title: The effect of deferment length on perennial ryegrass (Lolium perenne) in established grazing pasture and under controlled conditions

authors: North, Elizabeth

subjects: Deferred

abstract: Perennial ryegrass is the dominant sown grass species in New Zealand, however its persistence in pasture is an issue for hill country farms. Deferring the grazing of a pasture over the reproductive cycle of ryegrass may influence changes in the above and below ground biomass of pasture plants and offers a low input and sustainable method for farmers to manage dry matter yields and quality of feed supply.
The aim of this study was to investigate the above and below ground changes in biomass and tiller production of perennial ryegrass under different lengths of deferment, after which standard rotational grazing or simulated grazing was resumed. Two trials were set up to investigate this. A field study was undertaken in an established ryegrass/clover-based pasture with three grazing treatments. Standard rotational grazing already in use on the field site (Def x0), a period of deferment over late spring/summer from November to February (Def x14) and a longer period of deferment from late spring to autumn (Def x27). After deferment, standard grazing was resumed. Above and belowground biomass, tiller densities, nutritive value, pasture composition and ground cover were measured. A glasshouse-based study investigated the effects on perennial ryegrass of different lengths of delayed defoliation and cutting treatments applied to simulate grazing. The control was cut when 2.5 to 3 new leaves per tiller had grown since the last cutting (Def x0); cutting of other treatments was delayed for an extra 4 (Def x4), 8 (Def x8) or 12 weeks (Def x12). After the delayed cutting, plants in each treatment were cut whenever there were 2.5 to 3 new leaves present per tiller. Both trials were affected by an extra-long period of rest between grazing or cutting treatments from the end of February to late April/early May due to Covid-19. This acted as an additional period of deferment for all glasshouse treatments and for Def x0 and Def x14 in the field.
The main results of the field study were that deferring resulted in higher tiller densities in winter and more accumulated dry matter before the deferred was opened for grazing than the rotational grazed control. There was also less bare ground compared with the control during summer. Nutritive value was lower during deferred periods but returned to the same value as the grazed control after standard rotational grazing resumed. There were no differences between any of the deferred treatments in root biomass. The percentage of ryegrass in total dry matter or ryegrass ground cover did not differ significantly between treatments.
In the glasshouse study, delayed defoliation increased leaf biomass, live tiller number and reproductive tiller number. Treatments with longer periods of delayed defoliation reach higher peaks in above ground dry matter and reproductive tiller number. There was a temporary increase in root biomass at depth for treatments with delayed defoliation in January. After standard defoliation resumed, Def x12 had a higher percentage of dead tillers and lower biomass by the end of the trial in July. There were no differences between treatments for live tiller number or root biomass once standard defoliation resumed.
The results suggest that a period of deferred grazing on pasture may improve dry matter yield and tiller densities of ryegrass after normal grazing resumes. The longer deferred treatment accumulated more dry matter in autumn, however it is not certain how the longer grazing rest between February and May affected potential differences between the shorter and longer deferred period. Results from the glasshouse saw no lasting benefit to ryegrass once standard defoliation resumed. Deferment length had no significant effect on belowground biomass. It is concluded that while deferred grazing may offer some benefits to a pasture, the persistence of ryegrass will not be improved by deferring grazing if other variables such as heat, moisture stress or timing of grazing are limiting potential growth. However, due to the unforeseen consequences of the Covid-19 lockdown, further research is recommended.

