applying phosphorus (P), while reducing the support of the Primary Growth water soluble. environmental and financial losses. Partnership, Ballance developed SurePhos.” P fertiliser is vital for farming in New 100% Zealand’s naturally P deficient soils, SurePhos significantly reduces 90% but applying it without losses can be difficult. Commonly used P fertilisers P loss 80% such as superphosphate and di- “Many years were spent formulating ammonium phosphate contain mainly SurePhos, a fertiliser designed to 70% water soluble P (see Figure 1), which provide P where and when it is needed, is readily available to plants. In ideal and minimise losses to the environment 60% circumstances, this type of P remains and profit.” 50% on land for use by plants, as intended. SurePhos is a slow release P fertiliser But in more common, less than ideal 40% that gradually releases into the soil. circumstances, an environmentally This results in more P retained in the significant proportion of this P can be 30% soil and less lost to the environment. lost as runoff (see Figure 3). Independent tests conducted by 20% “P lost as runoff can lessen profits, and AgResearch show that compared to can be the tipping point for waterways, superphosphate products, SurePhos 10% providing a small amount of just what can reduce P loss by up to 75 per cent¹, 0% aquatic weeds and algal blooms need and in a laboratory trial was shown to SurePhos Serpentine Super Superphosphate Triple superphosphate Di-ammonium phosphate to take over,” says Ballance Innovation reduce P leaching by up to 83 per cent². Leader, Dr Jamie Blennerhassett. Most of the P in SurePhos is water “Farmers try to do their best for their insoluble P, so it slowly releases over a business and the environment by period of months, while it also contains minimising P losses via runoff. But a small amount of water soluble P that this can be challenging, with weather, pasture can use immediately. It also Figure 1 Percentage of P that is timing and proximity to waterways all contains sulphur. water soluble in fertilisers ¹ McDowell RW, Smith C, Balvert S 2011. The environmental impact and agronomic effectiveness of four phosphorus fertilisers: Report for Ballance Agri-Nutrients, October 2011 ² Dexter M, Kear M, Lucci G 2019. P leaching from SurePhos, Superten and Serpentine Super fertilisers in a laboratory evaluation: Report prepared for Ballance Agri-Nutrients by AgResearch Limited 04 / ballance.co.nz
Animal Effluent Plant Soil Stable P gradually converted to water soluble P Uniquely When SurePhos is applied, Water soluble P manufactured, microbial activity and soil chemical gradually released more stable P processes gradually convert the to pasture Acid is added to phosphate di-calcium phosphate into water SurePhos continues to rock to produce water soluble soluble phosphate. Pasture can also gradually release water phosphate. Reversion then use the small amount of water soluble phosphate to pasture converts this into water soluble phosphate it contains over a period of months. insoluble di-calcium straight away. phosphate. Figure 2 How SurePhos works How SurePhos can help you average of 30 mm within 21 days). The can be mixed directly with nitrogen slow release nature of SurePhos gives fertilisers such as SustaiN and urea, What’s in it flexibility of application, with less risk of so maintenance and capital fertiliser nutrients being washed away and lost needs can be combined into a single Phosphorus 7.8% via surface runoff. application, helping to minimise the 1.6% number of applications and pasture Water soluble Better spreading and mixing damage. (≤23% total P) SurePhos granules are round and 5.5% free flowing, allowing it to be spread FOR MORE INFORMATION Citric acid soluble (≥70% total P) evenly and accurately, and minimising segregation when mixed with other SurePhos is currently only available Sulphur 9.5% at limited stores in the North Island. granulated products. For more information, availability in Calcium 22% Highly compatible your region and to place your order, Magnesium 2% SurePhos is compatible to custom contact your local Ballance Nutrient blend with most other fertilisers. It Specialist. Slow release, environmentally friendly phosphate SurePhos gradually releases phosphate into soil, resulting in more P retained in the soil and less lost to the environment. More than 70 per cent of the P in SurePhos is citric acid soluble and can Most P entering Most P waterways is be utilised by pasture within a year. lost from from runoff A maximum of 23 per cent is water farm is as containing water soluble and is able to be utilised by runoff. soluble P and pasture on application. P bound to soil particles. These features significantly reduce P loss from runoff and leaching, making it ideal for use in catchments with P limited waterways (inherently low P levels) and in other sensitive catchments. Water soluble P fertiliser applied too soon before heavy rainfall Cost-effective can contribute up to 90% of P lost from pasture. SurePhos has a high P content for a reverted phosphate fertiliser. With less The amount of P In most soils P binds to product required, cartage and spreading lost to waterways soil exchange sites and costs are lower, making SurePhos cost- does not leach. is quite low, but effective compared to other reverted P can have a big fertilisers. impact. Flexible application The risk of P loss is particularly prevalent following application in high risk conditions – less than three weeks before irrigation or heavy rainfall (an Figure 3 P losses on farm Grow North Island / 05
Animal Effluent Plant Soil A regenerative future? Is regenerative agriculture the answer to the issues facing farmers? Is regenerative agriculture a fertiliser, clover, or manures and compost silver bullet that can improve – increases plant growth and production soil health and biodiversity, and of dry matter, in turn resulting in more mitigate climate change, while soil organic matter. still maintaining on-farm profits? Where chemical fertilisers do differ to As a science-based biological fertilisers is their superior organisation, Ballance Agri- cost-effectiveness and practicality. Nutrients is interested in what Relying solely on compost and manure regenerative agriculture can for nutrients poses an array of major offer New Zealand farmers. Are logistical challenges, such as the its practices scientifically robust massive increase in stock and land use and relevant to New Zealand, that would be needed to produce the and do they differ to ‘business required amount of manure. as usual’? Goal 1: Improve soil health New Zealand pastoral farmers already Originating in the USA aim to maximise clover and its fixation and Australia, regenerative Regenerative farming aims to improve of nitrogen, and to some degree, already agriculture is still in its infancy, soil health by using compost and use compost (plant residues) and so has no clear, universal manures and reducing chemical manure (dung and urine) to improve fertiliser use. soil health. Crop residues, for example, definition. It is best broadly are recognised as having an economic understood by its goals, which This infers chemical fertilisers are bad value for the nutrients they can provide. we look at in more detail, asking for soil health, which is not backed by how they relate to our context scientific research. Chemical fertilisers Regenerative agriculture reinforces and what opportunities they are just as effective as biological fertiliser what we already know – soil health may present. at improving soil health, biological is important, so we need to continue activity and organic matter. Research investigating realistic and practical shows that nitrogen – whether from means of maintaining or improving it. 06 / ballance.co.nz
