Conversion of native vegetation into farmed grassland in the Lake Taupo catchment commenced in the late 1950s. The lake’s iconic value is being threatened by the slow decline in lake water quality that has become apparent since the 1970s. Keywords: satellite remote sensing, nitrate leaching, land use change, livestock farming, land management
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(261 KB)Individual and group choices are determined by the structure of institutional arrangements, consisting of both conventions and entitlements (Bromley 1989). Four elements of the institutional structure governing agriculture are identified which embody privileges for the sector, and reduce its accountability. Keywords: environment, collaborative governance, privilege, institutions, pollution
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(67 KB)
This study aimed to examine the economic response to high rates of N in a winter lamb trading operation and was an “add on” to a commercial lamb trading operation in Hawkes Bay. The general policy of the lamb trading operation was to purchase store lambs in autumn at 35 kg liveweight, rotationally graze through winter and early spring and draft for slaughter at 45 kg liveweight. Keywords: nitrogen fertiliser, lamb performance, farmlet trials, lamb finishing, cost effectiveness
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(143 KB)Pasture herbs can increase pasture production and feed quality over summer when ryegrass based pasture often constrains livestock production. The growth and development of plantain (‘Ceres Tonic’), chicory (‘Choice’) and red clover (‘Redmore’) were related to thermal time during establishment. Keywords: Plantago, Cichorium, annual production, thermal time
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(129 KB)As the availability of water for irrigation becomes more limiting it is important to use the available water effectively and all potential avenues for improving irrigation efficiency should be examined. Improving irrigation system uniformity can lead to production gains and less loss of water through drainage, but such data are difficult to collect experimentally. Keywords: irrigation variability, LUCI, simulation modelling
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(127 KB)Gruner kale showed a linear increase (8.0 kg DM/ha per °Cd) in biomass with sowings on 1 October, 3 November and 1 December producing 23, 19 and 17 t DM/ha (respectively) by the 29 May. Regrowth following mid season defoliation was slow (5.3 kg DM/ha per °Cd) reducing total production (relative to undefoliated) by 7.5 and 5.5 t DM/ha for treatments defoliated on the 29 January and 14 March, respectively. Keyworks: defoliation, kale, quality, regrowth, sowing date, thermal time, yield
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(100 KB)The effect of lax or hard dairy cow grazing (residual stubble height of 10 and 5 cm) and grazing frequency (grazing when sward height reached 35 or 20 cm) on persistence, productivity and forage quality of pure pastures of Lotus corniculatus was evaluated over two growing seasons. Keywords: Lotus corniculatus, dairy cows, grazing management
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(146 KB)A field experiment was established in 2004 in the North Otago Rolling Downlands soils near Windsor, North Otago. The aim was to determine the biophysical consequences of different land use (pasture species, grazing animal, mowing, irrigation, nitrogen) treatments on the pasture and soil resources. Keywords: intensification, irrigation, nitrogen, sheep, dairy cattle, mowing, pasture
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(254 KB)Farmers throughout New Zealand are interested in pasture growth and quality but often this information is hard to obtain for their particular farm environment. The Meat and Wool New Zealand (M&WNZ) PasturePlan™ programme enabled participating farmers to measure growth on their farms and generated a large database across New Zealand. Keywords: pasture growth rates, pasture quality, PasturePlan™