text: The effect of deferment length on perennial ryegrass (Lolium perenne) in established grazing pasture and under controlled conditions Perennial ryegrass is the dominant sown grass species in New Zealand, however its persistence in pasture is an issue for hill country farms. Deferring the grazing of a pasture over the reproductive cycle of ryegrass may influence changes in the above and below ground biomass of pasture plants and offers a low input and sustainable method for farmers to manage dry matter yields and quality of feed supply.
The aim of this study was to investigate the above and below ground changes in biomass and tiller production of perennial ryegrass under different lengths of deferment, after which standard rotational grazing or simulated grazing was resumed. Two trials were set up to investigate this. A field study was undertaken in an established ryegrass/clover-based pasture with three grazing treatments. Standard rotational grazing already in use on the field site (Def x0), a period of deferment over late spring/summer from November to February (Def x14) and a longer period of deferment from late spring to autumn (Def x27). After deferment, standard grazing was resumed. Above and belowground biomass, tiller densities, nutritive value, pasture composition and ground cover were measured. A glasshouse-based study investigated the effects on perennial ryegrass of different lengths of delayed defoliation and cutting treatments applied to simulate grazing. The control was cut when 2.5 to 3 new leaves per tiller had grown since the last cutting (Def x0); cutting of other treatments was delayed for an extra 4 (Def x4), 8 (Def x8) or 12 weeks (Def x12). After the delayed cutting, plants in each treatment were cut whenever there were 2.5 to 3 new leaves present per tiller. Both trials were affected by an extra-long period of rest between grazing or cutting treatments from the end of February to late April/early May due to Covid-19. This acted as an additional period of deferment for all glasshouse treatments and for Def x0 and Def x14 in the field.
The main results of the field study were that deferring resulted in higher tiller densities in winter and more accumulated dry matter before the deferred was opened for grazing than the rotational grazed control. There was also less bare ground compared with the control during summer. Nutritive value was lower during deferred periods but returned to the same value as the grazed control after standard rotational grazing resumed. There were no differences between any of the deferred treatments in root biomass. The percentage of ryegrass in total dry matter or ryegrass ground cover did not differ significantly between treatments.
In the glasshouse study, delayed defoliation increased leaf biomass, live tiller number and reproductive tiller number. Treatments with longer periods of delayed defoliation reach higher peaks in above ground dry matter and reproductive tiller number. There was a temporary increase in root biomass at depth for treatments with delayed defoliation in January. After standard defoliation resumed, Def x12 had a higher percentage of dead tillers and lower biomass by the end of the trial in July. There were no differences between treatments for live tiller number or root biomass once standard defoliation resumed.
The results suggest that a period of deferred grazing on pasture may improve dry matter yield and tiller densities of ryegrass after normal grazing resumes. The longer deferred treatment accumulated more dry matter in autumn, however it is not certain how the longer grazing rest between February and May affected potential differences between the shorter and longer deferred period. Results from the glasshouse saw no lasting benefit to ryegrass once standard defoliation resumed. Deferment length had no significant effect on belowground biomass. It is concluded that while deferred grazing may offer some benefits to a pasture, the persistence of ryegrass will not be improved by deferring grazing if other variables such as heat, moisture stress or timing of grazing are limiting potential growth. However, due to the unforeseen consequences of the Covid-19 lockdown, further research is recommended.

year: 2020

title: New Zealand trends in animal behaviour research

authors: Guadarrama-Maillot, Veronica

subjects: animal behaviour literature

abstract: To identify trends in research on pure ethology (fundamental issues in animal behaviour) in New Zealand, we combined manual and database searches of the five ethological journals with the greatest impact factors (Animal Behaviour, Behavioral Ecology, Behavioral Ecology and Sociobiology, Ethology and Behaviour) published from 1937 to (and including) 2007. We counted all articles giving a New Zealand address for the first-listed and/or reprint author. Our analyses showed (1) a total of 131 articles in the five journals, with Animal Behaviour, the journal of preference, containing nearly half of the articles collected; (2) a sharp and steady increase in articles published per year; (3) all four of Tinbergen’s questions received attention, with mechanistic and functional studies being more common than studies of development and evolutionary history; (4) a recent resurgence of mechanistic research, representing 67% of all studies in the period from 2003–07; (5) a balance in research focusing on the proximate and ultimate causes of behaviour, shifting towards proximate research in the early 1990s; (6) many New Zealand institutions published papers in the five journals, although universities were the main contributors; (7) only a small subset of the research (28.8%) was done with overseas collaboration; (8) a total of 139 authors were involved in the research reviewed (when all authors for each paper were considered without taking address into account); (9) a maturation of the sampled research by the early 1990s (i.e., when "descriptive" and "explanatory" papers were supplemented with "synthesis" papers); and (10) a large number of investigations (55%) used birds as the study subject. Ethology in New Zealand, as represented in the five leading animal behaviour journals, was found to be a diverse, dynamic and growing field.

