South Otago Research Articles

A Nearest-Neighbour Gaussian Process Spatial Factor Model for Censored, Multi-Depth Geochemical Data

Abstract We investigate the relationships between local environmental variables and the geochemical composition of the Earth in a region spanning over 26,000 km2 in the lower South Island of New Zealand. Part of the Southland–South Otago geochemical baseline survey—a pilot study pre-empting roll-out across the country—the data comprise the measurements of 59 chemical trace elements, each at two depth prescriptions, at several hundred spatial sites. We demonstrate construction of a hierarchical spatial factor model that captures inter-depth dependency; handles imputation of left-censored readings in a statistically principled manner; and exploits sparse approximations to Gaussian processes to deliver inference. The voluminous results provide a novel impression of the underlying processes and are presented graphically via simple web-based applications. These both confirm existing knowledge and provide a basis from which new research hypotheses in geochemistry might be formed.

The target site mutation Ile-2041-Asn is associated with resistance to ACCase-inhibiting herbicides in Lolium multiflorum

ABSTRACT Acetyl-coenzyme A carboxylase (ACCase) inhibitors such as haloxyfop, pinoxaden and clethodim selectively control grass weed species in many types of crop. Here, we characterised two populations of Lolium multiflorum (Italian ryegrass), R and RV, from South Canterbury and Central Otago respectively, that were suspected to be resistant to ACCase-inhibiting herbicides. Based on 50% reduction in biomass (GR50), in two dose–response experiments, both populations were highly resistant to haloxyfop with resistance factors (RF) >400 times, but resistance to pinoxaden was low (RF of 2). Furthermore, population R was found to be moderately resistant to clethodim (RF >4, based on 50% reduction in survival (LD50)), but population RV had RFs barely greater than 1, based on GR50. Gene sequencing showed that the same target site mutation (Ile-2041-Asn) was associated with resistance to the three herbicides in both populations. The zygosity of the resistance alleles in the plants tested could cause the differences in resistance to clethodim observed between the populations, even though they carried the same mutation. This is the first report of the mechanism of resistance to ACCase-inhibiting herbicides in Italian ryegrass from New Zealand.

Chapter 13 Permian–Triassic felsic tuffs in South Island, New Zealand: significance for oceanic and active continental margin subduction

Abstract Felsic tuffs play an important role in the Permian–Triassic geology of the Eastern Province in South Island. In the Brook Street Terrane, primary felsic tuff is minor in the south (e.g. Takitimu Mountains) but abundant in the north (Grampian Formation, Nelson area). Felsic fallout tuff dominates one interval of the Maitai Group (Early Triassic Kiwi Burn Formation), south of the Alpine Fault, but is otherwise mainly redeposited by gravity flows. The Murihiku Terrane is characterized by two main intervals of felsic fallout tuff, the Middle Triassic Gavenwood Tuffs and the Late Triassic Bare Hill Tuff Zone, south of the Alpine Fault (e.g. Hokonui Hills and south Otago coast). Counterparts north of the Alpine Fault (Richmond Group) are mainly reworked, with terrigenous admixtures. Tuffaceous sediments are also abundant in the late Middle–early Late Triassic Willsher Group (south Otago coast). Based on combined field, petrographical, semi-quantitative X-ray diffraction (XRD) and chemical evidence, the felsic tuffs of the Brook Street Terrane in the south are interpreted as small-scale eruptions of fractionated oceanic-arc-type magmas. In contrast, the Triassic felsic tuffs of the Murihiku Terrane, Willsher Group and Maitai Group erupted violently and episodically in proximal to distal segments of the SE Gondwana continental margin.

A survey of antimicrobial use in dairy cows from farms in four regions of New Zealand

