Journal of New Zealand Grasslands 2020-10-19T01:03:04+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> NZGA President's Address 2019 - Smarter pasture renewal plus objective thinking 2020-09-10T01:01:48+12:00 Graham A. Kerr <p>-</p> 2020-09-09T00:00:00+12:00 Copyright (c) 2020 NZGA Levy Oration 2019: Musings on our sustainable agriculture journey 2020-09-10T01:01:17+12:00 Liz Wedderburn <p>-</p> 2020-09-09T20:02:24+12:00 Copyright (c) 2020 NZGA Calculation of sheep and beef economic weightings for the seasonal dry matter production trait for use in a forage-cultivar selection decision-support tool 2020-10-19T00:47:16+13:00 Cameron I. Ludemann <p>Development of an independent forage-cultivar selection decision-support tool (DST) could transfer substantial benefits to sheep and beef (S&amp;B) farmers. This study took a first step toward development of a S&amp;B DST by describing and assessing one method of calculating S&amp;B forage trait economic weightings. The ‘change in livestock production’ economic weighting method was applied to the Otago/Southland Breeding Finishing Farm Class in this study. The trait economic weightings for the seasonal dry matter (DM) production trait were applied to cultivar performance trial data using the DairyNZ Forage Value Index (FVI) framework. Analysis indicated the rankings of perennial ryegrass cultivars using the DST method varied from those calculated using the DairyNZ FVI when using the same seasonal DM production data. It was concluded the change in livestock production method is an option for calculating the economic value of traits for evaluation of perennial ryegrass cultivars that are more applicable to S&amp;B farmers. However, this method should be applied to a wider range of S&amp;B Farm Classes before a decision is made as to its suitability for the New Zealand S&amp;B industry.</p> 2020-09-09T20:29:49+12:00 Copyright (c) 2020 NZGA Genomic assessment of white clover and perennial ryegrass genetic resources 2020-09-16T01:00:37+12:00 Marty J. Faville Andrew G. Griffiths Abdul Baten Mingshu Cao Rachael Ashby Kioumars Ghamkhar Won Hong Anna Larking Michelle Williamson Zane Webber <p>Forage resources conserved in genebanks, such as the Margot Forde Germplasm Centre (MFGC; Palmerston<br>North), are reservoirs of genetic diversity important for the development of cultivars adapted to abiotic stresses and environmental constraints. Genomic tools, including genotyping-by-sequencing (GBS), can support identification of manageable subsets (core collections) that are genetically representative of these large germplasm collections, for phenotypic characterisation. We used GBS to generate SNP (single nucleotide polymorphism) profiles for 172 white clover (WC) and 357 perennial ryegrass (PRG) MFGC-sourced accessions and estimated genetic relationships amongst accessions. In WC, accessions aligned along an east-west transect from Kazakhstan to Spain, identifying major diversity in Caucasus/Central Asia and Iberian Peninsula. A key feature was the reduced diversity present in New Zealand (NZL) accessions. Similarly, for PRG, most NZL accessions coalesced as one group, distinct from large clusters associated with the Iberian Peninsula, Italy and eastern Mediterranean/Caucasian region. These results emphasise the relatively narrow genetic diversity in NZL WC and PRG, and the broad extent of largely unexploited global diversity. Capturing global genetic variation in<br>core collections will support pre-breeding programmes to mobilise novel genetic variation into New&nbsp; Zealand-adapted genetic backgrounds, enabling development of cultivars with non-traditional traits including enhanced<br>climate resilience and environmental performance.</p> 2020-09-15T18:32:31+12:00 Copyright (c) 2020 Real-time on-farm N loss measurement 2020-09-29T01:02:51+13:00 Samuel J. Dennis <p>Empirical measurements of nutrient-leaching losses on farms are required in order to allow validation of models used to assess nutrient losses from New Zealand farmland. However such on-farm measurements have, to date, been generally impractical.</p> <p>A new in-field leaching loss measurement system has been developed, based on well-established research methodologies. This system combines large strip lysimeters (10–20 m long) with largely automated, real-time leachate monitoring, which allows measurements to be taken over much larger areas for greatly reduced costs compared with other systems currently on the market.