FRNL New Knowledge Register

New Knowledge Register

March 2020

Forages for Reduced Nitrate Leaching

Scientific manuscripts and published conference proceedings

Forages for Reduced Nitrate Leaching

Scientific manuscripts and published conference proceedings

Forages for Reduced Nitrate Leaching was a DairyNZ-led collaborative research programme across the primary sector delivering science for better farming and environmental outcomes, aimed at reducing nitrate leaching through research into diverse pasture species and crops for dairy, arable and sheep and beef farms. The main funder was the Ministry of Business, Innovation and Employment, with co-funding from research partners DairyNZ, AgResearch, Plant & Food Research, Lincoln University, Foundation for Arable Research and Manaaki Whenua-Landcare Research.

Contents Introduction ................................................................................................................................4 Benefits of alternative species in pastures to reduce nitrate leaching from livestock systems ........ 5 Diverse pastures to reduce urinary N excretion: Effect of species composition in the diet on N partitioning in livestock ....................................................................................................................................................... 5 Plant characterisation, including the digestibility of forages, and the effect of management on pasture composition and DM production .................................................................................................................... 7 Nitrogen uptake and leaching in pure swards and diverse pastures, effects of pasture management ....... 10 Fate of Nitrogen in urine patches.................................................................................................................. 12 Forage and conserved feed crops and crop management systems that enhance the productivity and N use efficiency of arable and pastoral sector farms............................................................................. 15 Key components of high nutritive value, low N forage and conserved feed crops for livestock.................. 15 Performance and N partitioning response of livestock to high nutritive value, low N feed crops ............... 16 Effects of urine derived from high nutritive value, low N feed crops on soil N transformations ................. 17 Predicting soil N mineralisation for cropping soils ........................................................................................ 18 Protocol for using large area lysimeters to accurately quantify field scale drainage and N leaching .......... 18 Production of high nutritive value, low N forages and crops that maintain animal performance and mitigate N losses ........................................................................................................................................... 19 Feed quality of crops ................................................................................................................................. 19 Catch crops ................................................................................................................................................ 20 Animal grazing trials .................................................................................................................................. 20 High production, high N use efficiency crop sequences with forage and conserved feeds.......................... 21 Break-crop management systems that sustain high crop production and mitigate soil compaction and N losses ............................................................................................................................................................. 24 Closed loop nutrient management systems for optimising the use of effluent and manures ..................... 26 Farm systems for improved N use efficiency and reduced nitrate leaching losses......................... 28 Farm system modelling to evaluate effects of alternative pasture species and forage crops on production, profitability and environmental impact of livestock and arable farms......................................................... 28 Co-development for practice change to reduce nitrate leaching ................................................................. 30 Monitor farms’ performance – sheep and beef ........................................................................................ 31 Monitor farms’ performance – dairy......................................................................................................... 31 Monitor farms’ performance – arable....................................................................................................... 32

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FRNL New Knowledge Register 2013-2019

Introduction The Forages for Reduced Nitrate Leaching programme (FRNL; 2013-2019) combined fundamental, strategic and applied research, co-development and extension, to achieve and demonstrate practical, adoptable options for pastoral, arable and mixed farms to reduce nitrate leaching losses while maintaining or improving productivity and profitability. The main hypotheses of the programme were that this can be achieved by (1) reducing urinary nitrogen (N) excretion from livestock through the use of diverse pastures (i.e. mixtures containing grasses, legumes and herbs) and/or forage crops with a lower N content, without any reduction in animal performance; (2) improving N use efficiency of pasture and crops through the use of species and crop rotations that increase the uptake of soil N and thereby reducing N fertiliser input; and (3) a co-development approach ensuring close collaboration with end-users (farmers, rural professionals) to improve applicability and adoptability.

This document summarises key results of FRNL’s six years of research and co-development. It provides easy access to research results by listing all scientific output and papers published in proceedings of scientific and industry conferences and providing links to them.

The document is structured in accordance to the programme, with three clusters of work (so-called Research Aims): 1. Alternative pasture species (led by Grant Edwards; Lincoln University)

2. Crops (led by Mike Beare, Plant & Food Research) 3. Farm systems (led by Ina Pinxterhuis, DairyNZ)

Within each Research Aim, a number of projects were executed. In this document these are grouped where they contributed to a common goal. Titles of the various sections reflect these goals. We trust this structure helps you finding the publications relevant to your interest.

Benefits of alternative species in pastures to reduce nitrate leaching from livestock systems Nitrogen (N) excretion from livestock and N uptake by plants can be improved through the use of herbs, grass and legume pasture species other than perennial ryegrass and white clover. These alternative pasture mixtures can lead to more N being partitioned to animal product and less N excreted in urine. Additionally, herbs can reduce the N concentration of urine, which reduces the load of N (kg N/ha equivalents) in urine patches. Reduced urine N excretion and reduced N load can reduce nitrate leaching. Pasture species that exhibit greater growth rates in the cooler seasons can help when risk of drainage is greater, and hence risk of N leaching. This research aimed to define the critical plant species and amounts required in a mixture, and associated management, to decrease N excretion in urine and increase N uptake from soils by plants. Diverse pastures to reduce urinary N excretion: Effect of species composition in the diet on N partitioning in livestock Outdoor grazing studies in Canterbury and Waikato evaluated the effect of pasture species composition on milksolids production and urinary N excretion patterns, using urine sensors. Data from the trials, combined with forage chemical compositions from grazing and N fertiliser management studies were used to inform and validate animal model predictions of milksolids production and N partitioning in dairy cows. The validated model was used to test the effects of an array of diets with different pasture components on N partitioning and was used in the DairyNZ Whole Farm Model (WFM) to translate effects to the whole farm scale. A controlled feeding experiment in metabolism stalls was conducted with lactating dairy cows where the plantain content in the cows’ diet (with perennial ryegrass and white clover) was manipulated. Partitioning of dietary N into milk, urine, faeces and live weight was measured. K EY RESULTS OF THE WORK UNDERTAKEN • Urinary N excretion (g/cow/day) is closely related to N intake, irrespective of pasture type. N intake is related to the N% of the pasture species, and the pasture botanical composition. Greater plantain content may simultaneously reduce legume content, which is important for N intake: legumes have a consistently high N%. • Plantain in the diet altered the diurnal pattern of urine N excretion and reduced urinary N concentration in most experiments. e.g. urinary N concentration of cows grazing plantain was 56% lower than those grazing perennial ryegrass/white clover pastures, and 33% lower for cows grazing 50/50 pasture-plantain. • Urine patch area was larger for plantain-containing pastures due to greater urine volume and increased urine patch spread because of more open swards in partially or fully grazed pasture. • Urination frequency rather than urination volume is more likely to be increased when herb-containing pastures are fed. Herbs have a high water content and increase diet water intake and subsequently the number of urinations per day. • In grazing trials, urine N concentration was lower in the late and early lactation for cows grazing plantain (2.4 and 2.2 g N/L respectively) and 50:50 standard perennial ryegrass/white clover pasture : plantain (3.6 and 3.4 g N/L respectively) than standard pasture (5.4 and 4.7 g N/L respectively). Urine volume in late lactation from cows grazing plantain (73.8 L/cow/day) and 50:50 pasture : plantain (59.1 L/cow/day) was greater than from those grazing perennial ryegrass/white clover (46.5 L/cow/day).