AIMS: To assess the use of antimicrobials in dairy cows over three seasons in a group of dairy farms within the Southland and South Otago region, and to assess antimicrobial use in one season in a group of monitored dairy farms in four regions of New Zealand.METHODS: Sales data were collated for all antimicrobials purchased by 399, 406 and 436 dairy farms in the Southland and South Otago regions for the 2012–13, 2013–14 and 2014–15 seasons, respectively, and from 108 dairy farms in the Manawatu, Taranaki, North Canterbury, and Southland and South Otago regions of New Zealand for 2014–15. Antimicrobials were categorised by class and product type (injectable, or dry cow or lactating cow intramammary). Antimicrobial usage was calculated as the mass of active ingredient (ai) per kg biomass, or population correction unit (PCU), with biomass estimated from the number of cows and heifers in the milking herd on 1 June multiplied by 458 kg.RESULTS: Estimated annual use of antimicrobials in the Southland and South Otago herds was 8.47, 9.58 and 9.54 mg ai/PCU for the three seasons, and for herds in the four regions was 8.65 mg ai/PCU for 2014–15. Penicillins were the most commonly used antimicrobials. Between 2012 and 2015, penicillin use increased from 5.75 to 7.44 mg ai/PCU, whereas there was a decrease in use of macrolides (1.19 to 1.04 mg ai/PCU) and cephalosporins (0.82 to 0.45 mg ai/PCU). Estimated annual use in 2014–15 by herds in Manawatu, Taranaki, North Canterbury, and Southland and South Otago was 8.93, 5.28, 6.44 and 9.97 mg ai/PCU, respectively, and also varied with size of herd. In these herds, injectable products were most commonly used (4.89 mg ai/PCU), followed by dry cow intramammary (3.04 mg ai/PCU), then lactating cow intramammary treatments (0.71 mg ai/PCU).CONCLUSIONS: The use of antimicrobials in dairy cows in New Zealand appears low by international standards, but varied across years and across regions. The vast majority of antimicrobials used by class were penicillins. This is the first attempt at a national assessment of antimicrobial use by volume and type for dairy cows in New Zealand and will aid in the progression of a strategy of reduction, refinement and replacement of antimicrobial use in animals.

Identifying critical soil water thresholds to decrease cattle treading damage risk

ABSTRACTTo minimise soil compaction, land managers should limit cow grazing periods when soil water content (SWC) is greater than a critical water content (CWC) at which point soils are prone to treading damage. A laboratory-based method, the ‘proctor test’, has been used to identify the CWC in two intact Pallic soils collected from North and South Otago, New Zealand. We have attempted to relate the CWC to a simple field-based metric—the soil plastic limit—which can be measured by farmers as a proxy for CWC. Plastic limit was a suitable proxy for CWC in the North Otago soil only. In the South Otago soil, the CWC occurred at a lower SWC than the plastic limit. Although CWC varied across the two soil types, in both instances, it was reached at an SWC less than field capacity, while this was not always the case for plastic limit.

Effects of applying dairy wintering barn manure of differing C:N ratios directly to pasture on N mineralisation and forage growth

ABSTRACTTwo experiments were conducted to examine the effect of applying spent dairy wintering barn bedding (termed ‘manure’) to a pasture soil. An incubation study compared rates of nitrogen (N) mineralisation of manures of differing storage durations (fresh, 2.5 months and 12 months) and C:N ratios (26:1, 22:1, 17:1 and 12:1), added to soil at a rate of 289 mg N kg−1 soil. The second experiment was a field trial, conducted in South Otago in southern New Zealand which compared pasture dry matter responses to applications of stored manure (c. 70 kg N ha−1; C:N of 18:1) or urea (30 kg N ha−1) to an unfertilised control. Incubation results indicated the addition of urea as a N source to the manure product at a rate to reduce the C:N ratio to approximately 12:1 resulted in a large increase in apparent net mineralisation. Field experiment results showed that application to pasture of manure with a high C:N ratio (above 18:1) resulted in a period of net N immobilisation and pasture growth restriction although there was no difference in annual pasture growth or grass N uptake. Knowledge of the C:N ratio of a manure product may help guide farmers in determining the best time to apply manure to soil to both maximise pasture growth and minimise potential nutrient losses to the environment.

The effects of hillslope forage crop grazing in winter on soil erosion

Farming intensification has led to a greater use of forage crops to feed cows over winter. This farming practice is now commonly taking place on rolling to steep land in areas where stock are wintered off-farm, such as Southland and South Otago. While the impacts of forage crop grazing on soil physical properties such as compaction, and overland flow of nutrients, sediment and pathogens have been studied, there is a lack of understanding of how this practice influences soil transport. This study used a novel technique to quantify the rate soil is pushed downslope by the hooves of cows while grazing kale, and found a linear relationship between soil transport and slope for slope gradients of less than 0.25. The steep slope of the linear relationship, which defines the soil transport coefficient, indicates rapid downslope soil movement relative to slope gradient. As a consequence, soil erosion on convex sites occurs at rates that likely exceed soil production rates. The formation of stock tracks on slopes greater than 0.25 caused greater uncertainty in soil transport rates, and more research is required to determine the effect of track formation on soil movement. Keywords: winter cropping, brassica, forage crops, erosion, soil creep