</p> <p>A spatial computer modelling simulation showed that one such lysimeter can generate results of equivalent accuracy to an array of 12 fluxmeters, three lysimeters are equivalent to an array of 64 suction cups, and a larger number of lysimeters can be used to obtain more accurate results.</p> <p>Nutrient loss is measured using off-site chemical analysis of flow-proportional subsamples of drainage water. In addition, electrical conductivity (EC) of the drainage water is measured continuously and correlated with past chemical analyses to provide real-time estimates of nutrient loss. Real-time EC measurements were strongly correlated with Total N concentration determined off site (R<sup>2</sup> = 0.89), which suggests that EC can be used as a proxy for Total N. However, a site-specific regression of EC and N should be used for any actual estimation of N from EC.</p> 2020-09-28T00:00:00+13:00 Copyright (c) 2020 NZGA Nitrogen leaching losses from fodder beet and kale crops grazed by dairy cows in southern SouthlandNitrogen leaching losses from fodder beet and kale crops grazed by dairy cows in southern Southland 2020-09-29T13:03:57+13:00 L. Chris Smith Ross M. Monaghan <p>Fodder beet has become increasingly common as both a winter forage and as a supplement at the shoulders of the dairy season in southern New Zealand. One advantage over the more traditional kale crop option is that fodder beet results in less urinary nitrogen (N) excretion in dairy animals, potentially reducing N leaching. Two trials were undertaken to measure nitrogen leaching losses under both autumn-grazed or autumn-lifted fodder beet crops. Leaching losses were also measured from winter-grazed fodder beet and winter-grazed kale treatments. Results from Trial 1 show that leaching losses from autumn-lifted or autumn-grazed fodder beet&nbsp; treatments were large (108–131 kg N ha<sup>-1</sup>) relative to losses measured in the winter-grazed fodder beet treatment (82 kg N ha<sup>-1</sup>). This indicates that autumn-grazed fodder beet crops have a greater potential for N leaching than winter-grazed fodder beet. The practice of lifting and removing fodder beet during autumn appeared to reduce N leaching somewhat, but losses were still relatively large, perhaps due to carryover of N from the previous season as a result of the dry summer conditions that preceded the drainage season in in the first year of Trial 1. The amount of N leached from the winter-grazed fodder beet treatment from Trial 1 at 82 kg N ha<sup>-1</sup> was 50% less than the 176 kg N ha<sup>-1</sup> observed for the kale crop. Results from Trial 2 using larger plots showed a similar trend, with winter-grazed fodder beet leaching 42% less N than winter-grazed kale (41 vs 70 kg N ha<sup>-1</sup>; P&lt;0.001), despite not all the urine N being collected by the end of the drainage season. These losses are relatively large compared to the annual N leaching losses measured from pasture paddocks on the same farm, which ranged from 13–23 kg N ha<sup>-1</sup>. Considerations of grazing and/or harvest timing (autumn vs winter) as well as crop type appear to be important factors that determine N leaching losses from Southland dairy systems.</p> 2020-09-29T00:20:08+13:00 Copyright (c) 2020 NZGA Impact of winter fodder beet or kale allocation on body condition score gain and early lactation performance of dairy cows 2020-09-29T01:00:37+13:00 Dawn E. Dalley J. Paul Edwards Roshean R. Woods <p>Forage crops such as fodder beet (FB) and kale are an important feature of dairy farming in Southland and Otago where winter pasture growth is negligible. However, farmers are concerned about poor performance of cows following winter FB feeding. In winter 2017, cows were offered FB or kale both with pasture baleage at two allocation rates: target (crop allocated to achieve a winter body condition score (BCS) gain of 0.7) or high (<em>ad libitum </em>crop). Diets with FB were lower in fibre, phosphorus, sulphur and calcium, but had a higher metabolizable energy, compared with kale diets. Body condition change and early lactation performance were monitored to compare effects of winter FB and kale diets. Average daily BCS gain before calving was similar for FB and kale cows. Crop type had a greater impact on cow performance than allocation rate. Cows wintered on FB had better reproductive performance (3-week pregnancy rate), and greater average milk solids, fat and protein yield (kg/d) than cows wintered on kale. Therefore, winter FB did not reduce cow performance compared with kale. However, the cumulative effects of a FB diet long term are yet to be determined and future research should monitor the impact on animal health.