Animal Effluent Plant Soil Goal 2: Sequester carbon Goal 3: Grow topsoil Goal 4: Improve biodiversity Regenerative farming aims to mitigate Regenerative agriculture aims to grow One way regenerative agriculture climate change by sequestering carbon topsoil by minimising soil disturbance aims to improve biodiversity is by into the soil as organic matter. and keeping the soil covered using reducing nitrogen fertiliser use (by practices such as no-till or minimum 100 kg/ha), which it claims can result This approach is not currently backed tillage, cover crops and rotational in a sixteenfold increase in varieties by robust science and further research grazing. Ballance aims to create ‘the found in pasture, while still maintaining is needed to prove it can work in New best soil on earth’, and encourages productivity. Zealand. Evidence of regenerative the same practices employed by agricultural practices increasing soil The scientific research behind this regenerative agriculture. claim involved natural grassland with organic carbon (SOC) comes largely from the USA and outback Australia, Ballance leads and/or supports a range predominantly tropical grasses, very both with very different farming systems of projects that are investigating soil different to New Zealand pastures. to ours, and typically with low soil conservation practices. These include The research also did not suggest that fertility and biological activity. the Sustainable Farming Fund projects production could be maintained by Helicropping – protecting our soils (see reducing nitrogen fertiliser application, As our SOC levels are already relatively Grow Spring 2019), which is finding the but instead that doing so over a 25 high, the same effect is not as readily best tools to protect soil when cropping, year period might result in a balance seen here, despite pastoral farmers and Catch crops to reduce N leaching between biodiversity and productivity. already using some of the regenerative (see Grow Autumn 2019), a practice agriculture practices promoted for At a soil level in New Zealand, growing which also stabilizes soil. as much dry matter as possible feeds achieving this goal, such as keeping ground in long term pasture, rotational In New Zealand, rotational grazing is the worm and microbial population. grazing and cover crops. already practised, and our soils are Through their efforts to improve water relatively young, so soil organic matter quality or to sequester carbon, many Research in 1997 reported no net levels are already very high. For us, farmers have been providing habitat change in SOC, but more recent growing pasture (perennial ryegrass and improving biodiversity by planting research has reported declines in SOC. and clover) using conventional farming productive and unproductive areas, and The jury’s still out as to why SOC levels methods is the most soil regenerative restoring or creating wetlands. may be declining in New Zealand, with practice we can do. further research currently underway. In Not encroaching on existing habitat the meantime, there is an opportunity As a company and country, we should by more efficient use of agricultural for further research, with the New continue to explore and adopt practical land already in production is vital for Zealand Pastoral Greenhouse Gas soil conservation practices. maintaining land with high biodiversity Consortium saying: “Despite a wealth value. of theories and ongoing research, there Biodiversity varies across New Zealand, are not yet any robust general rules "Regenerative agriculture and is best addressed at a farm specific about how to reliably and sustainably level. A reduction in applied nitrogen reinforces what we already know – increase soil carbon in New Zealand is unlikely to result in biodiversity soil health is important, so we need pasture soils.” gains. Instead, farmers should continue to continue investigating realistic and practical means of maintaining to work with councils and industry groups to identify the most effective or improving it." and practical solutions to enhance biodiversity for their properties. Grow North Island / 07
Animal Effluent Plant Soil N for pre-tupping feed Tactical nitrogen (N) use to content and low total N levels. In most N should be applied to hill country at no provide feed before tupping can summer-dry hill country conditions, more than a moderate rate – no more a minimum response of 15 kg DM than 50 kg N/ha in a single application have a big impact on returns. per kg N applied can be expected. If – and sensitive areas such as streams Good body condition for ewes before conditions, primarily soil temperature should be avoided. Timing of N should mating in autumn is important, and and moisture, are right greater allow enough time to generate a with a little help, pasture is the most responses are highly likely, reducing the valuable response before grazing off the cost-effective way to provide the feed cost of feed grown significantly. Factors pasture. “About six weeks is ideal and a required. such as aspect and altitude can also good rule of thumb, but four weeks can influence the level of response. suffice,” says Josh. “The critical feeding period for increasing ewes to body condition score (BCS) 3-4 is typically when Choosing the right N My Pasture Planner pasture cover is likely to be limited and fertiliser for the job This decision support software after a long, dry summer, its content Factors to consider include tool uses soil total N test high in fibre and low in energy,” says other nutrients required such information to improve N use Ballance Science Extension Officer as sulphur (as provided by efficiency on pastoral farms. It Josh Verhoek. PhaSedN) or phosphorus, as can help improve feed budgeting “But this can be overcome by using well as the need to reduce and economical use of N fertiliser nitrogen tactically from late summer volatilisation, using a product as a low cost supplementary to early