Journal of New Zealand Grasslands 2020-04-02T09:35:48+13:00 Dr Ruth Falshaw Open Journal Systems <p>ISSN:&nbsp;2463-2880 (online); 2463-2872 (print)</p> <p>The <em>Journal of New Zealand Grasslands</em> publishes peer-reviewed papers with a focus on temperate grassland research. The scope of the journal includes all aspects of pastoral research&nbsp;including agronomy, soils, animals, agricultural extension and farm-systems research.</p> <p>Types of paper published include research articles, literature reviews, perspectives on specific topics and agricultural practice papers that demonstrate the application of previously published scientific research.</p> <p>The Journal is published by the New Zealand Grassland Association (NZGA) at its annual conference in November each year. The aim of the NZGA is <em>“to enhance pastoral agriculture”</em> by providing a forum for communication of science, technology and knowledge. Formed in 1931, the NZGA facilitates discussion on grassland farming, and promotes the value of research and its application. Our membership includes a wide range of scientists, consultants, agribusiness and farmers – making it truly <strong><em>“fuelled by science and tempered by experience.”</em></strong></p> <p>The Journal has been published since 1932 (prior to 2015 as the <em>Proceedings of the NZ Grassland Association</em>) so provides a long-term resource reflecting agricultural research and innovation.&nbsp;All past papers are freely available from the <a href="">NZGA</a> website.</p> <p><em><strong>Open access:</strong></em> All articles published by the&nbsp;<em>Journal of New Zealand Grasslands</em>&nbsp;are freely and permanently accessible online immediately upon publication.</p> President's Address 2018 2019-11-18T12:39:25+13:00 Graham A. Kerr <p>-</p> 2019-10-21T00:14:20+13:00 Copyright (c) 2019 Levy Oration 2018: Our industry through the eyes of a pasture agronomist 2019-11-18T12:41:01+13:00 Cory Matthew <p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</p> 2019-10-21T00:18:03+13:00 Copyright (c) 2019 Farming in Hawke’s Bay 2019-11-21T14:26:44+13:00 Garth O. Eyles <p>Hawke’s Bay’s diverse physical environments have enabled a wide range of farming enterprises to prosper. This paper provides a summary of the physical environments and the major farming industries in the region. It identifies changes since the last Grasslands Conference held in the area in 1999 and some of the issues that will need addressing in the future as climate changes.</p> 2019-10-21T00:19:40+13:00 Copyright (c) 2019 A review of research on the fertiliser and lime requirements of pasture on the eastern coast of the North Island 2019-11-21T14:26:14+13:00 Maurice H. Gray Jeffrey D. Morton <p>The soils on the eastern region of the North Island (Wairarapa, Tararua, Hawke’s Bay, Poverty Bay, East Coast) are mainly of the Brown, Pallic, Recent (Sedimentary) and Pumice orders and are most are farmed with sheep and cattle on hill pastures. Several field trials have been carried out to determine the pasture growth requirements for phosphorus (P), sulphur (S), potassium (K), nitrogen (N), lime and molybdenum (Mo) in this region since the 1960s and the results published in various papers. This review considers the results of these studies collectively and in relation to national datasets. Sedimentary and Pumice soils with Olsen P levels of less than 12 µg/mL required annual application of P. Significant pasture production responses to S were measured where initial soil sulphate-S levels were less than 6 ppm. Additional K for sheep and beef pastures was required mainly on Pumice and Brown soils with soil QTK levels of 6 or less. Large pasture DM responses to N were measured in most trials, especially on steep slopes and sunny aspects with low legume content. Lime is needed to maintain soil pH once it decreases to 5.4 on hill soils. Molybdenum deficiency in legumes can occur on sedimentary soils and should be monitored by clover-leaf analysis.</p> 2019-10-22T00:22:45+13:00 Copyright (c) 2019 Photogrammetry for assessment of pasture biomass 2019-11-21T14:25:31+13:00 Kathryn Wigley Jennifer L. Owens Matthias Westerschulte Paul Riding Jaco Fourie Armin Werner <p>New tools are required to provide estimates of pasture biomass as current methods are time consuming and labour intensive. This proof-of-concept study tested the suitability of photogrammetry to estimate pasture height in a grazed dairy pasture. Images were obtained using a digital camera from one site on two separate occasions (May and June 2017). Photogrammetry-derived pasture height was estimated from digital surface models created using the photos. Pasture indices were also measured using two currently available methods: a Rising Plate Meter (RPM), and Normalised Difference Vegetation Index (NDVI). Empirical pasture biomass measurements were taken using destructive sampling after all other measurements were made, and were used to evaluate the accuracy of the estimates from each method. There was a strong linear relationship between photogrammetry-derived plant height and actual biomass (R2=0.92May and 0.78June) and between RPM and actual biomass (R2=0.91<sub>May</sub> and 0.78<sub>June</sub>). The relationship between NDVI and actual biomass <br>was relatively weaker (R2=0.65<sub>May</sub> and 0.66<sub>June</sub>). Photogrammetry could be an efficient way to measure pasture biomass with an accuracy comparable to that of the RPM but further work is required to confirm these preliminary findings.</p> 2019-10-22T00:28:07+13:00 Copyright (c) 2019 Determining yield of forage crops using the Canopeo mobile phone app 2019-11-21T14:25:01+13:00 José M. Jáuregui Fernando G. Delbino María Inés Brance Bonvini Gonzalo Berhongaray <p>One of the biggest challenges in pastoral systems is accurately determining forage availability. Destructive sampling is the most accurate method to use but it is very time-consuming, so non-destructive methods are usually preferred. This study compared data on the percentage of green canopy cover (%GCC) obtained using a recently developed image-analysis mobile phone app (Canopeo®) with crop biomass, light interception and NDVI measurements. Data were obtained for a range of crop species from two dryland experiments of lucerne (E1) and winter forage crops (E2). Linear and quadratic regression models were constructed to evaluate the data obtained using Canopeo® to estimate biomass accumulation, light interception and NDVI. For lucerne, positive linear relationships were found between %GCC and biomass (0.77 and 0.79 for Spring + Summer and Autumn + Winter, respectively; P&lt;0.05), and between %GCC and light interception (R<sup>2</sup>=0.83; P&lt;0.05). For winter forage crops, there was a linear relationship between biomass and %GCC (R<sup>2</sup>=0.81; P&lt;0.05), and a linear relationship between %GCC and light interception (R<sup>2</sup>=83; P&lt;0.05). NDVI data obtained using the GreenSeeker® crop sensing system was linearly related to %GCC data from Canopeo® in both experiments (R<sup>2</sup>=0.84 in E1 and R<sup>2</sup>=0.93 in E2; P&lt;0.05). The Canopeo® app proved to be a fast and reliable method to estimate biomass accumulation and light interception of forage crops in this study and has potential wider applications. However, it does not distinguish between crops and weeds.