Land use is described by a combination of statistical data, MAF monitoring (using a representative model to characterise the farm) and historical case studies. The ways in which the region’s farmers have adapted to the changing environment, both economic and biophysical, is described. Science and education are essential infrastructural elements of this region. Keywords: case studies, farm monitoring, statistics
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(65 KB)My first contact with the NZ Grassland Association was in 1996 when I was asked to convene the organizing committee for the Oamaru Conference. I soon found that the Grassland Association was a great mix of farmers, researchers, industry advisors and scientists. To me AgResearch Grasslands at Palmerston North is the home of pastoral research in NZ and with the conference here in Palmerston North it will be a great opportunity to see where it all happens.
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(26 KB)This paper considers several of the forces that will shape the future of grassland farming in New Zealand over the next 15 years, including: global changes in food consumer needs, international competition in commodity food production, national regulations for sustainable resource management, global biotechnology advances, biosecurity threats and global climate change. Our current state of preparedness for change is considered, including an assessment of how education, research, grasslandbased industry infrastructure and New Zealand businesses should be preparing for these future changes. The role of innovation to create biotechnology and high-value products (such as functional foods and therapeutic proteins) is given particular attention. It is suggested that region-specific clusters of education, research and business are required to develop these future opportunities. Keywords: competitive forces, grassland farming, research and development
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(86 KB)
For the New Zealand (NZ) beef farmer, deciding on a business direction, developing and successfully implementing a strategy is critical for future success. Gathering information on future trends and issues is an important part of the process to ensure appropriate capabilities and contingencies are developed. The aim of this paper is to examine some of the future trends and issues for the NZ beef industry through to 2010, this is done through the use SWOT and PEST analysis. Secondly the paper suggests potential competencies farmers will need to develop to successfully survive in 2010. Keywords: beef industry, beef farmer s, business competencies, future trends, PEST analysis, SWOT analysis
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(69 KB)During a span of 20 years, eight farmlet-scale experiments conducted in the Manawatu used a simple system of grazing management to maximise pasture growth and utilisation. Farmlets of 1.6 ha were stocked annually with 12 Friesian bulls (7.4 wintered/ ha) from early November at 3 months-of-age (70-80 kg liveweight (LW)) until slaughter during December – March at 16 – 19 months (350 – 420 kg LW). The grazing management system involved seasonal adjustment in pasture spelling intervals, and an increase in grazing pressure in spring by addition of 3-month-old weaner bulls followed by the progressive removal of ‘finished’ animals during summer. With this control over feed supply and demand and the inherent capacity of growing bulls to cope with changes in feed availability, old permanent pasture producing approximately 13 t dry matter/ha/yr was conver ted to approximately 1000 kg/ha/yr of net carcass weight gain. Using loafing pads in winter to reduce treading damage on wet soils and increase pasture utilisation and growth, increased annual LW gain (LWG)/ha by 2%. Controlling the intensity of defoliation in summer through timely removal of bulls for slaughter increased average daily gain (ADG) during autumn and winter, but annual LWG/ha by only 1%. Pastures renewed with improved cultivars and species produced more forage in summer (red clover), autumn (prairie grass) and winter, identified as per iods of feed deficit for old permanent pastures. Strategic inputs of nitrogen (N) fertiliser (100 kg N/ha/yr) in autumn or in spring on old permanent pasture, in conjunction with irrigation (approximately 250 mm/ season) during November - March, and in combination with cool season active grasses, all increased annual meat output by up to 12% above that possible from old permanent pasture, by extending the duration of stocking in summer, increasing ADG, or a combination of both. While these gains are important, the studies highlighted the very high levels of output sustained from year-round all-grass grazing systems based on principles for maximising pasture growth and utilisation. Those high yields remain a benchmark in terms of the biological efficiency of growing and converting pasture to animal product, although the economic optimum was at a lower stocking rate and level of output. Keywords: dairy beef, grazing systems, liveweight gain, pasture utilisation
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(86 KB)The numbers of beef animals in New Zealand have increased markedly since 1960. In particular the number of animals (especially bulls) reared within the dairy industry for beef production has grown. Early research into aspects of intensive pasture-based beef production systems concentrated on high levels of pasture utilisation and beef production per ha. Farmers have adapted these results and systems and the carcass weight (CW) of bulls slaughtered now at 15-18 months of age have increased and often are over 300 kg CW. It is shown simplistically that profit/ ha will also increase with increasing CW and increased efficiency in use of feed within 1yr bull beef systems. In practice however, utilising more of the pasture dry matter (DM) grown and maintaining pasture quality are important issues. Two year bull systems are shown to be just as profitable as the more technically efficient 1yr bull system. Where beef production is carried out in conjunction with sheep production, especially on hill country, some commonly used benchmarks of technical and economic efficiency may be misleading with regard to overall system profitability and the contribution of various classes of beef animals. Keywords: beef animals, bulls, economic efficiency, feed efficiency, profitability
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(78 KB)Farmer perceptions of the productive potential of land influence their attitudes to productivity improvement. Pasture production information has generally been gathered within management systems that were considered feasible at the time. A sheep grazing trial was run over 2 years in southern Hawkes Bay hill country in which a Fer tiliser treatment involving a very high rate of nitrogen (N) fertiliser (400 kg N/ha annually as 8 split dressings of 50 kg N/ha) was applied to blocks with historically low, medium or high fertility. Additional fertiliser P and S was also applied as part of the Fertiliser treatment, however the responses were judged to have been mainly due to the N fertiliser Annual pasture production increased from an average 9.2 t DM/ha in Control areas to 17.1 t DM/ha in Fertiliser treatment areas. Similar responses of 18 to 22 kg DM/kg N fertiliser occurred across the 3 fer tility blocks. Average annual pasture production for the historically high fertility-Fertiliser treatment combination was 19.4 t DM/ha, higher than on most dairy farms. Pasture content of high-fertilityresponsive grasses such as ryegrass increased, at the expense of low-fertility-tolerant grasses such as browntop, legumes such as white clover, and herbaceous weeds. Nitrate leaching measurements suggested annual losses were increased by 25 kg N/ ha or 6% of the N applied. Given present-day cost structures and returns, these results suggest use of higher rates of N fertiliser than is current practice is an economic option for hill farmers. However longterm sustainability of systems receiving such high dressings of fertiliser N r equires further investig ation before such an approach should be adopted as part of commercial practice. Keywords: botanical composition, hill country, New Zealand, nitrate leaching, nitrogen fertiliser, pasture production potential
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This paper reports the findings from a study of 218 farm management consultants, 118 of whom had Maori farmers in their client base. The paper presents information on the experience of the consultants, their ethnicity, age and professional development activities the consultants undertook to improve their ability to consult with Maori, together with the ownership structures of the Maori clients. The paper reports the consultants’ perceptions of the factors important for successful consultancy with Maori as being good consulting practice, cultural sensitivity, understanding the complexities of Maori ownership structures and appropriate personal practice. Information for the study came from a mail survey and from personal interviews with ten consultants, each of whom had at least six Maori clients. The personal interviews enabled issues raised in the survey, in particular factor s important for successful consultancy with Maori, to be explored in more depth. Keywords: consultancy services, Maori farmer
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(71 KB)In 2003 the NZ Institute of Economic Research, in collaboration with Te Puni Kokiri, produced a report entitled Maori Economic Development. This report had the goal of bringing together different strands of analysis in a single overview of the Maori economy, and providing new insights on approaches to Maori development. The objective was to find a way to think about the Maori economy in the same way that we think about the New Zealand, or any other, national economy. As a result of preparing a series of research papers on different aspects of Maori economic development, the report is able to provide useful insights: • For Maori, on the things Maori organisations can do to enhance their economic development prospects – in particular, investment in high quality governance is the most critical next stage of development, which must be guided by Maori; • For New Zealand businesses, on the opportunities available to them to transact with, and invest in, the emerging Maori economy; and • For the Government , on the broad direction of policies which would enhance Maori economic development. In par ticular , the government’s interest in Maori development is not just about social responsibility or Treaty of Waitangi risk management. Rather, it is a policy area with significant potential to enhance New Zealand’s overall economic performance.