• Substitution of tall fescue and summer grass with either lucerne, or lucerne and plantain, resulted in small improvements in feed digestibility but did not increase feed intake in late lactation. Inclusion of lucerne reduced dry matter intake but maintained milk production while inclusion of plantain with lucerne maintained intake and increased milk production. Inclusion of plantain at 46-70% of DM intake increased total water intake by 8-21% over grass/lucerne swards but significantly decreased trough water intake. A high proportion of plantain in the diet of lactating cows induced a reduction in urinary N concentration in both mid-lactation and late-lactation. Increasing plantain intake decreased lucerne intake and subsequently N intake in summer. • Voluntary daily dry matter intake of dairy cows in a metabolism stall trial increased with increasing proportion of plantain in the diet, however dietary N intake was similar (mean 545 g N/cow/d). Urinary N concentration was reduced in cows fed plantain at 30% or more of the diet compared with cows fed ryegrass only. The effect is described by a significant negative quadratic relationship between UN concentration and percentage of plantain in the diet. Increasing plantain in the diet reduced the partitioning of N to urine resulting in 15% less (39 g N /day) N partitioned to urine in cows fed 30% plantain compared to cows fed ryegrass only. When cows were fed diets containing 45% plantain, urine volume was 25% more (+9 L/cow/day) and urinary N excretion was 41% less (-66g/c/d) than from cows fed ryegrass only diets. • Variations in circadian patterns for N excretion and urine N concentration between pasture species offers opportunity to tailor nitrate leaching mitigation options to individual pasture species, i.e. strategic use of off paddock infrastructure, low N feeds etc. • Researchers need to take a cautionary approach when using daily urine creatinine excretion from spot samples to estimate urinary N excretion due to a 2-fold variation in urinary creatinine concentration over 24 hours. • Modelling the effect of increase in urination frequency on nitrate leaching revealed limited reduction in leaching in Canterbury (6%) due to greater area covered in urine, though a greater reduction in N leaching was predicted for Waikato (20%) compared with conventional ryegrass/clover pastures. • Comparison of experimental and modelled results indicated that urination behaviour can be simulated with acceptable accuracy and precision using MINDY, a mechanistic and dynamic model of a grazing ruminant. This may reduce the need of expensive and time-consuming animal experiments. P UBLICATIONS Bryant, R. H., Miller, M. E., Greenwood, S. L. and Edwards, G. R. “Milk yield and nitrogen excretion of dairy cows grazing binary and multispecies pastures”. Grass and Forage Science 72.4 (2017): 806-817. https://doi.org/10.1111/gfs.12274. Bryant, R. H., Welten, B., Costall, D., Shorten, P. R. and Edwards, G. R. “Milk yield and urinary-nitrogen excretion of dairy cows grazing forb pasture mixtures designed to reduce nitrogen leaching”. Livestock Science 209 (2018): 46-53. https://doi.org/10.1016/j.livsci.2018.01.009. Bryant, R. H., Snow, V., Shorten, P. R. and Welten, B. G. “Can alternative forages substantially reduce N leaching? findings from a review and associated modelling”. New Zealand Journal of Agricultural Research 63 (2019): 3-28. https://doi.org/10.1080/00288233.2019.1680395 Chapman, D. F., Edwards, G. R. and Pinxterhuis, J. B. "Plants for dairy grazing systems operating under nitrate leaching limits”. Proceedings of the New Zealand Society of Animal Production 74 (2014): 102- 107. https://www.cabdirect.org/cabdirect/abstract/20153127418. Dodd, M. B., Dalley, D. E., Elliott, D. and Wims, C. M. “Establishment year productivity, botanical composition and nutritive value of grass/lucerne/plantain dairy pasture mixtures”. Journal of New Zealand Grasslands 79 (2017): 229-235. https://www.grassland.org.nz/publications/nzgrassland_publication_2871.pdf.

