Diet selection and productivity of sheep grazing contrasting pastures

2002 ◽  
Vol 53 (5) ◽  
pp. 529 ◽  
Author(s):  
W. Chen ◽  
J. Scott ◽  
G. Blair ◽  
R. Lefroy ◽  
K. Hutchinson ◽  
...  
Keyword(s):  
White Clover ◽  
Nutrient Recycling ◽  
Diet Selection ◽  
Total N ◽  
Preferential Selection ◽  
Pasture Degradation ◽  
Dietary Nutrient ◽  
Alternative Species ◽  
Sheep Production ◽  
Over Time

A grazing experiment was conducted at the Big Ridge 2 site CSIRO, Chiswick (30˚31′S, 151˚39′E), 20 km south of Armidale, New South Wales, Australia. The site was established in 1955. In March 1966, phalaris and white clover were sown and pastures were fertilised annually with superphosphate until 1993. There were 3 pasture treatments, each with 2 replicates: degraded pasture (low phalaris content), phalaris-dominant, and phalaris–white clover. The effect of pasture type on animal production (liveweight gain and wool) was only significant in 1996, when there were large differences in pasture composition and production between the 3 pasture types. n-Alkane based estimates showed that pasture degradation affected diet selection and nutrient intake and thus sheep production. The estimates in this study also showed no clear preference for a single pasture species over time and lack of strong preferential selection for clovers when sheep were grazing 3 contrasting pastures. Preferential selection of a particular species varied over time depending on the presence and availability of alternative species. Although there were large differences in total N and S intake and faecal output between the 3 pastures, the proportion of the dietary nutrient used for production was similar. This observation reveals the importance of further improving pasture and grazing management, particularly in productive phalaris–white clover pasture with high nutrient flux, to improve nutrient recycling through plant uptake and retention by animals in the grazing ecosystem, and reduce losses.

De novo protein synthesis in relation to ammonia and proline accumulation in water stressed white clover

2004 ◽  
Vol 31 (8) ◽  
pp. 847 ◽  
Author(s):  
Tae-Hwan Kim ◽  
Bok-Rye Lee ◽  
Woo-Jin Jung ◽  
Kil-Yong Kim ◽  
Jean-Christophe Avice ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Water Deficit ◽  
White Clover ◽  
De Novo ◽  
Proline Accumulation ◽  
Leaf Water ◽  
Total N ◽  
Water Parameters ◽  
Leaves And Roots ◽  
De Novo Protein Synthesis

The kinetics of protein incorporation from newly-absorbed nitrogen (N, de novo protein synthesis) was estimated by 15N tracing in 18-week-old white clover plants (Trifolium repens L. cv. Regal) during 7 d of water-deficit treatment. The physiological relationship between kinetics and accumulation of proline and ammonia in response to the change in leaf-water parameters was also assessed. All leaf-water parameters measured decreased gradually under water deficit. Leaf and root dry mass was not significantly affected during the first 3 d when decreases in leaf-water parameters were substantial. However, metabolic parameters such as total N, proline and ammonia were significantly affected within 1 d of commencement of water-deficit treatment. Water-deficit treatment significantly increased the proline and NH3–NH4+ concentrations in both leaves and roots. There was a marked reduction in the amount of N incorporated into the protein fraction from the newly absorbed N (NANP) in water-deficit stressed plants, particularly in leaf tissue. This reduction in NANP was strongly associated with an increased concentration of NH3–NH4+ in roots (P≤0.05) and proline (P≤0.01) in leaves and roots. These results suggest that proline accumulation may be a sensitive biochemical indicator of plant water status and of the dynamics of de novo protein synthesis in response to stress severity.

Effect of ground covers and tillage between raspberry rows on selected soil physical and chemical parameters and crop response

1993 ◽  
Vol 73 (4) ◽  
pp. 481-488 ◽  
Author(s):  
B. J. Zebarth ◽  
S. Freyman ◽  
C. G. Kowalenko
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Cover Crops ◽  
General Pattern ◽  
Aggregate Stability ◽  
Rubus Idaeus ◽  
Perennial Grasses ◽  
Total N ◽  
Organic C ◽  
Wet Aggregate Stability

The use of inter-row ground covers has been suggested to reduce soil degradation in raspberry (Rubus idaeus L.) production. The effect after 6 yr of consistent inter-row management of ground covers or roto-tillage in raspberry on soil wet aggregate stability (WAS), bulk density, organic C and total N, and mineralizable nitrogen in the Fraser Valley of British Columbia was studied. Management treatments included no cover crop or cover crops of barley (Hordeum vulgare L.), sheep's fescue (Festuca ovina L.), perennial ryegrass (Lolium perenne L.), and white clover (Trifolium repens L.). A general pattern of perennial grasses > legume and barley > control was observed for soil WAS. Some quantitative and qualitative differences in the organic component of the soil profile to 30 cm were detected among management treatments. The differences were not statistically strong because the changes were small relative to the large pool present, but were relatively consistent overall. The white clover treatment tended to have more organic carbon, particularly in the subsurface, than the other treatments. The four treatments that included inter-row vegetation tended to have a greater amount of total and mineralizable N than the clean-tilled control. Crop vigour, as indicated by cane diameter, was reduced by the perennial grasses, but the inter-row management had only limited effects on berry yield. White clover appears to provide the best compromise between improving soil quality and minimizing competition with the berry crop. Key words: Wet aggregate stability, barley, sheep's fescue, perennial ryegrass, white clover