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(57 KB)Established in 1987 and now with a membership of 150 Maori Authorities throughout the country, the Federation of Maori Authorities (FoMA) is easily New Zealand’s largest Maori business network. An 11- member Executive is elected tri-annually on the basis of rohe representation. All of FoMA acti vity falls under the following broad purposes: • To provide the necessary infrastructure of representation through which a coordinated approach to Maori economic independence can be achieved compatible with the development of New Zealand as a nation • To foster and promote the development, sound management and economic advancement of Maori Authorities • To work in political and commercial harmony with all sector groups in NZ society to ensure the interests of Maoridom receive the appropriate recognition to enable economic, social and cultural programmes to be initiated and implemented consistent with the objective of Maori selfdetermination The recognition of our rights implicit in the Treaty of Waitangi provides the mana to approach Maori economic development with confidence, and the resolve to unite our efforts for the common good of all Maori.
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(75 KB)Ngati Whakaue Tribal Lands Incor porated (NWTL) is a Maori farming business formed in 1960 with the amalgamation of some 34 parcels of land into 3 large farms as a Maori Incorporation formed under the provisions of the Maori Land Act. The Act is administered by the Maori Land Court. The stated purposes at the time of formation related to protecting land ownership and using the land for productive purposes. This has since led to the properties being developed into a modern, high performing ‘agri-business’. The properties (Wharenui Station, Tihiotonga Station and Ngongataha Station) totalled 2970 ha in size and were run in the style of traditional “Maori Affairs” sheep and beef farms until fairly recently. In 1988 a dairy conversion was established on part of Wharenui. A further 265 ha property (Crater Lake) has subsequently been purchased to be run as a specialist deer unit together with an adjacent, largely undeveloped, 500 ha property (Okataina 10) which was leased r ecently. The Incorporation has pastoral farming, forestry, tourism, property rental and real estate development interests.
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(65 KB)First and foremost Maori land is taonga to the tangata whenua; and secondly a potential source of produce and income. W.H. Christy (1984) emphasised these values when the New Zealand Grassland Association focussed on Maori and the land. This order of importance is common to all Maori entities whether they are small family land holdings or big Maori Incorporations. However, what may differ is the way in which these entities are able to work with science. How well positioned are Maori to use the products and services of agricultural research and development? Since the release of land control from Maori Affairs and various lease arrangements (in the 1970’s and 80’s) the prior ities have been to reduce debt and establish effective governance. However, many small family and trust holdings still lack the capital and size to be financially viable within a commodity, pastoral farming context. They are not immune to the current pressures of greater efficiency and resource aggregation. In addition, those people who have a governance responsibility often lack the knowledge of modern farm practices and businesses. Many are urban people. For many Maori who set the direction and expectations of Maori land use, the knowledge and skills residing in R&D institutions is unfamiliar territory. At the moment, it seems that research is best received by Maori land based enterprises that have an informed governance body which oversees the operation of sound, farm business practice, i.e. “doing the business right”. These commercially orientated Incorporations and Trusts are seeking new innovations to sustain their future business. In the recent Maori Farmer of the Year contest, structured arrangements between governance and farm management levels (e.g., performance criteria and communication channels) and high skill levels of farm managers were significant features of the farm enterprises that succeeded. Financial performance and productivity levels would place these farms in the 75-80% performance zone. These enterprises also sought to achieve high return on asset value and were therefore willing to invest in technological advancement (e.g., genetics, market channels). This attitude toward realising the full earning potential of land assets is not common for Maori farm businesses. Often a positive bottom line is sufficient and the need for new innovations and changes is deemed to be unnecessary.
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Coopworth ewes in a farm system study mated from 21 June had a lambing percentage (lambs weaned/ ewe mated) of 126% in Southland New Zealand (lat 46o 12’S), 13% lower than the farm September lambing average of 139%. Total farm production records showed that 221 kg/ha of lamb meat and 127 kg/ha of wool were produced. Pasture production was 15800 kg DM/ha, while 58% of the farm area was used for silage making in late October. Extra inputs required included fertiliser where silage was made, labour for silage feeding in winter, the costs of silage making and feeding out, concentrate feeds during winter, and extra shearing costs. Savings were made in crutching costs and labour costs at lambing due to lambing ease. November lambing systems provide the opportunity to produce heavyweight lambs for slaughter at 9 to 11 months of age but price structures need to account for the increased production costs. Keywords: Coopworth, farm systems, November lambing, pasture production
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(83 KB)Introduction My wife Pauline and I have two teenage children. We farm a property at Makuri, approximately 60 km east of Palmerston North. The property comprises 311 effective ha and runs approximately 3000 stock units (SU). Ninety hectares of adjoining land has recently been added to the unit through a six-year lease. The land at Makuri is medium hill on a belt of limestone that runs from Wairarapa through to Central Hawkes Bay. The belt of limestone has been tilted over to form a westerly facing dip slope running from 300 metres to 750 m above sea level (average approximately 550 m above sea level). Because of this, the farm is very exposed to the prevailing westerly wind. Because the farm is situated east of the low area between the Tararua and Ruahine ranges, it is not in a rain shadow and therefore gets rain from the west as well as in easterly conditions. The environment is summer moist, with average rainfall between 1500 and 1800 mm per annum. Because of the altitude we experience long cold winters but tend to have good growthy summers and autumns. Pauline and I also have a small block of 26 ha at Mangamutu on the outskirts of Pahiatua. This farm comprises flat to rolling country, with the majority mowable. The property carries approximately 390 SU.