Evaluating the effects of dicyandiamide (DCD) on nitrogen cycling and dry matter production in a 3-year trial on a dairy pasture in South Otago, New Zealand

The nitrification inhibitor dicyandiamide (DCD) has been reported to significantly reduce nitrate () leaching and nitrous oxide (N2O) emissions under urine patches in New Zealand trial conditions. However, results on the efficacy of DCD for increasing pasture production have been inconclusive. As part of a national series of nitrous oxide mitigation research (NOMR) trials, a 3-year study was conducted at a dairy farm in South Otago to examine the effect of DCD on pasture production and N leaching under mowing and/or (simulated) grazing conditions and on N2O losses from dung and urine patches. Over the three trial years, DCD significantly inhibited nitrification in urine-amended soil, reducing peak concentrations in the soil by >50% and the N2O emission factor from urine by 33%–72%. Nitrate concentrations in drainage under simulated grazing plots with or without DCD applications were low and consequently no effect of DCD was detected. The N2O emissions and N leaching results suggested that high rates of denitrification occurred in the imperfectly draining soil, particularly in years 2 and 3 of the study. DCD significantly increased spring pasture dry matter (DM) yields from urine patches by 9%–21% in all years under mowing, but no significant annual effect on DM response was detected under either mowing or grazing. The observed increases in DM response in the urine patches under mowing were not detectable under the variable pasture responses under true grazing conditions.

Bayesian network for point and diffuse source phosphorus transfer from dairy pastures in South otago, new zealand.

Many factors affect the magnitude of nutrient losses from dairy farm systems. Bayesian Networks (BNs) are an alternative to conventional modeling that can evaluate complex multifactor problems using forward and backward reasoning. A BN of annual total phosphorus (TP) exports was developed for a hypothetical dairy farm in the south Otago region of New Zealand and was used to investigate and integrate the effects of different management options under contrasting rainfall and drainage regimes. Published literature was consulted to quantify the relationships that underpin the BN, with preference given to data and relationships derived from the Otago region. In its default state, the BN estimated loads of 0.34 ± 0.42 kg TP ha for overland flow and 0.30 ± 0.19 kg TP ha for subsurface flow, which are in line with reported TP losses in overland flow (0-1.1 kg TP ha) and in drainage (0.15-2.2 kg TP ha). Site attributes that cannot be managed, like annual rainfall and the average slope of the farm, were found to affect the loads of TP lost from dairy farms. The greatest loads (13.4 kg TP ha) were predicted to occur with above-average annual rainfall (970 mm), where irrigation of farm dairy effluent was managed poorly, and where Olsen P concentrations were above pasture requirements (60 mg kg). Most of this loading was attributed to contributions from overland flow. This study demonstrates the value of using a BN to understand the complex interactions between site variables affecting P loss and their relative importance.

Pasture growth and quality on Southland and Otago dairy farms

There is debate on how pasture growth rates and annual production on dairy farms in Southland/Otago compare to the comprehensive data collected at AgResearch Woodlands under sheep grazing. Additionally, there are no good data on seasonal variation in dairy pasture quality from the region. Six farms in different geographical regions of Southland and south and west Otago were monitored from spring 2007 until May 2012 to measure pasture growth rate, soil temperature and pasture nutrient composition (with the exception of south Otago). Pasture growth rates varied between farms and between years. The highest growth rates were recorded in coastal Southland and the lowest in northern Southland. Rainfall and soil temperature differences explained some of the changes in pasture growth rate throughout the seasons. Sharp drops in pasture quality in early summer were recorded on all farms. Considerable variation in pasture growth rate occurs across the Southland/Otago regions. Times of year when the greatest variability occurs have now been identified for each region. Keywords: Southland, Otago, pasture growth, pasture quality, dairy

An outbreak of haemolytic anaemia associated with infection of Theileria orientalis in naïve cattle