autumn to boost pasture. It’s such as SustaiN. feed. See ballance.co.nz/My- the cheapest way to provide good feed Pasture-Planner leading up to tupping, and can have a big impact on lambing returns.” Better body condition benefits Increasing ewes’ body condition for Table 1 Benefits of increasing body condition pre-tupping to BCS 3 mating has a number of significant benefits, including increased Increase Do nothing Gross margin conception rates, higher birth weights, condition (15% ewes ≤ difference increased chance of multiples, and (5% ewes ≤ BCS 2.5)* ($/ha) increased lamb survival. BCS 2.5) If ewes are on good leafy feed and Scanning % 160% 171% + $42 gaining weight as the rams go out there will be an additional benefit of Lamb survival 78.2% 80% + $36 possibly 5-10 per cent in lamb drop. Ideally ewes should be rotated rapidly, Weaning weight 26.5 kg 27.5 kg + $50 going on to about 5-6 cm of pasture (2200 kg DM/ha) and not grazing Gross margin $/ha $770 $898 + $128 below 3 cm (1500 kg DM/ha). * Typical percentage of ewes below ≤BCS 2.5. “All of the benefits from improving Source: Trevor Cook, 2017 body condition lead to more lambs, and if well fed, heavier weights,” says Josh. “Heavier lambs at birth are more likely to reach prime weights quicker, so there’s more chance they’ll be sold before Christmas when meat schedules are typically higher. Lambs sold before the period leading into and during mating also help reduce competition ewes face for feed.” Using N to improve body condition Hill country is very responsive to N applications, as it has less clover 08 / ballance.co.nz
Animal Effluent Plant Soil Fodder beet findings Farmers can benefit from optimise yields, but no notable increase The trial highlighted the value of soil results of local research into in yield from a third application was tests such as Ballance’s fodder beet apparent. Response to N fertiliser profile test. Taken before sowing to a fodder beet. depended on the level of available N depth of 150 mm, the test identifies A recently completed three-year in the soil, demonstrating the benefit available N, K and B, as well as Sustainable Farming Fund project, led of soil testing to avoid unnecessary N phosphorus, pH, sulphur, sodium and by Plant & Food Research and involving applications and expenditure. magnesium levels (see Table 1 for target Ballance Agri-Nutrients, has shed light levels). Testing well before the crop is on the role of fertiliser management and Fodder beet took up large amounts of sown can give you time to adjust soil crop establishment in optimising fodder K, depending on the soil K level and test levels, especially soil pH. beet yields. the amount applied. Across the trial sites K application rate and timing did If nutrient deficiencies are suspected The impacts of different rates and not affect yields, even at low K soil test once the crop has established, a timings of nitrogen (N), potassium (K) levels (as low as QTK of 3), suggesting herbage test at canopy closure will and boron (B) applications were trialled fodder beet response to added K is confirm if further nutrient addition is at sites (including dairying, arable minimal. However, as it is important to required. cropping and sheep and beef, in both consider fodder beet in the full crop/ irrigated and rain-fed conditions) across pasture rotation, soil testing is still five key fodder beet production regions. suggested. If QTK is less than 3, adding According to results, as fodder beet is a up to 100 kg K/ha is sufficient to supply Test Target level luxury feeder of N, N should be applied K for the fodder beet and subsequent prudently. While crop N uptake and crops/pasture. If QTK is 3-5, 50 kg K/ha pH 6.0-6.2 N concentration increased as result of is sufficient and for QTK greater than 5, K can be withheld as its addition will not Phosphorus (Olsen P) ≥15 increased N application rates, yield did not consistently increase. In year 1 of affect yield. Potassium (QTK) ≥3 the study, yield response to N fertiliser The essential micronutrient B did varied across sites, with responses from not affect yield in the trial, however B Sulphur (sulphate S) Not determined 100 to 200 kg/ha of added N. Three soil test levels across the sites were Magnesium (QTMg) ≥8 sites had no response to added N. not in deficiency ranges. Due to its Similar results were observed in year 2, importance for crop health, B should Sodium (QTNa) ≥4 with peak N response up to 100 kg/ha still be supplied adequately at sowing, of added N. as deficiencies can result in brown heart Boron (mg/kg) 1.1 On average adding up to 100 kg N/ha rot. Unlike other nutrient deficiencies, B deficiency cannot be remediated after Table 1 Target soil test results for optimised yield. Applying N at sowing the crop has established. growing fodder beet and again at canopy closure assists to Grow North Island / 09
Animal Effluent Plant Soil Spread more accurately Accurate spreading is vital for getting the best returns from fertiliser. “Fertiliser can be a significant In New Zealand, most fertilisers range performance once applied. investment for farmers, and if you’ve from SGN 95-475 (a higher value invested in a quality product you want indicating a larger mean particle size) Products with a similar SGN and UI (a to make sure you use it well,” says and UI 5-68 (a higher value indicating a difference of less than 20) blend and Ballance Nutrient Dynamics Specialist more uniform range of particle sizes). spread better (see Table 1). “Blends Jim Risk. will segregate, resulting in uneven Heavier, larger granules (with a higher spreading, if a low SGN product is “Fertilisers such as Superten and SGN) will throw further than lighter, mixed with a high SGN one, as smaller SustaiN supply plant nutrients in a smaller granules. Spread width also particles fall to bottom of spreader. very concentrated form, so to be most depends on spreader equipment and Segregation and uneven spreading also effective they must be spread evenly. how it is calibrated to the product being occurs when a low UI product is mixed Uneven spreading can result in striping spread. “Ideally spreaders should be with a high UI product, as the small, in crops and pasture, reduced yields calibrated for specific products, so medium and large particles separate and variation in soil fertility.” using the information on the fertiliser’s out,” says Jim. physical characteristics ensures the Spreading accuracy depends on spreader is set up correctly for different product quality, physical and chemical products,” says Jim. compatibility (if blending), and spreader calibration. The UI of the products being spread Difference Physical also impact the quality of the spread between SGN compatibility Product quality achieved. When a high proportion of the or UI values The product quality of a fertiliser granules are within a narrow particle Under 20 Compatible impacts how far it can be thrown size range (have a higher UI) the spread (known as spread width or bout width). will be more consistent than if the Moderately Product quality refers to a fertiliser’s: particle size varies largely. 20-40 compatible (some segregation likely) • mean particle size (represented by Physical compatibility the size guide number - SGN) Over 40 Incompatible If blending two fertiliser products, • range of particle sizes (represented their compatibility affects their flow by the uniformity index - UI) through a spreader, impacting the Table 1 The effect of SGN and UI on • bulk density (BD). quality of the spreading and their physical compatibility 10 / ballance.co.nz