</p> 2019-10-22T00:33:21+13:00 Copyright (c) 2019 Preliminary investigation into the feasibility of combining satellite and GPS data to identify pasture growth and grazing 2019-11-21T14:24:24+13:00 Simon J.R. Woodward Mark B. Neal Peter S. Cross <p>Regular estimation of pasture availability is a time-consuming on-farm task, but one that is vital for good grazing management. The ability to automate this task is, therefore, highly valuable. Combining satellite sensing of pasture mass with global positioning for herd location provides raw data that can potentially be used to automatically estimate pasture mass, pasture growth and pasture grazing events across a farm. The feasibility of automatically obtaining and processing this information was demonstrated on a Waikato dairy farm from 22 October 2018 to 21 February 2019 (123 days), with 13 global positioning collars recording the location of grazing mobs 16 times per hour on average, in a dairy herd of initially 380 animals. Satellite sensing of pasture cover over the same period was only possible on 16 days during this period, with November being particularly cloudy, resulting in fewer pasture cover estimates. A non-linear regression model was constructed with parameters representing initial pasture cover, average pasture growth rate through time, pasture growth differences between paddocks, pasture disappearance rate relative to the density of cow GPS samples, and an ungrazeable residual. A Bayesian approach was used to infer the model parameters from the satellite-measured pasture cover data. This allowed interpolation of pasture mass through the whole period with an RMSE of 225 kgDM/ha, as well as identifying growth rate differences between paddocks, which may provide a useful basis for improved pasture management. Rough estimates of cow average daily pasture disappearance were also made, which peaked at 20 kgDM/d in November, falling to 5 kgDM/d by February. This pilot study demonstrated the feasibility of combining satellite pasture cover data with herd location data from a small number of GPS collars to infer pasture growth rates in individual paddocks through time.</p> 2019-10-22T23:05:25+13:00 Copyright (c) 2019 Evaluation of LiDAR scanning for measurement of yield in perennial ryegrass 2019-11-21T14:23:56+13:00 Richard M. George Brent A. Barrett Kioumars Ghamkhar <p>mproving pasture yields is a primary goal for plant breeders. However, measuring and selecting for yield is a major bottleneck in breeding, requiring methods that are laborious, destructive, and/or imprecise. A computerised scanner developed in Canterbury using LiDAR (light detection and ranging) technology was evaluated in the Waikato on perennial ryegrass paired-row breeding plots. At eight timepoints, all plots were scanned prior to mechanical defoliation and recording of fresh weight (FW) and dry matter (DM) yield on a random subset of plots. Yield data on 1206 FW and 504 DM samples were compared with LiDAR scan results on a seasonal basis by regression. Winter, spring, summer and autumn correlation with FW were R<sup>2</sup> = 0.81, 0.92, 0.94 and 0.90, respectively, and with DM yield R<sup>2</sup> = 0.87, 0.73, 0.87 and 0.79, respectively. These results indicate LiDAR estimation of DM yield was accurate within seasons for the paired-row breeding plots, although it was sensitive to large changes in dry matter content (%) among seasons, which may require seasonal algorithms to correct for this variation if this technology is to be adopted. In conclusion, the scanner could be useful in removing a major bottleneck in perennial ryegrass breeding and may have application for agronomy and farm management in cases where precise non-destructive real-time estimation of DM yield are of value.</p> 2019-10-22T23:07:53+13:00 Copyright (c) 2019 Assessing the ability of a stationary pasture height sensing device to estimate pasture growth and biomass 2019-11-21T14:23:27+13:00 Andrew Milsom Olivia Bell Kris Bailey Stuart C. Brown Richard A. Barton Cristian A. Moreno Garcia Ao Chen Racheal H. Bryant Thomas M.R. Maxwell Colin C. Eady <p>Good pasture management requires an accurate knowledge of whole-farm feedbase, yet most systems for measuring pasture growth are manually operated and time consuming. A newly developed pasture-measuring device enables remote measurement of pasture height on a regular basis. This study investigated the accuracy of such a device compared with a rising plate meter, then assessed the device on a pure perennial ryegrass paddock at a research farm, followed by field testing in a perennial ryegrass/white clover paddock on a commercial dairy farm. A strong correlation (R<sup>2</sup> = 0.93) was obtained between collected DM yield and device-derived pasture height within the pure perennial ryegrass paddock but the correlation was weaker (R<sup>2</sup> =0.68) with data from the dairy farm perennial ryegrass/white clover paddock. There is considerable potential to improve upon these initial data through the use of adjusted calibrations. Findings demonstrate the device has the potential to accurately estimate pasture growth.</p> 2019-10-22T23:11:05+13:00 Copyright (c) 2019 Relationships between sheep liveweight production and dry matter yield for lucerne-based pastures in spring 2019-11-21T14:22:56+13:00 Annamaria Mills Malcolm C. Smith Derrick J. Moot <p>A five-year dryland grazing experiment explored the relationship between sheep liveweight (LWt) production and dry matter (DM) yield of lucerne-based pastures in spring. In 2011, a randomised complete block experiment with a lucerne monoculture, a lucerne/brome mix and a lucerne/cocksfoot mix were established at Ashley Dene, Canterbury and replicated six times. Pastures were managed under dryland conditions. Ewes with twin lambs at foot grazed in spring and LWt production, DM yield and botanical composition were quantified.<br>Regression analysis showed total DM feed on offer accounted for only 11% of the observed variation in spring LWt production. Subsequent analysis of the botanical composition of the three pastures showed total feed on offer in spring was unaffected by pasture treatment in four out of five years. However, yield of the lucerne component on offer was 77–230% greater in the monoculture than the mixes in Years 3–5. Brome yields declined from Year 3 and did not recover. By Year 5, weeds accounted for 41% of the feed on offer in spring in the lucerne/brome mix. <br>Net spring ewe + lamb liveweight production increased at a rate equivalent to 246 kg LWt +71 kg LWt per tonne of lucerne DM on offer (R<sup>2</sup> = 0.83). There was no effect of pasture type. Where possible lucerne should be established as a monoculture to maximise liveweight gain. A runout stand was overdrilled with a companion grass to extend the productive stand life. The loss of lucerne over time indicated renewal should be initiated within 2–3 years of oversowing to ensure LWt production is not compromised.