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(56 KB)Sheep have a higher intake of nutrients when offered continuous free access to ryegrass and white clover growing separately than when offered the same species growing as a mixture. To determine if this greater nutrient intake would translate to higher animal performance, three experiments of 3-6 weeks duration measured liveweight gain by ewes+twin lambs in early spring, weaned lambs in mid-late spring and hoggets during late winter to identify the class of sheep most responsive to this form of forage presentation. Offering pasture comprised of ryegrass and clover growing separately resulted in higher average daily gains for weaned lambs (330 vs 185 g/ day, P<0.01) and hoggets (240 vs 190 g/day, P<0.05), compared with ryegrass-only pasture. The farm simulation model STOCKPOL and the experimental results reported above were then used to examine four scenarios for implementing this form of pasture arrangement on-farm. This analysis predicted that using pastures comprised of ryegrass and clover growing separately on 15-20% of the area of a typical sheep breeding/finishing farm is feasible and could increase lamb carcass output and net farm income. A higher proportion of area than this shifts the distribution of feed supply towards summer and would be appropriate for systems having higher feed demand in summer, such as specialist lamb-finishing or highly prolific breeding flocks. Keywords: average daily gain, forage presentation, grazing behaviour, ryegr ass, STOCKPOL, white clover
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(132 KB)Abstract This study set out to demonstrate what could be achieved in terms of lamb growth rates under controlled experimental conditions. Ewes with high breeding values for progeny growth rate were selected from within a flock of 900 ewes and mated using AI to a ram with a high breeding value for progeny growth rate. Of the 70 ewes mated, 44 reared 75 lambs (170%) to 12 weeks of age. Lamb birth weights averaged 4.8 kg. Ewes and lambs were fed on pasture covers between 1800 and 2600 kg DM/ha throughout lactation. At 12 weeks of age, the average weight of all lambs in the mob averaged 39 kg. Average growth rate of all lambs from birth to 12 weeks was 409 g/d, with single, twin and triplet lambs averaging 437, 407 and 380 g/d respectively. The best individual lamb grew at 549 g/d and weighed 51.6 kg at 12 weeks. This demonstration sets a new benchmark for both mob and individual lamb growth rates and indicates what can be achieved with a combination of genetics for growth, ewes with good milking ability and good pasture feeding conditions. Keywords: breeding value, lamb growth rate, milking ability, pasture quality
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(61 KB)
Phosphorus (P) is both an essential element for pasture and animal production and a limiting nutrient for nuisance weed and algal growth in many New Zealand water bodies. Research results, mainly measured under mowing, have shown that pasture production increased with fertiliser P application up to a target range of soil Olsen P values (20-30 mg/L for sedimentary and Allophanic soils; 35-45 mg/L for Pumice and Organic soils). A dairy farmlet trial in Taranaki on an Egmont Allophanic soil measured small increases in pasture production and larger economic responses in milksolids (MS) production as Olsen P levels increased from 30-50 in a management system with high stocking rates and a long lactation. The relative response in pasture production to Olsen P was similar under mowing and grazing, indicating that the MS response to high Olsen P measured on Allophanic soils would also apply to other soils. Only small amounts of dissolved P (< 1 kg/ha) are required to promote nuisance weed and algal growth in water bodies. P can be sourced from soil, fertiliser and dung and transported in dissolved and particulate forms from soil to water through overland and subsurface runoff flow. Data from a P runoff study on different soils is presented which shows that the potential for P to be lost to water bodies increases with Olsen P level. On a high anion storage capacity (ASC) Egmont Allophanic soil (83%), the concentration of dissolved reactive P (DRP) in overland flow was lower than the critical level of 0.03 mg/L at Olsen P levels of 20-110 mg/L. In contrast, on the more weakly weathered Waikoikoi Pallic soil with low ASC (15%), the critical DRP level was exceeded at an Olsen P of about 30 mg/L, and on the moderately weathered Waikiwi Brown soil (ASC 49%), at an Olsen P of about 50 mg/L. These results indicate that there is a greater risk of P enrichment of surface water bodies in areas with low ASC than in areas with high ASC soils. Keywords: allophanic soils, milksolids production, pasture, phosphorus loss, sedimentary soils, water bodies
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(76 KB)Abstract This 3 year (1996–1998) study compared grazing regimes for minimising soil compaction and pugging damage. The treatments were conventional yearround dairy cow grazing, grazing for 3 hours when soil was susceptible to pugging damage, never pugged when soil was susceptible to pugging damage, and never grazed. In October 1997, macroporosity at 0– 5 cm (air-filled porosity), a measure of soil compaction, was: never grazed (21.6%), never pugged (21.3%), 3 hour grazing (16.3%) conventional grazing control (12.8%). During July–September 1997, the never grazed and never pugged treatments had 35%, and 28% greater pasture yields than the control, with a similar trend in July–September 1998. The 3 hour grazing treatment had better soil physical quality than the control but this was not reflected in greater pasture production. The never pugged treatment greatly improved soil physical condition and had greater winter/spring pasture growth compared with conventional grazing so would be justified by farmers implementing “standing-off” pasture management strategies. Keywords: compaction, pasture yield, pugging, treading
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(80 KB)In 1998 a three-year dairy farm monitoring programme funded by AGMARDT (Agricultural Marketing and Research Development Trust) was established on twelve dairy farms in the southern North Island of New Zealand where policy had changed from a focus on high production per ha through high stocking rate to a management based on reduced stocking rate and strategic use of supplements to enhance both production per cow and per ha. The project involved a detailed three-year data collection which included measurements of the quantity and composition of pasture and supplements consumed as well as animal performance. Analysis of the results of the third year (2000/2001) on nine of these farms with complete data sets identified a range of metabolisable energy (ME) intake (50669 – 70135 MJ ME/cow/yr). Supplementary feed represented on average 24% (21 – 27 %) of the total intake of ME, the main supplements being pasture silage (summer to winter), turnips (summer) and maize silage (autumn and winter) consumed by lactating cows, and grazing off by dry stock. There was a range of milksolids (MS) production per cow (372 – 424 kg/year) and per hectare (921 – 1264 kg/year). The average economic farm surplus per hectare of NZ$3077 (NZ$2425 – NZ$3867) for the case-study farms was approximately 43% higher than the top 25% farms in the Manawatu region. Mean values of return on assets for the case-study farms (12.9%) and top 25% farms in Manawatu (13.0%) were similar. Good pasture management based on controlled preand post-grazing herbage mass targets (mean 2650 and 1900 kg DM/ha, respectively), strategic use of supplementary feed to control pasture deficits, and moderate stocking rates (overall mean 2.7 cows/ha), provided high allowances of high quality herbage (organic matter digestibility ranging from 742 to 845 g/kg DM) and maintained high levels of milk production (411 kg MS/cow and 1100kg MS/ha). The comparison with industry data showed that the casestudy farms were highly productive and profitable dairy systems, at least under the conditions of the 2000/2001 season. However, the result indicated the need to improve management skills to limit feed wastage under generous feeding management, and also the limitation of conventional procedures for monitoring pasture consumption in farming systems. Keywords: animal performance, dairy systems, energy intak e, herbage quality, pasture management, profitability