Animal Effluent Plant Soil Chemical compatibility settings and ability to throw products to can optimise spread widths, resulting Mixing chemically incompatible specific spread widths,” says Jim. in more even application and fewer fertilisers is most likely to pose a health passes. Spread testing can demonstrate Spread testing determines the CV at product quality, but it is ultimately the and safety risk, but it can also impact certain spread widths. For nitrogen the spreading. spreader calibration and settings that maximum CV is 15 per cent, whereas determine maximum spread width,” A product’s tendency to attract for phosphorus it is 25 per cent. When says Jim. moisture, which is usually associated looking at spread testing graphs you with nitrogen-based fertilisers, is the determine the maximum spread width most common chemical compatibility for that product from that spreader by issue that can impact spreading. looking at where the line intercepts FOR MORE INFORMATION the CV. “For example, avoid blending nitrogen For more information on Ballance products with superphosphate-based “Spread testing has shown that by products and their compatibility, fertilisers, as the mix can turn into using uniform products (well granulated contact the Ballance Customer a wet sludge,” says Jim. If used, the with even particle size), spreaders Service team on 0800 222 090. sludge clogs spinners in groundspread machines, and in top-dressing planes can get stuck in the hoppers and prevent the fertiliser from being Truck travels in circles Truck travels back and forth Good discharged, as well as creating a health and safety risk. Even if a blend is only 50 CV at 15% slightly affected by moisture issues, 45 intercepts the uneven spreading and striping can still 40 line at a bout Coefficient of variation % occur. 35 width of 8 m. For nitrogen, the maximum CV is 15%, Moisture from rain or humidity causes 30 so for a desired spread fertiliser to deteriorate and storing 25 width of 20 m, a CV over 15% means the fertiliser products in cool dry conditions 20 actual application rate minimises the chance of any product 15 has varied from the degradation. 10 set application rate by more than 15%. 5 Spreader calibration and 0 testing 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Like any machinery, regularly Bout width (m) maintaining, calibrating and testing a spreader are important for ensuring its Figure 1 Example spread testing graph, showing a poor spread pattern. On this accuracy. spreader with the current settings a nitrogen product (CV 15%) will spread to 8 m. On a well-calibrated spreader, the disc speed and drop point of the fertiliser onto the disc is right for the product or mix being spread (generally based on Truck travels in circles Truck travels back and forth Good its bulk density), and the actual and set application rates are similar. 50 CV at 15% The coefficient of variation (CV) refers to 45 intercepts the how much the actual distribution of the 40 line at a bout Coefficient of variation % fertiliser varies from the desired spread width of 35 23 m. rate, as set on the spreader. A lower 30 CV means a more even spread. “CV 25 properties depend on the spreader’s 20 design; a poorly designed spreader can only operate effectively at lower spread 15 widths. Testing a spreader with different 10 fertiliser types determines the best 5 spread width.” 0 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Spread testing helps to calibrate a spreader and ensure the settings are Bout width (m) correct for a particular product or mix, and can also help determine how Figure 2 Example of a spread testing graph showing a good spread pattern. far a product or mix can be thrown. On this spreader with the current settings a nitrogen product (CV 15%) will “Spreaders usually have their own spread to 23 m. Grow North Island / 11
Animal Effluent Plant Soil S products: side-by-side What’s the difference between sulphur products, and what are their best uses? “PhaSedN, PhaSedN Quick Start and Nrich SOA are related fertiliser products, all with sulphur (S) and nitrogen (N), but they’re best used at slightly different times of the year for different purposes,” says Ballance Science Extension Officer Josh Verhoek. The key difference in these products is the S they contain – sulphate S (plant available and can leach), elemental S (not available to plants and does not leach), or both. We look at them in more detail below to better understand them. What’s in it N (SustaiN), S, calcium (small amount, as lime) N, S S content 28.5% 17% 22% (and type) (100% elemental S) (32% sulphate S, 68% elemental S) (100% sulphate S) N content 25.3% 31.3% 19.5% (and type) (100% urea) (85% urea, 15% ammonium) (100% ammonium) autumn (March to May) and late autumn to end of winter (May spring (August to November) When best early winter in areas with milder to August) to cover winter and early to cover high S demand and used conditions spring S and N needs* typically low supply from soil What it does N gives pasture an immediate boost Sulphate S and N give pasture an immediate boost Fine elemental S particles sit in the soil over winter and are increasingly converted to sulphate S as soil temperatures rise, - supporting early spring growth SustaiN helps minimise N volatilisation losses - Best for • low S soils • strategic N application to • high rainfall areas at risk of S leaching over winter pastures in early spring • areas high in phosphate but low in S and N • where soil S supply is low enough to limit pasture • effluent blocks requiring tactical S and N response to N applications Dairy farm • where phosphate isn’t needed, but S availability needs to be increased/ • in place of straight N uses maintained products in late winter/ • on effluent blocks with a tactical requirement for S and N, but no need for early spring when pasture potassium demand is high, • on effluent blocks that haven’t had effluent since autumn Sheep and • on hill country where cost of applying phosphate is uneconomic, but • on hill country as a pre- beef farm applying S and N (which are constraining pasture production) is economic lamb N application, swap uses • on hill country with low organic S levels (< 8) and with soils with low- straight N for N and S for medium anion storage capacity (ASC < 60) further growth in spring • include with/instead of (if budget constraints) phosphate application on finishing areas on fertile sheep and beef farms to boost pasture - growth, helping to provide sufficient quality feed to rapidly finish stock *assuming suitable conditions (mild, no heavy rainfall, not waterlogged, actively growing pasture) 12 / ballance.co.nz