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(88 KB)Effective monitoring of pasture cover on a regular basis is essential if dairy farmers are to increase profitability by making better pasture management decisions. We present results of a two-year study on the use of satellite imagery to estimate pasture cover on dairy farms in the Waikato region. Data collection concentrated on the critical time for dairy farm pasture management between June and December. Two distinct relationships between the remotely-sensed normalised difference vegetation index (NDVI) and pasture cover were observed, with an inflexion point in the relationship at NDVI = 0.74. A two-part exponential model was fitted to the data, allowing the prediction error to be minimised both above and below the inflexion point. Model development showed that an algorithm based on NDVI and time-of-year accounted for approximately 80% of the variability in pasture cover measured within paddocks. The validation studies show that pasture cover was estimated with an error of prediction of approximately 10%, which equates to 260 kg DM/ha for a pasture cover range of 1500 to 3400 kg DM/ha. The accuracy demonstrated in this study has given the project’s funders the confidence to explore a staged rollout of development, validation and commercial delivery, to make the technology available to all major dairy regions in New Zealand over the next five years. Keywords: Pasture cover, dairy, satellite imagery, rising plate meter, normalised difference vegetation index
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(202 KB)The effect on pasture productivity of sowing birdsfoot trefoil (Lotus corniculatus) and white clover (Trifolium repens) as pure and mixed swards was evaluated over two growing seasons. Different sowing techniques were used for mixed sward treatments: species sown in alternate rows, mixed within rows or broadcast. Keywords: birdsfoot trefoil, Lotus corniculatus, pasture production, plant nematodes, white clover
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(120 KB)
Conversion of land planted in exotic forestry to pastoral farming has accelerated in recent years, particularly in South Waikato and Bay of Plenty. The implementation of these conversions has sometimes been to the detriment of the environment. Keywords: forestry, water quality, pasture yield, environment, soil fauna
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(187 KB)A field trial was established to quantify the impacts of lime (0, 2.5, 5 and 10 t/ha) and nitrogen (N) fertiliser (0, 50, 100, 200 and 400 kg N/ha/year) addition on the dry matter (DM) production of a crop sequence of triticale followed by dryland pasture that was established on a site converted from long-established plantation forestry. Results are reported for the first 22 months. The application of lime up to 10 t/ha had no effect on triticale DM production. In the subsequent pasture, the percentage of clover increased from 15% without lime to 25-30% when 5-10 t/ha of lime was applied. Lime application only increased pasture DM production in the last 4 months. Annual pasture DM production increased significantly with increasing levels of N fertiliser application from 5.3 t DM/ha with no N applied to 7.5 t DM/ha at 400 kg N/ha. The observed response to N addition was mainly attributed to the low N status of the soil following conversion, which in turn was compounded by the ongoing decomposition of large quantities of mulched woody debris. Keywords: land-use conversion, plantation forestry, pasture, lime; nitrogen fertiliser
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(128 KB)Lucerne sown immediately or after different forage crop sequences was investigated as a pasture option for post forestry conversion. In this experiment superphosphate and lime were applied in March 2005 before final seedbed preparation and establishment of seven cropping sequences; 1) lucerne sown in April 2005; 2-5) greenfeed cereals (oats or triticale) sown in April 2005 followed by lucerne in October 2005 with or without a rape cover crop; 6-7) winter fallow followed by glyphosate presowing in October 2005 or March 2006. Keywords: Avena sativa L., Brassica napus L., forestry conversion, lucerne, Medicago sativa L., oats, rape, Trifolium repens L., triticale, white clover
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(124 KB)Dry matter production and pasture composition were measured over 22 months in eight cropping sequences on a dryland site converted from forest to pasture. Cropping sequences involved different combinations of: (i) autumn and spring sowing; (ii) sowing immediately into pasture or into oat and triticale forage crops followed by pasture; and (iii) undersowing pasture beneath rape or conventional sowing. Keywords: land-use conversion, plantation forestry, pasture, clover, weeds
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(87 KB)With its first National Annual General Meeting in 1955, The New Zealand Farm Forestry Association was formed by farmers interested in planting trees for a variety of reasons: soil erosion control, shade and shelter for livestock, timber and round wood production for use on farm and logs for sale.
