114 research outputs found
The Grail theorem prover: Type theory for syntax and semantics
As the name suggests, type-logical grammars are a grammar formalism based on
logic and type theory. From the prespective of grammar design, type-logical
grammars develop the syntactic and semantic aspects of linguistic phenomena
hand-in-hand, letting the desired semantics of an expression inform the
syntactic type and vice versa. Prototypical examples of the successful
application of type-logical grammars to the syntax-semantics interface include
coordination, quantifier scope and extraction.This chapter describes the Grail
theorem prover, a series of tools for designing and testing grammars in various
modern type-logical grammars which functions as a tool . All tools described in
this chapter are freely available
Caucasian Clover is More Productive Than White Clover in Temperate Pastures
White clover (wc) (Trifolium repens) is present and is often the dominant legume in the \u3e11 m ha of grassland in New Zealand (NZ). However, wc has limitations and normally contributes less than 20% of total annual pasture dry matter (DM) production. The use of a wider range of legume species is one way to increase legume percentage in wc/grass pastures. Caucasian (Cc) or Kura clover (Trifolium ambiguum) is a persistent legume which is slower to establish than wc but can increase total legume production (Cc plus volunteer wc) and hence N2 fixation and animal productivity. This paper compares the productivity of Cc and wc in irrigated and dryland environments, and relates their relative establishment success to differences in seedling development
Net Photosynthesis Rate and Chlorophyll Content of Caucasian and White Clover Leaves Under Different Temperature Regimes
In spring and summer in intensive temperate pastures, Caucasian clover (Cc) (Trifolium ambiguum) has higher dry matter (DM) production rates than white clover (wc) (Trifolium repens) (Black et al., 2003). An examination of the physiological basis for these differences can provide a greater insight into the suitability of Cc for inclusion in temperate pastures. Specifically, leaf photosynthesis rate is a major driver of seasonal growth and is strongly regulated by temperature and chlorophyll content. This study aimed to compare the net photosynthesis rate (Pn) and chlorophyll content of Cc and wc leaves under different temperature regimes
Effect of rate and method of phosphorus application on the growth and development of 'Pasja' crops
‘Pasja’ (Brassica campestris x napus) was grown at
Lincoln in 2008, with banded or broadcast phosphorus
(P) fertiliser applied at 0, 20, 40 or 60 kg/ha at
establishment on a Templeton silt loam soil of moderate
fertility (Olsen P of 9-17 mg/ kg range for individual
plots). Total dry matter (DM) production, leaf to stem
ratios and leaf area development were measured over
time and related to the biophysical environment. Final
DM yield increased with P rate from 3,730 kg DM/ha
for the control to ~5,000 kg DM/ha at 60 kg P/ha. The
leaf to stem ratio declined from between 22 and 31 at
17 days after emergence to 10.3 at the final harvest.
Leaf area index (LAI) for the control crops was lower
than for those that received P fertiliser, but there were
no differences among the P fertilised crops. Total
accumulated intercepted solar radiation (RIcum) was 8%
greater when P was applied compared with the control.
This difference was the main contributor to differences
in total dry matter yield and was independent of the
application method.
Keywords: BrassicaPastoral 21’ program and New Zealand Institute for Plant & Food Limited
Clover species cover on summer dry hill country in Central Otago
The prevalence of annual clover species and white
clover (Trifolium repens) during the critical late winter
to early summer period (mid Aug – Dec) are compared
in relation to aspect, altitude, temperature and rainfall on
Mt Grand at Hawea Flat. Measurements were at four
north facing sites (450, 620, 750, 910 m a.s.l.) and one
shady site at 630 m a.s.l. The rainfall was similar for all
altitudes and aspects but annual clovers dominated on
sunny faces and the perennial white clover dominated on
the shady face with suckling (T. dubium) the only
adventive annual clover present. Annual cluster clover
(T. glomeratum) dominated on the lower sunny faces at
450 and 620 m and sub clover (T. subterraneum)
dominated at 750 m. Suckling and striated clover (T.
striatum) were present on all sunny aspect sites and
were unaffected by altitude while haresfoot (T. arvense)
presence increased with altitude. Air thermal time
accumulation for the mid Aug-Dec period was 1440 °Cd
at the 450 m site and declined at 100 °Cd per 100 m of
elevation (r² = 0.99). Thermal time at 910 m was <1000
°Cd and may limit seed production of some annual
clover species at or above this altitude. The dominance
of adventive annual clovers on the sunny aspects
indicates areas that are probably suitable for
introduction of improved annual species such as balansa
clover (T. michelianum) or modern cultivars of sub.