</p> 2019-10-22T23:13:33+13:00 Copyright (c) 2019 Animal performance changes over 11 years after implementing a lucerne grazing system on Bog Roy Station 2019-11-21T14:22:26+13:00 Derrick J. Moot Pete V.A. Anderson Lisa J. Anderson David K. Anderson <p>In 2008, Bog Roy was run as a typical high-country station with merino ewes and lambs set stocked for long periods of the year, with 60 ha of lucerne grown for hay. Over the next 7 years, the lucerne and ryecorn areas increased by 30 ha per year. Total lamb meat weaned increased from 91 to 130 t in the first three years direct feeding of lucerne commenced, which improved ewe and two-tooth performance at lambing (% and survival). In the second phase, ewe numbers and pre-weaning lamb growth rates increased. Lambs were weaned earlier and ewes returned to higher pasture covers on hills, which improved their condition score and weights at mating and lambing. In 2016, a change from flood to pivot irrigation resulted in a further production increase to 160 t weaned lamb. By 2018, the mixed age ewes had 141% lambing (to tailing), and pre-weaning lamb growth rates of over 270 g/hd/d which allowed weaning after 80 days. The lamb weaned per ewe mated has increased from 25 to 37 kg over the decade despite increased feed demand from 900 more ewes. These animal performance indicators quantify the transformational change achieved through a focus on grazing and increasing the area of lucerne. This was followed by lucerne and red clover based pastures being established under pivots. The ability to record and quantify changes in stock performance has given the farmer confidence to trust and embrace the transformational change.</p> 2019-10-23T23:24:28+13:00 Copyright (c) 2019 The performance and profitability of plantain/clover pasture mixtures in East Coast farming systems 2019-11-21T14:21:53+13:00 Paul D. Muir Beverley C. Thomson Noel B. Smith Kathleen R. Ward Lochie MacGillivray Malcolm J. Macfarlane <p>Yield and animal performance data from plantain/clover and resident ryegrass-based pastures were collected over several years from six properties on the East Coast of the North Island. This information was used in a FARMAX® model developed for a hypothetical farm based on data collected by the Beef + Lamb Economic Service. The hypothetical farm was 495 ha with 50 ha of flats used for silage and/or winter forage crop. The base model had a gross margin of $703/ha. The 50-ha flat block was modelled as if in a plantain rotation with two thirds in plantain and one third in annual ryegrass each year. The higher yields and better-quality feed on the plantain block improved animal performance and carcass weights. Early mating of one-year ewes for feeding on plantain provided a very high-returning enterprise. More ewes and lambs were killed early at heavier carcass weights with a premium before the onset of summer-dry conditions. This became a force multiplier across the entire farm as more feed was available for other stock and lamb carcass weights increased across the farm. Highest returns were generated by using the extra quality feed to increase ewe liveweights by 8 kg. Whilst ewe numbers had to be decreased, this was more than compensated for by the higher lambing percentage and greater number of lambs from mated hoggets. The combined effect was an increase in farm gross margin by around $200/ha and in farm returns of $100,000.</p> 2019-10-23T23:27:36+13:00 Copyright (c) 2019 Evaluating the benefits of mixed plantain/chicory/clover pastures in a Hawke’s Bay sheep breeding and finishing farm 2019-11-21T14:21:27+13:00 Jim Spall Graeme I. Ogle Paul D. Muir <p>Farming in the inland Hawke’s Bay, New Zealand with traditional pasture is limited by pasture quality in summer and early autumn. Low lamb growth rates in spring/summer pushes lamb finishing into the late summer and early autumn when feed demand competes with sheep mating and compromises pasture cover entering winter. We discuss our process for investigating and adopting high legume herb-based pastures that thrive within the constraints of our soils. This process involved learning from other farms and trials, small-scale on-farm trials and farm-system modelling. We gain considerable confidence from observing plantain, chicory and clover pastures within a learning group run by Massey University. Our on-farm trial measured by On-Farm Research showed favourable forage production (+20% greater than ryegrass-clover pastures for spring, autumn and winter) and longevity (4–6 grazing seasons). From this we modelled our farm using Farmax software. Farmax calculated an historically poor performance in February, March and April from ewes (-65, -45, -15 g/day respectively) and lambs (55, 0, 35 g/day respectively). Based on six key assumptions, we have calculated the profitability of herb-based pastures. These are compared with the performance we are currently achieving on herb-based pastures. For each value we are achieving better than assumed, i.e. ewe weaning weight 64.0 versus 62 kg, lamb weaning weight 33.0 versus 31.3 kg, ewe lamb growth rate 132 versus 100 g/day, male lamb growth rate 253 versus 235 grams/day and ewe hogget scanning percentage 144 versus 130.</p> 2019-10-23T23:38:13+13:00 Copyright (c) 2019 Maximising the subterranean clover content on a summer-dry Wairarapa hill-country farm through grazing management 2019-11-21T14:20:57+13:00 Sonya T. Olykan Richard J. Lucas Dan J. Nicholson Crile Doscher Derrick J. Moot <p>Tokaroa Farm is a 608-ha sheep and beef farm, in the Wairarapa. Paddock slopes range from flat to steep (&gt;25°) with a predominance of gentler north facing slopes and steeper south facing slopes. Annual rainfall is 810 mm and average summer dry is three months. Resident subterranean (sub) clover (<em>Trifolium subterraneum</em> L.) populations were identified on an uncultivatable north-west facing hill slope in 2015, and a management plan devised to increase its contribution to pastures. <br>Exclosure plots showed that an eight-week spell in spring 2016 increased resident sub clover groundcover from 13 to 54%, while in the lightly grazed paddock control sub clover increased from 10 to 28%. There was a positive linear relationship (R<sup>2</sup>=0.51) between the total number of established sub clover seedlings on 30 March 2017 and the previous spring sub clover groundcover (%) on 25 November 2016. In October 2017, the effect of the spring 2016 exclosure treatments was still evident with 57% sub clover groundcover in the eight-week spelled areas compared with 37% in the control despite all the exclosures being grazed in 2017.