</p> 2020-09-29T00:39:43+13:00 Copyright (c) 2020 NZGA Effect of cultivar, timing of establishment and cutting interval on yield and seed set of arrowleaf clover 2020-09-30T01:01:43+13:00 Paul D. Muir Beverly C. Thomson Noel B. Smith <p>Arrowleaf clover is an erect hard-seeded annual clover with potential to improve the typically low legume content of dryland hill country. A number of small plot experiments were undertaken to better understand arrowleaf management. Cultivar maturity impacted on single-cut yields, with later maturing cultivars (‘Arrotas’ and ‘Zulu 11’) having significantly higher yields than an early maturing cultivar (‘Cefalu’). When autumn oversowing was practised, the slow growth of arrowleaf during winter caused weed issues. Delaying sowing of arrowleaf clover from April to winter (July) did not affect dry matter yield, seed set or seed viability and avoided the need for a weed spray as the vigorous spring growth of arrowleaf out-competed weed species. Arrowleaf oversown on hill country and allowed to set seed to build a large bank of hard seed resulted in a bulk of fibrous trash that was difficult to clean-up with grazing stock. Four mowings to simulate grazing encouraged weed invasion and reduced legume yields (and trash). Whilst two mowings were optimal for seed yield, up to three mowings provided a compromise between setting seed, utilising feed for grazing and reducing trash after flowering.</p> 2020-09-29T20:11:08+13:00 Copyright (c) 2020 NZGA Understanding water losses from irrigated pastures on loess-derived hillslopes 2020-10-16T21:46:34+13:00 Stephanie Langer Rogerio Cichota Steve Thomas Dirk Wallace Gina van der Klei Mike George Tom Johns Peter Almond Shane Maley Nathan Arnold Wei Hu MS Srinivasan Channa Rajanayaka Matt Dodson Roderick Hayman Chandra Ghimire <p>Irrigation is likely to increase water losses from hillslopes, particularly on loess-derived soils with impeded drainage. This is important as irrigation of these soils in New Zealand is increasing. A field site was established to measure runoff from a pasture hillslope irrigated by a centre-pivot in South Canterbury. Between November and March, 161 and 199 mm of irrigation was applied, with 23% more at the bottom of the slope. Runoff varied with position in the hillslope, with 3.5 times from the bottom plot (52 mm) compared to the top. Over the length of the slope (40 m) this represents a potential loss of 9% of precipitation, or 21% of the irrigation. Evidence for saturation excess and infiltration excess runoff was observed, with antecedent soil moisture conditions being a key factor. Pasture production and water use efficiency (WUE) also varied with slope, the least (4.6 t DM/ha or 12 kg DM/ha/mm) observed at middle and most at the top of the slope (10.1 t DM/ha or 23 kg DM/ha/mm). This was likely due to a combination of differences in radiation and soil conditions. There was indication that pasture growth was limited by water availability at the top and potentially excess at the bottom of the slope. Our results indicate potential for improving irrigation practices.</p> 2020-09-29T20:26:00+13:00 Copyright (c) 2020 NZGA Winter-forage crop grazing in the Gore-Mataura area of Southland: using time-series mapping to estimate location and frequency of cropping 2020-10-07T01:01:10+13:00 John J. Drewry Heather North Stella E. Belliss Alexander Amies <p>Winter grazing of forage crops is a key land-use in southern New Zealand, providing important feed for livestock but has been identified as risky if not managed well, potentially resulting in soil degradation and nutrient losses. We hypothesised that analysing an existing time series of winter-forage maps, derived from satellite imagery could be used to identify how often paddocks are re-used for winter forage. A pilot study was undertaken to explore the practicality and utility of this new method by examining maps derived from satellite images of the Gore-Mataura area, Southland taken in 2013, 2014, 2017, and 2018. Within the study site (67,618 ha), 8925 ha was classed as winter forage in one or more of the source maps. Eighty-five percent of this area was used in only one of the four years, and just 1% in three or four years. High-certainty class pairs for 2013/14 and 2017/18 show two consecutive years of winter forage in the same paddock, 31% or 21% of the time, respectively. These winter-forage crops were generally grown on Brown soils (63%), followed by Pallic and Gley soils. Although, this study was limited by differences in the mapping methodologies of the source maps, it nonetheless&nbsp; demonstrated that potentially valuable data can be derived. It showed a low level of repeat use of paddocks for winter forage grazing over all the years studied, and that Brown soils are more commonly used for winter forage than previous studies suggested.