Productivity of perennial white clover which has
persisted on the shady faces may be increased by more
intensive grazing management
Changes in New Zealand red meat production over the past 30 yr
Implications
• Consumer attitudes globally and nationally influence pasture production systems in New Zealand.
• New Zealand red meat production has decreased its environmental footprint per unit of production over the last 30 years.
• The national ewe flock has halved but gains in animal production have maintained similar levels of meat production.
• Meat production has been improved through increased lambing percentages and lamb growth rates on fewer but larger farms.
• Greater animal production has been supported through improved pastures with an emphasis on their legume component which has increased lamb growth rates and reduced methane emissions per unit of product
Potential Yield of Cocksfoot (\u3ci\u3eDactylis Glomerata\u3c/i\u3e) Monocultures in Response to Irrigation and Nitrogen
Cocksfoot is a widely sown grass in temperate pastures. However, while potential yield of cocksfoot can exceed 28 t DM/ha per year, it is often restricted by water, temperature and nitrogen (N). Of these, Peri et al. (2002) showed that N was severely limiting in all seasons. The aim of this study was to confirm the potential yield of cocksfoot and quantify the extent of yield reductions due to environmental constraints
Pasture Improvement Needs and Options for New Zealand Sheep and Beef Farms
In recent years in New Zealand, sheep and beef farming has been outcompeted for prime land. This means that the government and industry targets to increase sheep and beef production have to be achieved on farms with significant constraints on pasture production. They are increasingly restricted to hilly and other locations with variable climates and soils, and landscape constraints on farming practices. Thus there are limits on the ability to improve pasture production – whether by pasture renewal or through means like grazing management, fertiliser use, or weed and pest control
Optimizing Yield and Quality of Orchardgrass Pasture in Temperate Silvipastoral Systems
The objective of this study was to provide grazing management recommendations for a silvipastoral system by determining the effects of shade and nitrogen (N) on the pattern of dry matter accumulation and nutritive value of orchardgrass (Dactylis glomerata) in a subhumid temperate environment. Orchardgrass in open pasture (100% transmittance) and under 10 year old Pinus radiata tree shade (60% transmittance) at 200 stems/ha was used as the main plot and nitrogen (0 and 300 kg N/ha as synthetic urine) was the subplot factor. Dry matter (DM) production of orchardgrass in the first 60-day spring rotation was similar in open and shade conditions (2.6 t/ha) but approximately doubled by the application of N. In the 60- day summer rotation, DM production was about 22% lower in the shaded plots and was increased by about 60% by the addition of N. Crude protein and organic matter digestibility declined with herbage age and the onset of reproductive tiller growth. It was concluded that to maximise DM production without compromising pasture quality, grazing management of orchardgrass should be similar in open and shaded pastures in spring (30-35 day regrowth) but a shorter regrowth length used for open (20 days) than silvipastoral (25-30 days) systems in summer
Dry Matter Production and Nutritive Value of Alfalfa (\u3ci\u3eMedicago sativa\u3c/i\u3e L.) and Orchardgrass (\u3ci\u3eDactylis glomerata\u3c/i\u3e L.) under Different Light Regimes
Spring and summer alfalfa dry matter and nitrogen production rates were greater than orchardgrass in open pasture and under three shade levels. Ten years old Pinus radiata allowed 60% light transmissivity. The addition of artificial shade resulted in 45% and 25% transmissivity. Orchardgrass pastures were nitrogen deficient and water stressed. In contrast, alfalfa was not stressed and it was more light responsive than orchardgrass. Differences in nutritive value were relatively small between species and between light regimes. Sheep liveweight gain on alfalfa was greater than on orchardgrass. Orchardgrass demonstrated shade tolerance, but alfalfa was more productive even at 25% transmissivity. Conventional concepts of shade tolerance may not be appropriate when screening pasture species for silvipastoral systems
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