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(190 KB)2001/2002 and 2002/2003 were the final two seasons of a replicated dairy farm systems trial designed to evaluate the effects of progress in perennial ryegrass and white clover breeding programmes on whole farm productivity and profitability (Economic Farm Surplus, EFS). All the pastures were sown in late autumn 1998. There were four treatments with all combinations of 1980’s (80R), and late 1990’s (98R) ryegrasses, and 1960’s (60C) and late 1990’s (98C) white c lover s, each replicated two times in a randomised block design giving eight 4 ha, self-contained farmlets stocked with three Friesian cows/ha and rotationally grazed. In agreement with the first two years of the trial, the last two seasons have demonstrated no major benefit in terms of either milksolids (MS) production or EFS to sowing different combinations of perennial ryegrass and only a small advantage in one season (2001/2002) to sowing new (98C) white clover cultivars. There were no effects of ryegrass or clover cultivar type on total dry matter (DM) production during the last two seasons but, as observed during the first two seasons of the trial, there were differences in the distribution of pasture growth through the year with old ryegrass (80R) treatments having more pasture growth during spring. During 2001/2002 and 2002/2003 the clover content of the swards was determined more strongly by clover type than by the type of companion ryegrass, in contrast to events during the first two seasons of the trial. Thus clover type, rather than a ryegrass x clover interaction, had a small effect on MS production and EFS during 2001/2002, but not 2002/2003, due to significantly higher clover content in both the new clover (98C) treatments than the old clover (60C) treatments. Any differences between ryegrass or white clover cultivars in terms of lower DM production at certain times of the year, and consequent small differences in total DM production and pasture quality caused only minor differences in EFS between treatments because effective farm management decisions compensated for these effects. Keywords: cultivars, dairying, economic farm surplus, milksolids, perennial ryegrass, white clover
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(191 KB)A 3-year farmlet experiment was carried out at Dexcel, Hamilton to evalua te the effects of AR1 (no lolitrem B or ergovaline production) and wild (standard or natural) endophyte-infected ryegrass on milksolids production and cow health. Two farmlets (7 ha each) were managed as self-contained systems with cows rotationally grazing treatment paddocks from September 2000 to May 2003. In the 2000/2001 milking season, cows grazing AR1 endophyteinfected ryegrass produced 10% more milksolids than those grazing wild endophyte-infected ryegrass (247 versus 224 kg/cow, SED = 8.4, P<0.01). Treatment differences were smaller and not statistically significant in the second and third milking seasons. A combined analysis of the 3 milking seasons data, showed a significant milksolids production advantage to cows grazing AR1 endophyte-infected ryegrass pastures (318 versus 292 kg/cow, SED=9.2, P<0.01). Milk composition was similar in all seasons. Milksolids production averaged over 3 milking seasons was significantl y higher in cows grazing AR1 endophyte-infected ryegrass in summer (110 versus 103 kg/cow, SED=2.9, P<0.01) and autumn (50 versus 44 kg/cow, SED=2.1, P<0.01), and showed a similar effect in spring (157 ver sus 147 kg/cow, SED=5.5, P<0.1). Ryegrass staggers occurred in cows grazing wild endophyte-infected pastures in January 2001, coinciding with the highest concentrations of lolitrem B over the 3 seasons (>3.5 mg/kg). Cow temperatures, respiration rates and plasma prolactin concentrations were seldom affected by endophyte treatment. Annual pasture production was similar across AR1 and wild endophyte-infected ryegrass farmlets from September 2000 to September 2001 (14.7 versus 14.4 t DM/ha, SED = 1.11, NS) and from September 2001 to September 2002 (14.1 versus 12.9 t DM/ha, SED = 0.73, NS). AR1 endophyte-inf ected ryegrass pastures remained free of contamination from wild endophyte-infected ryegrass for at least 3 years after establishment, as indicated by low concentrations of lolitrem B detected in pasture samples. Keywords: dairying, heat str ess, Lolium perenne, Neotyphodium lolii, novel endophytes, pasture production, prolactin, ryegrass staggers
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(103 KB)
Although plant roots take up nitrogen (N) both as ammonium (NH4 +) and nitrate (NO3 -) ions, under most soil conditions uptake of NO3 - dominates. Once absorbed by the plant roots, the NO3 - is reduced to NH4 +, which is subsequently assimilated into organic compounds. However, when the rate of uptake exceeds the rate of NO3 - reduction, accumulation of NO3 - in plants occurs. Ruminant animals with high NO3 - levels in their diets accumulate nitrite (NO2 -). Nitrite is absorbed into the blood and combines with hemoglobin to form methemoglobin. This condition is known as nitrate poisoning (i.e., methemoglobinaemea). Nitrate poisoning occurs when animals eat forage material with high NO3 - content. The most common causes of high NO3 - content in forage tissue include: (i) high application of N fertilizers; (ii) drought conditions; (iii) damage to plant tissue (such as defoliation as a result of herbicide application); (iv) low light intensity, which reduce photosynthetic activity; and (v) presence of NO3 - accumulating plant species, such as annual weeds. In this review paper, the processes of uptake and assimilation of N by plants, factors affecting NO3 - accumulation in plants, and the treatment and prevention of nitrate poisoning in grazing animals are discussed. Keywords: forage crops, methemoglobinaemea, methylene blue, N fer tilizer, nitrate accumulation, nitrate poisoning, nitrate reductase
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(208 KB)The agronomic performance of an experimental white clover (HT) selection bred for increased floral condensed tannin (CT) production and extended flowering season was compared with Grasslands Huia white clover, under dairy cow grazing in the Waikato. Pure clover swards were sown at 5 kg/ha in autumn 2001. Seedling establishment was better in HT than Huia, but stolon growing point densities from January 2002 to May 2003 were 13 to 62% greater in Huia than HT. Huia swards had higher clover contents than HT, and produced 0.8 t/ha more DM (dry matter) in the first year. CT concentr ations in the flower heads varied over the season, but were similar in the two clovers (1 to 8% of DM). Higher flower densities in HT resulted in higher clover CT concentrations (peak of 0.6 vs 1.2 % of DM for Huia and HT, r espectively). Further testing is required to determine any effects of HT on animal performance. Keywords: condensed tannins, flowering, growing point density, Trifolium repens, white clover
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(91 KB)We conducted an experiment at two hill country sites in the North Island to determine whether more diverse pasture swards were beneficial in terms of pasture herbage yield and resistance to weed invasion. In this study diversity was characterised by variation in the number (between 0 and 8) of functional groupings of pasture plant species. Seed mixtures were oversown into sprayed resident pastures in low and high fertility paddocks and steep and easy slopes within those paddocks. We measured pasture yield in terms of net herbage accumulation in spring and autumn of 1999-2000 and the botanical composition of the harvested material, identifying unsown species in the plots. The dominant influences on pasture yield were site, fertility and slope, rather than species diversity. The presence of particular functional groups was also weakly associated with differences in pasture yield. Increasing the number of functional groups sown had a negative effect on the invasion of unsown species, and their contribution to yield, and this may be the main benefit of pasture diversity. Keywords: functional groups, hill country, pasture yield, species diversity, weed invasion
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(148 KB)Genetic diversity provides the raw material for plant improvement programmes. The assessment of genetic diversity is commonly based on plant morphology; however, this indirect measure of genetic diversity is often confounded by environmental effects. Microsatellite (SSR) markers are a powerful tool that directly measures variation among plants at the DNA level. We assayed the pattern of relatedness among 32 white clover (Trifolium repens L.) cultivars using 39 SSR markers that are evenly distributed within the white clover genome. The 390 alleles detected were used to quantify the 496 pairwise genetic similarity estimates among the cultivars, detecting a mean value of 0.56 (range 0.44 – 0.68). Cluster analysis assigned the 32 cultivars to 14 clusters based on their genetic similar ity. The resulting clusters revealed strong correlation with known genetic relationships based on pedigree and the geographic origin of the parental germplasm. The development of a DNA fingerprinting technique based on high-throughput SSR markers has potential applications in plant variety rights, seed certification and variety identification in grazed pastures. Keywords: cluster analysis, DNA fingerpr inting, genetic diversity, microsatellite , molecular markers, Trifolium repens L