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(145 KB)After the removal of Pinus radiata forests, conditions for establishing pastures are often sub optimal. The ability of rape to aid pasture establishment and suppress weeds was investigated at Darfield, Canterbury between November 2005 and February 2007. Keywords: Brassica napus, cover crop, Dactylis glomerata, Festuca arundinacea, forest conversion, Lolium perenne, pasture establishment, Trifolium pratense, T. repens, undersowing
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(128 KB)
Abstract New Zealand dairy farmers are lifting stocking rates and increasing available feed through nitrogen (N) fertiliser applications to pasture, growing maize for silage and other supplementary crops for silage or grazing on-farm, and/or procuring feed supplements off-farm. This has raised concerns about the possibility of increased risk of nutrient losses to waterways and the atmosphere. This paper reviews NZ and overseas data on the integration of maize silage into dairy systems. Maize silage is a low protein forage which helps optimise animal protein intake and reduces N loss. Maize silage-supplemented dairy farms leached more nitrogen per hectare but less per kg milksolids (MS) than intensive all-grass systems. Feeding maize silage on a feedpad and spreading the resulting effluent uniformly over the farm further reduces N leaching. In the Resource Efficient Dairying (RED) trial, total emissions of nitrous oxide (N2O, a potent greenhouse gas) for the maize-supplemented farmlet was 14% lower on a per hectare basis and 22% lower on a kg MS basis than the all-grass system when both received 170 kg N/ha as urea. The increases in maize dry matter production in response to incremental additions of N and water, where production is constrained by these inputs, can be 2-3 times greater than that for pasture. Using a feed and stand-off pad and managing maize growing through minimising tillage effects, determining soil N status at planting and timing N applications appropriately further reduce the environmental impact of maize silage-based dairy systems. Keywords: all-grass, environment, greenhouse gases, intensive dairy systems, maize silage, nitrates
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(137 KB)Planned implementation of a nitrogen (N) “cap” on land in the Lake Taupo catchment has led to the need for a range of N mitigation options for pastoral farmers to increase profitability while farming within the N cap. A multi-disciplinary research programme has focused on the potential of targeting different parts of the N cycle to increase N efficiency and reduce N leaching losses. A range of research areas have been examined which focussed on soil amendments, improved pasture plants, animal manipulation and farm system options with potential for reduced N leaching. The “best bets” of practical options from this research have been selected, in consultation with local farmers through the Taupo Lake Care group. These are being tested in a new farm grazing system trial with beef cattle in the Lake Taupo catchment. The treatments are; a control (beef heifers), high sugar ryegrass (to potentially increase N absorption by cattle and reduce N excretion in urine), strategic salt supplementation (to increase urine spread), animal DCD supplementation (to achieve delivery of DCD in urine thereby inhibiting nitrification and reducing nitrate leaching) and steers (to compare spread of urine with female cattle). This long-term trial commenced in April 2007 and will evaluate effects of these N mitigation options on pasture production, N cycling and N leaching. Keywords: DCD, grazing, Lake Taupo, mitigation, nitrogen leaching, salt
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(128 KB)To farm efficiently within a nitrogen (N) cap, Taupo farmers need to know the relative N-leaching potential of existing and potential farming enterprises. We quantified production and N leaching in four ‘cut and carry’ cropping treatments (Trial 1), and two cattle grazing systems (Trial 2), in replicated trials over 3 years. Annual crop systems Triticale and Maize, which included annual ryegrass as a winter cover crop, leached 104 and 222 (1 year only) kg nitrate-N/ha respectively, while perennial crops Lucerne and Pasture leached 19 and 12 kg nitrate- N/ha/yr respectively. In grazing systems, removing cattle between May and August reduced N-leaching from 13 to 5 kg nitrate-N/ha/yr and could be achieved by strategic selling and buying, grazing-off, or using feed-pad systems. N-fertilised annual crops, can lead to high N leaching whereas in cattle grazing systems, strategic destocking over winter can greatly reduce N leaching. Some enterprise choices based on quantified N leaching data can now be made. Keywords: cropping, lucerne, maize, triticale, cattle grazing, nitrogen leaching, environment
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(155 KB)The decline in water quality in Lake Taupo has been attributed to nitrogen (N) leaching from surrounding land areas. Pastoral agriculture has been identified as a significant contributor to this N transfer to the lake through animal urine deposition. There is therefore an immediate need for new management options to reduce N losses. The objective of this study was to measure the effectiveness of using a nitrification inhibitor (eco-n) to reduce nitrate leaching losses from a pasture soil of the Taupo region. A 3-year study was conducted using 20 lysimeters on Landcorp’s ‘Waihora’ sheep and beef farm, within 10 km of Lake Taupo. The results show that animal urine patches were the main source of nitrate leaching (>95% of the total annual loss) and that eco-n significantly (P<0.05) reduced nitrate leaching losses from urine treated lysimeters. When the lysimeter results were combined with a detailed GPS survey and GIS analysis of urine patch coverage of the farm it is concluded that eco-n reduced annual nitrate leaching losses by between 23 and 32%, with an average reduction of 27%. Thus eco-n represents a practical technology that pastoral farmers could adopt today, to assist them to meet new water quality standards in sensitive catchments near Lake Taupo and the upper Waikato River. Keywords: nitrate, urine patch, nitrification inhibitor, eco-n