Dodd, M., Dalley, D., Wims, C., Elliott, D. and Griffin. A. “A comparison of temperate pasture species mixtures selected to increase dairy cow production and reduce urinary nitrogen excretion ”. New Zealand Journal of Agricultural Research 62.4 (2019): 504-527. https://doi.org/10.1080/00288233.2018.1518246. Gregorini, P., Beukes, P. C. and Romera, A. “Screening for forages and foraging managements that reduce nitrogen excretion and methane emissions while maintaining or increasing animal production”. Journal of Animal Science 94.Suppl_5 (2016): 328. https://doi.org/10.2527/jam2016-0687. Gregorini, P. and Edwards, G. R. “Simulating the effect of frequency and timing of Plantago lanceolata allocation on diurnal urination patterns of grazing dairy cows ”. Proceedings of the International Symposium of Nutritional Herbs, Clermont Ferrand, France (2018, 2-6 September). https://www.cambridge.org/core/services/aop-cambridge- core/content/view/534EC354FE5AB94AA77905505CF6BFB4/S2040470018000146a.pdf/proceedings_of _the_10th_international_symposium_on_the_nutrition_of_herbivores.pdf#page=469. Gregorini, P., Bryant, R. H., Beck, M. R. and Edwards, G. R. “Plantain: It is not only the dietary content, but also how we graze it”. New Zealand Society of Animal Production 78 (2018): 151-160. www.nzsap.org/system/files/proceedings/plantain-it-not-only-dietary-content-also-how-we-graze- it….pdf. Gregorini, P., Provenza, F. D., Villalba, J. J., Beukes, P. C. and Forbes, M. J. “Diurnal patterns of urination and drinking by grazing ruminants: A development in a mechanistic model of a grazing ruminant, MINDY”. (2019) https://doi.org/10.1017/S0021859617000806. Gregorini, P., Bryant, R. H., Beck, M. R., Edwards, G. R. “Plantain: It is not only the dietary content, but also how we graze it”. Proceedings of the New Zealand Society of Animal Production 78 (2018): 151-160. http://www.nzsap.org/system/files/proceedings/plantain-it-not-only-dietary-content-also-how-we- graze-it%E2%80%A6.pdf. Minnée, E. M. K., Leach C. M. T. and Dalley D.E. “Substituting a pasture-based diet with plantain (Plantago lanceolata) reduces nitrogen excretion from dairy cows in late lactation”. (2019, Submitted). Waghorn, G. C., Griffin, A., Bryant, M. and Dalley, D. “Digestion and nitrogen excretion by Holstein/Friesian cows fed grasses with lucerne or lucerne and plantain”. Animal Production Science 59.6 (2019): 1070- 1080. https://doi.org/10.1071/AN18105. Plant characterisation, including the digestibility of forages, and the effect of management on pasture composition and drymatter production A range of field and lysimeter experiments in Canterbury and Waikato were used to test the effect of pasture botanical composition and management strategies on herbage dry matter (DM) yield and quality, N uptake and N leaching. These data were used to produce new APSIM Next Generation models for plantain, chicory, white clover and red clover. Improvements were made to the underlying plant modelling framework to simulate forages and N-fixing/nodulated plants. Diverse mixtures of forages were simulated to understand the limitations of the current modelling platform for plants competing for space and light. K EY RESULTS OF THE WORK UNDERTAKEN • Plantain has similar feed value and milksolids (MS) production potential to perennial ryegrass/white clover pasture when offered as green leafy herbage to dairy cows at a similar herbage allowance. • Italian ryegrass, prairie grass, high sugar ryegrass and plantain, with lower N fertiliser rates and 4-week regrowth intervals may be used to reduce herbage N intake. • Legumes were higher in non-protein nitrogen (180 mg/g N), than grasses (111 mg/g N) and herbs (chicory and plantain, 76 mg/g N). Herbs contain N that is more available to be utilised by the animal for growth and production, reducing the amount of N lost as urinary N.

• MS production of cows grazing diverse pastures containing a mixture of legumes, herbs and grasses and managed at high herbage mass in spring was not altered by defoliation management strategies such as pre graze mowing. • Managing diverse pastures in spring through lenient grazing is a potential management option for an irrigated Canterbury dairy farm system to increase herbage dry matter (DM) production and thereby profitability. • Forages that tended to have greater herbage crude protein (CP) and non-protein N (NPN) concentrations tended to release more N during maceration. • Increasing N fertiliser rate applied to ryegrass, chicory and plantain swards also reduced the ratio of fermentable carbohydrate to CP in herbage, which is thought to increase loss of N in urine. The greatest increase in the amount of CP released and greatest decline in the ratio was observed at N rates exceeding 200 kg N/ha/y, coinciding with reductions in herbage mass and leaf growth response to increased rates N fertiliser application. • Predictions of MS production and N excretion by the MINDY model for cows grazing chicory, ryegrass or plantain, suggests that rates of N fertiliser of 200 kg/ha/y could be the optimal point for MS production before total daily N excretion increases substantially. • Scenario-based modelling using APSIM showed a 21% and 6% reduction in annual N leaching loss could be achieved by reduced urine N concentration in Waikato and Canterbury regions, respectively. • Combining all forage, management and systems-based solutions lead to the greatest reductions in nitrate leaching of 59 and 31% for Waikato and Canterbury respectively. • Direct drilling was more effective than broadcast sowing for establishing plantain in existing pastures. The method of defoliation after sowing (pre-graze mowing or grazing) was not as important as timing of early defoliation in the resulting plantain populations. Early grazing, while seedlings were small enough to avoid defoliation, improved plantain establishment is likely by reducing competition from the pre- existing pasture. P UBLICATIONS Box, L. A., Edwards, G. R. and Bryant, R. H. “Milk production and urinary nitrogen excretion of dairy cows grazing perennial ryegrass/white clover and pure plantain pastures”. New Zealand Journal of Animal Science and Production 76 (2016): 18-21. http://www.nzsap.org/proceedings/milk-production-and- urinary-nitrogen-excretion-dairy-cows-grazing-perennial-ryegrass. Box, L. A., Edwards, G. R. and Bryant, R. H. “Diurnal changes in the nutritive composition of four forage species at high and low N fertiliser”. Journal of New Zealand Grasslands 79 (2017): 111-118. https://www.grassland.org.nz/publications/nzgrassland_publication_2853.pdf. Box, L. A., Edwards, G. R. and Bryant, R. H. “Milk production and urinary nitrogen excretion of dairy cows grazing plantain in early and late lactation”. New Zealand Journal of Agricultural Research 60.4 (2017): 470-482. https://doi.org/10.1080/00288233.2017.1366924. Box, L. A., Edwards, G. R. and Bryant, R. H. “Seasonal and diurnal changes in aucubin, catalpol and acteoside concentration of plantain herbage grown at high and low N fertiliser inputs”. New Zealand Journal of Agricultural Research 62.3 (2017): 343-353. https://doi.org/10.1080/00288233.2018.15055641. Box, L. A., G. R. Edwards and R. H. Bryant. “In sacco digestion kinetics of plantain and ryegrass-white clover harvested in the morning and afternoon”. New Zealand Journal of Animal Science and Production 78 (2018): 34-39. http://www.nzsap.org/proceedings/sacco-digestion-kinetics-plantain-and-ryegrass- white-clover-harvested-morning-and. Box, L. “Can plantain maintain milk production of dairy cows whilst reducing urinary N losses”. Doctoral dissertation, Lincoln University (2018). https://researcharchive.lincoln.ac.nz/handle/10182/10170.

