12 results on '"Edwards, Grant"'
Search Results
2. Nitrate leaching losses are lower from ryegrass/white clover forages containing plantain than from ryegrass/white clover forages under different irrigation.
- Author
-
Carlton, Anna J., Cameron, Keith C., Di, Hong J., Edwards, Grant R., and Clough, Tim J.
- Subjects
LEACHING ,NITRATE analysis ,RYEGRASSES ,FORAGE ,WHITE clover ,IRRIGATION - Abstract
The aim of this research was to assess the potential of using perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) forages containing plantain (Plantago lanceolata L.) (PRGWC + Plantain) to mitigate nitrate (NO
3 − ) leaching in grazed grassland. Lysimeter studies were carried out to determine NO3 − leaching losses from the PRGWC + Plantain forage, compared with the standard perennial ryegrass and white clover forage (PRGWC) under three different irrigation conditions (flood, rotorainer and pivot). Fresh dairy cow urine (700 kg N ha−1 ) was applied to these lysimeters in early summer (December) and late summer (February). Nitrogen (N) dynamics and the abundance of ammonia oxidising bacteria (AOB) and archaea (AOA) were also determined in companion mini-plots alongside the lysimeters. Nitrate leaching losses from the PRGWC + Plantain forage were 82% lower than those from the PRGWC forage when urine was applied in December and 74% less when urine was applied in February (P < .05). This was possibly due to the release of biological nitrification inhibitors by plantain which slowed down the nitrification process and this, combined with a lower drainage volume, was largely responsible for the lower NO3 − leaching losses in the PRGWC + Plantain forages. The three different irrigation schemes did not significantly affect NO3 − leaching losses under the two forage types. These results demonstrate the potential of using PRGWC + Plantain forages as an effective mitigation option for NO3 − leaching in grazed grasslands. [ABSTRACT FROM AUTHOR] more...- Published
- 2019
- Full Text
- View/download PDF
Catalog
3. Reducing nitrogen leaching losses in grazed dairy systems using an Italian ryegrass‐plantain‐white clover forage mix.
- Author
-
Woods, Roshean R., Cameron, Keith C., Edwards, Grant R., Di, Hong J., and Clough, Tim J.
- Subjects
NITROGEN in soils ,GRAZING ,WHITE clover ,SOIL leaching ,FORAGE ,DRY matter content of plants - Abstract
In grazed agricultural systems, animal urine patches are the major source of nitrogen (N) leaching losses and can cause a decline in water quality. Urine‐N rates often exceed plant requirements, and there is a need for mitigation options to reduce the impact of agriculture on the environment. One approach is to use alternative forages to reduce urine‐N loading rates, or to increase N uptake. This study used lysimeters to determine the N leaching losses, dry matter yields and N uptake following ruminant urine application to an Italian ryegrass‐plantain‐white clover forage mix (IRPWC, Lolium multiflorum Lam.‐Plantago lanceolata L.‐Trifolium repens L.) or perennial ryegrass‐white clover (PRWC, Lolium perenne L.‐T. repens L.). Three urine treatments were applied: Control (no urine), Urine Actual (urine from cows grazing each of the forages: 508, and 664 kg N/ha, for IRPWC and PRWC, respectively) and Urine 700 (700 kg N/ha). Compared with PRWC (113 kg N/ha), N leaching losses were 88.9% lower from IRPWC‐Urine Actual (12.5 kg N/ha) and 45.5% lower from IRPWC‐Urine 700 (61.8 kg N/ha). These reductions were attributed partly to the IRPWC having higher cool season activity and ability to take up N during the cool period, and partly to the lower concentration of urine‐N, compared with PRWC. IRPWC is a promising alternative forage for future farm systems with the ability to reduce urine‐N excretion from grazing animals and cause large reductions in N leaching losses while producing the same herbage dry matter yields as PRWC. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
- View/download PDF
4. Implications of grass-clover interactions in dairy pastures for forage value indexing systems. 6. Cross-site analysis and general discussion.
- Author
-
Chapman, David F., Crush, Jim R., Lee, Julia M., Cosgrove, Gerald P., Stevens, David R., Rossi, Laura, Popay, Alison J., Edwards, Grant R., and King, Warren M.