Animal Effluent Plant Soil Finish fast with legumes Legumes can provide quality is to apply a very low rate of herbicide feed at the right time to finish (such as Roundup Topping, applying Things to watch 200-250 ml Roundup/ha) just before • When establishing clover- stock fast. grasses start to bolt. The Roundup acts only crops, the ideal is a spell Profitable finishing farms aim to grow as a plant growth regulator, stopping without clover at some point in stock fast and get them on the truck as grass seed head development and the cycle to manage nematode soon as possible, reducing costs and allowing clovers to flourish. pests. Also a clover-only sward freeing up feed for other stock classes. “Suppression is key,” says Murray. “You is very attractive to brown don’t want to kill anything, just prevent beetle/grass grub, which could “Good feed quality speeds up stock brown top and Yorkshire fog seed head cause problems on light soil in growth, but having it available when emergence. An early November spray subsequent pasture. needed can be an issue. When the can be used to park areas of the farm • If mixing the clover with other spring flush occurs, for example, there that would normally go rank in the summer herbs like plantain or may not be enough mouths on farm spring flush and have them ready for chicory, seek advice to get the to utilise it,” says Ballance Forage grazing six to eight weeks later. The clover seed rate right. Clovers Specialist Murray Lane. leafy grass will still be there, you’re establish slower and are likely “Of all the ways of improving feed quality, just preventing a proportion of it from to be suppressed, so higher growing a legume crop – white clover, seeding, while releasing the legumes. clover seed sowing rates may red clover or lucerne – is potentially the It’s a great option for areas you’re be needed to get good plant key.” Legumes can provide excellent, planning to crop the following year as it numbers in the sward. Better still high energy feed in a timely manner minimises grass weed seed drop.” follow the chicory/plantain crop for a targeted stock class. Using part of with a clover crop. the farm to grow legumes results in an • Clover is more susceptible to increased stocking on the rest of farm nutrient deficiencies than other and helps to maintain feed quality. species, so soil test to check and adjust pH and phosphate In the North Island, mixes of red and levels. Don’t forget to check white clover have proven successful molybdenum, which is needed for lamb finishing operations. “Some for nitrogen fixation and is farmers set up targeted cropping areas often overlooked (see page 20). as part of a regrassing program. They spray out runout pastures and establish summer finishing crops (brassica, FOR MORE INFORMATION chicory and plantain) followed by one to two years in a clover mix before re- Contact your Ballance Nutrient Specialist. establishing a perennial pasture. This means they always have a ‘high quality finishing block’ on the farm, useful for +400 lamb finishing, and for ewe and hogget flushing.” +300 Liveweight gain (g/day) Growing a legume crop +200 “Creating a strong area of clover is +100 easier than you might think. With the 0 right tools, even undeveloped land can 8 9 10 11 12 13 be quickly converted into good finishing -100 country,” says Murray. Energy value of diet (MJME/kg DM) -200 Legume seed can be helicropped – -300 applied with fertiliser from the air to a All dead 50% stem or dead, Average ryegrass Mostly clover Ewe sprayed out area – ideally after another and stem little clover clover growing pasture pasture milk crop (if brassicas check herbicide withholding periods). “This boosts hill Poor hay Good Good quality hay quality lucerne country production and keeps soil on Rape the hills, but be sure to match stock Pasja Baleage/Silage Swedes and class, crop type, crop harvest season turnips and terrain.” Figure 1 Growth rate changes as feed quality improves. The liveweight gain Another option for undeveloped land of a 30 kg lamb and the energy value of the diet. Grow North Island / 13
Animal Effluent Plant Soil Valuable but variable Testing soil from the same place, and in similar conditions each year means better results. Soil testing provides valuable and the exact location it’s taken from can be much higher, and Olsen P information to help determine what are far more likely to be behind the slightly elevated. In dry conditions, nutrients are required, but variability can variability. Soil’s a biological system, microbial activity is much higher impact the reliability and accuracy of so it’s highly variable from location to and plant available nutrients such as results. location. Furthermore, soil conditions sulphate sulphur and phosphorus are such as temperature and moisture levels released into the soil at a rate faster than “Soil testing is about optimising are known to affect soil test results.” plants can use, elevating levels in the production and profits. Knowing the soil. Also during this time soil moisture level of nutrients in the soil means Timing (and conditions) are tends to be low so leaching and plant you can apply the fertiliser needed to uptake of nitrate nitrogen reduces, optimise pasture or crop growth,” says everything which can cause it to accumulate in the Ballance Science Extension Officer “Taking samples at the same time of soil and push up mineral nitrogen levels. Aimee Dawson. year as previous samples, ideally in similar conditions and not in extreme Even though soil testing is important, dry or wet, minimises variability in trials have indicated that there is soil test results due to seasonal and variability in soil test results (see Table Soil test Variability (%) climatic factors, such as moisture and 1). “So an Olsen P result of 20 could temperature,” says Aimee (see Figure 1). pH 2-5 mean, with a potential variability of 20 per cent as seen in the trials, that the “Recent application of fertiliser and Calcium 10 - 15 soil’s Olsen P levels could be anywhere grazing by stock can also affect soil between 16 and 24,” she says. “This test results. Ensuring you don’t soil Potassium 20 - 30 doesn’t mean that soil tests aren’t to be test within three months of fertiliser trusted, but that you should ensure that application and avoid dung and urine Magnesium 10 - 15 you look at results over multiple years to patches will reduce test variability.” Olsen P 15 - 20 determine trends in soil fertility.” If you test during very dry or wet Sulphate But what causes this variability? conditions there are a few ‘watchouts’ 20 - 40 sulphur Laboratory environments and methods for nutrient levels. Compared to other are strictly controlled, so are only likely times of the year, during drought or to play a small part. “The conditions summer dry soil conditions sulphate Table 1 Typical variability in laboratory under which a soil test sample’s taken sulphur and potassium soil test results soil tests¹ 14 / ballance.co.nz