Bryant, R., Dodd, M., Moorhead, A., Edwards, P. and Pinxterhuis, I. “Effectiveness of strategies used to establish plantain in existing pastures. Journal of New Zealand Grasslands 81 (2019):131-137. https://www.nzgajournal.org.nz/index.php/JoNZG/article/view/406/63. Carlton, A., Gardiner, C., Woods, R. and Clough, T. “What really goes on under a urine patch?”. Proceedings of the South Island Dairy Event , Dunedin (2018, 25-26 June): 99-104. https://side.org.nz/wp- content/uploads/2018/07/side-proceedings-2018-web.pdf Chapman, D. F., Lee, J. M., Rossi, L., Edwards, G. R., Pinxterhuis, I. J. B. and Minnee, E. M. K. “White clover: the forgotten component of high-producing pastures?”. Animal Production Science 57.7 (2017): 1269- 1276. https://doi.org/10.1071/AN16453. Cichota, R. and Snow, V. “Simulating plant growth in diverse pastures with new forage models in APSIM”. Agronomy New Zealand 48 (2018): 77-89. https://www.agronomysociety.org.nz/files/ASNZ_2018_08._APSIM_simulating_plant_growth.pdf. Cichota, R., McAuliffe, R., Lee, J., Brown, H. E. and Moot, D. J. “Forage chicory model: Development and evaluation”. Field Crops Research 246 (2020). 20pp. https://doi.org/10.1016/j.fcr.2019.107633. Cun, G. S., Edwards, G. R. and Bryant, R. H. “The effect of defoliation severity during late autumn on herbage production, regrowth and nitrogen uptake of diverse pastures in Canterbury, New Zealand”. Journal of Animal Science 94.Suppl_5 (2016): 305. https://doi.org/10.2527/jam2016-0640. Cun, G. S., G. R. Edwards and R. H. Bryant. “Milk production does not benefit from mowing previously lax- grazed diverse pastures” . New Zealand Journal of Agricultural Research 61.4 (2018): 468-476. https://doi.org/10.1080/00288233.2017.1411954. Cun, G. S., Al-Marashdeha, O. and Edwards, G. R. “Whole farm modelling using different grazing management strategies with diverse pastures within an irrigated dairy farm system”. New Zealand Journal of Animal Science and Production 78 (2018): 1-5. http://www.nzsap.org/proceedings/whole- farm-modelling-using-different-grazing-management-strategies-diverse-pastures. Cun, G. “Grazing management strategies of diverse pastures on irrigated dairy farm systems”. Doctoral dissertation, Lincoln University ( 2018). https://researcharchive.lincoln.ac.nz/handle/10182/10613. Dodd M. B., Moss R. A. and Pinxterhuis J.B. “A paddock survey of on-farm plantain use”. Journal of New Zealand Grasslands 81 (2019): 125-130. https://doi.org/10.33584/jnzg.2019.81.408. Martin, K., Edwards, G., Moir, J., Chapman, D. and Cameron, K. “Herbage dry matter (DM) accumulation and nitrogen concentration of grass, legume and herb species grown at different nitrogen fertilizer rates under irrigation”. Animal Production Science 57 (2017): 1283-1288. https://doi.org/10.1071/AN16455. Martin, K. E., Bryant, R. H., Hodge, S. and Edwards, G. R. “Effect of autumn regrowth interval and nitrogen fertiliser on dry matter yield and plant characteristics of six forage species”. Journal of New Zealand Grasslands 79 (2017): 67-72. https://www.grassland.org.nz/publications/nzgrassland_publication_2847.pdf. Martin, K., “Effects of nitrogen fertiliser and regrowth interval on herbage dry matter yield, chemical composition and nitrogen solubility of alternative pasture forages in irrigated Canterbury conditions”. Doctoral dissertation, Lincoln University (2018). https://researcharchive.lincoln.ac.nz/handle/10182/10456. Minnée, E. M. K., McCready, T. B. and Woodward, S. L. “Herbage production, botanical composition, and survival of perennial ryegrass and tall fescue based swards in simple and diverse species mixtures in a dryland environment”. Animal Production Science 57.7 (2017): 1405-1413. https://doi.org/10.1071/AN16475. Minnée, E. M. K., Waghorn, G. C., Lee, J. M. and Clark, C. E. F. “Including chicory or plantain in a perennial ryegrass/white clover-based diet of dairy cattle in late lactation: Feed intake, milk production and rumen digestion”. Animal Feed Science and Technology 227 (2017): 52-61. https://doi.org/10.1016/j.anifeedsci.2017.03.008.