</p> 2020-10-06T21:59:05+13:00 Copyright (c) 2020 NZGA Yield of subterranean clover after post-emergence herbicide application for broadleaf weed control 2020-10-07T01:01:42+13:00 Breanna J. O. Taylor Rainer W. Hofmann Derrick J. Moot <p>A field experiment was established in Lincoln, Canterbury in autumn 2018 to evaluate the effect of acetolactate synthase (ALS) inhibiting herbicides on subterraneun (sub) clover. Two herbicides, imazethapyr and flumetsulam, were applied to seven sub clover cultivars at the 4-5 trifoliate leaf stage during July 2018. By December 2018, both herbicides had reduced the broadleaf weed yield by 1000 kg DM/ha. Sub clover herbage yield in spring (3 Oct 2018) increased only for ‘Antas’ and ‘Napier’ cultivars but all cultivars had an increase in total annual herbage yield when herbicides were applied. Plots were managed for seed set so re-establishment was examined. Imazethapyr had a longer residual than flumetsulam with greater control of broad-leaved dock (<em>Rumex obtusifolius</em>) eight months after application. Herbicide application had no effect on subsequent sub clover emergence the following year. This experiment demonstrated the potential to establish a pure sward of sub clover with the use of ALS inhibiting herbicides, which could be used to create a high legume base in pasture before overdrilling grass the following year.</p> 2020-10-06T00:00:00+13:00 Copyright (c) 2020 NZGA Identifying morphological traits associated with vegetative persistence in the perennial ryegrass (Lolium perenne L.) cultivar 'Grasslands Samson' 2020-10-07T01:00:38+13:00 Jessica R. O'Connor James R. Crush Zulfi Jahufer <p>Perennial ryegrass (<em>Lolium perenne</em> L.) vegetative persistence (maintained herbage growth and survival without reseeding) is an important economic trait for farmers in New Zealand as it decreases the frequency of reseeding pastures. Vegetative persistence is difficult to breed for due to a lack of long-term trials to observe the complex interactions between plant genotype and the environment. In a long-term trial a genetic shift in the sown cultivar population could occur as individual plants with advantageous traits outcompete other plants and survive. The objectives of our study were to investigate the occurrence of a potential genetic shift in a sample (30 plants) of a persistent population of ‘Grasslands Samson’ perennial ryegrass. Persistent plants were collected from a nine-year-old trial at Poukawa, Hawke's Bay. To identify a genetic shift, these plants were compared to a sample of 30 plants sourced from commercial seed of ‘Grasslands Samson’ representing the original population. This study estimated genotypic variation within and between the populations for eight morphological traits after 10 weeks' growth under glasshouse conditions. Phenotypic and genotypic correlations between the traits were estimated. Results showed that the persistent population had significantly (P&lt;0.05) greater means for tiller number, reproductive tiller number, lamina sheath length, and dry weight. Future research studying these traits across farm environments would further understanding of their roles in vegetative persistence of ryegrass.</p> 2020-10-06T22:53:38+13:00 Copyright (c) 2020 NZGA Persistence of perennial ryegrass, tall fescue and cocksfoot following sequential annual sowings: pasture yield, composition and density in three establishment years under cattle grazing in Waikato 2020-10-17T01:00:40+13:00 Gerald P. Cosgrove Michael R. Trolove Maryann R. Staincliffe Katherine N. Tozer <p>Persistence is an important component of perennial pasture-grass productivity. Defining the traits that affect persistence is essential for improving pasture longevity through plant breeding and for identifying criteria that should be included in cultivar ranking indices. Compared with a conventional longitudinal study (a single study monitored over time), repeated annual sowings allow the effects on persistence of sowing year and the ensuing interactions between environment and age of pasture to be identified. An experiment commenced in 2016 in Waikato, in which eight cultivars of perennial ryegrass representing different ploidy, flowering date, and cultivar age, and one each of tall fescue and cocksfoot were sown each autumn in a randomised complete block design with four replicates in autumn 2016, spring 2017 and autumn 2018. This paper reports interim data on pasture yield, composition and density in the autumn following each sowing, and for the 2018 sowing only, in the 6 months after sowing. For the three successive autumn measurements there were significant effects due to cultivar, year of sowing and their interactions for all pasture variables. These differences in establishment may have consequences for the future resilience of these pastures under natural biotic and abiotic stressors.