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(160 KB)Strategies to reduce nitrogen leaching losses from pastoral farming in the Lake Taupo catchment are required to address declining water quality in the lake. This study used a biophysical whole farm simulation model, EcoMod, to explore the potential for four mitigation strategies to reduce N leaching in a soil and climate typical of the region. The strategies were use of: a nitrification inhibitor (DCD); steers instead of heifers (STEER); salt as a diuretic (SALT) and; high sugar ryegrass (HSG). These were compared to a BASE scenario of grazed heifers. Each of the simulated mitigation strategies showed the potential to significantly reduce nitrogen leaching compared to BASE by 25 to 45%. All mitigation strategies reduced nitrogen fixation due to more efficient plant use of nitrogen from urinary and faecal sources. This also contributed to an increase in pasture intake for SALT, STEER and DCD, but not for HSG. These mitigation strategies were explored at a single-paddock level and planned experimental studies will further examine the effectiveness of the strategies. Keywords: nitrogen leaching, mitigation, Lake Taupo, simulation, EcoMod
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(175 KB)
There are currently a range of programmes breeding ryegrasses with enhanced water-soluble carbohydrate concentrations leading to enhanced metabolisable energy (ME) contents when this herbage is consumed by grazing ruminants. High ME concentrations in grasses have the potential to increase milk and meat production through improved energy supply and more efficient rumen fermentation. However, the first ‘high sugar’ grass cultivars sown in Australia and New Zealand have not always delivered the animal production benefits that have been realised when these cultivars were sown in the UK. This illustrates not only the need to develop agronomic practices that are suited to exploiting the potential of germplasm with high energy concentrations but also the need to not view the high energy trait in isolation from other breeding objectives such as adaptation, seasonal production and disease resistance. Keywords: perennial ryegrass, carbohydrate, sugar, fructan, breeding
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(69 KB)There has been mounting interest over the proposed production and environmental benefits from using perennial ryegrass cultivars bred to have higher water soluble carbohydrate content (high sugar grasses). Here, we objectively review published evidence, from the EU and New Zealand, of the effects of these on milk yield per cow, liveweight gain in sheep, N utilisation and wider trophic interactions. The literature reveals substantial variation in animal responses, though some of the uncertainty in interpretation can be resolved by combining the data from multiple trials, and showing this forms a continuum of response to diet quality. It also reveals variation in the degree to which the sugar trait has been expressed, possibly reflecting a gene x environment interaction. Achieving a more consistent, and probably greater than current, expression of the high sugar trait would be a valuable goal. We suggest ‘proof of concept’ has been shown, notably for the potential for improving N utilisation in the rumen, and so reducing the proportion of N intake lost in urine. The evidence suggests that this may be a greater challenge, albeit a more valuable goal, because of the relatively high N (crude protein) content forages that predominate in the New Zealand pasture industry. Keywords: animal performance, high sugar grass, Lolium perenne, perennial ryegrass, nitrogen utilisation, trait expression, water soluble carbohydrates
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(168 KB)An elevated concentration of water soluble carbohydrate (WSC) in grasses may increase the availability of readily degradable energy, increase milk production and improve the efficiency of nitrogen utilisation. Two ryegrasses with elevated WSC, a tetraploid Italian (IRG) and a diploid perennial selected for higher WSC (HSG), were compared against a standard diploid perennial (STG) during spring 2004 and 2005, and autumn 2006 and 2007. Groups of cows (n=20) grazed each grass type for periods of 6 weeks in spring and 2 weeks in autumn. During spring, the ‘high’ WSC grasses were 20-40 g/kg DM higher in concentration of WSC than the standard (P<0.01), whereas in autumn the difference was smaller and not significant. The production of milk and milksolids (MS) did not differ significantly among grasses in spring or in autumn 2006. In autumn 2007, MS production was higher for HSG than STG (1.09 and 0.99 kg MS/cow/day for HSG and STG, respectively, P=0.006). While the greater MS production cannot be attributed to higher WSC per se, it may be related to other differences between grass types, such as a lower fibre content of the high WSC grasses, or factors affecting intake and the partitioning of nutrients to production or body reserves by cows during late lactation. Keywords: perennial ryegrass, annual ryegrass, water soluble carbohydrate, milk production, milksolids production