- Subjects
PASTURES ,GRASSES ,NITROGEN fertilizers ,RYEGRASSES ,CULTIVARS ,MONOCULTURE agriculture - Abstract
Herbage accumulation (HA) data from four sites were combined to (1) address the hypothesis that adjustments to the New Zealand Forage Value Index to account for grass-clover interactions are not required and (2) explore the main effects of clover and nitrogen (N) fertiliser treatments on pasture productivity. In summer and autumn, pastures based on mid-season heading ryegrass cultivars consistently supported a greater clover content than pastures based on late heading cultivars. However, the clover × cultivar interaction was significant in only 2 of 17 HA data sets available for analysis. Thus, the hypothesis is supported. Compared with ryegrass monocultures, mixtures yielded an additional 2.4 (in the Low-N treatment) and 1.2 (High-N treatment) t DM/ha/year. Apparent N transfer from clover to grass was 79 (Low N) and 27 (High N) kg N/ha/year, derived from estimated N fixation efficiencies of 66 (Low N) and 50 (High N) kg N/t clover DM grown. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
- View/download PDF
5. Implications of grass-clover interactions in dairy pastures for forage indexing systems. 4. Canterbury.
- Author
-
Chapman, David F., Rossi, Laura, Lee, Julia M., Edwards, Grant R., Popay, Alison J., McNeill, Mark N., Wilson, Derrick J., and Bell, Nigel L.
- Subjects
RYEGRASSES ,PHENOTYPES ,CULTIVARS ,MONOCULTURE agriculture ,EXPERIMENTAL design - Abstract
This paper describes how the core treatments in the national experimental design (all combinations of with/without clover and high/low nitrogen (N)) were implemented at an irrigated Canterbury site and monitored for three years. There was a consistent N × clover interaction, caused mainly by substantially lower yields in the Low N without clover treatment compared with all other treatments. At the phenotypic contrast level, the main effect of perennial ryegrass heading date on white clover content was significant in four of the nine seasonal data sets available: on these occasions, mixtures based on mid-season heading cultivars had higher clover content than later season-heading cultivars. However, this difference was not sufficient to cause any clover × cultivar interactions in herbage accumulation. Hence, the hypothesis that relative yield rankings of ryegrass cultivars do not differ when ryegrass is grown in monoculture or in mixture with white clover is supported. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
- View/download PDF
6. Implications of grass-clover interactions in dairy pastures for forage value indexing systems. 1. Context and rationale.
- Author
-
Chapman, David F., Lee, Julia M., Rossi, Laura, Cosgrove, Gerald P., Stevens, David R., Crush, Jim R., King, Warren M., Edwards, Grant R., and Popay, Alison J.
- Subjects
RYEGRASSES ,CULTIVARS ,PLANT breeding ,PASTURES ,GRAZING ,NITROGEN fertilizers - Abstract
The development of economic indexing systems for ranking cultivars of forage species requires new knowledge of factors that may influence the scaling of agronomic data collected in controlled, small-plot evaluation trials to whole farm systems. In the case of perennial ryegrass indexing, one such knowledge gap is the effect of growing clover with ryegrass on the relative rankings of different ryegrass cultivars. The objective of the investigation reported in this series was to test whether the relative yield rankings of perennial ryegrass (
Lolium perenne L.) cultivars representing the range in phenotypes now available to New Zealand farmers as a result of recent breeding differed when those cultivars were grown in monocultures (as per standard protocols for cultivar yield trialling systems such as the National Forage Variety Trials) versus mixtures of grass and clover. This paper presents the rationale for the investigation by reviewing developments in perennial ryegrass breeding and evaluation in the context of grass-clover relationships in grazed pasture systems. The papers that follow report results from a multi-year, multi-site investigation comparing the yield, nutritive value and other productivity-related variables of eight perennial ryegrass cultivars grown with or without white clover (monoculture versus mixture respectively) at two levels of nitrogen fertiliser. Key considerations in the design of the experiment on which the investigation was based are discussed. [ABSTRACT FROM AUTHOR] more...- Published
- 2018
- Full Text
- View/download PDF
7. Integrating Plantain (Plantago lanceolata L.) and Italian Ryegrass (Lolium multiflorum Lam.) into New Zealand Grazing Dairy System: The Effect on Farm Productivity, Profitability, and Nitrogen Losses.