Animal Effluent Plant Soil 5.5 Temperature can affect soil pH, with pH dropping by up to 0.2 units in warm soil conditions due to microbes releasing 5.4 organic acid and plant roots growing. pH Wet winter conditions can also affect 5.3 test results, with pH increasing slightly due to reduced microbial activity and plant growth. In soils that leach easily, significant rain events can lower sulphate sulphur. In soils with low cation 35 exchange capacity such as coarse or sandy soils, potassium can also leach, reducing its soil test value. Phosphorus, Phosphorus 30 however, is not affected as it does not readily leach in most soils. 25 In the spring and autumn flush, rapid nutrient uptake by plants can cause phosphorus, potassium and sulphate sulphur levels to be temporarily 25 depleted. Sulphate sulphur "The best timing for testing is spring or 20 autumn, when soil’s not too wet or dry. Also this is when pasture and crops are 15 actively growing so results will better reflect the nutrient levels available to 10 growing plants." 5 Location, location, location Setting up soil testing transects (lines along which samples are collected) and 14 taking samples from the same transects 13 Magnesium in subsequent years also helps to tackle 12 variability in test results. 11 “When you initially set up the transects, 10 make sure you mark them on a map 9 or with painted pegs, or take GPS coordinates so you can use them again,” says Aimee. 10 9 “One-off soil tests can be useful but they can also be misleading; the full 8 Potassium value comes from soil testing over 7 several years, so you can identify trends in the soil’s nutrient status over 6 time, and then adjust fertiliser inputs 5 accordingly.” FOR MORE INFORMATION See Hill Laboratories Technical Notes 4 Seasonal and environmental effects on Calcium 3 soil tests and Soil test variability or talk to your Ballance Nutrient Specialist. 2 1 ¹ Edmeades, DC, Cornforth IS, Wheeler DM 1985. NZ Fertiliser Journal. J F M A M J J A S O N D ² Edmeades DC, Cornforth IS, Wheeler DM. Month of year Occasional article: Getting maximum benefit from soil testing. Ruakura Soil & Plant Research Figure 1 Soil test variability by month in a single paddock of a high producing dairy Station, Hamilton farm from a MAF study on a Taupō soil² Grow North Island / 15
Animal Effluent Plant Soil Recovering from drought Nitrogen (N) helps pasture The research, commissioned by conditions, or PhasedN, containing bounce back after a drought. Ballance and independently performed SustaiN and sulphur. and reported on, was on drought- affected land in the Bay of Plenty and Drought followed by rain (or moist Getting pasture back on track after Hawke’s Bay, and indicated that any N overcast days) is when the risk of drought is crucial for animal production not immediately used is not lost, and nitrate poisoning is greatest, but certain and profit, as well as ongoing pasture produces a pasture response when practices can reduce the risk. “Avoid persistence. more rain arrives. grazing within three weeks of applying Drought causes many spring tillers to N, or minimise intake one to two weeks die or become stressed, and summer after drought-breaking rain. If stock tillers do not emerge. “Supporting must be put on high risk pastures, autumn tillering is important to prevent the risks of nitrate poisoning can be pastures thinning out over winter and reduced by limiting access overnight becoming vulnerable to weed invasion. and in the morning, when nitrate levels This could reduce production and start a are highest, feeding well on low nitrate cycle of decline,” says Ballance Science feeds such as straw hay or silage before Extension Officer Joshua Verhoek. grazing, and stocking lightly to avoid hard grazing, as the lower parts of “Drought doesn’t affect all pastures stems have the highest nitrate levels. equally, so they’ll need to be treated These measures will protect recovering differently when the drought breaks.” pastures as well as stock.” Pastures dominated by productive species, with plants still alive or the “While applying N to dry ground is not crown of the plant at ground level, ideal, if it’s your only opportunity, it will recover well with support. Those with not leach but a small percentage could weeds and large bare patches need still be lost through volatilisation, and regrassing. “So the current recommendation is to using SustaiN minimises this loss.” “While it’s traditionally been advised to apply N fertiliser to any live pasture “Regrassing will be needed for pasture wait until pasture begins to recover from as soon as the first drought-breaking that’s beyond recovery. Assuming your drought before applying N fertiliser, rains fall, so you’re not missing any base fertility is fine, you’ll need DAP more recent research suggests that N opportunity for growth in this critical or a similar starter product to drill with applied after the first significant rains period.” SustaiN, which does not need seed, followed by post-emergence N, produces a similar pasture response to 5 to 10 mm of rain within eight hours provided growing conditions are good.” deferring it until further rain has fallen,” of application to reduce volatilisation says Josh. losses, is an ideal N option for such 16 / ballance.co.nz