CASE HISTORY: An outbreak of haemolytic anaemia occurred when 87 cattle were introduced from a presumed non-infected herd from south Otago to a herd in Northland (n=580 cows), New Zealand, where theileriosis is endemic. CLINICAL FINDINGS: Clinical signs associated with Theileria spp. infection included lethargy, anorexia, inappetance, pale mucous membranes, and varying severity of anaemia. In the naïve imported cattle, 11/29 (38%) of those tested showed haematological signs of anaemia (haematocrit (HCT) <0.25 L/L). A negative association was present between the HCT and the number of Theileria spp. organisms counted using light microscopy (correlation coefficient=−0.4; p<0.05). Haemoparasites consistent with Theileria spp. were observed on examination of a blood smear. Theileria orientalis group (Theileria buffeli/orientalis) species was confirmed using PCR and DNA sequencing, and other causes for anaemia were excluded in the most clinically severely affected cow. The 18S sequence data and phylogenetic analysis of the CoxIII sequences showed samples had the greatest similarity to T. orientalis Chitose from Japan. DIAGNOSIS: Haemolytic anaemia associated with infection of T. orientalis. CLINICAL RELEVANCE: Previous reports have suggested that T. orientalis group species may be non-pathogenic in healthy cattle, and an incidental finding in blood samples. However, this investigation provided evidence that in New Zealand, this pathogen is capable of causing clinical disease in cattle not necessarily debilitated by another disease. The potential for disease should be considered when naïve cattle are brought in from non-endemic to endemic regions, for instance cattle from the South Island moved to regions where the vector for T. orientalis group species, Haemaphysalis longicornis, is active, and T. orientalis is present.

The use of low-rate sprinkler application systems for applying farm dairy effluent to land to reduce contaminant transfers

Runoff of farm dairy effluent (FDE) is a major concern in New Zealand water management. To improve handling and applying FDE, this work evaluated the performance of a low-rate (K-line) sprinkler application system compared with that of a travelling irrigator. The volumes of FDE discharged in either mole-pipe drainage or overland flow were monitored at two sites, as were nutrient concentrations and loads (and Escherichia coli (E. coli) at one site). The low-rate sprinkler decreased overland flow losses of applied FDE compared to the travelling irrigator. The relative concentrations of E. coli, total P and ammonium-N (presented as C/C o, the measured concentration in drain flow divided by the concentration in applied effluent) in overland flow at South Otago and mole-pipe drainage at West Otago were also consistently less for the low-rate sprinkler. There were significant and positive correlations between drainage C/C o values and effluent application rate for E. coli, total P and turbidity. Modelling predicted potentially large contamination with E. coli, total P and ammonium-N in mole-pipe drainage with no pond storage when using a travelling irrigator. Modelled loads were considerably less for FDE application to mole-pipe drained land using a low-rate sprinkler. Practical implications are that: (i) effluent pond storage is important for decreasing FDE losses in overland flow and mole-pipe drainage when soils are wet; (ii) a low-rate sprinkler application system requires less pond storage; (iii) a low-rate low-depth management system can decrease mole-pipe drainage discharges of pollutants when soils are wet.

Zircon megacryst ages and chemistry, from a placer, Dunedin volcanic area, eastern Otago, New Zealand

Zircon megacrysts from a sapphire‐bearing placer near Glenore, South Otago, New Zealand, gave U‐Pb ages linked to the Miocene Waipiata Volcanics. Yellow and brown (zoned) zircons gave ages almost within error of a mean age of 19.1 ± 0.2 Ma. Laser‐ablation inductively coupled plasma mass spectrometry analysis suggests these two zircons crystallised from separate magmas. The Ti‐in‐zircon thermometer gave different formation temperatures, between 550–685°C for yellow zircon and 700–730°C for brown zircon. The zircons have typical felsic chemistry, with positive Ce anomalies, while negligible Eu depletion indicates little plagioclase fractionation in their source magmas. Incompatible element values are enriched in the brown zircon. Such zircon megacrysts are rare in New Zealand, but they resemble east Australian zircons from basalt fields and may come from metasomatised mantle melts or fractionated alkali basalt magmas.