Minnée, E. “The release of nitrogen and carbohydrate from herbage during comminution”. Doctoral dissertation, Lincoln University (2017). https://researcharchive.lincoln.ac.nz/handle/10182/10284. Minnée, E. M. K., Bryant, R. H., Chapman, D. F. and Gregorini, P. “Simulating the intake and nitrogen excretion from cows grazing swards fertilised with increasing rates of nitrogen”. New Zealand Journal of Animal Science and Production 78 (2018): 141-145. https://researcharchive.lincoln.ac.nz/bitstream/handle/10182/10791/MInnee%20et%20al%202018%20 NZSAP.pdf?sequence=1&isAllowed=y. Minnée, E. M. K., Waghorn, G. C., Gregorini, P., Bryant, R. H. and Chapman, D. F. “Characteristics of boli formed by dairy cows upon ingestion of fresh ryegrass, lucerne or chicory”. Animal 13.6 (2018): 1188- 1197. https://doi.org/10.1017/S1751731118002938. Minnée, E. M. K., Kuhn-Sherlock, B., Pinxterhuis, J. B. and Chapman, D. F. “Meta-analyses comparing the nutritional composition of perennial ryegrass (Lolium perenne) and plantain (Plantago lanceolata) pastures. Journal of New Zealand Grasslands 81 (2019): 117-123. https://www.nzgajournal.org.nz/index.php/JoNZG/article/view/402/61. Woods, R., Carlton, A., Martin, K., Box, L. and Cun, G. “Practical options for reducing the environmental impacts of intensive, forage-based dairy systems”. South Island Dairy Event, Lincoln (2017, 26-28 June): 201-211. https://side.org.nz/wp-content/uploads/2017/06/5.4-Practical-options-for-reducing- environmental-impacts-Racheal-Bryant.pdf. N uptake and leaching in pure swards and diverse pastures, effects of pasture management Lysimeter and small outdoor plot trials were carried out to determine the effect of irrigation management (frequency, timing, level of water stress) and gibberellic acid application on nitrate leaching from multi- species and standard perennial ryegrass/white clover pastures. The impact of plant species on soil C and N transformations (mineralisation and nitrification) and legume N 2 fixation was measured using 15 N tracer studies on pastures. K EY RESULTS OF THE WORK UNDERTAKEN • Italian ryegrass and the late-heading date and late-season maturing perennial ryegrass cultivar, One 50, were found to be the most effective pasture grass options to reduce N leaching loss. • Italian ryegrass leached 33 to 46% less nitrate-N than Tyson, AberDart, Tyson-Italian and Arrow swards. • Italian ryegrass swards took up 1.2 to 1.4 times more N than any other grass type reducing the amount of N available for leaching. • Italian ryegrass produced significantly less drainage: 31-46% less than all other pure swards. • Drilling Italian ryegrass into established perennial ryegrass swards did not significantly reduce nitrate leaching losses. • Large leaching losses occurred from urine applied to lucerne (> 200 kg N/ha) due to low plant uptake during the autumn-winter drainage period. • Plantain reduced N leaching losses by 15% in summer and by 30 – 50% in winter (average 39%) compared to perennial ryegrass grown in free draining volcanic ash soil. • Allied research has shown plantain can affect soil microbial biota and reduce nitrous oxide emissions from urine excreted on soil. • Mechanisms influencing reduced N leaching when using plantain appear to be associated with a combination of urine N concentration, plant N uptake and nitrification inhibition.

• Compared with perennial ryegrass/white clover, N leaching from perennial ryegrass/white clover/plantain was 82% and 74% lower when standardised urine was applied in December and February, respectively. Growth of ammonia oxidising bacteria was significantly reduced with plantain in the mixture, indicating a biological nitrification inhibiting effect. • Compared with perennial ryegrass/white clover, N leaching from Italian ryegrass/white clover/plantain was reduced by 46% when using a standardised urine N load, due to greater cool-season growth with water and N uptake, and by 89% when using urine from cows grazing these pastures, due to the additional effect of reduced urinary N concentration. • Irrigation system (simulated pivot, rotorainer and flood irrigation, with the same total amount of water applied over the dry season) did not affect N leaching. • A comparison of N leaching from a single urine application to monocultures of perennial ryegrass, plantain or lucerne showed that plantain exhibited large seasonal variation in its efficacy to reduce urine-N leaching relative to ryegrass (ranging from 15% to 50% reduction for summer or winter urine applications, respectively) with an overall reduction of 39% (53 and 87 kg N/ha leached for plantain and ryegrass, respectively). Leaching from lucerne was consistently high (>200 kg N/ha). • Application of gibberellic acid had no effect on N leaching losses, DM yield, or N uptake of perennial ryegrass/white clover, Italian ryegrass or Lucerne treated with 700 kg N/ha urine. • Annual N 2 fixation was 3-fold higher in mixed (white clover, lucerne, perennial ryegrass, chicory and plantain) relative to standard perennial ryegrass/white clover pasture (averaged 193 vs. 75 kg N/ha/year, respectively) due to higher legume yield in mixed pastures. Both pasture types showed an exponential decline in annual N 2 fixed as fertiliser-N input increased. • Laboratory soil incubation studies with urine (equivalent to 300 and 600 kg N/ha) applied to ryegrass or plantain soil showed that plantain inhibits nitrification of urinary-N over a short-period (<28 days) with the level of inhibitory effect decreasing over time. • Detailed 15 N-isotope studies with ryegrass and plantain monocultures by two fertiliser-N rates (0 vs. 500 kg N/ha/year) showed evidence that plantain manipulates short-term nitrogen processes controlling plant N availability. P UBLICATIONS Carlton, A. J., Cameron, K. C., Edwards, G. R., Di, H. J. and Clough, T. J. “The effect of optimum vs. deficit irrigation on plant nitrogen uptake and nitrate leaching loss from soil”. In: Integrated nutrient and water management for sustainable farming. (Eds L.D. Currie and R. Singh). http://flrc.massey.ac.nz/publications.html. Occasional Report No. 29. Fertilizer and Lime Research Centre , Massey University, Palmerston North, New Zealand (2016). https://www.massey.ac.nz/~flrc/workshops/16/Manuscripts/Paper_Carlton_2016.pdf. Carlton, A. J. “The effect of diverse forage species and irrigation management on plant nitrogen uptake and nitrate leaching losses”. Doctoral dissertation, Lincoln University (2018). https://researcharchive.lincoln.ac.nz/handle/10182/8950. Carlton, A. J., Cameron, K. C., Di, H. J., Edwards, G. R. and Clough, T. J. “Nitrate leaching losses are lower from ryegrass/white clover forages containing plantain than from ryegrass/white clover forages under different irrigation”. New Zealand Journal of Agricultural Research 62 (2019): 150-172. https://doi.org/10.1080/00288233.2018.1461659. Maxwell, T. M. R., McLenaghen, R. D., Edwards, G. R., Hong, D. J. and Cameron, K. C. “Italian ryegrass swards reduce N leaching via greater N uptake and lower drainage over perennial ryegrass cultivars varying in cool season growth rates”. New Zealand Journal of Agricultural Research 1.14 (2018): 69-82. https://doi.org/10.1080/00288233.2018.1426615.