- Author
-
Al-Marashdeh, Omar, Cameron, Keith, Hodge, Simon, Gregorini, Pablo, Edwards, Grant, and Paolucci, Marina
- Subjects
ITALIAN ryegrass ,RYEGRASSES ,DAIRY farms ,WHITE clover ,GRAZING ,PLANTAGO ,PROFITABILITY - Abstract
Simple Summary: Short-term studies have suggested plantain and Italian ryegrass as alternative forages to ryegrass–white clover sward to reduce the environmental footprint of grazing dairy farms. However, the adoption of such forages by farmers will likely be limited until more certainty around its effect on farm productivity and profitability. The objective of this study was to provide multiple-year and farm-scale evidence to farmers with respect to the effects of integrating plantain and Italian ryegrass into the ryegrass and white clover-based dairy system on farm productivity, profitability, and nitrate leaching losses. Under similar farming system input, the plantain plus Italian ryegrass-based dairy system could be used by dairy farmers to mitigate the environmental footprint while maintaining farm productivity and profitability. A two-year farm system study was conducted at Canterbury, New Zealand to evaluate the effects on farm productivity, profitability, and nitrogen (N) losses of integrating plantain (Plantago lanceolate L.) and Italian ryegrass (Lolium multiflorum Lam.) into a ryegrass and white clover (RGWC)-based dairy system. Three farm systems were compared: (1) a lower input RGWC-based system (LIRG) with stocking rate of 3.5 cow/ha, annual N fertiliser rate of 150 kg/ha, and imported feed level of <1.2 t DM/cow/year; (2) a lower input ryegrass + plantain-based system (LIRG + PL) with a stocking rate of 3.5 cow/ha, annual N fertiliser rate of 150 kg/ha, and imported feed level of <1.2 t DM/cow/year; and (3) a higher input RGWC-based system (HIRG) with a stocking rate of 5.0 cow/ha, annual N fertiliser rate of 300 kg/ha, and imported feed level of >1.2 t DM/cow/year. Cows in the LIRG + PL system grazed a diverse mix of Italian ryegrass, perennial ryegrass, white clover, and plantain (60% of farmlet area), and a mixed sward of plantain–white clover (40% of farmlet area). The average annual herbage harvested was similar between LIRG + PL and LIRG (11.7 t DM/ha), but greater in HIRG (12.7 t DM/ha) with the increased N fertiliser rate. During the calving to dry-off period, the average imported supplement feed per ha was higher in HIRG (8.0 t DM) compared with LIRG (3.2 t DM) and LIRG + PL (3.7 t DM). Average milk solid production (MS; fat + protein) was similar in LIRG + PL (1640 kg/ha) and LIRG (1622 kg/ha), but greater in HIRG (2130 kg/ha). Estimated profitability (NZD/ha) at milk price of NZD 6.5/kg MS was 10% greater for HIRG than LIRG + PL and LIRG, and similar (<1.5% numerical difference) between LIRG + PL and LIRG. The average estimated annual N leaching loss from the LIRG and LIRG + PL was 31% and 56% less than the loss from the HIRG. These large reductions in N leaching loss were achieved without a large decrease in profitability (i.e., LIRG and LIRG + PL compared to HIRG). In addition, the estimated reduction in N losses from the LIRG + PL system compared to LIRG suggests that an Italian ryegrass + plantain-based dairy system is a viable strategy to reduce the environmental footprint while maintaining farm profitability. However, the environmental benefits of plantain and Italian ryegrass estimated in this study require further confirmation through direct measurements at full farm level. [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
- Full Text
- View/download PDF
8. Influence of the endophyte fungus in ryegrass on grazing preference by sheep
- Author
-
Edwards, Grant
- Subjects
- Acremonium lolii, Lolium perenne, Festuca arundinacea, Trifolium repens, perennial ryegrass, white clover, tall fescue, lolium endophyte, grazing preference, sheep, endophyte
- Abstract
Animal productivity may be enhanced through greater intake associated with the use of preferred pasture species provided they are of high nutritional value. Grazing preference by ewe hoggets was investigated in three grazing trials and an indoor feeding trial. The first grazing trial (April 3-12, 1990) examined the preference of ewe hoggets for three grass treatments, each containing white clover. The grass treatments were endophyte (Acremonium lolii) infected (+E) perennial ryegrass, endophyte free (-E) perennial ryegrass and tall fescue. Two 0.2 ha blocks, each containing three replicates of the three grass treatments were sown in spring 1989. Endophyte incidence (% infected tillers) was 40% in +E ryegrass and 0% in -E ryegrass. Tillers were vegetative. Ewe hoggets (15) were introduced into the plots and their preferences recorded by visual observations