<br>Sub clover management strategies were developed, using slope and aspect, and applied to a GIS map of Tokaroa Farm. This suggested that 53% of the farm could have sub clover overdrilled into it and 29% could have the resident sub clover population actively managed and/or oversown with sub clover seed.</p> 2019-10-23T23:40:59+13:00 Copyright (c) 2019 Mitigating greenhouse gas emissions from New Zealand pasture-based livestock farm systems 2019-11-21T14:20:24+13:00 Sinead C. Leahy Laura Kearney Andy Reisinger Harry Clark <p>The reduction of the agricultural greenhouse gases, methane and nitrous oxide is likely to play an important role in New Zealand’s transition to a low-emissions economy. A limited range of options currently exists to reduce emissions from pasture-based livestock farming systems. However, several promising options are under development which have the potential to considerably reduce on-farm emissions, such as inhibitors and vaccines. On-farm forestry can be used to offset emissions through carbon sequestration in trees, but more scientifically robust and consistent evidence is needed if soil carbon sequestration is to be used to offset New Zealand’s greenhouse gas emissions.</p> 2019-10-24T23:13:05+13:00 Copyright (c) 2019 Nitrification inhibition by urine from cattle consuming Plantago lanceolata 2019-11-21T14:19:54+13:00 H. Glenn Judson Patricia M. Fraser Michelle E. Peterson <p>Plantain (<em>Plantago lanceolata</em> L.) has the potential to indirectly reduce nitrate leaching from urine patches via compounds excreted in the urine of animals grazing the forb acting as biological nitrification inhibitors. Proof-of-concept research was previously undertaken using sheep urine, but it is important to examine whether this effect also occurs with cattle urine since cattle pose a greater N-leaching risk due to their higher urinary-N load. Housed dairy heifers (n=4) were assigned ad libitum dietary treatments of perennial ryegrass/ white clover or plantain for 14 days. On day 14, urine was collected through a sterile Foley catheter into a sealed container. Cattle then switched dietary treatment and urine was collected after a further 14 days. Urine samples were applied to soil microcosms and the net nitrification rate during a 35-day incubation determined. Similar urine-N concentrations were applied initially but a slower rate of soil nitrification was observed in the microcosms treated with urine from plantain-fed cows compared with those treated with urine from ryegrass/white clover-fed cows. The urine samples collected after the crossover showed a wider treatment difference in total N concentration, but also demonstrated a reduction in soil nitrification rate under the plantain urine. These results show similar trends to those previously reported for sheep urine.</p> 2019-10-24T23:15:25+13:00 Copyright (c) 2019 Meta-analyses comparing the nutritional composition of perennial ryegrass (Lolium perenne) and plantain (Plantago lanceolata) pastures 2019-11-21T14:19:21+13:00 Elena M.K. Minneé Barbara Kuhn-Sherlock Ina J.B. Pinxterhuis David F. Chapman <p>Studies comparing livestock responses to diets containing plantain with traditional ryegrass/clover diets suggest differences in the nutritional composition between the species might explain some of the variation in results. To explore this theory, a meta-analysis was performed to compare the nutritional composition of plantain and perennial ryegrass pastures, and define key differences between the species. Standardised effect sizes (plantain vs ryegrass pastures), expressed as correlation coefficients (<em>r</em>) with values from -1 to +1, and treatment means from 34 studies were determined using a weighted random effects model. Pastures containing plantain had lesser herbage dry matter content than ryegrass pastures across all seasons (mean 13.4 vs. 19.4%, P&lt;0.001;<em> r</em>&lt;-0.65). Structural fibre content was consistently smaller (mean 32.1 vs. 43.4% DM), but non-structural fibre content larger in plantain compared with ryegrass pastures (large effect sizes of r&gt;0.70). There was no difference in total herbage nitrogen concentration (g/100 g DM; <em>r</em>&lt;0.03). However, plantain pastures contained less soluble and degradable nitrogen compared with ryegrass pastures (<em>r</em>&lt;-0.78). Herbage digestibility did not differ significantly between pastures (<em>r</em>=-0.13; P=0.168). Generally, the effect of plantain on nutritional composition was consistent across seasons. Experiments and models investigating the effects of pasture mixes on environmental nitrogen losses ought to include detailed nitrogen and carbohydrate fractions data for accurate interpretation and prediction.</p> 2019-10-24T23:24:41+13:00 Copyright (c) 2019 A paddock survey of on-farm plantain use 2019-11-21T14:18:49+13:00 Michael B. Dodd Ray A. Moss Ina J.B. Pinxterhuis <p>The use of narrow-leaved plantain (Plantago lanceolata) in pasture sowing mixtures has recently increased following research demonstrating the value of the ‘Tonic’ cultivar in reducing cattle urinary N concentration, with likely benefits for reducing N leaching from pasture systems. The purpose of this study was to document the ways in which farmers are using plantain, investigate the factors that enhance successful establishment and persistence, and to test a method of visual estimation of plantain content in paddocks. This information will support verification of animal intake, given that there is evidence that a critical level of plantain is required in the diet to achieve significant effects on N cycling. In grass-based pastures, plantain content declined with age since sowing and few paddocks had more than 20% of their available dry matter as plantain after three years. A systematic visual assessment of plantain cover correlated well with a formal visual dry matter assessment and could be used to establish when plantain content at a paddock scale is&nbsp; &gt;20–30%. Plantain content tended to be highest when sown without grass, when established by direct drilling and on clay soils, but optimal sowing rates have yet to be determined.</p> 2019-10-24T23:27:53+13:00 Copyright (c) 2019 Establishment of plantain into existing pastures 2019-11-21T14:18:17+13:00 Racheal H. Bryant Mike B. Dodd Allister J.E. Moorhead Paul Edwards Ina J.B. Pinxterhuis <p>In recent years plantain (<em>Plantago lanceolata</em>) has emerged as a potential forage for reducing nitrogen losses from dairy farm systems. However, achieving sufficient proportions of plantain in pastures to help meet target reductions in nitrate leaching presents on-farm challenges. To investigate sowing methods for establishing plantain into existing pasture to achieve high plantain populations, direct drilling was compared with broadcasting before and after grazing. Additionally, pre-graze mowing versus grazing only, and early versus late first defoliation after sowing were investigated to assess their effect on reducing competition from existing pasture. Botanical composition was determined in a small-plot study at Lincoln following summer sowing under irrigation, and from commercial dairy farms in Canterbury (irrigated) and Waikato (not irrigated). Generally, direct drilling was more effective than broadcast sowing for establishing plantain. 