</p> 2020-10-16T22:35:18+13:00 Copyright (c) 2020 NZGA Commercial practice of out-wintering dairy heifers in Great Britain 2020-10-19T01:03:04+13:00 Norton E. Atkins Keith E. Walley Liam A. Sinclair <p style="margin-bottom: 0cm; line-height: 150%;" align="left"><span style="font-family: Times New Roman, serif;">The majority of dairy cattle in Great Britain (GB) are housed during winter but replacement heifers are out-wintered on some farms, a practice that may reduce the need for high capital-cost housing and facilitate herd expansion. Dairy farmers that were out-wintering replacement heifers in GB in 2012 were surveyed to determine current practice and attitudes. A typical system involved heifers strip grazing pasture or a crop, with baled grass silage as supplementary feed;<span style="color: #000000;"> strongly resembling outdoor wintering systems in New Zealand. </span><span style="color: #000000;">Many used more than one grazed forage; predominantly, p</span><span style="color: #000000;">asture on </span><span style="color: #000000;">68%, kale on 53% and fodder beet on 33% of farms. Supplementary feed </span><span style="color: #000000;">w</span><span style="color: #000000;">as</span><span style="color: #000000;"> 44% of the diet in younger, and 35% in older heifers. </span><span style="color: #000000;">Although farms were approximately three times larger than the national average and 60% were expanding, expanding herd size was not the primary reason for out-wintering, with the main reasons being to reduce cost and improve animal health and welfare. Farmers that out-wintered heifers typically reported good animal average dairy gain of 0.6 kg/d </span><span style="color: #000000;">and </span><span style="color: #000000;">h</span><span style="color: #000000;">igh</span><span style="color: #000000;"> body condition</span><span style="color: #000000;">, however, this contrasts with </span><span style="color: #000000;">some </span><span style="color: #000000;">measured performance in GB. Farmers may benefit from accurate feed allocation and monitoring heifer live weight during winter to ensure high performance.</span></span></p> <p class="western" style="margin-bottom: 0cm; line-height: 150%;" align="left"><span style="color: #000000;">&nbsp;</span></p> 2020-10-18T22:05:23+13:00 Copyright (c) 2020 NZGA Potential profit gains from improving pasture productivity on New Zealand South Island high-country farms 2020-10-19T01:01:56+13:00 Charles A. Morrison Victoria C.F. Westbrooke Jim L. Moir <p>Soil acidity combined with low levels of key nutrients on New Zealand hill-country farms are limiting factors for legume establishment/growth. However, legumes are a critical component of these farms as they provide nitrogen and high-quality feed. A farm-systems model was developed to estimate the impact of targeted fertiliser and lime application, combined with sowing clover, on whole-farm productivity and profitability. A base model was developed that incorporated 17 years’ worth of Beef + Lamb NZ survey data for Class 1: South Island Farms. This base model was then used investigate two lime-application/oversowing models where part of the modelled high-country farm was targeted for improvement: (1) Conservative, i.e. 0.6% farm area; and (2)&nbsp; Aggressive, i.e. 2.8% farm area. Three scenarios to utilise the additional pasture grown were then investigated for each model by: (a) increasing ewe numbers; (b) increasing ewe performance (lambing percentage); and (c) increasing liveweight gain of stock. Scenario 2a, generated the highest profitability level (Earnings before Interest Tax and Rent, EBITR $58,870) above the base model but became less financially attractive when the two years required to build the maternal ewe flock were factored in. Scenarios 2c and 1b generated increases in profitability (EBITR) between $33,310 and $41,290 above the base model. Variation in product prices, production levels and time to develop the final farm-management system would also influence the productivity and profitability of the scenarios. Environmental aspects, infrastructure and staff availability would affect the suitability of the development for individual farming businesses.