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(301 KB)N-alkane marker techniques are commonly used in the measurement for forage intake in grazing animals. Traditionally sample preparation of feed for subsequent n-alkane analysis has been conducted on freeze-dried samples, however oven-drying is both less time consuming and less expensive. Ten mixed age rumen fistulated wethers were housed in individual metabolism cr ates in the Animal Physiology Unit of Massey University for 30 days. The wethers were randomly allocated to one of four treatments fed either 0.5, 1.0, 1.5 or 2.0x maintenance requirement based on individual liveweight, with 2, 3, 3 and 2 animals in each respectively. Fresh ryegrass/white clover pasture was offered twice-daily. Following a 10 day adaptation period, each animal had an n-alkane capsule inserted via rumen fistulae from d0-d20. Feed and faeces was sub-sampled for subsequent analysis of C31 , C32 , C33 , C35 and C36 alkane content on alternate days from d5-20. Capsules were removed temporarily on alternate days from d0, for measurement of the plunger travel, as an indirect measure of capsule release rate. All faecal samples were oven-dried at 60°C until a constant dry weight was achieved. Herbage sub-samples collected on d5, 9, 13 and 17 were stored at -5°C before freeze-drying, while subsamples collected on d7, 11, 15 and 19 were oven dried at 60°C for 48 hours. The capsules achieved a constant release rate within four days post-insertion and remained at a steady rate up to day 20 postinsertion. No difference was found between estimated intakes using either C31:C32 or C32:C33 alkane ratios. Day had no significant effect on either actual or estimated intakes. Oven-drying the feed was found to produce a weak linear relationship whereas freezedrying the feed samples produced a much stronger relationship when compared to in vivo intake. A significant difference (P<0.05) in relationship between the two methods of sample preparation was found. Keywords: drying method, freeze-drying, herbage intake estimation, intra-ruminal capsule, n-alkane, oven-drying
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(100 KB)Dry matter (DM) yield responses and field nitrogen (N) leaching losses were assessed following the application of 4 rates of N fertiliser to an Italian ryegrass (Lolium multiflorum) crop grown after maize. The trial was conducted on a free-draining Horotiu silt loam (typic orthic allophanic soil) at Dexcel’s Scott Farm near Hamilton, New Zealand. The grass was direct dr illed into maize stubble on 13 April 2002. Small plots received a total of 0, 40, 100 or 160 kg N/ha as urea, split into 4 equal applications from May to July. Total DM production over 24 weeks for the 0, 40, 100 or 160 kg N/ha treatments was 2730, 3487, 4238 and 4840 kg DM/ha, respectively. Additional kg DM produced/kg N applied was 19, 15 and 13, respectively. The ‘apparent’ proportion of applied N removed in the herbage from all plots was 55- 60%. Herbage nitrate-N concentrations exceeded the commonly accepted critical level of 0.21% on the 160 kg N/ha treatment at the first harvest on 3 July 2002, when only half of each N rate had been applied. There were no significant treatment differences in leaching losses (range 17-34 kg N/ha). Italian ryegrass grown on a silt loam soil after maize showed an almost linear yield response to N fertiliser over the range 40-160 kg N/ha, without increased inorganic N leaching. Further work is necessary to confirm these results and to establish whether or not higher rates of N fertiliser can be used to increase winter dry matter yields from Italian ryegrass, without increasing N leaching losses. Keywords: annual ryegrass, dairy systems, double cropping, nitrogen leaching
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(76 KB)Grasslands Tribute is a medium-large leaved white clover released in 2003. It was initially bred for drought tolerance and winter activity in Victor ia, Australia from crosses among elite New Zealand germplasm. Tr ibute was then screened for agronomic performance in New Zealand and reselected for medium-large leaf size, uniform flowering pattern, absence of foliar disease and high seed yield potential. Almost half of the 11 parental lines of Tribute came from half-sib families based on a Syrian accession with the remaining half-sibs based on Sustain, Southern Europe II and Crau in approximately equal proportions. The decision to release Tribute was based on its consistent performance and persistence under grazing in a series of seven New Zealand trials. Tribute was the best medium-large leaved variety under both sheep and dairy grazing, with only the large-leaved Kopu II having better performance under dairying. It shows strong growth in all seasons but has very good coolseason growth, and good drought tolerance in Canterbury. Keywords: breeding, cultivars, dairy, sheep, Trifolium repens, white clover
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(85 KB)Using isotopic signatures from animal tissue, it is possible to recover certain information about the environment of the animal – notably the diet – at the time the hair was laid down. In the case of tail switch hair of cattle, a single hair may often represent an archive of information spanning a year or more in time. Isotopic analysis by mass spectrometry is now becoming cheap enough to be considered accessible for routine diagnostic or scientific investigation. The ratios of 13carbon (C):12carbon and 15nitrogen (N):14nitrogen ar e ideal for such investig ation, since C and N are constituents of all animal proteins. This paper explains the theory of isotopic analysis in layman’s terms, and repor ts an exper iment in which tail switch hair of 9 cattle from three Northland dairy farms was analysed in a ‘proof of concept’ study, to demonstrate the information-retrieval potential offered by isotopic analysis. Changes in isotopic abundance are measured in parts per thousand (, ‰). When matching signatures on replicate hairs, the average distance from the ‘interpolation’ line was ± 0.13‰ for 13C, and ± 0.11‰ for 15N. In contrast to this, differences in 13C between different hair segments analysed exceeded 11‰ , while between farm dif ferences in 15N exceeded 2.0‰ . We suggest possible reasons for these differences in isotopic signature. Keywords: 13C, 15 N, isotopic archive, nutritional ecology, stable isotope
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(121 KB)Clover root weevil (CRW) has now spread through the northern North Island, and south into Taranaki and Hawke’s Bay r egions. Sever e infestations can decimate white clover in pasture. In 1998, 2000 and 2002, trials were estab lished on a Warkworth Northland dairy farm to test a range of legume species for resistance or tolerance to CRW damage. Trial lines were regularly assessed for relative vigour and levels of CRW damage. No plant resistance w as identified among white clover, red clover, lucerne, Lotus corniculatus, Lotus pedunculatus or Caucasian clover seed lines. A few lines were adapted to the site and showed tolerance to CRW. Red clover suf fered the least damage and tolerant selections were made from a creeping red clover and nine white clover lines. Two further trials confirmed that red clover showed the least damage. Further cycles of selection are required to develop the potential tolerance shown in field tests. Red clover or a well-adapted white clover offers potential to cope with the CRW stress. Keywords: clover root weevil, clover selections, legume tolerance, Sitona lepidus
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(107 KB)For the past decade maize silage has been planted at 100000 plants/ha in New Zealand. Modern maize silage hybrids have enhanced stress tolerance making them more adaptable to higher plant populations. This study examined the effect of a range of established plant populations (85000, 100000, 115000, 130000 and 145000 plants/ha) on the yield and quality of 12 Pioneer® brand maize silage hybrids grown at 13 locations over two seasons. As plant population increased maize silage dry matter (DM) yield increased significantly (P<0.01) from 18.66 to 20.52 t DM/ha (Year 1) and from 22.10 to 23.69 t DM/ha (Year 2). Location x hybrid interaction was significant (P<0.01) for total DM yield and DM percentage. Hybrid x population and location x population x hybrid interactions were not significant. There was a significant effect of population and location x population on crude protein (Year 2) with the highest population plots having slightly lower crude protein percentages. The effects of population, location x population on all other nutritional quality parameters were not significant. Even when the cost of additional seed and seed insecticide treatment is considered, lifting established populations to 115000 to 130000 plants/ha is profitable for dairy farmers growing and feeding maize silage. Keywords: maize silage, plant population, supplementary feed