Animal Effluent Plant Soil Sustainability snaphot We talk to Ballance National job, and how other areas can be helped be heavily involved in the Ballance Farm to perform better. Environment Awards judging process, Farm Sustainability Services and their wide range of voluntary work Manager Claire Bekhuis about The team have also been working to support good management practices her team’s work. alongside farmers and growers to within the industry. support them to farm within limits while maintaining profitability. We provide With a continuously changing policy What has the Farm sound advice and use expert tools to environment, the team are focused on Sustainability Services team inform decision making. We’re expert being ahead of the change, upskilling been working on recently? users of tools such as OverseerFM and with the latest science to ensure they MitAgator, and come with strong farm can remove a lot of the stress from There’s been a flurry of interest in our systems knowledge and a practical farmers in this space and support them new MitAgator services (see page 19) attitude to farming within limits. to farm into the future. Some of the team which started in 2019. We’ve produced have completed the latest Massey GHG risk maps for a number of farmers, What does your team do to course to support farmers with queries bringing their critical source areas on the Zero Carbon Bill. for nitrogen, phosphorus, sediment ensure farmers get the best and E. coli to life and deepening their possible advice? How many people are in the understanding of their farming systems, We collaborate across a wide range of ultimately supporting better decision industries, working with stakeholders Farm Sustainability team and making. The team have also been such as milk companies, industry where are they based? using MitAgator to run mitigation bodies and working groups, regional The team’s nationally based, with 18 scenarios and complete farm councils, consultants, real estate agents, staff. In the last four years we’ve grown environment plans. Helping land hold irrigation schemes, catchment groups to meet demand from the regions, on to nutrients is vital for keeping it and banks throughout New Zealand, and now have a presence in Otago, healthy and productive for the long haul, so we can provide the best advice to Canterbury, Hawke's Bay/Manawatu, and MitAgator removes the guesswork farmers in the regions. Bay of Plenty and Waikato. We plan and gives sound insights into a farm’s to extend our team into Southland to strengths and weaknesses, identifying I’m exceptionally proud of the team’s support our shareholders with the Land which soil is well equipped to do the passion and drive that have led them to and Water plan. Consultation Understanding regulatory Nutrient budgets Produce risk maps framework Ongoing support Risk and opportunity Farm environment plans Run mitigation scenarios recommendations FOR MORE INFORMATION Contact the Ballance Farm Sustainability Services team to discuss how they can help support your farming business on 0800 222 090 or farm.sustainability@ballance.co.nz Grow North Island / 17
Animal Effluent Plant Soil A vehicle for action Farm environment plans are a “A farm plan’s purpose will be guided over time as actions are implemented by issues within the farm and as well or new risks and challenges emerge. useful tool for making moves in as any catchment-wide issues, such They become a vehicle to show the right direction on farm. as sediment management. So while environmental improvements over they’re specific to each property, all time, and can be provided to milk or Farm environment plans are good farms within a catchment can address a meat companies you supply, as well as business practice and a way of common risk in their farm environment environmental regulators,” he says. demonstrating and guiding increasing plans,” says Jim. sustainability on farm. Creating a farm plan involves an FOR MORE INFORMATION Farm plans could also become individualised risk assessment followed compulsory across New Zealand as • Find out how the Ballance by the development of an action plan to part of the Government’s proposed Farm Sustainability Services reduce the risk. “It’s possible to develop freshwater management reforms. team can help you to create a farm your own farm plan or you can use a environment plan on 0800 222 090 “In some parts of the country, farms certified farm planner, but in some places or farm.sustainability@ballance.co.nz meeting certain criteria (for example, if you make your own plan it must be over a set size) are already required by signed off by a certified planner.” • See page 23 for Ballance’s regulation to have a farm plan, or may submission on the proposed “MitAgator (see page 19) is an excellent need to do so in the near future,” says freshwater management reforms. first step in getting your farm plan Ballance Nutrient Dynamics Specialist underway,” says Jim. The risks and Jim Risk. mitigations identified by MitAgator can “The beauty of farm plans is their be used to produce a list of prioritised, recognition of the uniqueness of each time bound actions, displayed spatially farming system and farm landscape, on a map of the farm (see Figure 1). giving farmers the freedom to “A farm plan’s a living document that implement management practices and can be reviewed annually to see what’s mitigations that best suit their farm. been achieved, what needs to be done They also identify key actions already in in the future and if anything’s changed place to address risks, such as riparian that may impact future planning. The management, and prioritise future plan can be added to and changed actions.” A farm environment plan reflects the environmental risks and opportunities a farm faces and sets out how soil, water and nutrients will be sustainably managed. They can also be multi- purpose, integrating other areas such as biodiversity, biosecurity, winter grazing, waste and greenhouse gases. They always include: • Risks on farm – current and potential losses of the four key contaminants to water (nitrogen, phosphorus, sediment and E. coli) • Actions – current mitigations and prioritised planned mitigations to reduce the risks • Timelines – when good management practices and Figure 1 MitAgator action map for Why-One Farms. Actions are numbered mitigations will be implemented and their colour indicates the level of risk being addressed (pink=high risk, green=medium risk, blue=low risk). 18 / ballance.co.nz
Animal Effluent Plant Soil MitAgator cost-effectiveness, so Darryl could see which mitigations had the best bang for buck,” she says. “As a result understanding of sediment loss risks, highlighting the role of slope and soil type in sediment loss. As a result, a at work of MitAgator analysis, he’s creating a wetland to further reduce N losses, with MitAgator showing it would reduce the structure will be installed to serve as a sediment trap. farm’s overall N loss by around 9 per An E. coli risk map highlighted areas A powerful new tool is helping with greatest risk of E. coli loss, cent.” a farmer on his journey towards particularly unfenced streams and greater sustainability while MitAgator’s identification of the critical drains allowing stock access. “This source areas for P loss (Figure 2) showed the benefit of fencing off these remaining profitable. helped Darryl understand the key areas. Small drains are now fenced off Second generation Te Puke dairy drivers of P loss such as soils and and planted on the northern side, also farmer Darryl Jensen wanted to slope and the effect it was having on providing shading, and the farm’s main better understand and reduce the farm, especially in the steeper areas drain is fenced off, reducing E. coli loss environmental impact of his farming With above optimal Olsen P levels in risk from high to low within this area of practices on the property his