Welten, B. G., Ledgard, S. F, Judge, A. A., Sprosen, M. S., McGowan, A. W. and Dexter, M. M. “Efficacy of different temperate pasture species to reduce nitrogen leaching from cattle urine applied in different seasons: A soil lysimeter study”. Soil Use and Management Journal (2019, 31 March). https://doi.org/10.1111/sum.12512. Welten, B., Ledgard, S., Sprosen, M., Judge, A. and Waugh, D. “Nitrogen fixation by white clover and lucerne in contrasting temperate pasture species mixtures with varying nitrogen fertiliser input”. New Zealand Journal of Agricultural Research (2019, Submitted). Woods, R. R., Cameron, K. C., Edwards, G. R., Di, H. and Clough, T. J. “Does gibberellic acid reduce nitrate leaching losses from animal urine patches?”. In: Integrated nutrient and water management for sustainable farming. Currie, LD, Singh R (Eds.). http://flrc.massey.ac.nz/publications.html. Occasional Report No. 29. Fertilizer and Lime Research Centre , Massey University, Palmerston North, New Zealand (2016). http://www.massey.ac.nz/~flrc/workshops/16/Manuscripts/Paper_Woods_2016.pdf. Woods, R. R., Cameron, K. C., Edwards, G. R., Di, H. J. and Clough, T. J. “Effects of forage type and gibberellic acid on nitrate leaching losses”. Soil Use and Management 32.4 (2016): 565-572. https://doi.org/10.1111/sum.12297. Woods, R. R., Cameron, K. C., Edwards, G. R., Di, H. J. and Clough, T. J. “Reducing nitrogen leaching losses in grazed dairy systems using an Italian ryegrass-plantain-white clover forage mix”. Grass and Forage Science 73.4 (2017): 878–887. https://doi.org/10.1111/gfs.12386. Woods, R. R., Cameron, K. C., Edwards, G. R., Di, H. J. and Clough, T. J. “ 15 N recoveries from urine patches on different forage types”. Plant and Soil. 417.1-2 (2017): 453-465. https://doi.org/10.1007/s11104-017- 3270-5. Woods, R. “The effect of alternative forage species and gibberellic acid on nitrate leaching”. Doctoral dissertation, Lincoln University (2017). https://hdl.handle.net/10182/8271.

Fate of N in urine patches This work was supported with co-funding from the Strategic Science Investment Fund (SSIF) of AgResearch.

Lysimeters and small plots were used to measure N uptake and nitrate leaching from applied urine for various pasture species and mixed-species pastures. Differences in urine patch size and associated edge- effects were evaluated to identify urine-specific effects of pasture species mixture on nitrate leaching. APSIM simulation was developed to represent the urine patch edge effects of the pasture species. The new and improved modules were validated against data collected in the field and lysimeter trials. Potential impact of diverse pastures to reduce leaching while maintaining or improving production at the paddock scale was examined using the validated modelling system and information generated in grazing trials • N offtake from the urine patch was greater with plantain than with standard pasture; however, the relative contribution to uptake from the wetted area and surrounding edge was the same for both species. Most (>90%) of the apparent offtake of urine N by plantain and standard pastures was within 20cm of the edge of the urine patch. • 30-40% of the pasture N uptake from urine deposited on the wetted zone came from outside the wetted zone, with the edge contribution larger in small urine patches. Lysimeters with a confined edge may potentially underestimate pasture N uptake. regarding urine patch characteristics. K EY RESULTS OF THE WORK UNDERTAKEN

• Detailed model (HYDRUS 2-D and APSIM) of a single urine patch including water and N flow beyond the wetted edges of a urine patch, suggests that typically about 0.1 m spread might be expected. This was consistent with independent experimental work. • The vegetation model AgPasture was updated, fully documented and converted to the APSIM Next Generation framework. It is currently in peer review and should be in release in the next month. • Information from the patch-scale modelling was used to set some key parameters in a new paddock- scale model that explicitly incorporates urine patches. • The paddock-scale model was used to investigate the likely improvement in leaching from diuretics in the diet. Although a lower urine N concentration reduced the N load in urine patches, it also led to a larger area of the paddock covered by urine and a greater occurrence of overlapping urine patches. Therefore, the effectiveness of the diuretic decreased as stocking rate rose and high rates of N fertiliser were used. P UBLICATIONS Badham, J., Elsawah, S., Guillaume, J. H. A., Hamilton, S. H., Hunt, R. J., Jakeman, A. J., Pierce, S. A,. Snow, V. O., Babbar-Sebens, M., Fu, B., Gober, P., Hill, M. C., Iwanaga, T., Loucks, D. P., Merritt, W. S., Peckham, S. D., Richmond, A. K., Zare, F., Ames, D., Bammer, G. “Effective modeling for Integrated Water Resource Management: A guide to contextual practices by phases and steps and future opportunities, Environ. Model. Softw ., 116 (2019) 40-56. https://doi.org/10.1016/j.envsoft.2019.02.013. Balvert, S. and Shepherd, M. “Does size matter - the effect of urine patch size on pasture N uptake”. In: Moving farm systems to improved attenuation. Currie LD, Burkitt LL (Eds.). Occasional Report No. 28. Fertilizer and Lime Research Centre, Massey University, Palmerston North, New Zealand. (2015). http://www.massey.ac.nz/~flrc/workshops/15/Manuscripts/Paper_Balvert_2015.pdf. Cichota. R., Vogeler, I., Snow, V., Shepherd, M., McAuliffe, R. and Welten, B. “Lateral spread affects nitrogen leaching from urine patches”. Science of Total Environment 635 (2018): 1392-1404. https://doi.org/10.1016/j.scitotenv.2018.04.005. Fitton, N., Bindi, M., Brilli, L., Cichota, R., Dibari, C., Fuchs, K., Huguenin-Elie, O., Klumpp, K., Lieffering, M., Lüscher, A., Martin, R., McAuliffe, R., Merbold, L., Newton, P., Rees, R. M., Smith, P., Topp, C. F. E. and Snow, V. “Modelling biological N fixation and grass-legume 1 dynamics with process-based biogeochemical models of varying complexity”. European Journal of Agronomy 106 (2019): 58-66. https://doi.org/10.1016/j.eja.2019.03.008. Holzworth, D. P., Huth, N. I., Fainges, J., Brown, H., Zurcher, E., Cichota, R., Verrall, S., Herrmann, N. I., Zheng, B. and Snow, V. “APSIM Next Generation: Overcoming challenges in modernising a farming systems model, Environmental Modelling & Software 103 (2018): 43-51. https://doi.org/10.1016/j.envsoft.2018.02.002. Shepherd, M. A. and Carlson, W.T. “Urine patch size and nitrogen load: effects on nitrogen uptake from the urine patch in plantain and ryegrass/white clover pastures”. Journal of New Zealand Grasslands 80 (2018): 195-200. https://www.nzgajournal.org.nz/index.php/JoNZG/article/view/321. Shepherd, M., Shorten, P. and Carlson, B. “The contribution of the urine patch edge to pasture-N uptake”. New Zealand Journal of Agricultural Research (2018, Submitted). Snow, V. O., Eckard, R. J., Rotz, C. A., Johnson, I. R. and Hutchings, N. J. “The challenges of incorporating urine and dung patches in process-based modelling of grazed agricultural systems”. In: Ames DP, Quinn NWT, Rizzoli AE (Eds.) International Environmental Modelling and Software Society (iEMSs), 7th Intl. Congress on Env. Modelling and Software , San Diego, CA, USA. (2014). https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=1088&context=iemssconference. Snow, V. O., Rotz, C. A., Moore, A. D., Martin-Clouaire, R., Johnson, I. R., Hutchings, N. J. and Eckard, R. J. “The challenges - and some solutions - to process-based modelling of grazed agricultural systems”.