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(72 KB)
Nitrogen (N) is the major nutrient that limits pasture growth in New Zealand. Here we test the hypothesis that N supply to herbage from soil microbial mineralization is a function of both the quantity and quality of the soil organic matter, and that this underlying process is similar under conventional and organic management. Preliminary results for October– November 2002 from nine sites with a wide range of soil N status at AgResearch, Ballantrae show that microbial-mineralized N supply from the soil to herbage was the dominant factor controlling the differences in herbage growth. Herbage N was also highly correlated with the soil N supply, as estimated from a 56-day laboratory incubation of soil (0–7.5 cm, and 7.5–20 cm depths). For these soils, spring herbage production could be estimated from the negative relationship with the C:N ratio of the topsoils. This suggests the over-riding factor in the N supply at the nine sites was the quality of soil organic matter in the topsoils. Quality is enhanced through the growth of legumes that in turn depend on the P status of the soil. The soil parent material at some sites (1996 organic farmlets) is calcareous mudstone, which has a high P status, and may explain some differences in site fertility not explained by past P applications. The relationship between the quantity and quality of organic matter and microbial N mineralization in the four farmlets that had organic management appeared to be on the same trend-lines as those in the conventional farmlets, indicating that the underlying net N mineralization process was similar under conventional and organic management. Other factors statistically related to herbage yield and soil net N mineralization were some groups of nematodes and microbial P, but not microbial biomass C or N. Keywords: N mineralisation, non-chemical farms, organic farms, soil fertility
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(69 KB)Nutrient budgets are useful tools for assessing the sustainability of nutrient flows within a farm and for highlighting potential negat ive environmental impacts of nutrient use. The OVERSEER® nutr ient budgets program is a decision support model to help users develop nutrient budgets. This paper outlines an upgrade to the OVERSEER® nutrient budgets program, with improvements in nitrogen (N), phosphorus (P), potassium (K) and sulphur (S), and addition of calcium (Ca), magnesium (Mg), sodium (Na) and hydrogen (potential acidity). Energy use and greenhouse gas emission profiles from farms have been included in the model. Using ‘typical farm’ and simulation studies, the paper then outlines how nutrient budget can be used to improve farm nutrient management. Keywords: acidity, calcium, energy, green house gas, inventory, lime, magnesium, maintenance fertiliser, nitrogen, nutr ient budgeting, phosphorus, potassium, resource accounting, sodium, sulphur
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(67 KB)A life cycle assessment (LCA) approach was used to estimate whole-system (dairy farm + grazing and forage land) resource use and environmental emissions for an averag e Waikato dairy farm enterprise. Effects of increased production from 850 to 1020 kg milksolids/ha using more nitrogen (N) fertiliser (+200 kg N/ha/yr) or forage (+2 t DM/ha/yr maize and oats silage) were also assessed. Fertiliser N increased production and economic efficiency, but decreased environmental efficiency through a predicted increase in N leaching and greenhouse gas (GHG) emissions. In contrast, using forage increased the use of land but increased milksolids/ha and with no loss in environmental ef ficiency (per kg milksolids). A preliminary compar ison of the average Waikato farm system and an example Swedish dairy farm system showed small dif ferences in environmental efficiency (GHG or N leaching/m3 milk) but much higher (5-fold) energy efficiency on the Waikato farm. This is important to maintain, particularly as farms intensify, if “food-miles” (energy use in transpor ting produce to markets) become a component of our “ecolabel” for supplying produce to overseas markets. Keywords: dairy farm, ef ficiency, environment, intensification, maize, nitrogen, resource use
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(74 KB)While it is widely believed that intensive dairy farming is a major contributor to the increased nutrient loads in surface waters, there is little current research quantifying the magnitude of nutrient loss from dairy farms to waterways, particularly from artificial drainage. An experimental site has been established on a Pallic soil (Tokomaru silt loam) to measure the impacts of intensive dairying on the quality and quantity of drainage water exiting from an artificial drainage system. A key component of this study is the development and evaluation of a land-based treatment system for farm dairy effluent (deferred irrigation). The research site has eight replicated plots, each with an isolated mole and pipe drain network. All the plots are subjected to the farm’s standard grazing management. Four of the plots receive fer tiliser according to the farm’s fertiliser programme, while the other four plots receive applications of farm dairy effluent. Measurements of drainage flows during year one of this study showed that the average concentrations of total nitrogen (12.9 mg N/L) and total phosphorus (0.15 mg P/L) in drainage water for the winter of 2002 under standard dairy farming practices were all well above the levels necessary to prevent aquatic weed growth in fresh water bodies. Adherence to the scheduling criteria prescribed by the ‘deferred irrigation’ system prevented the direct loss of nutrients during irrigation of farm dairy effluent in the summer of 2001/2002. Summer applications of farm dairy effluent did not increase N loss in subsequent winter drainage. Effluent irrigation increased P loss during the subsequent winter drainage period by 0.52 kg total-P/ha (0.38 kg P/ha as DIP). However, this increase in total loss corresponds to less than 4% of the P (16 kg/ha) applied as effluent. Deferred irrigation proved to be a very successful tool for minimising nutrient losses from effluent irrigated areas in direct drainage of effluent at the time of irrigation and subsequent winter drainage. Dairy cattle grazing events also increased nutrient concentrations in drainage waters following grazing by approximately 5 mg total-N/L (nearly all in the nitrate form) and 0.1 mg total-P/L (nearly all in the DIP form). The effect of an application of urea in spring on nitrate-N concentrations in drainage water was minimal. Keywords: dairying, effluent irrigation, mole and pipe drainage, nitrogen, nutrient leaching phosphorus, water quality
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(118 KB)
Farm business success for challenge and satisfaction may include wealth aggregation. Analysis of the importance of asset management compared to production/cash flow to aggregate wealth suggests they are linked but that asset management is more lucrative. Influences on farmland prices are discussed, as well as observations of top wealth aggregators in farming. Keywords: asset management, production/cash flow, wealth aggregation
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(64 KB)The effort to promote formal feed planning and monitoring systems in New Zealand has been considerable. Despite this, several studies indicate that relatively few farmers have adopted these systems. Reasons for non-adoption of formal feed planning systems have been identified, but little is known about how farmers manage their pastoral farms in the absence of these systems. To this end, the feed management processes used by three successful farmers (2 dairy, 1 sheep and cattle) were investigated. Farmers separated the year into distinct planning horizons and alternated between formal and informal feed planning. Formal feed planning was used when critical decisions had to be made, accurate pasture measurement could be undertaken and the level of environmental uncertainty was perceived to be low. Informal feed planning, used at other times of the year, involved farmers accessing, from memory, plans that had worked in the past. These “typical” plans were modified in response to learning. In the face of uncertainty, micro-budgets were prepared at paddock level. Our findings raise the question with respect to planning and monitoring – should we continue to promote formal systems or learn how farmers do this and develop decision support systems in this context? Keywords: decision making, farmer knowledge, feed budgeting, planning, tactical management