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 likely by reducing competition from the pre-existing pasture.</p> 2019-10-24T00:00:00+13:00 Copyright (c) 2019 Barriers to IPM adoption for insect pests in New Zealand pastures 2020-03-25T08:55:39+13:00 Sarah Mansfield Colin M. Ferguson Toni White Scott Hardwick Sean D.G. Marshall Sue M. Zydenbos Simone C. Heimoana Russell Gorddard Mary E.A. Whitehouse <p>New Zealand’s pastoral sector faces significant challenges to pest management as long-standing insecticides are deregistered. To protect their pastures, farmers need to shift from reactive responses that lead to poor economic outcomes to pre-emptive responses that are viable in the long term. Current management practices (insecticides, endophytes, biological control) for New Zealand’s pasture insect pests were assessed from the perspective of Integrated Pest Management (IPM). Potential impacts from novel control strategies and emerging digital technologies were evaluated to determine how these could improve pest management. Cryptic IPM is present within the New Zealand pastoral sector: that is, farmers practise various elements of IPM but these elements are not integrated into a cohesive system, so farmers often fail to recognise pest impacts until significant economic losses have occurred. We identified important networks by which farmers, industry and researchers communicate and share information, and can develop strategies to raise awareness of IPM. To encourage adoption, farmers need to feel ownership of pasture IPM. Investment in IPM training for farmers through industry extension networks is essential to prepare farmers for the shift away from chemical insecticides to new biologically based control methods. Adoption of IPM will help pastoralists respond to current and new pest challenges.</p> 2019-10-24T23:32:57+13:00 Copyright (c) 2019 Farm systems analysis of two thistles of differing seasonal pasture growth impacts in North Island hill country 2020-03-30T09:02:59+13:00 David R. Stevens Katherine N. Tozer Tim Rhodes Sue M. Zydenbos Robyn A. Dynes Michael J. Manning Ants H.C. Roberts Michael White Alister Metherell <p>Models for infestations of Californian thistle (<em>Cirsium arvense</em>) and variegated thistle (<em>Silybum marianum</em>) were used to modify fortnightly pasture growth forecasts using Agricultural Production Systems simulator software using climate and soil data from a single farm (Tangihanga Station) over four aspects and three slope classes. Modelling using Farmax software was used to estimate profitability using the current farm enterprises with or without either the Californian or variegated thistles. Modelled pasture production, based on field observations of thistle infestation, was similar to estimates using animal intake (from Farmax). Californian thistle reduced pasture production in summer and autumn, while variegated thistle reduced autumn, winter and spring pasture growth. Californian thistle had a much greater overall presence (20%) than variegated thistle (9%). Both types of thistle reduced the potential to finish lambs in summer and reduced ewe wintering numbers, while the presence of Californian thistles also reduced over-wintering cattle numbers, by reducing summer-autumn pasture accumulation. Cost of control for Californian thistle ($233/ha) over two years was higher than for variegated thistle ($184/ha) over four years. Net profitability was reduced by 24% ($87/ha) by the presence of Californian thistle, and by 37% ($135/ha) by the presence of variegated thistle.</p> 2019-10-27T23:55:55+13:00 Copyright (c) 2019 Modelling the economic and environmental implications of reducing biosecurity risk by changing to a self-contained dairy grazing system in New Zealand 2020-04-02T09:34:49+13:00 Taisekwa L. Chikazhe Mark B. Neal Paul Bird <p>This study examines the economic and environmental implications of reducing the spread of contagious pathogens and diseases by implementing a self-contained dairy grazing system. Three typical New Zealand grazing-off systems were examined represented by a Waikato farm where all young stock are grazed off the milking platform, a Canterbury farm where both non-lactating cows and young stock are grazed off the milking platform and a Lower North Island farm where two thirds of the non-lactating cows and all young stock are grazed off the milking platform. For each grazing-off system (base), two options were modelled to reduce biosecurity risk: 1) reducing stocking rate to allow non-lactating cows and young stock to be grazed on the milking platform (self-contained); and 2) leasing support land to graze only owned non-lactating cows and young stock (lease). FARMAX and OVERSEER® models were used to predict the economic and environmental implications of each option. The results were tested at different milk prices representing low ($4.25/kg) milksolids (MS), medium ($6.25/kg MS) and high ($8.25/kg MS) prices. The results showed that a self-contained grazing system reduced profitability by at least 15% across all regions and milk prices when compared with the base farms. The self-contained options leached 3–7% more nitrogen and had 7–10% more greenhouse gas (GHG) emissions per hectare, compared with the base and lease options when grazing-off land was accounted for. However, at a catchment level, the land freed by moving to self-contained might be utilised by other farming enterprises that might have a different environmental footprint compared to dairy grazing.</p> 2019-10-28T00:07:05+13:00 Copyright (c) 2019 An innovation systems approach to understanding the impacts of grass grub damage in irrigated Canterbury dairy pastures 2020-04-02T09:34:19+13:00 Sue M. Zydenbos Anna L. Taylor Wei Yang Maureen O'Callaghan Scott Hardwick Richard J. Townsend Esther D. Meenken Michael J. Manning Ants H.C. Roberts Robyn A. Dynes <p>An innovation systems approach involving agribusiness representatives, researchers and farmers identified that damage caused by grass grub (<em>Costelytra giveni</em>) was a key factor contributing to areas of reduced yield within high-producing pastures. Using a recognised yield mapping technique, areas of ‘Low’ and ‘High’ pasture height were identified in different paddocks over 3 years; ‘Low’ areas had significantly higher numbers of grass grub larvae than ‘High’ areas. Pasture production was measured for the ‘Low’ and ‘High’ pasture height areas, and the difference was calculated to be 6800 kg DM/ha for 2018/19. This difference persisted after grass grub larvae were no longer active. Farm systems modelling analysis estimated this ‘yield gap’ led to a $650/ha/year difference in profit. A survey of farmer perceptions of grass grub damage on 23 central Canterbury dairy farms estimated 19% of pastures were affected by grass grub, with 11% of the area in those paddocks being damaged. Econometric modelling showed differences in farmer perceptions of grass grub damage. Data from the survey and the pasture measurements were combined with the farm systems modelling results to estimate a $1,870,000/year regional-scale impact of the ‘yield gap’. An integrated pest management approach is suggested to control grass grub damage.