from a raised viewing tower, and agronomic measurements on the plots. On day 1 of grazing a high proportion (76%) of ewe hoggets grazed tall fescue while a low proportion (12%) grazed both +E and –E ryegrass. From day 2 to 10 of grazing a similar number of sheep grazed each grass treatment. Grass leaf height declined less in +E ryegrass (48%), than -E ryegrass (64%) and tall fescue (71%) during grazing. Pseudostem height of grasses was reduced 4.2mm in tall fescue and -E ryegrass but only 1.5mm in +E ryegrass by grazing. Pasture mass declined more in -E ryegrass (1230 kg DM/ha) than +E ryegrass (1100 kg DM/ha) or tall fescue (1020 kg DM/ha). The percentage green grass cover (point analysis first hits) decreased with grazing in all grass treatments but less in +E ryegrass (21%) than -E ryegrass (34%) and tall fescue (28%). White clover percentage was low in all grass treatments (4-7%) prior to grazing and declined with grazing. Both +E and –E ryegrass contained more dead material than tall fescue. In a second grazing trial (May 14-21) the same plots were either mown to 30mm or left unmown two weeks prior to grazing and also subdivided into urine and non-urine patches. No endophyte was detected in either +E or -E ryegrass. Ewe hoggets (20) were introduced and agronomic measurements made during grazing. The height of grass leaves in all treatments was always greater in urine than non-urine patches but grass leaf height declined more rapidly in urine patches. The grass leaf height of +E and –E ryegrass was twice that of tall fescue in urine and non-urine patches throughout grazing. Pasture mass, prior to grazing, over all treatments was higher (1990 vs 1578 kg DM/ha) but declined more during grazing (928 v 751 kg DM/ha) in urine than non-urine patches. Mowing created a constant pseudostem height (30-32 mm) but did not influence pasture mass or grass leaf height changes. In the third grazing trial (25 September - 5 October) measurements of grass leaf height were made throughout grazing on +E (60% infection) ryegrass and -E ryegrass (0% infection) plots that were part of a grazing preference study consisting of four replicates of eight grasses or herbs. Plots had been ungrazed since May 23, 1990. Reproductive tiller development had begun. The height of +E and -E ryegrass were similar prior to grazing (180mm) but declined more in -E ryegrass (135mm) than +E ryegrass (80mm). Endophyte incidence in laxly grazed areas of +E ryegrass plots was 70% but only 30% in intensively grazed areas. The rate of eating of different feeds (white clover, tall fescue, +E ryegrass (70% infection) and -E ryegrass (0% infection)) was measured by offering 100g fresh samples of each alone to eight hungry sheep and recording time taken to consume each sample. Eating rates were highest for white clover (5.52 g DM/minl and lowest for +E ryegrass (2.89 g DM/min) with tall fescue (3.86 g DM/min) and -E ryegrass (3.94 g DM/min) intermediate. The three grass feeds were then separated into pseudostem and leaf, and the rate of eating measured. Leaf material was eaten at similar rate for all grasses (3.86-4.21 g DM/min). The +E ryegrass pseudostems were eaten more slowly (1.85 g DM/min) than -E ryegrass (2.65 g DM/min) or tall fescue (3.47 g DM/min). The slower rate of decline of grass leaf height, the smaller amount of pseudostem, pasture mass and green leaf removed, and the lower rate of eating of endophyte infected +E ryegrass when compared to -E ryegrass is interpreted as discrimination by sheep against endophyte infected +E ryegrass. It is proposed that low animal production of sheep grazing +E ryegrass can be attributed to the reduced intake of +E ryegrass because of avoidance behaviour. It is also suggested that the avoidance of sheep by fungus from eating the grass, is an adaptive mechanism of the fungus to ensure continued survival via seed spread. more...
- Published
- 1990
9. Productivity and seedling recruitment of naturalised annual clovers versus sown clovers Trifolium repens and Trifolium subterraneum
- Author
-
Maxwell, Thomas, Moir, James, and Edwards, Grant
- Published
- 2014
10. The effects of substituting autumn nitrogen fertiliser with gibberellic acid on feed supply and milk production
- Author
-
Miller, Melanie, Edwards, Grant, Hague, Helen, and Bryant, Racheal
11. Dietary preference of dairy cows for perennial ryegrass cultivars growing with and without white clover
- Author
-
Chen, Ao, Bryant, Racheal H., and Edwards, Grant
12. Lucerne establishment sequences to maximise weed control in ex-Pinus radiata L. plantations
- Author
-
Moot, Derrick, Mills, Annamaria, Marshall, Alan, and Edwards, Grant
- Full Text
- View/download PDF
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.