father some areas, Darryl is working with. the farm,” says Hannah. purchased in 1958. This led him to Ballance Nutrient Specialist Dan Griffin to plan all paddock soil tests, so future Summing up, Darryl says: “It was a lot of Ballance’s MitAgator service, one of information to digest but in my opinion many steps taken towards a more P applications can be more strategic, optimising Olsen P levels and reducing it has made the path forward clearer sustainable and profitable farming in helping me understand my on-farm operation. loss from above optimal soil test levels. The P risk map also highlighted issues.” “What’s in front of our farming a critical source area from which P community is daunting in the way of lost in runoff could enter a stream FOR MORE INFORMATION environmental compliance. Farmers running through the farm. This could be need as many tools as possible in their reduced by further appropriate riparian Visit ballance.co.nz/mitAgator. To find toolbox to help them understand and management. out more about the MitAgator service put actions in place so they can farm phone 0800 222 080 or email farm. in a sustainable, profitable, practicable A sediment risk map enabled a better sustainability@ballance.co.nz. way. MitAgator is one of those tools,” says Darryl. Risk map - Nitrogen Risk map - Nitrogen MitAgator, cutting-edge software, Risk map Classification: Natural breaks Risk map Classification: Natural breaks Load Loss (kg/ha/yr.) spatially identifies critical source Load Loss (kg/ha/yr.) areas of nitrogen (N), phosphorus (P), sediment and E. coli losses on farm and then finds the best mitigation options to reduce losses. Darryl teamed up with Ballance Farm Definition - Natural breaks groups similar values and Sustainability Services Specialist Definition best -maximizes Natural breaks groups similar the differences values between and classes. best maximizes the differences between classes. Total loss (kg/yr.) Total loss rate (kg/ha/yr.) Hannah Stewart and used MitAgator 4,299.00 Total loss (kg/yr.) 38.51 Total loss rate (kg/ha/yr.) 4,299.00 The high nitrogen (N) risk 38.51 areas on the farm map are illustrated by the dark and light pink on the map. The high N risk area on farm The high nitrogen (N) risk areas on the farm map are illustrated contributes to 16.73% of the total N load. The high N risk ranges by the dark and light pink on the map. The high N risk area on farm to produce risk maps, identifying areas from 42.08 – 52.18 kg N/ha/yr. Figure 1 contributesoto 16.73% The highofN the risk total N load. The area displayed high on the N is map risk theranges Lucerne from 42.08 – 52.18 kg N/ha/yr. paddocks. It also includes the effluent area located on o The high theN risk area Pukeroa displayed sandy on the map is the Lucerne loam soil. of greatest risk for contaminant losses paddocks. It also includes the effluent area located on MitAgator Thethe Pukeroa medium risksandy area onloam soil. is illustrated by the green area the farm on the map. The medium risk area contributes to 21.28% of total N loss.risk area on the farm is illustrated by the green area The medium on the map.o The This area is risk made up of the effluentto block containing the on the farm, showing the relative risk of medium area contributes 21.28% of total nitrogen risk N loss. Paengaroa sandy loam soil and the Rest of farm containing the Pukeroa sandy loam soil. o This area is made up of the effluent block containing the Paengaroa sandy loam soil and the Rest of farm The low risk areas on the farm are illustrated by the light and dark loss within the property and prioritising containing the Pukeroa sandy loam soil. blue areas on the map. This contributes to 61.99% of total N map for Why- losses on farm. The low risko areas Theon the blue light farm on are the illustrated by the lightthe map represents andeffluent dark blue areas on Raparapahoe the map. Thissiltcontributes loam soil to 61.99% and of total the rest N of farm areas for mitigations. losses on farm.Paengaroa sandy loam soil. One Farms. o The o light blueblue The dark on represents the map the represents rest of farmthe effluent Raparapahoe silt loam soil Raparapahoe silt loam soil and the rest of farm Paengaroa sandy loam soil. o The dark blue represents the rest of farm Raparapahoe Page 11 of 39 silt loam soil “MitAgator’s ability to spatially display Risk map - Phosphorus Risk map - Phosphorus Page 11 of 39 the critical source areas for N loss Risk map Classification: Natural breaks Risk map Classification: Natural breaks Load Loss (kg/ha/yr.) (Figure 1) allowed the losses to be Load Loss (kg/ha/yr.) relatable to the property, showing their location and providing an understanding of the background drivers, such as soils vulnerable to leaching. This helped Darryl identify key areas to target such as the effluent area Definition - Natural breaks groups similar values and Definition - Natural breaks best maximizes groups similar the differences betweenvalues and classes. best maximizes the differences between classes. where reduced applications, only during Total loss (kg/yr.) Total500.00 loss (kg/yr.) Total loss rate (kg/ha/yr.) Total loss rate (kg/ha/yr.) 4.48 500.00 4.48 Figure 2 low risk periods, will better manage N Phosphate loss risk reflects the management practices influenced by soil and slope on a Phosphate loss risk reflects the management management block. MitAgator practices influenced by soil and slope on a management The high P block. risk areas on the farm are illustrated by loss,” says Hannah. the darker pink and pinks areas on the map. The The high highPP risk areasareas on thetofarm contribute areof 60.08% illustrated by total P load phosphorus the darker pink and are andaround found pinks the areas on the steeper map. parts The of the high Pfarm. areas contribute to 60.08% of total P load and are found around the steeper parts of the The medium risk area is illustrated by the green on farm. the map. The medium risk area contributes to “MitAgator provided a number of risk map for 13.39% of The medium total risk P load. area is illustrated by the green on the map. The medium risk area contributes to The lower risk areas are illustrated by the light and 13.39% of total P load. dark blue. This contributes to 26.53% of total P mitigations to reduce nutrient losses, Why-One load. The lower risk areas are illustrated by the light and dark blue. SomeThis contributes of the to 26.53% drivers behind of total high P loss P can be load. attributed to soil type, drainage class of soil, effluent application, P fertiliser and Olsen P levels. and prioritised them by efficiency and Farms. Some of the drivers behind high P loss can be attributed to soil type, drainage class of soil, effluent application, P fertiliser and Olsen P levels. Page 12 of 39 Page 12 of 39 Grow North Island / 19
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