text: New Zealand trends in animal behaviour research To identify trends in research on pure ethology (fundamental issues in animal behaviour) in New Zealand, we combined manual and database searches of the five ethological journals with the greatest impact factors (Animal Behaviour, Behavioral Ecology, Behavioral Ecology and Sociobiology, Ethology and Behaviour) published from 1937 to (and including) 2007. We counted all articles giving a New Zealand address for the first-listed and/or reprint author. Our analyses showed (1) a total of 131 articles in the five journals, with Animal Behaviour, the journal of preference, containing nearly half of the articles collected; (2) a sharp and steady increase in articles published per year; (3) all four of Tinbergen’s questions received attention, with mechanistic and functional studies being more common than studies of development and evolutionary history; (4) a recent resurgence of mechanistic research, representing 67% of all studies in the period from 2003–07; (5) a balance in research focusing on the proximate and ultimate causes of behaviour, shifting towards proximate research in the early 1990s; (6) many New Zealand institutions published papers in the five journals, although universities were the main contributors; (7) only a small subset of the research (28.8%) was done with overseas collaboration; (8) a total of 139 authors were involved in the research reviewed (when all authors for each paper were considered without taking address into account); (9) a maturation of the sampled research by the early 1990s (i.e., when "descriptive" and "explanatory" papers were supplemented with "synthesis" papers); and (10) a large number of investigations (55%) used birds as the study subject. Ethology in New Zealand, as represented in the five leading animal behaviour journals, was found to be a diverse, dynamic and growing field.

year: 2008

title: William Grey Nicholls and Rihitoto Mataia

authors: Hart, Philip

abstract: The son of a Pakeha Maori, Nicholls had an illustrious ancestry on his mother’s side, and his wife Rihitoto Mataia also had a distinguished whakapapa. From the 1870s Nicholls farmed in Ohinemuri, and as a licensed interpreter played an important role in land transactions at the same time as he was becoming prominent in the Pakeha community. For over 30 years he invested in mining, starting at Te Aroha in 1880. He also invested in a variety of other enterprises, becoming prosperous through these investments, his farming, and in particular by acquiring and selling land. Over a 40-year period, Nicholls conducted many cases in the land court, and assisted Pakeha to acquire Maori land, and also acquired a considerable amount of land for himself and Rihitoto, who inherited many blocks from her father (but had to pay off his massive debts).
         Whereas Rihitoto was a prominent leader in the Maori community of Hauraki, Nicholls had the same role in Pakeha society. Active in a variety of initiatives to benefit the Ohinemuri community, he was a popular member and chairman of the Ohinemuri County Council, and late in life was elevated to the Legislative Council. Reputedly he assisted Maori in various ways, but clearly he identified rather more with his Pakeha ancestry. His career was a remarkably successful one, and his wife was also successful in maximizing the benefits that could be derived from her ancestry.

text: William Grey Nicholls and Rihitoto Mataia The son of a Pakeha Maori, Nicholls had an illustrious ancestry on his mother’s side, and his wife Rihitoto Mataia also had a distinguished whakapapa. From the 1870s Nicholls farmed in Ohinemuri, and as a licensed interpreter played an important role in land transactions at the same time as he was becoming prominent in the Pakeha community. For over 30 years he invested in mining, starting at Te Aroha in 1880. He also invested in a variety of other enterprises, becoming prosperous through these investments, his farming, and in particular by acquiring and selling land. Over a 40-year period, Nicholls conducted many cases in the land court, and assisted Pakeha to acquire Maori land, and also acquired a considerable amount of land for himself and Rihitoto, who inherited many blocks from her father (but had to pay off his massive debts).
         Whereas Rihitoto was a prominent leader in the Maori community of Hauraki, Nicholls had the same role in Pakeha society. Active in a variety of initiatives to benefit the Ohinemuri community, he was a popular member and chairman of the Ohinemuri County Council, and late in life was elevated to the Legislative Council. Reputedly he assisted Maori in various ways, but clearly he identified rather more with his Pakeha ancestry. His career was a remarkably successful one, and his wife was also successful in maximizing the benefits that could be derived from her ancestry.

year: 2016