&nbsp;</p> 2020-10-18T23:22:13+13:00 Copyright (c) 2020 NZGA Mitigation of saturation in satellite pasture measurement via incorporation of a statistical pasture growth model 2020-10-19T01:01:14+13:00 Grant Anderson Mitchell Rawlings Graeme Ogle <p>Measurement of pasture biomass is useful to farmers, as it enables timely and accurate management decisions. Satellite pasture measurement allows this information to be obtained with minimal time and labour on the part of the farmer. However, the accuracy of satellite measurements for high levels of pasture biomass can be impacted by a phenomenon called saturation, in which the response of the satellite estimate to increased biomass is diminished in situations of high biomass. In this investigation, a statistical pasture growth model was combined with satellite pasture measurements, with the aim of mitigating the effect of saturation on estimation accuracy. Data were captured for five farms, across two regions and an 18–21 month measurement period. Where satellite measurements appeared to be saturated, the growth model estimate was substituted. This process resulted in improved accuracy (R<sup>2</sup> improved from 0.672 to 0.703; RMSE improved from 334 to 309 kg DM/ha; and average bias improved from -62 to -9 kg DM/ha). The statistical improvements were more pronounced where terrestrial estimates were higher so the impact of saturation would be greatest. These results indicate that the problem of saturation in satellite pasture measurement can be addressed by the incorporation of modelled data.</p> <p>Prior research has predicted that improved accuracy of pasture measurement would be associated with increased profitability, and this work helps achieve that goal for farmers using satellite measurement services.</p> 2020-10-18T23:39:13+13:00 Copyright (c) 2020 NZGA Quantifying the value proposition for white clover persistence on a New Zealand summer-dry hill-country farm 2020-10-19T01:00:40+13:00 Mike B. Dodd Katherine N. Tozer Iris Vogeler Rose Greenfield David R. Stevens Tim Rhodes Sue Quilter <p>The improvement in forage quality and quantity of summer-dry hill country pasture resulting from the introduction of clover is well recognised. However, ensuring the persistence of the commonly available<br>cultivars is challenging, in the face of seasonal moisture stress, intensive grazing, competition from established well-adapted pasture species, low soil fertility and low soil pH – conditions typical of the East Coast of the North Island. Here we quantify the value proposition associated with the introduction of white clover into a case study on a Gisborne sheep and beef farm, using a six-step process. A topographically explicit approach is taken, using an understanding of the underlying spatial variability, based on a combination of soil and pasture measurements, APSIM simulation modelling of pasture growth and farm system modelling of enterprise performance. We show that from a baseline of a typical low-fertility, diverse species hill country pasture, white clover introduction can increase spring and summer forage consumption by 17%, enabling inclusion of an additional 6-month bull finishing enterprise generating a 32% greater carcass weight production and leading to a 49% improvement in farm system EBIT. This represents a positive net present value of over $360,000 for the original investment in white clover establishment into existing pastures.</p> 2020-10-18T23:55:10+13:00 Copyright (c) 2020 NZGA Application of circular economy principles to New Zealand pastoral farming systems 2020-09-29T01:01:45+13:00 Vicki T. Burggraaf Gina M. Lucci Stewart F. Ledgard Diogenes L. Antille Val O. Snow Cecile A. M. de Klein <p>Global food production is under pressure to produce more from limited resources, with further expectations to reduce waste and pollution and improve social outcomes. Circular economy principles aim to design out waste and pollution, minimise the use of nonrenewable external inputs and increase the lifespan of products and&nbsp; materials. Waste sources on New Zealand farms and options to reduce waste and improve circularity were reviewed. Waste reduction should begin with systems design, while recycling should be at the bottom of the hierarchy. On-farm resource use efficiency has been widely studied, but there are also opportunities to&nbsp; repurpose waste and integrate systems. The use of organic waste products as fertiliser and supplementary feed occurs to some extent, as does use of excess dairy calves in the beef industry, but they present both&nbsp; opportunities and challenges. More farm waste recycling opportunities are becoming available, with new products available from waste processing, such as plastic fence posts. Circular strategies in New Zealand agriculture require more analysis to determine economic, social, cultural and environmental outcomes.