Effect of land use and moisture on phosphorus forms in upland stream beds in South Otago, New Zealand

Land use can influence stream sediment composition and water quality, whereas moisture status affects sediment phosphorus (P) bioavailability to algae. Declining upland surface-water quality in South Otago, New Zealand, may reflect land-use changes from sheep- to dairy-farming. I sampled sediment (0–20 cm) from streams draining 12 dairy- and 12 sheep-farmed catchments in spring (wet) and autumn (dry). 31P nuclear magnetic resonance (NMR) spectroscopy and the EDTA-fractionation scheme were used to determine different P forms and infer P bioavailability. Significantly more P was present in the sediment of streams draining dairy- than sheep-farmed catchments. Total P did not differ with the moisture regime; however, changes occurred in the following P fractions: acid-soluble organic P, NaOH-P, CaCO3≈P, Fe(OOH)≈P and residual organic P. Extraction for 31P NMR analysis removed 78–85% of sediment total P and isolated five P classes. More bioavailable P such as orthophosphate (23–40% of P extracted) and diesters (2–6% of P extracted) was present in dry than in wet sediments, and in sediments draining dairy streams than in those from sheep-farmed catchments. This indicates substantial reserves of bioavailable P in sediment from these catchments, especially from dairy-farmed catchments, sustaining in-stream P concentrations for many years even without additional P input from land.

LOOKING AT NEW ZEALAND GEOGRAPHY

New Zealand Journal of GeographyVolume 51, Issue 1 p. 34-34 LOOKING AT NEW ZEALAND GEOGRAPHY A. E. D. Dowall, A. E. D. Dowall South Otago High School.Search for more papers by this author A. E. D. Dowall, A. E. D. Dowall South Otago High School.Search for more papers by this author First published: November 1971 https://doi.org/10.1111/j.0028-8292.1971.tb00496.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume51, Issue1November 1971Pages 34-34 RelatedInformation

Computer Assisted Learning

New Zealand Journal of GeographyVolume 77, Issue 1 p. 21-21 Computer Assisted Learning RICHARD EDLIN, RICHARD EDLIN South Otago High SchoolSearch for more papers by this author RICHARD EDLIN, RICHARD EDLIN South Otago High SchoolSearch for more papers by this author First published: October 1984 https://doi.org/10.1111/j.0028-8292.1984.tb00169.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume77, Issue1October 1984Pages 21-21 RelatedInformation

FORAMINIFERAL EVIDENCE OF HOLOCENE SUBSIDENCE AND FAULT DISPLACEMENTS, COASTAL SOUTH OTAGO, NEW ZEALAND

Foraminiferal assemblages preserved in estuarine sedimentary sequences along the coast of South Otago, New Zealand, provide evidence for three Holocene fault-displacements and associated earthquakes within the 250 km-wide continental collision zone along the Australian-Pacific plate boundary. The modern analogue technique was used to estimate paleotidal elevations of the fossil foraminiferal faunas, based on an analogue set of 334 modern New Zealand faunas (including data from three new intertidal transects taken from the studied estuaries). These elevation estimates provide a record of abrupt changes in tidal elevation, which are inferred to have been produced by vertical displacements on nearby faults. The foraminiferal record in cores (0.75–2.8 m long) from Akatore Estuary identify the previously recognized last rupture (,1100 cal yrs BP) on the Akatore Fault, with ,0.4 m of subsidence on the western side produced by actual downthrow or shaking-related compaction of underlying sediment. The foraminiferal record in cores (1.4– 7.0 m long) and in an uplifted terrace section from tidal Catlins Lake provides the first evidence of Holocene fault rupture and major earthquake risk south of the Clutha River mouth. Three displacement events on the Settlement Fault, which forms the eastern margin of Catlins Lake, are recognized. The youngest (,1000 cal yrs BP) resulted in 0.4 m of subsidence (downthrow or compaction) on its west side. The penultimate (,3600 cal yrs BP) resulted in ,1.2 m of uplift of an extensive terrace on the east side of the fault with consequent narrowing of the estuarine entrance and reduced salinity in the tidal lake (recorded by foraminiferal faunas). The earliest event (,5000–4500 cal yrs BP) is recognized by ,1 m of abrupt subsidence on the west (Catlins Lake) side of the fault. Foraminiferal faunas in the upper parts of the majority of cores (from high tidal salt meadows) also document ,0.3 m of sea-level rise within the last 150 years.