Environmental Modelling & Software 62 (2014): 420-436. https://doi.org/10.1016/j.envsoft.2014.03.009. Snow, V. O., Cichota, R., McAuliffe, R. J., Dynes, R. A., Vogeler, I., Ledgard, S. F. and Shepherd, M. A., “What is “sufficient” complexity when modelling urine patches in grazed pastures?”. In: Syme, G., Hatton MacDonald, D., Fulton, B., Piantadosi, J. (Eds.), MODSIM2017, 22nd International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand ISBN: 978-0-9872143-7- 9 (2017, December): 22–28. http://www.mssanz.org.au/modsim2017/Keynote/snow.pdf. Snow, V. O., Cichota, R., McAuliffe, R. J., Hutchings, N. J. and Vejlin, J. l. “Increasing the spatial scale of process-based agricultural systems models by representing heterogeneity: The case of urine patches in grazed pastures”. Environmental Modelling & Software 90 (2017): 89-106. https://doi.org/10.1016/j.envsoft.2017.01.005. Snow, V. O., Meenken, E., Cichota, R., Holzworth, D. P. and Dynes, R. A. “Are diuretic-based mitigations of leaching and N 2 O emissions from urine patches effective at farm scales and higher stocking rates”. (2020, submitted).

Forage and conserved feed crops and crop management systems that enhance the productivity and N use efficiency of arable and pastoral sector farms High-nutritive value, low-N forage and conserved feed crops can maintain or increase the performance of livestock while reducing the excretion of N in animal urine and associated N losses. Integrated soil, crop and effluent management practices for the production of forage and conserved feed crops can increase the N use efficiency of continuous cropping, mixed and livestock farms, and significantly reduce N losses associated with either the production or consumption of these feeds. Key components of high nutritive value, low N forage and conserved feed crops for livestock A database of crop quality characteristics has been developed and populated with available NZ and overseas data. Meta-analysis of these data identified the key nutritive components of forage and feed crops that explain variability in livestock performance and returns of N in excreta. Data were used in the mechanistic animal performance model (MOLLY) to identify the key crops and crop combinations that maintain or increase livestock performance and reduce partitioning of N into urine and methane emission. Crops identified from these livestock modelling experiments were used in small plot crop management trials and large plot grazing trials. K EY RESULTS OF THE WORK UNDERTAKEN • A database comprising forage quality tests and associated field management metadata was derived from literature, FRNL trials and historical crop sampling. At the time of analysis for a scientific manuscript, the dataset comprised 2770 samples, representing 71 crops or crop mixes. Since then, more crop data has been added, and the database has been extended with pasture quality data. This is a valuable resource base for future crop and pasture quality reference. • The feed quality database comprises a framework for assessing indices for crude protein (CP) and total soluble carbohydrates (SSS) content and classifying diet suitability for lactating and non-lactating dairy animals, with or without an environmental weighting to achieve minimised N leaching. • Assessment of the crop quality database collated in FRNL, showed that rape, turnips, and whole crop silages featured strongly in pre-defined critical ranges for lactating dairy cows of 16-20% crude protein (CP) and >25% soluble sugars and starch (SSS). • Other feeds with high SSS and low CP concentrations such as fodder beet, maize silage, wheat and barley grains are useful dietary supplements but are below the CP requirements for lactation if fed alone. Additional protein from pasture, pasture silage or legume supplements (peas, tick beans, clovers, lucerne) is necessary to meet requirements. • For non-lactating cows with a CP requirement of 10-16%, whole crop cereal silages, brassicas (turnips, kale, swedes) and legumes (peas and tick beans) are the best fit. Cereal grains, maize silage and fodder beet meet the non-lactating feed requirements, but these are best incorporated into a mixed diet. • N fertiliser was the only agronomic management factor that could consistently be used to adjust the quality for animal requirements. Factors such as delayed sowing and plant population had minor systematic influence on quality. Much of the variation in quality was accounted for by crop selection and/or the environment in which the crop was grown. • The DairyNZ Whole Farm Model with the animal model Molly was used to screen 11,526 binary diets comprising 51 feeds (forages and grains) combined in different proportions. Combinations with the best