</p> 2019-10-28T00:10:34+13:00 Copyright (c) 2019 Modelling long-term changes in soil phosphorus and carbon under contrasting fertiliser and grazing management in New Zealand hill country 2020-04-02T09:33:48+13:00 Franco Bilotto Ronaldo Vibart Alec Mackay Des Costall <p>Soil carbon (C) stocks under permanent New Zealand pastures vary with slope and aspect due to differences in primary production, animal behaviour and nutrient return. An existing nutrient transfer model was extended using a web-based, general-purpose modelling tool to simulate long-term changes in soil phosphorus (P) and C in hill country under contrasting fertiliser and sheep stocking regimes. Three self-contained farmlets were examined: no P applied; 125 kg single superphosphate (SSP)/ha/year; and 375 kg SSP/ha/year, since 1980. The refined spatial model was able to simulate P and C distribution with varying slopes and aspects. For example, the mean annual changes in soil P and C were greater on low slopes and eastern aspects than on the other two slope and aspect positions, consistent with observed changes in these nutrients. However, the model overestimated changes in soil C, which highlighted both gaps in current knowledge and key factors influencing change in soil C stocks. Understanding the spatial patterns of soil C across the landscape will be critical in the design of soil C monitoring regimes, should soil C stocks be considered at a national level as a sink or <br>source of CO<sub>2</sub> emissions.</p> 2019-10-28T00:14:07+13:00 Copyright (c) 2019 The impact of possible changes to nitrogen loss regulations on the financial viability of dairy farms in the Upper Manawatu River catchment 2020-04-02T09:35:48+13:00 Terry G. Parminter Scott D. Ridsdale Stefan A. Bryant Ian G. McNab Kate A. Proctor Lynette A. Baish <p>The Manawatū-Wanganui Regional Council regional plan (the One Plan) regulates the use of natural resources in the Region and includes a table of nitrogen leaching maxima reflecting the natural capital of soils in the Region and based on Overseer® results from 2007. Dairy farms applying for controlled consents for intensive land-use activities in the Region need to comply with these maxima. However, the maxima in the Table have not been adjusted as new versions of Overseer® have been introduced since the table was produced.<br>This study compares the impact on representative dairy farms of complying with the original figures in the table with results from a revised table that takes into account more recent versions of Overseer®. Cluster analysis was used to select five representative farms in the Tararua District and their farm systems were modified to comply with both the original and the revised table. <br>The current version of Overseer® was used to model the farm outputs based on the original table of leaching maxima. Compared with the baseline farm results, nitrogen losses were reduced by over 50% and milk production by 40%. When the same comparison was undertaken with the table of revised maxima, the nitrogen losses were expected to reduce by almost 40% and milk production by 5%. Applying the original nitrogen leaching maxima to the five representative farms resulted in about two thirds of farms within the catchment being unable to pay the interest on their debts. The revised nitrogen leaching maxima reduced this to &lt;10%.<br>The nitrogen leaching maxima in the One Plan should be revised to: better reflect the changes in the science underpinning current versions of Overseer®; achieve the nitrogen reduction targets in the region; and minimise the impact of the One Plan policies and rules on the financial viability of existing dairy farms.</p> 2019-10-28T00:00:00+13:00 Copyright (c) 2019 The influence of spring grazing management on yield and water use of rainfed lucerne 2020-04-02T09:33:18+13:00 Richard E. Sim Derrick J. Moot <p>Flexible spring grazing management can increase the use of lucerne on farms. However, the negative impacts of set stocking on the survival of plants usually preclude its use. In this experiment, crops of ‘Stamina 5’ lucerne at Ashley Dene, Lincoln University were rotationally grazed, semi-set stocked or set stocked from September to December 2011. Dry matter (DM) yield to December was 6.3 t DM/ha, and consistent among crops. However, the larger leaf area of the semi-set- and set-stocked crops intercepted 45% more solar radiation and transpired 25% more water than the rotationally grazed crop. The set-stocked regime had a lower efficiency of resource use. This was probably due to greater respiration and/or partitioning of DM to the root mass. Set-stock regimes required continual initiation of new shoots from basal buds, which remobilised and, therefore depleted, stored assimilates. To minimise this impact, farmers should maintain a canopy cover of 2 to 2.5 t DM/ha (~20 cm tall) on any set-stocked lucerne. This will maximise radiation interception and compensate for reserve losses. In the study year, grazing management did not influence feed supply through the manipulation of water use because soil evaporation losses were inversely related to crop water use. Consequently, total water use was consistent among crops, with higher soil evaporation from frequent rewetting of the soil for rotationally grazed crops. For farmers, these results suggest continuous grazing of lucerne is possible, but it should be managed to maintain full canopy cover and minimise reserve depletion that will reduce DM yields and stand persistence.</p> 2019-10-28T00:22:40+13:00 Copyright (c) 2019 Improving environmental benefits of white clover through condensed tannin expression 2020-04-02T09:32:41+13:00 Derek R. Woodfield Marissa B. Roldan Christine R. Voisey Greig R. Cousins John R. Caradus <p>Forage legumes improve both the intake and quality of the diet in pasture-based livestock systems. However, the high protein content of these forages can lead to inefficient nitrogen utilisation in the rumen and to high nitrogen (N) losses in urine and dung. Condensed tannins in forages have been shown to significantly reduce N leaching and also methane emissions. <br>The use of classical breeding approaches over more than 50 years has failed to elevate condensed tannins in forage legumes. However, molecular biology approaches have achieved condensed tannin expression in white clover at levels that are biologically significant (&gt;2% of dry matter). Results from a field trial in the USA showed that while condensed tannin levels in white clover (<em>Trifolium repens</em>) were similar to those produced by birdsfoot trefoil (<em>Lotus corniculatus</em>), plants did suffer a yield penalty. Protein binding assays were conducted by incubating soluble white clover leaf CTs in a solution containing the protein bovine serum albumin (BSA). The CTs in white clover leaves efficiently precipitated BSA from the supernatant at pH 6.5, and these CT-protein complexes dissociated at pH 2.5.