</p> 2020-09-28T23:19:02+13:00 Copyright (c) 2020 NZGA Impact of pasture height and herbage mass on suppression of variegated thistle in North Island East Coast hill country 2020-10-08T14:08:12+13:00 Katherine N. Tozer Rose Greenfield Renee Grigson Catherine Cameron Ants Roberts Emma Noakes Tim Rhodes Sue Zydenbos <p>Variegated thistle in East Coast North Island hill country reduces pasture and livestock productivity. To quantify the impact of increasing amounts of pasture cover (herbage mass) on this weed, variegated thistle seeds were hand-sown in autumn into pasture swards that ranged in height from 0 cm (bare ground) to 12 cm, on an East Coast property near Gisborne. Sward height was maintained by mowing without damaging the thistle plants. Increasing pasture cover reduced thistle emergence, height, diameter, biomass, survival, and seed production. By early June, 7 weeks after sowing, thistle emergence was greatest from bare ground and from maintaining a pasture at a height of 3 cm (&gt;1100 kg DM ha<sup>-1</sup> in autumn) and declined with increasing pasture height. By December, thistle height, diameter, biomass, flowerhead production and survival were highest in the bare ground treatment (thistle biomass ≈760 g plant<sup>-1</sup>), much lower in the 3-cm pasture height treatment (≈20 g plant<sup>-1</sup>), negligible in the 6-cm (&gt;1600 kg DM/ha) and nil in the 8-cm (&gt;1800 kg DM ha<sup>-1</sup>) and 12-cm (&gt;2700 kg DM ha<sup>-1</sup>) pasture treatments (P&lt;0.002). Maintaining pasture height of 3 cm severely reduced variegated thistle establishment, growth and flowerhead production. Results infer that grazing management strategies, such as lengthening the interval between grazing events in autumn and early winter, will increase pasture cover and are likely to severely reduce thistle establishment, growth and seed production.</p> 2020-10-05T21:29:50+13:00 Copyright (c) 2020 NZGA Effect of deferred grazing during late spring and summer on pasture productivity in Waikato and Bay of Plenty hill country 2020-10-08T13:00:38+13:00 Katherine N. Tozer Karin Müller Tony Craven Ian Tarbotton Allen Coster Rick Burke Jon Sherlock Catherine Cameron <p>Deferred grazing is a commonly used tool to manage feed surpluses. The effect of deferred grazing on pasture nutritive value and productivity was quantified in a split-paddock trial on three hill country farms in Waikato and Bay of Plenty from October 2018 until May 2020. Livestock were excluded from the deferred pasture between mid-October 2018 and March 2019. Thereafter, both treatments were rotationally grazed in common with cattle or sheep depending on the farm. Total annual dry matter production was 15% greater in the deferred than grazed treatment for the 12 months after deferring (8.9 vs 7.7 t DM/ha, P&lt;0.05). Metabolisable energy (ME) values at the end of the deferred period were lower in the deferred than grazed treatment (P&lt;0.01) but similar in both treatments thereafter. The content of legumes other than white clover (<em>Trifolium repens</em>) was higher in deferred than grazed pastures in spring 2019 on one of the farms (treatment × farm interaction P&lt;0.05). Ground cover of perennial ryegrass was greater and the area of bare ground smaller, in the deferred than grazed treatment on three of five occasions from after the beginning of the deferred period until up to 8 months after deferring (P&lt;0.05). There was no difference between treatments in decomposition and stabilisation of organic matter (P&gt;0.05). The topsoil water content was higher in the deferred than grazed treatment for 12 months after deferring. In comparison to regular grazing between October and March, deferred pastures provided drought feed in autumn 2019. Pasture productivity was increased after the deferred period without negative impacts on ME.