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(91 KB)Metabolisable energy (ME) is frequently used as the sole indicator of forage quality by researchers, rural professionals and farmers, but it is hardly ever measured and is not always a good predictor of feeding value. Forage ME is usually calculated from chemical composition and digestibility, often by near infrared reflectance spectroscopy (NIRS). Although ME is superior to dry matter (DM) as a measure of feeding value and can indicate forage quality, it should not be used to predict animal production. The ME content of DM may imply a potential for production, but other components of the diet, especially protein, structural fibre and feed availability will provide more information than ME alone. Researchers, rural professionals and farmers should understand the basis for measuring ME, exercise discretion when using ME, and include fibre and protein concentrations in their criteria for feed appraisal. Keywords: metabolisable energy, forage quality, feeding value
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(95 KB)
The agronomic merits of a perennial ryegrass (Lolium perenne) cultivar infected with a new endophyte (Neotyphodium lolii), AR37, were compared with the same cultivar infected with currently available endophytes (AR1, Standard) at two sites in northern New Zealand for at least 3 years. AR37-infected ryegrass was the highest yielding treatment at both sites (11 080 kg DM/ ha/yr) producing more dry matter than either AR1 or Standard-infected ryegrass which yielded similar amounts (8870 kg DM/ha/yr). Yield advantages of AR37-infected ryegrass were greater at Kerikeri (36%) than Hamilton (17%), with differences increasing over successive years at both sites. At Hamilton, tiller populations were lowest in AR37-infected ryegrass in Year 2, and lowest in AR1- infected ryegrass 3 and 5 years after sowing. At both sites AR37-infected ryegrass had the lowest infestation scores for root aphid. At Hamilton in Year 4, more damage by African black beetle larvae occurred to AR1-infected plants than to AR37 and Standard-infected plants. These pests are likely to have contributed to the differences in agronomic performance observed. These agronomic results suggest AR37-infected ryegrass cultivars will be a useful choice for farmers in northern New Zealand. Keywords: endophyte, Neotyphodium lolii, perennial ryegrass, Lolium perenne, dry matter yields, plant persistence, root aphid, Aploneura lentisci, African black beetle, Heteronychus arator
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(157 KB)A base population of 80 cultivars or seedlines of white clover from around the world was used to develop nematode tolerant selections. Clover plants were grown in strips of black plastic, akin to strawberry growing, in order to increase soil temperature and thence nematode activity in clover roots. Clover growth was assessed visually and by dry matter determination in five rounds of selection from 1989–2001. After each round of selection the 20–30 best performing plants for each of three leaf sizes (large, medium and small) were polycrossed and the seed collected. The resulting selections have performed at least as well as, and in many cases better, than standard commercial cultivars at a range of field sites. Keywords: Meloidogyne, Heterodera, Pratylenchus, Trifolium, field selection, nematode tolerance, nematode resistance
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(78 KB)This study set out to compare plant function and performance of strawberry clover to that of white clover. To test this, the two species were exposed to drought for 4 weeks under controlled environmental conditions. Water stress reduced the size and dry matter of white clover leaves by more than 50%, whereas strawberry clover leaves remained unaffected. White clover photosynthesis decreased by nearly 50% under drought, accompanied by a reduction in leaf water status (water potential) by more than one third. In contrast, strawberry clover maintained a higher water status, photosynthesis and transpiration rate under drought than white clover. In addition, we observed drought-induced reductions in white clover leaf quality, including lower nitrogen levels. We conclude that strawberry clover displays drought resistance in a number of key leaf parameters. The findings suggest value in testing strawberry clover as a complement or alternative to white clover in droughtprone pasture environments. Keywords: drought, strawberry clover, Trifolium fragiferum L., Trifolium repens L., white clover
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(84 KB)The effect of clover root weevil (Sitona lepidus) (CRW) larval feeding on subterranean, suckling, striated and clustered clovers was compared with white clover in a glasshouse experiment. Growth of suckling, striated, and clustered clover was significantly reduced by CRW, approaching the levels of damage recorded in white clover. N fixation in suckling and clustered clovers was also reduced. Growth and nitrogen fixation of two subterranean clovers (cv. Denmark, cv. Leura) were changed relatively little by CRW larval feeding. The relatively high level of the isoflavonoid biochaninA that was present in subterranean clover roots may explain the species’ tolerance of CRW. These results suggest that CRW may not pose a major threat to dryland farming systems based on subterranean clover. Keywords: annual clover, clover root weevil, roots, Trifolium dubium, Trifolium glomeratum, Trifolium striatum, Trifolium subterraneum
