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Lincoln University

1. Rossi Rodriguez, Laura Ines. Interactions between pasture species and management and their implications for evaluating perennial ryegrass (Lolium perenne L.) cultivars in dairy systems.

Degree: 2016, Lincoln University

An index to rank perennial ryegrass cultivars based on their relative economic benefit to pasture-based dairy systems, has been developed in New Zealand (Chapman et al., 2016; DairyNZ) in recent years. Performance values in this system are calculated for the key trait of seasonal dry matter (DM) production, using data from cultivar evaluation trials conducted using perennial ryegrass monocultures and high nitrogen (N) fertiliser inputs. To determine if the index should account for genotype × management interactions, experiments with a common design were established in four regions of New Zealand in 2012. Results of the first two years of the Canterbury experiment are presented in this thesis. The experiment was conducted at the Lincoln University Research Dairy Farm, Lincoln, Canterbury, and used a split plot design with eight subplots randomly allocated within four main plots each replicated in five blocks. Main plots comprised all combinations of pasture sown with or without white clover receiving either low (100 kg N/ha) or high (325 kg N/ha) rates of nitrogen fertilizer annually, randomized within blocks. In the plus clover treatments, pastures were sown with a 50:50 mixture of two clover cultivars commonly used in dairy pastures. The eight perennial ryegrass cultivars were selected to provide contrasting phenotypes for two traits that may influence competition between grass and clover: morphology, and heading date. The morphological contrast was between high tiller density/fine leaf material (both diploids) and low tiller density/broad leaf material (both tetraploids). The heading date contrast was between mid-season and late-season heading date materials, all of them diploids. Each main plot was grazed by dairy cows following standard farm management practices. Total DM yield was estimated in each subplot before grazing by cutting, using a Haldrup forage harvester. Botanical and pasture nutritive value sampling was conducted pre-grazing in spring, summer and autumn each year. Ryegrass and clover population density were measured in autumn each year. Results of the first two years of the experiment show that seasonal and total annual yield of the High N treatments was greater than from the Low N treatments. With the exception of spring of the establishment year, seasonal and total annual yield of the plus clover treatments was greater than from the minus clover treatments. N and clover interactions were observed in summer of the first year, autumn of both years, and for the total annual yield from both years. In general, the Low N plus clover treatment yielded similarly to the High N treatments, and yielded significantly more DM than the Low N minus clover treatment. The effect of cultivar on DM yield was significant in spring and autumn in both years, in winter 2013, and in the annual total of the second year. The clover content of pastures was always greater in the Low N treatments compared with the High N treatments and was affected by the ryegrass cultivar during spring in both years and in the second…

Subjects/Keywords: Lolium perenne L.; white clover; Trifolium repens L.; DairyNZ Forage Value Index; dairy; DM yield; N fertiliser; phenotype; heading date; tiller density; white clover growing points; botanical composition; quality; grazing; competition; perennial ryegrass; DairyNZ; dry matter yield

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APA (6th Edition):

Rossi Rodriguez, L. I. (2016). Interactions between pasture species and management and their implications for evaluating perennial ryegrass (Lolium perenne L.) cultivars in dairy systems. (Thesis). Lincoln University. Retrieved from http://hdl.handle.net/10182/7734

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Rossi Rodriguez, Laura Ines. “Interactions between pasture species and management and their implications for evaluating perennial ryegrass (Lolium perenne L.) cultivars in dairy systems.” 2016. Thesis, Lincoln University. Accessed January 16, 2018. http://hdl.handle.net/10182/7734.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Rossi Rodriguez, Laura Ines. “Interactions between pasture species and management and their implications for evaluating perennial ryegrass (Lolium perenne L.) cultivars in dairy systems.” 2016. Web. 16 Jan 2018.

Vancouver:

Rossi Rodriguez LI. Interactions between pasture species and management and their implications for evaluating perennial ryegrass (Lolium perenne L.) cultivars in dairy systems. [Internet] [Thesis]. Lincoln University; 2016. [cited 2018 Jan 16]. Available from: http://hdl.handle.net/10182/7734.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Rossi Rodriguez LI. Interactions between pasture species and management and their implications for evaluating perennial ryegrass (Lolium perenne L.) cultivars in dairy systems. [Thesis]. Lincoln University; 2016. Available from: http://hdl.handle.net/10182/7734

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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