</p> 2020-10-08T09:50:47+13:00 Copyright (c) 2020 NZGA Can Lotus pedunculatus over-sowing in low-fertility tussock country increase farm resilience? 2020-10-19T01:02:30+13:00 David R. Stevens J. Pat Garden Nick Garden Marie J. Casey <p>The range of legumes to boost farm productivity in low-fertility hill country are limited. <em>Lotus pedunculatus</em> (Lotus) provides an option when soil pH is below 5 but is intolerant to severe and regular grazing. However, it<br>can be used at sites that are only grazed occasionally during spring summer and autumn. Oversowing of <em>Lotus pedunculatus</em> has been used to improve 17% of the total area of Avenel Station, Millers Flat. Measurements of pasture growth and animal production were collected over three years post-sowing, indicating a doubling of pasture production from the native form while providing liveweight gains of 0.135 and 0.75 kg/d in lambs and yearling cattle respectively. Systems modelling was used to re-examine the current farm-system configuration to test the possible outcomes from implementing further enterprises that may capture the increased late spring and summer production effectively. Reducing ewe numbers and concentrating on improving lamb survival were the most cost-effective and environmentally effective options. Buying in further finishing lambs to use the summer surplus also improved profitability. Increasing cow numbers was similarly profitable. Increasing ewe&nbsp; numbers also required an increase in winter feed supply and was the least profitable way to capture the&nbsp; benefits. Testing using climatic extreme scenarios demonstrated that the oversowing of Lotus on the higher, wetter tussock country increased the resilience of the farm by providing a buffer during dry summers.</p> 2020-10-18T22:13:56+13:00 Copyright (c) 2020 NZGA Factors influencing fertiliser and lime decisions on South Island high- and hill-country farms 2020-09-29T01:02:18+13:00 Xiaomeng K. S. Lucock Jim L. Moir <p><strong>Highlights</strong><br>• Fertiliser and lime decisions by high- and hill-country farmers directly impact on their farm performance, but the factors influencing these decisions are not well understood.</p> <p>• Factors influencing South Island high- and hill-country farmers’ fertiliser and lime decisions are a complex matrix of both biophysical and socio-economic components, such as costs, location, soil conditions and public perception.</p> <p>• Factors influencing these farmers’ fertiliser and lime decisions reflect the complex farm systems and the wider socio-economic environment that they operate within. A greater empathy between the farming and non-farming communities will help alleviate some of the challenges faced by these farmers.</p> 2020-09-28T00:00:00+13:00 Copyright (c) 2020 NZGA Ammonia-oxidizing bacteria dynamics affected by plantain under synthetic cattle urine patches 2020-09-30T01:00:39+13:00 Priscila Simon Cecile De Klein Emily Gerard Shenjing Shi <p>Plantain has been suggested as a nitrous oxide (N<sub>2</sub>O) and nitrate (NO<sub>3</sub><sup>-</sup>) leaching mitigation option as it may induce biological nitrification inhibition (BNI) via plantain root exudation, which affects the activity of ammonia-oxidizing bacteria. This preliminary study compared the abundance of the ammonia monooxygenase gene (<em>amoA</em>) in soils containing either plantain and white clover, or ryegrass and white clover. Plants were sown in pots and grown in a greenhouse. Two months after sowing, synthetic cattle urine was applied to half the pots, and rhizosphere and bulk soil samples were collected 30 and 90 days after urine application. The abundance of the <em>amoA</em> gene was measured using real time quantitative PCR. The abundance of <em>amoA</em> genes in rhizosphere soil around ryegrass plants and in bulk soil under ryegrass/white clover were higher in pots treated with urine than the no-urine controls.&nbsp;<em>AmoA </em>gene abundance in bulk soil under plantain/white clover was higher in pots treated with urine (P&lt;0.05) but not in rhizosphere soil around plantain plants (P&gt;0.05) compared with the control. Furthermore, <em>amoA</em> gene copy numbers in the rhizosphere soil around plantain plants were lower than for ryegrass plants (P&lt;0.05). However, there was no difference in the abundance of <em>amoA</em> genes in bulk soil of either combination of plant species evaluated (P&gt;0.05). The results suggest that, in the time frame of our experiment, plantain could induce a BNI effect in the rhizosphere soil but not in the bulk soil.</p> 2020-09-29T20:46:05+13:00 Copyright (c) 2020 NZGA