<br>While the use of genetically modified organisms in New Zealand is regulated, this development has the potential to improve environmental, animal health and animal productivity outcomes from grazed pasture systems.</p> 2019-10-28T21:44:55+13:00 Copyright (c) 2019 Inclusion of persistence in the DairyNZ Forage Value Index 2020-04-02T09:35:19+13:00 Cameron I. Ludemann David F. Chapman <p>Inclusion of a persistence trait into the DairyNZ Forage Value Index (FVI) is an important step toward developing a holistic assessment of the relative value to dairy farm businesses of perennial ryegrass (<em>Lolium perenne</em>) cultivars. For the purposes of the FVI, ‘persistence’ was defined as the persistence over time of yield differences between diploid and tetraploid functional groups, and implemented (as an interim step) via two measures: a mean persistence scaling factor (μ<em>PS</em>) and a relative pasture renewal cost (<em>RRC</em>). The values of μ<em>PS </em>and <em>RRC </em>were estimated by analysing four long-term dry matter (DM) production data sets from across New Zealand, then applied to all cultivars in the 2019 FVI lists. Incorporating persistence reduced the difference in overall FVI value between tetraploids and diploids between $117 and $202/ha (depending on diploid heading date, and region), partially re-balancing the sharp rise in tetraploid values and rankings resulting from incorporation of the metabolisable energy (ME) content trait. Implementing persistence in the FVI at the ploidy level is the first step toward inclusion of cultivar-specific persistence information. This next step will require persistence data for cultivars, plus more information on processes and criteria used by farmers when they decide to renew pastures.</p> 2019-10-28T00:00:00+13:00 Copyright (c) 2019 Scaling issues in the interpretation of dry matter yield differences among perennial ryegrass (Lolium perenne) cultivars 2020-04-02T09:32:11+13:00 David F. Chapman Gerald P. Cosgrove Barbara Kuhn-Sherlock David R. Stevens Julia M. Lee Laura Rossi <p>Perennial ryegrass breeding is estimated to be delivering rates of genetic gain in dry matter (DM) yield of 50–60 kg DM/ha per year of breeding effort. These estimates are based on DM yield data from tightly managed small-plot trials which are not necessarily representative of typical farm management. To assess the possible <em>realised</em> (on-farm) DMY gains from breeding, seasonal DMY data were collected contemporaneously at two ‘scales’ of evaluation for eight perennial ryegrass cultivars over a total of 14 seasons (comprising 5 ‘seasons’ in each of three years excluding the first winter) in each of four regions. The scales were denoted ‘small plot’ (SP, 10 m2, perennial ryegrass monocultures only) and ‘large plot’ (LP, 65–90 m2, subject to more intensive dairy cattle grazing and including all combinations of two nitrogen fertiliser rates with or without white clover as treatments). Relationships between DMY measured in SP versus LP were statistically significant (P&lt;0.001) for all combinations of region, N fertiliser level and clover presence/absence, indicating good general agreement in cultivar performance trends. However, the slope of the relationship (range 0.492 to 1.171, mean 0.733) was significantly less than 1 in three-quarters of the region by treatment combinations. The slope was closely and inversely related to the size of the difference in total N supply between and SP (N from fertiliser only) and LP (where N was supplied as fertiliser at a lower rate but included biological fixation): the smaller the difference in N supply between the two ‘scales’, the greater the slope. Estimated realised DMY differences between cultivar ranking positions on New Zealand dairy farms under future projected N fertiliser rates were in the range 0.7–0.8 of those predicted from the SP scale of evaluation.</p> 2019-10-28T21:52:21+13:00 Copyright (c) 2019 Beyond ruminants: discussing opportunities for alternative pasture uses in New Zealand 2020-04-02T09:31:40+13:00 Gina M. Lucci Maeve M. Henchion Lene Lange Stewart F. Ledgard Stewart R. Collie Gerald P. Cosgrove Anne S. Meyer Florian H.M. Graichen Susanne Barth James J. Lenehan <p>The New Zealand government has set ambitious goals for primary sector growth and of zero net carbon emissions by 2050. This presents an opportunity and obligation to develop new ideas for grassland production systems to increase export value and generate new job opportunities, while reducing environmental impacts. The aim of this paper is to draw on recent research in Europe to investigate some of the alternative and complementary uses for pasture as a feedstock for a green biorefinery. A biorefinery is a facility, or a series of processes, that convert biomass into a spectrum of value-added products. For example, protein can be extracted mechanically from green biomass once harvested. The residual fibre fraction could be used as a low-nitrogen feed for ruminants to reduce urinary nitrogen, while the liquid protein fraction could be processed to make it suitable for mono-gastric or human consumption. Enzymes can promote protein extraction and controlled conversion of insoluble plant fibres and oligosaccharides to foster gut-health promoting prebiotic food ingredients. Anaerobic digestion of residues can then be used to create energy and soil-improving products. Research and demonstration of these approaches in practice, along with the results of feasibility studies, will be required to see which of these opportunities is a good fit for New Zealand pasture systems.</p> 2019-10-28T21:54:46+13:00 Copyright (c) 2019 Maximising the value of irrigation through improved use of soil resources and sensor technology 2020-04-02T09:31:09+13:00 John J. Drewry Carolyn B. Hedley Jagath Ekanayake <p>This paper presents a case-study approach focussing on variability of soils, soil physical properties, and how the use of proximal sensor surveys and soil moisture monitoring can be used to improve irrigation management at fine spatial scales (&lt;10 m). Proximal sensor survey data have been used to map soil variability and statistically derive management zones, which are then correlated with S-map siblings using soil moisture release curves. At the first case study site, soil moisture monitoring of these management zones showed the poorly drained soil had wetter conditions than the other zones, which is likely to have been a factor contributing to reduced barley yield. Less irrigation could therefore have been applied to the poorly drained soil, with a saving in cost and yield penalty. In the second case study, we provide an overview of research focussing on practical applications of near real-time soil moisture monitoring and visualisation through smart phone apps, enabling new irrigation software and hardware to be matched to specific farm circumstances, so soils and crops can be managed to reduce water and nutrient losses.