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(358 KB)Investing in farmland is fraught with conflicting signals. While investing in land may generally be profitable it is seldom, if ever, feasible on a cash f low basis. The non-depreciable nature of land and longterm capital gains are incompatible with the capital recovery terms sought by investors and lenders. The literature on this subject tends to focus on either the returns (profitability) or the cash flow (feasibility) but not on both simultaneously. Too frequently rural professionals use the terms profitability and cashflow (liquidity) interchangeably. This paper presents a range of profitability measures and distinguishes between them and commonly used liquidity measures. The profitability measures include activity based costing which involves full economic costing and the entrepreneur’s profit/loss is the difference between cost of production and market price. It is concluded that a number of measures are relevant to farm businesses but these should not be used in isolation. The critical importance of liquidity measures is reinforced but their use as profitability measures is criticised. Keywords: business success, farming business, liquidity, profitability, pr operty business
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(134 KB)Measures of farm business – biophysical, financial, personal, community – are traversed in this paper. What constitutes success in farming has evolved over time, reflecting changes in the business operating environment and advances in measurement tools. Farmer of the Year competitions weigh success differently: community involvement and leadership are important criteria for one national award; others are heavily biased towards financial performance. Not surprisingly farmers view success in different ways too, emphasising the importance of understanding personal-family goals when evaluating success. While “success is in the eye of the beholder”, on an aggregate basis continuous improvement for the pastoral sector is vital in sustaining competitive advantage in the marketplace. Looking to a future with fewer, larger farms, increased market competition and shortages of competent labour, better measures than those currently used are needed in relation to meeting customer needs, growing the farmers’ share of market returns and optimising the human element in a farm business. Measures and their use by management are important if New Zealand farm businesses are to maintain their competitive edge in global markets. Keywords: farm business, performance measures, top farms.
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(72 KB)
Accelerated improvement of two cornerstones of New Zealand’s pastoral industries, per ennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), may be realised through the application of markerassisted selection (MAS) strategies to enhance traditional plant breeding programmes. Genome maps constructed using molecular markers represent the enabling technology for such strategies and we have assembled maps for each species using EST-SSR markers – simple sequence repeat (SSR) markers developed from expressed sequence tags (ESTs) representing genes. A comprehensive map of the white clover genome has been completed, with 464 EST-SSR and genomic SSR marker loci spanning 1125 cM in total, distributed across 16 linkage groups. These have been further classified into eight pairs of linkage groups, representing contributions from the diploid progenitors of this tetraploid species. In perennial ryegrass a genome map based exclusively on EST-SSR loci was constructed, with 130 loci currently mapped to seven linkage groups and covering a distance of 391 cM. This map continues to be expanded with the addition of ESTSSR loci, and markers are being concurrently transferred to other populations segregating for economically significant traits. We have initiated gene discovery through quantitative trait locus (QTL) analysis in both species, and the efficacy of the white clover map for this purpose was demonstrated with the initial identification of multiple QTL controlling seed yield and seedling vigour. One QTL on linkage group D2 accounts for 25.9% of the genetic variation for seed yield, and a putative QTL accounting for 12.7% of the genetic variation for seedling vigour was detected on linkage group E1. The application of MAS to forage breeding based on recurrent selection is discussed. Keywords: genome map, marker-assisted selection, perennial ryegrass, QTL, quantitative trait locus, SSR, simple sequence repeat, white clover
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(607 KB)Livestock grazing ryegrass infected with endophytic fungi are susceptible to staggers, a neurological disorder characterised by uncoordinated movement and loss of appetite. A possible strategy to minimise staggers is to dilute the toxic effects of ryegrass by providing other non-toxic pasture species in the diet. Therefore, the incidence and severity of ryegrass staggers, and liveweight gain, was monitored in lambs grazing varying mixtures of ryegrass-cocksfoot pastures during four six-week periods throughout summer and autumn over two years. There was a significant effect of pasture type on staggers. On a scale of 0 (no staggers) to 5 (severe muscular tremors invariably resulting in collapse and tetanic spasm), pure ryegrass resulted in a mean of 3.1, S.E.M. + 1.6 compared with 0.3, S.E.M. + 0.9 with pure cocksfoot. Ryegrass/cocksfoot mixtures were slightly less toxic than pure ryegrass with means (+ S.E.M.) ranging from 2.2, S.E.M. + 1.6 to 2.9, S.E.M. + 1.8. Mean liveweight gains ranged from 62 g/d on both pure ryegrass and 80:20 ryegrass:cocksfoot mix, to 83 g/d on pure cocksfoot, with no significant effect of pasture type. In those periods when ryegrass staggers was significant, the percentage of ryegrass in the sward was positively related to the severity of staggers and negatively correlated with liveweight gain. The inclusion of cocksfoot in ryegrass-dominant pastures is thus able to reduce to some extent the adverse neurological effects of endophyte on lambs. Keywords: cocksfoot, endophyte, lambs, liveweight gain, ryegrass, ryegrass staggers
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(254 KB)Canada geese (Branta canadensis) and other herbivorous birds (e.g. paradise ducks, pukeko) can be a significant problem for both pastoral farmers and recreational turf managers in a number of locations in New Zealand. Canada geese were offered seeds and herbage of selected ryegrass combinations of (Lolium perenne) and endophyte (Neotyphodium lolii) to examine the effects of endophyte and the associated alkaloids on feeding behaviour. Forty geese were captured annually during the moult in January and contained in fenced areas by wing clipping. In both choice and no-choice feeding trials, geese consumed up to four times more endophyte-free than endophyteinfected ryegrass herbage. In a seed feeding trial, the geese did not discriminate on first exposure between the endophyte-free seed and that containing endophyte. However on Day 2 there was an 80% rejection of the seed containing endophyte compared to the endophyte-fr ee seed. A similar rejection of 80% was observed after a three month endophyte-free feeding period, suggesting the rejection was a long term learned response involving post-digestion feedback. Grass/endophyte associations may add to the armoury of bird control methodology as a tool to manage birds using habitat modification. Keywords: alkaloids, Canada geese, endophyte, herbage, post-digestion seed
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(69 KB)Reported problems with inconsistent white clover establishment in pastures prompted a MAF SFF project to investigate the causes. The establishment of white clover in 32 new and renovated paddocks on 16 farms in the Wanganui-Manawatu-Southern Hawke’s Bay region was monitored and the inconsistency confirmed in the f irst year. Seedling emergence at 44% (range 22 to 84) for ryegrass and 35% (range 9 to 73) for white clover was low (expected 70%+) and inappropriate grazing management inhibited subsequent plant growth and sward performance to 20% of potential. There were a few good performances, but the ‘grass to grass’ technique was particularly hard on clover. These problems have arisen as a result of modern methods (e.g. direct drilling and fertiliser N) that are less ‘clover friendly’, and have moved away from the older proven techniques. Minimal seedbed preparation and method of sowing, combined with lack of knowledge of white clover growth strategies and management requirements are seen as the main causes. Change is inescapable and while modern farming techniques and expectations may have currently placed clover at a disadvantage, the challenge now is how to balance the requirements of the pasture species with the expectations of the farming production system in the future. Keywords: emergence, establishment, farmer knowledge, grazing management, life cycle, sowing conditions, white clover.