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(82 KB)Two AR542-endophyte infected tall fescue breeding pools were subjected to one cycle of selection for increased endophyte hyphal density. Hyphal density was assessed subjectively by microscopic examination of the leaf sheath. Levels of alkaloids produced by both the original and selected populations were subsequently measured during summer. Levels of lolines and peramine alkaloids increased significantly in one breeding pool (by 40% and 29%, respectively), with non-significant increases (by 24% and 2%) in the other breeding pool. The apparent correlation between observed hyphal density and levels of alkaloids supports the hypothesis that levels of lolines and peramine produced by fungal endophytes in their host grass are at least partly due to endophyte hyphal mass in the host sheath tissue. Measured lolines in one breeding pool were 21 times greater than the other, while sheath hyphal density was less. Possible explanations include contrasting patterns of hyphal colonisation beyond the sheath, and/or variation in the quantity of lolines produced per unit hyphal mass. Keywords: Neotyphodium coenophalium, endophyte, Festuca arundinacea, tall fescue, peramine, lolines, hyphal mass
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(104 KB)The reaction of ingested forage plant fragments to the rumen environment may contribute to the rapid degradation of plant cell contents in the rumen. A series of experiments were used to explore the hypothesis that plant-mediated proteolysis (PMP) contributes to N loss from fresh forage entering the rumen, and to investigate the potential for identifying cultivars with reduced PMP. During an in sacco time-course experiment, chopped fresh field grown perennial ryegrass (Lolium perenne L.) leaf samples lost 15% of their total N within the first 8 hours in the absence of rumen microbes; whereas 40% was lost from samples incubated with exposure to rumen microbes. Accumulation of free amino acids in the buffer accounted for 75% of the N loss after 24 hours. In a subsequent experiment, in vitro incubation of samples from five perennial ryegrass cultivars detected significant (P<0.05) differences in the extent of PMP for one cultivar. A further in vitro experiment detected significant (P<0.05) variation in PMP among ryegrass genotypes (n=24) within two cultivars. Percentage N loss was not correlated with N concentration in the fresh forage sample. These data indicate PMP contributes to N loss from intact fresh plant cells in the rumen, that it is possible to identify cultivars with reduced PMP, and that there may be potential to further reduce PMP by selection within ryegrass populations. Keywords: forage, protein, rumen, proteolysis
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(108 KB)Significant variation for both root diameter and shoot dry weight was found among 20 commercially available hybrid and Italian ryegrass cultivars screened for root diameter. Nitrate interception by four selected cultivars was then compared with perennial ryegrass in a lysimeter trial. The shoot size of selected cultivars was significantly higher than perennial ryegrass. Drainage volumes from hybrid/Italian ryegrasses were half that of perennial ryegrass and contained significantly less nitrate. 15N absorption was also significantly higher for thin (79- 80%) and thick rooted (75-76%) hybrid/Italian cultivars than for the perennial ryegrass (63%). Root diameter of the different hybrid/Italian cultivars did not have a major impact on nitrogen interception and leaching. However the concept of a large, winter active grass with high nitrogen demand during periods of high leaching activity is supported by this study. Further selection for finer roots could increase the nitrogen interception ability of these plants without compromising shoot growth. Keywords: leaching, nitrate, roots, ryegrass
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(81 KB)
This research was completed for school science fairs, to see whether agricultural lime affects facial eczema spore numbers. Lime was applied at various rates on grazed plots, and using the Pithomyces chartarum (L) spore count wash method, the effect of lime on spore counts was measured. The residual effect of recent and past lime applications up to 3 years old was also measured. Lime applied at 2.5 tonnes/hectare killed nearly all of the spores within 5-8 days and maintained levels below the danger level of 50 000 spores/g for several weeks (whilst spores were present). As well as this short term effect, 2007 spore counts on plots last treated with lime in 2006 and 2005 averaged 44 167 and 35 833 spores/g respectively which were well below the 2007 control plot counts, which averaged 123 333 spores/g pasture. In these experiments, lime was effective at reducing facial eczema spore numbers when applied at 2.5 t/ha, with up to 2 year’s residual effect. Therefore tactical use of lime applications could potentially protect farmers and stock from the effects of facial eczema for up to 3 years. Keywords: facial eczema, lime, Pithomyces chartarum (L), sporidesmin