Temporal and spatial variability of acid rock drainage in a rehabilitated coal mine, Wangaloa, South Otago, New Zealand

The Wangaloa open cast coal mine ceased operations in 1989, with no restoration of the 252 ha site, and moderate acid rock drainage developed. A major rehabilitation programme was initiated in 2002 with removal of exotic vegetation, and extensive planting (>60 000) of native seedlings was begun in 2003. By 2006, most seedlings were thriving, and, combined with adventive exotic weeds, a 70% vegetation cover had been achieved. The site substrates were highly variable on the 10–100 m2 scale, and have been characterised by paste pH (>700 measurements). In 2003, substrates had moderate acidity (pH = 4.5 ± 0.9) with distinctly acid patches (pH down to <2). By 2006, the average substrate pH was essentially unchanged. Some distinctly acid patches had higher pH, and one patch had apparently become more acid. Water compositions (>100 samples from 15 sites) were also highly variable spatially and temporally. Incoming stream and rainwater (pH 5–6) chemically interacted with acid substrates, especially waste rock piles that contain pyrite‐bearing material, and evolved to lower pH (pH down to 3.4), sulfate‐rich waters. A pit lake on the site receives most surface and groundwater runoff, and this lake, with a water residence time of 1–2 yr, controls the site discharge water quality. The lake pH varies on a monthly time‐scale from 4.5 to 6.5, synchronised with pH variations in groundwater boreholes in waste rock. In addition, there has been a general increase in pH of the lake during rehabilitation from consistent pH 4.6–4.8 before rehabilitation to near pH 6 during rehabilitation. The sulfate/chloride ratio of lake water has decreased from 20 to <10 during rehabilitation as well. These changes in lake water composition from year to year may be a result of increased input of rainwater that has had less interaction with substrate than runoff water had before rehabilitation began.

Relationships in the alpine Ranunculus haastii (Ranunculaceae) complex and recognition of R. piliferus and R. acraeus from southern New Zealand

Growth habit, vegetative, floral characters, and molecular data support the recognition of Ranunculus haastii and R. piliferus at species rank, rather than as intraspecific taxa at the rank of subspecies. Therefore, R. piliferus is a new combination at species rank for plants previously known as R. haastii subsp. piliferus. R. acraeus is a new species distinguished from R. piliferus by its finely crenate leaf and bract margins, glabrous peduncle, and in having 6–7 sepals that are hairy on the abaxial surface and glabrous on the adaxial surface. R. piliferus occurs in northern Southland and South Otago and R. acraeus occurs in North Otago and South Canterbury. R. piliferus and R. acraeus grow in relatively stable alpine rock‐fields that comprise rock fractured into large, coarse, and angular blocks of differing sizes and shapes. R. haastii occurs in Canterbury and Marlborough where it grows on mobile fine‐grained scree in the alpine zone. Phylogenetic analyses of nrDNA ITS and cpDNA JSA sequence data provide support for the segregation of R. piliferus from R. haastii, and for the recognition of R. acraeus. R. piliferus forms a distinct genotype in both the ITS and JSA analyses. R. acraeus and one sample of R. haastii have a distinct JSA genotype, and R. acraeus and R. buchananii share a nine‐base‐pair indel. In the ITS analysis R. acraeus and most samples of R. grahamii share the same genotype, and along with R. haastii form a northern, alpine group of diverse genotypes.

Soil physical quality under cattle grazing of a winter-fed brassica crop

Abstract This 2-year study investigated the effects of winter brassica forage crop grazing treatments on soil physical properties on a Fragic Pallic soil, susceptible to compaction, in South Otago, New Zealand. Soil physical measurements including bulk density, percentage of pores &gt;300 μm, macroporosity (air-filled porosity; percentage of pores &gt;30 μm), total porosity, air permeability, and saturated hydraulic conductivity (Ksat) were taken 1.5 and 4 months after completion of winter grazing in year 1, and 2.5 months after grazing in year 2. Treatment main effects in year 1 for macroporosity were ungrazed crop (P &lt; 0.05, 15.5%), established pasture (12.2%), crop on-off grazing (12.8%), crop grazed with back fence (9.6%), and current practice (strip grazing without a back-fence, 8.6%). During both winters the soil was generally more compact at 0.05–0.10 m depth than at 0.15–0.20 m, particularly for the current practice treatment, which may increase the risk of overland flow. Micro-topography differences between hump and hoof-hollow areas for the current practice treatment were also investigated during one sampling, with very low values of Ksat at 0–0.05 m in hoof-hollow areas (P &lt; 0.05, 5 mm/h), compared with hump areas (129 mm/h). Overall, the crop on-off grazing treatment and, with some exceptions, the grazed with back fence treatment have some merit for reducing damage to soil physical properties compared with current practice.