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(80 KB)
The amount of soil carbon is the net effect of carbon inputs and decomposition and is influenced by many factors including the level of herbage utilisation, root production, litter quality, soil fertility and soil moisture status. Long term experiments at Winchmore, in mid- Canterbury, show soil carbon levels increased after initial development, but after 50 years fertiliser input has had no net effect on soil carbon, while increasing the frequency of irrigation has actually resulted in lower soil carbon levels. Pasture development at Ballantrae , in the southern Hawke’s Bay, has been associated with a decline in soil C levels, with the high fertility treatment having only slightly higher soil C than the treatment receiving a lower rate of fertiliser. At Tara Hills, in South Island semi-arid high country, increased stocking rate is associated with a decrease in soil C. Contrary to common perceptions increases in pasture and farm productivity do not necessarily result in increased soil carbon storage. Keywords: carbon, fer tiliser, grazing management, irrigation, soil organic matter
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(78 KB)In grazed-pastures animal treading is an important cause of soil compaction. Soil compaction influences the denitrification rate as well as the amounts of nitrous oxide (N2O) and dinitrogen (N2) production in the soil mainly through its impact on soil moisture conditions and porosity. A field experiment was undertaken to determine the loss of nitrogen (N) through N2O emission from different N sources as affected by a compaction treatment. Experiment comprised of two main treatments (uncompacted and compacted) to which four N sources (cattle urine, potassium nitrate, ammonium sulphate and urea at the rate of 600kg N/ha) and a control (water only) were applied, each replicated four times. Compaction was obtained through driving close parallel tracks by the wheels of the vehicle. Var ious soil properties related to soil compaction (b ulk density, water filled pore space (WFPS), oxygen diffusion rate (ODR)) were measured. The N2O fluxes were measured for 3 months (between 10th September and 4th December, 2002) using closed chamber technique. Overall, the bulk density of compacted soil was 12.8 % higher than that of the uncompacted soil. Results suggest that maximum compaction occurred in the top 0-2 cm layer. Soil matric potential measured at the 0-5 cm soil depth suggests that uncompacted soil had lower water content, except at low matric suctions, than compacted soil. The ODR in uncompacted soil was 79.3% higher than that in the compacted soil. Compaction caused a seven fold increase in N2O emission. Nitrate source was the most effective of all the treatments in causing potential emission. Under compacted soil 9.87% of the total N applied in form of nitrate was emitted whereas under uncompacted soil this loss was only 0.54%. N2O loss was found to decrease progressively from the time of application of N treatments. Total N2O emission for the three month experimental period ranged from 2.62 to 61.74 kg N2O-N/ha for compacted soil and 1.12 to 4.37 kg N2O-N/ha for uncompacted soil. Keywords: compaction, grazed pastures, Nfertilisers, nitrous oxide emissions, urine-N
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(99 KB)New targets for increased productivity from the sheep and beef industry are about 4% annually, at a time of ever heightening environmental awareness. A major part of this will occur by applying current technology to increase the productivity from the presently lowerthan- average farms. However leading farmers will also have to increase efficiency or productivity if they are to remain economically viable. One prospect is to examine the natural variability in hill pastures and determine if this can be more appropriately managed to improve economic returns. Hill farms have soil and topographic var iability, which can result in a wide range in pasture production. Yet a uniform rate of fertiliser is usually applied to such land. This results in under prescription of fertiliser for high yield potential zones, and similarly over prescription for low yielding zones. The conversion of easier hill land to dairying has shown how pasture productivity can be improved by applying higher rates of fertiliser and utilising the extra pasture efficiently. This approach could be applied within parts of hill farms. The main fertiliser used on hill farms is superphosphate which supplies phosphorus (P) and sulphur (S) for legume growth. This assumes that there is enough clover present to make it worthwhile. However most hill pastures, especially on steep slopes, are low in clover and as a result most are predominantly nitrogen (N) deficient for a large part of the year. The pasture responses to P and S are therefore limited by low soil N levels and N fertilisers give a better economic return. The application of a high rate of N fertiliser to hill country could more than double pasture production. The technology is almost ready to allow accurate, differential application of fertiliser to hill farms from fixed wing aircraft. This should further improve economic benefits. A differential fertiliser management plan has environmental benefits through improved soil stability and associated water quality from hill catchments. Keywords: differential fertiliser application, hill country, hill country variability
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(176 KB)During summertime in New Zealand, white clover experiences high levels of ultraviolet-B (UV-B) radiation. This frequently coincides with periods of summer drought. We investigated responses to UV-B and to the combination of UV-B and drought in various white clover populations, including New Zealand cultivars and ecotypes as well as overseas germplasm. The results were obtained under controlled environmental conditions in three independent trials. Overall, white clover growth was reduced by UV-B. The population comparisons indicated that low growth rate and adaptation to other forms of stress may be related to UV-B tolerance under well-watered conditions, but not during extended periods of drought. Flavonoid pigments that are involved in stress protection were strongly increased under UV-B and were further enhanced in the combination of UV-B and drought. The responses among these flavonoids were highly specific, with more pronounced UV-B-induced increases in quercetin glycosides, compared to their closely related kaempferol counterparts. UV-B toler ance of the less productive white clover populations was linked to the accumulation of quercetin compounds. In conclusion, these studies suggest (i) that slow-growing white clover ecotypes adapted to other stresses have higher capacity for biochemical acclimation to UV-B under well-watered conditions and (ii) that these biochemical attributes may also contribute to decreased UV-B sensitivity across white clover populations under drought. The findings alert plant breeders to potential benefits of selecting productive germplasm for high levels of specific flavonoids to balance trade-offs between plant productivity and stress tolerance. Keywords: Drought, flavonoids, genetic variation, HPLC, kaempferol, quercetin, str ess, Trifolium repens L., ultraviolet-B, white clover
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(139 KB)
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