possible compromise between urinary N excretion, methane emission and milksolids production were identified. Fodder beet and cereals featured strongly. P UBLICATIONS Chakwizira, E., Fletcher, A. L., Johnstone, P. R., de Ruiter, J. M., Pearson, A. J. and Parker, M. “Maize silage- winter crop sequences that maximise forage production and quality”. New Zealand Journal of Agricultural Research 62.1 (2017): 1-22. https://doi.org/10.1080/00288233.2017.1415943. Dalley, D.E., Malcolm, B. J., Chakwizira, E. and de Ruiter, J. M. "Range of quality characteristics of New Zealand forages and implications for reducing the nitrogen leaching risk from grazing dairy cows”. New Zealand Journal of Agricultural Research 60.3 (2017): 319-332. https://doi.org/10.1080/00288233.2017.1345762. de Ruiter, J. M., Malcolm, B. J., Chakwizira, E., Johnstone, P., Maley, S., Arnold, N. and Dalley, D. E. “Crop management effects on supplementary feed quality and crop options for dairy feeding to reduce nitrate leaching”. New Zealand Journal of Agricultural Research 62.3 (2019): 369-398. https://doi.org/10.1080/00288233.2018.1508042. Gregorini, P., Beukes, P. C., Dalley, D. and Romera, A. J. “Screening for diets that reduce urinary nitrogen excretion and methane emissions while maintaining or increasing production by dairy cows”. Science of the Total Environment 551–552 (2016): 32–41. https://doi.org/10.1016/j.scitotenv.2016.01.203. Performance and N partitioning response of livestock to high nutritive value, low N feed crops This work was supported with co-funding from the Strategic Science Investment Fund (SSIF) of AgResearch. Animal metabolism stall trials were conducted to define N partitioning, rumen turnover, and digestive responses of livestock to fodder beet, a key crop identified in the work summarised above. Amino acid concentrations in blood plasma was determined to identify potential limitations in amino acid supply for dairy cows to maintain milk production while reducing N excretion. K EY RESULTS OF THE WORK UNDERTAKEN • Fodder beet feeding reduced urinary N excretion compared with that observed from most good quality pasture diets. • A diet of 65% fodder beet and 35% pasture silage supplied adequate nutrition for non-lactating dairy cows although there was some risk of acidosis. A diet containing 85% fodder beet with barley straw resulted in low dry matter intake, poor rumen function and negative N balance compromising both animal nutrition and welfare. Straw should not be fed as a sole fibre source with fodder beet because of the risk of inadequate nutrition and high incidence of acidosis. • Substitution up to 45% of a pasture diet DM with fodder beet had no detrimental effects on the health or production of cows in late lactation but 60% fodder beet resulted in clinical acidosis. When offered at less than 23% of diet dry matter (DM), fodder beet increased DM digestibility but this trend was reversed when >45% of the diet DM was fodder beet. Caution is required when offering diets with greater than 40% fodder beet to ensure they contain sufficient N, phosphorus and sulphur. • Variations in the N:creatinine ratio over 24 h with each diet as well as lower measured creatinine excretion compared to published values indicate a likelihood of substantial errors in the prediction of daily urinary excretion if using spot sampling. • Feeding fodder beet alters the profile of amino acids to the lactating dairy cow, as demonstrated by the reductions in the plasma concentrations in amino acids such as arginine and glutamine. The use of fodder beet as a tool to manage nitrogen excretion needs to take these findings into account, because

these amino acids are involved in critical development functions, such as fetal development and intestinal integrity. P UBLICATIONS Dalley, D. “The foibles of fodder beet and other forage crops – animal and environmental considerations for successfully feeding forage crops”. South Island Dairy Event , Lincoln University, Lincoln (2016, 26-28 June). https://side.org.nz/wp-content/uploads/2016/06/1.1-The-Foibles-of-Fodder-Beet-and-Other- Forage-Crops.pdf. Pacheco, D., Waghorn, G. and Dalley, D. “BRIEF COMMUNICATION: Plasma amino acid profiles of lactating dairy cows fed fodder beet and ryegrass diets”. Proceedings of the New Zealand Society of Animal Production 76 (2016): 62-64. http://www.nzsap.org/system/files/proceedings/%2363%20Pacheco.pdf. Pacheco, D., Muetzel, S., Lewis, S., Dalley, D., Bryant, M. and Waghorn, G. C. “Rumen digesta and products of fermentation in cows fed varying proportions of fodder beet ( Beta vulgaris L.) with fresh pasture or silage or straw”. Animal Production Science 60 (2020): 524-534. https://www.publish.csiro.au/AN/AN18002. Waghorn, G. C., Collier, K., Bryant, M. and Dalley, D. “Feeding fodder beet (Beta vulgaris L.) with either barley straw or pasture silage to non-lactating dairy cows”. New Zealand Veterinary Journal 66.4 (2018): 178-185. https://doi.org/10.1080/00480169.2018.1465484. Waghorn, G. C., Law, N., Bryant, M., Pacheco, D. and Dalley, D. “Digestion and nitrogen excretion by Holstein/Friesian cows in late lactation fed ryegrass pasture with fodder beet”. Animal Production Science 59 (2018): 1261-1270. https://doi.org/10.1071/AN18018. Effects of urine derived from high nutritive value, low N feed crops on soil N transformations Urine was collected from cows in the various animal trials described above, with a range of composition. The dairy cows were fed the standard high-N reference diet and high nutritive value, low-N feeds. Concentrations of allantoin (a chemical constituent of ruminant urine) were determined in the cow urine and a methodology for measuring allantoin in soil samples was developed. Urine was applied to soil and the • In a small range of urine samples from animals fed plantain, the total N concentration was lower than from animals fed standard ryegrass/clover pastures. There was also a tendency for a lower allantoin content. • Given the rapid degradation of allantoin observed in the soil, we disproved our hypothesis that the concentration of allantoin in urine may be sufficient to modify the activity of soil micro-organisms involved in transforming N deposited in the urine of grazing livestock. P UBLICATIONS Peterson, M., Fraser, P. M. and Curtin, D. “A Plant & Food Research report prepared for: Dairy NZ. Milestone No. 67732. Contract No. 32051. Job code: P/442056/03. SPTS No. 13193 ”. Commissioned report: CS1.2.6 (2016). half-life of allantoin was determined. K EY RESULTS OF THE WORK UNDERTAKEN • Allantoin is broken down rapidly in soil, with a half-life of only around 2 to 3 hours.

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