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(141 KB)While it has been shown that bird species can benefit from organic farm management internationally, there is little information on birds in production landscapes in NZ. In this paper we apply spatial analysis techniques to compare the spatial distribution and habitat use of birds on selected North Island dairy farms, half of which are undergoing a 3-year organic conversion process and half of which are remaining under conventional management. There were significantly more skylarks recorded on conventionally managed farms. Overall however, there were few differences in overall bird abundance or diversity between the two management systems. The comparable use of woody vegetation and open pasture may reflect similar proportions and composition of these on the study farms. Once fully converted, organic dairy production systems may offer benefits for some bird species, although the composition and management of the farm and surrounding landscape are probably also key factors for bird numbers and diversity. Keywords: birds, dairy farming, landscape composition, organic conversion, pasture composition
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(183 KB)Humping/hollowing and flipping are land development practices widely used on the West Coast to overcome waterlogging constraints to pasture production. However, there is very limited information about how the resulting “new” soils function and how their properties change over time following these extreme modifications. We hypothesised that soil quality will improve in response to organic matter inputs from plants and excreta, which will in turn increase nutrient availability. We tested this hypothesis by quantifying the soil organic matter and nutrient content of soils at different stages of development after modification. We observed improvements in soil quality with increasing time following soil modification under both land development practices. Total soil C and N values were very low following flipping, but over 8 years these values had increased nearly five-fold. Other indicators of organic matter quality such as hot water extractable C (HWC) and anaerobically mineralisable N (AMN) showed similar increases. With large capital applications of superphosphate fertiliser to flipped soils in the first year and regular applications of maintenance fertiliser, Olsen P levels also increased from values <10 ìg/g to values well within the target range (20-30 ìg/g) after about 7 years. Humps and hollows responded differently following modification. The increases in total soil C and N, HWC and AMN levels on humps were similar to those of flipped soils over 8 years of development, whereas soil quality changes in the hollows were much slower. This has important implications for nutrient availability and losses. As soils develop, fertiliser and effluent applications should be adjusted to optimise production while minimising nutrient losses. Keywords: humping and hollowing, flipping, soil quality, soil organic matter, effluent
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(145 KB)Clover Hill Dairies is a progressive and highly intensive dairy farm, which currently milks 200 cows on 50 hectares three times a day on steep rainforest hinterland country. Milk production (305 day) currently averages 13 000 litres and 850 kg of milk solids per cow making Clover Hill Dairies one of the highest production dairy farms in Australia. The stud Holstein herd is fed a predominately pasture based diet with supplementary feeding comprising 35-40% of the dietary intake. Clover Hill Dairies aims to optimise the genetic potential of our high end genetic merit herd through close attention to pasture and soil management, biodiversity and the environment. Combining this with the application of the latest scientific principals and technology skills, we produce over 50 000 litres per hectare from the 200 cows. We recognise agriculture is no longer just about farming; it is intrinsically tied in with managing the environment and minimising the impact of human endeavours, hence the ongoing need to balance productivity and progress with minimal environmental footprint. Clover Hill Dairies strives to adopt a holistic decision making process to ensure higher quality of life, financial stability including managing and reducing debt, consistent profitability, and the confidence of knowing that our decisions are improving the environment and the community we live in. The key factors are herd genetics; best practice herd and farm management; the management and operational team; and interaction with the environment and the community.
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(63 KB)With increased use of feed from outside the effective milking area on dairy farms, milksolids (MS) per effective ha is no longer a sound basis for comparing farms and evaluating options for improving efficiency and profitability. Development of new, quantitative measures for feed and land use efficiency is required. These measures should take account of the extra land used to grow all feed types used for MS production and define how well the feed grown and purchased is converted into MS. Two methods were used to re-calculate MS per ha for six high performing farms (average of 2073 kg MS per effective ha) using a wide range of imported feed. Using these calculations, the farms averaged 1513 kg MS per total ha used and 1450 kg MS per ha produced from home grown pasture and crops. Yields of home grown pasture and crop harvested per effective ha ranged from 14.7 to 17.5 t DM per ha and feed conversion efficiency ranged from 85-94 kg MS per tonne DM. These benchmarks can be used to identify opportunities to improve pasture grown, harvested and converted into milksolids on NZ dairy farms. Keywords: milksolids per hectare, imported feed, pasture harvested per ha, feed conversion efficiency