</p> 2019-10-28T21:57:10+13:00 Copyright (c) 2019 Increasing biological nitrogen fixation by white clover-rhizobia symbiosis 2020-04-02T09:30:40+13:00 Shengjing Shi Laura Villamizar Emily Gerard Clive Ronson Steve Wakelin Ross Ballard John R. Caradus Maureen O'Callaghan <p>Biological nitrogen fixation (BNF) is the process of converting atmospheric nitrogen to ammonia through legume–rhizobia symbiosis. The nitrogen fixed by rhizobia in root nodules is available for plant use. This process can be harnessed to improve N fertility on farm. Field surveys across New Zealand (NZ), within a farm and within paddocks, have revealed large spatial variability of rhizobial population size and symbiotic effectiveness with white clover. These results indicate that naturalised rhizobia may not be supporting optimal BNF. Over 500 strains of clover-nodulating rhizobia were isolated from NZ pasture soils, with more than 90 demonstrating greater N-fixation capacity with white clover than the commercial inoculant strain TA1. Seven NZ isolates were tested for nodule occupancy and all seven had significantly higher occupancy rates than TA1 in an in vitro assay, indicating increased competitiveness of those strains. In addition, novel seed-coating technology improved the survival of TA1 and isolate S10N9 from 1 month to more than 4 months compared with a standard coating formulation. There is potential to increase the symbiotic capacity of white clover in pastures through use of more effective and competitive rhizobial strains, along with their improved survival on seed provided by a new coating technology.</p> 2019-10-31T01:10:00+13:00 Copyright (c) 2019 Identifying the pasture potential for New Zealand dairy farms 2020-04-02T09:30:09+13:00 Mark B. Neal Simon J.R. Woodward Brian T. Dela Rue <p>Higher amounts of pasture and crop eaten on farm are associated with higher profit, and it is likely that many dairy farms have an opportunity to improve their financial performance. Regional averages of pasture and crop eaten are readily available but locally relevant estimates of achievable potential pasture and crop eaten are not, so farmers do not know what improvement to pasture and crop eaten and profitability might be possible. The Pasture Potential Tool was developed to provide a locally relevant estimate of that potential. Data on pasture and crop eaten were sourced from DairyNZ’s DairyBase farm performance database, and made available using an interactive web-based tool after testing with pilot groups of farmers. The tool defined a farm’s potential pasture and crop eaten in a particular year as the 90th percentile of farms within a defined radius, or the level that is exceeded by only one in ten farmers, with the data being filtered for comparable soil type and elevation, and adjusted for nitrogen fertiliser application. The tool is available on the DairyNZ website, and has been accessed more than 1300 times in the first 5 months since it went live (as of May 2019).</p> 2019-10-31T01:12:10+13:00 Copyright (c) 2019 Sampling methods for clover species in grazed pastures to diagnose mineral deficiencies 2020-04-02T09:29:39+13:00 Sonya T. Olykan Richard J. Lucas Derrick J. Moot <p>Diagnosis of clover nutrient status is important for legume-based pasture systems. The protocols for sample collection and setting of nutrient guidelines are ill-defined. This research quantified how nutrient concentrations differed between laminae (leaflets) and petioles (leaf stems) of subterranean (sub) clover (<em>Trifolium subterraneum</em>) and white clover (<em>T. repens</em>) as a first step in developing appropriate sampling procedures to examine the nutrient status of clover species.</p> <p>Field samples of sub and white clovers from three pasture sites in the Wairarapa and Canterbury were separated into lamina and full petiole and chemically analysed for nitrogen (N), phosphorus (P), potassium (K) and sulphur (S). Lamina + petiole K concentrations were lower in sub clover (2.3%) than white clover (3.2%). Across both species, the lamina concentrations of N (4.9%), P (0.36%) and S (0.28%) were higher than in the petiole (1.8%, 0.29% and 0.12% respectively) but the reverse was found for K (1.8 % lamina, 3.7% petiole). As a consequence, increasing the proportion of petiole added with the lamina affected the nutrient concentration of lamina + petiole samples so that N, P and S% declined but K% increased.</p> <p>In a subset of samples, NIR analysis found the crude protein of lamina + petiole in white clover was 24% compared with 21% in sub clover. Clover laminae of both species had 33% crude protein compared with only 11% in the petiole.</p> <p>The diagnosis of clover nutrient status for fertiliser recommendations should be based on lamina-only samples. In contrast, mixed pasture samples for nutritive value analysis should include clover laminae and petioles, plus grass and herb pasture components, to simulate grazing intake by livestock.</p> <p>The lack of defined sampling protocols may explain some of the difficulties previously reported in herbage nutrient interpretation and reconciling soil test results.</p> 2019-10-31T01:14:49+13:00 Copyright (c) 2019 Use of pasture botanical composition data on the accuracy of satellite pasture biomass estimates 2020-04-02T09:29:09+13:00 Grant P.S. Anderson Mitchell Rawlings Zoe Lunniss Lorna McNaughton Laura Rossi Cathal Wims Chris Roach Cameron I. Ludemann <p>Pasture biomass estimates are valuable to farmers, and satellite pasture biomass estimates can potentially provide the required data for less time and labour. However, the accuracy of satellite estimates of pasture biomass can be affected by the botanical composition of the pasture. In this study, botanical composition data were combined in linear regression models and a general additive model with on-farm and satellite pasture biomass estimates to quantify the increase in predictive power from including botanical composition data. The inclusion of botanical composition data improved the accuracy (model R<sup>2</sup>) of the satellite pasture biomass estimation; the smallest increase was 0.035 (from 0.725 to 0.760) and the largest increase was 0.111 (from 0.599 to 0.710). <br>Improving the accuracy of satellite estimations of pasture biomass will allow farmers to make more timely and accurate grazing management decisions.</p> 2019-10-31T01:17:05+13:00 Copyright (c) 2019 Starting out in farming – ownership, goals and opportunities 2020-04-02T09:28:38+13:00 Isabelle S. Crawshaw Patrick R. Crawshaw <p>&nbsp;&nbsp;</p> 2019-10-31T01:18:53+13:00 Copyright (c) 2019