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(125 KB)Assessment of energy use and greenhouse gas emissions associated with dairy products needs to account for the whole life cycle of the products, particularly with the debate about “food miles”(the transportation of product from producer to consumer). A life cycle assessment (LCA) of an average NZ dairy farm for 2005 showed that total energy use per kg milk from the “cradle-tomilk- in-the-vat” was 45-65% of that from EU farms. The greenhouse gas (GHG) emissions or carbon footprint showed similar relative trends although differences were smaller due, at least in part, to lower methane efficiency from lower-producing NZ cows. Energy use associated with shipping dairy product (e.g. cheese) from NZ to UK is equivalent to about one-quarter of the on-farm use. Even when added together, the energy use from the NZ farm and from shipping would still be less than onfarm energy use for the EU farms. However, this is affected by intensification and the Dexcel Resource Efficient Dairying trial showed that increasing maize silage use, and nitrogen fertiliser use in particular, increased the energy use and GHG emissions per kg milk by up to 190% and 23%, respectively. Thus, the trend for intensification on NZ dairy farms means that our comparative advantage with EU farms is diminishing. A focus on improved farm system practices and integration of mitigation options is required to reverse this trend. Keywords: food miles, greenhouse gases, energy, life cycle assessment, milk, New Zealand, efficiency
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(179 KB)The Kaipara clay soils and associated soil types occupy some 36 000 ha in Northland. The soils are naturally high in P and P fertilisers have been used sparingly in the past but with increasing farming intensity a fall in soil Olsen P values (to < 20) is occurring and responses to P fertilisers are becoming more common. Lime is widely used. In December 1996, a field trial, conducted over 6 years, was established on a Kaipara clay soil near Ruawai. The first phase (1996-1999) consisted of six rates of P (0, 20, 40, 60, 80, 100 kg P/ha) with or without lime at 5 t/ha applied once. The initial pH was 5.8 and Olsen P was 16. Results indicated a marked rates response to P without lime but with lime a marked Psparing effect occurred equivalent to 50-60 kg P/ha. The effect was consistent over 3 years. An explanation for this finding is due to lime improving plant growth probably by N mineralisation and N uptake, thus giving improved root growth and allowing those roots to explore a greater volume of soil and absorb more P. Plant chemical analyses and soil P fractionation studies indicated that more P was being taken up by plants on the lime/no P plots. The second phase (2000-2003) involved splitting plots and applying additional lime to some to give a pH range from 5.6-7.0. Results indicated no benefit to increasing pH above 6.0 but there was a suggestion that the reapplication of lime itself was beneficial. The P sparing effect of lime will best be utilised where soil Olsen P levels remain above 20. Keywords: P-sparing effect, lime, phosphate, Kaipara clay
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(113 KB)A dynamic model for nematode parasites in lambs which links their adult parasite burden with liveweight gain was extended to investigate alternate grazing with cattle to provide relatively larval-free pasture for finishing lambs. Liveweight performance of weaned lambs was tracked fortnightly under rotational grazing using three cattle:sheep ratios, with three initial parasite burdens and two initial infective larval densities on pasture. Lambs were removed from grazing at 37 kg or if they failed to gain weight during the preceding fortnight. An 80%:20% cattle:sheep ratio reduced larval pasture contamination by 75% but did not affect parasitic burden and total lamb liveweight gain compared with an all-lamb treatment. For low and moderate initial parasitic burdens in the 80%:20% cattle:sheep ratio, 25% of lambs reached 37 kg and 100% gained weight until week 18. This simulation indicated that in organic lamb finishing systems, alternate grazing with cattle provides substantial benefit but only when the initial parasite burden was low or moderate. Keywords: modelling, parasites, liveweight gain, alternate grazing
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(165 KB)Changes in land use and management were applied to a 296 ha catchment farm at the Whatawhata Research Centre in 2000-2001 to improve its economic and environmental performance. The area had erosion and weed reversion challenges, poorly performing beef and sheep breeding enterprises, and degraded streams. Changes included conversion of the steepest land to plantation forestry; indigenous forest restoration; intensification of the farming enterprises onto easier terrain with better pasture production; changes in stock type; poplar planting for soil stabilisation; and exclusion of livestock from streams. Significant improvements have followed. The per hectare economic surplus for the pastoral enterprise improved from 30% below industry average to 13% above. The forestry enterprise will further improve economic performance in the long-term. There were reductions in the export of suspended sediment (76%), total phosphorus (62%), and total nitrogen (33%). Water clarity has increased, stream temperature has declined and stream invertebrate indices indicate improvements in the fauna. Keywords: agriculture, forestry, macroinvertebrates, riparian, water quality, nitrogen, phosphorus
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(246 KB)
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