Growth responses in red deer calves and hinds grazing red clover, chicory or perennial ryegrass/white clover swards during lactation

1993 ◽  
Vol 121 (2) ◽  
pp. 255-263 ◽  
Author(s):  
J. H. Niezen ◽  
T. N. Barry ◽  
J. Hodgson ◽  
P. R. Wilson ◽  
A. M. Ataja ◽  
...  
Keyword(s):  
Food Intake ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Red Deer ◽  
Red Clover ◽  
Growth Responses ◽  
Total N ◽  
Calf Growth ◽  
Calf Performance ◽  
Voluntary Food Intake

SUMMARYTwo experiments were conducted at the Massey University Deer Unit, New Zealand in 1990 and 1991 to evaluate the performance of lactating red deer hinds and their calves grazing conventional perennial ryegrass-based pastures, red clover or chicory. In both experiments, hind and calf performance was evaluated from 1 month post-parturition over a 2½ month summer period to weaning at 3½ months of age.In Expt 1, hinds and calves were grazed on low (5·4 kg dry matter (DM)/hd/day), medium (10·8) or high (16·4) allowances of red clover, or on a medium allowance of a conventional ryegrass/white clover sward (9·9 DM/hd/day). In Expt 2, hinds and calves grazed equal DM allowances (12 kg DM/hd/day) of perennial ryegrass/white clover, chicory or red clover.Red clover generally had higher organic matter digestibility (OMD) and higher total N than ryegrass/white clover, and when grazed at equal DM allowances, promoted higher voluntary food intake in the hinds, increased calf growth (430 v. 330 g/day) and increased hind liveweight change. Although decreasing the red clover allowance in Expt 1 slightly but non-significantly decreased hind voluntary food intake and decreased both calf and hind liveweight change, all low red clover values were still consistently higher than all ryegrass/white clover values (P < 0·05). In Expt 2, chicory was of higher OMD and ash content than red clover but N content was lower and similar to ryegrass/white clover. Chicory promoted lower levels of calf liveweight change than red clover but higher than ryegrass/white clover. Hind liveweight change on chicory was lower than on red clover and was similar to ryegrass/white clover. It was concluded that red clover offers potential as a special purpose forage for deer production and that further experimental work is needed with chicory.

Master Narratives, Expectations of Change, and Their Effect on Temporal Appraisals

2021 ◽  
Vol 39 (6) ◽  
pp. 717-746
Author(s):  
James G. Hillman ◽  
David J. Hauser
Keyword(s):  
The Self ◽  
Effect Sizes ◽  
Master Narratives ◽  
Total N ◽  
Culture Differences ◽  
Over Time

People hold narrative expectations for how humans generally change over the course of their lives. In some areas, people expect growth (e.g., wisdom), while in others, people expect stability (e.g., extroversion). However, do people apply those same expectations to the self? In five studies (total N = 1,372), participants rated selves as improving modestly over time in domains where stability should be expected (e.g., extroversion, quick-wittedness). Reported improvement was significantly larger in domains where growth should be expected (e.g., wisdom, rationality) than domains where stability should be expected. Further, in domains where growth should be expected participants reported improvement for selves and others. However, in domains where stability should be expected, participants reported improvement for selves but not others. Hence, participants used narrative expectations to inform projections of change. We discuss implications for future temporal self-appraisal research, heterogeneity of effect sizes in self-appraisal research, and between-culture differences in narratives.

Impact of insect root herbivory on the growth and nitrogen and carbon contents of white clover (Trifolium repens) seedlings

1996 ◽  
Vol 74 (10) ◽  
pp. 1591-1595 ◽  
Author(s):  
P. J. Murray ◽  
D. J. Hatch ◽  
J. B. Cliquet
Keyword(s):  
Root Exudates ◽  
White Clover ◽  
Trifolium Repens ◽  
Sequential Sampling ◽  
Sand Culture ◽  
N Fixation ◽  
Total N ◽  
Nitrogenous Compounds ◽  
Root Herbivory ◽  
The Impact

The impact of root herbivory by larvae of the weevil Sitona flavescens (Marsh.) on the growth and carbon and nitrogen economies of seedlings of white clover (Trifolium repens L.) and the nature and extent of nitrogenous compounds found in the root exudates taken from the rhizosphere were investigated. The seedlings were grown in sand culture in a system of microlysimeters that enabled sequential sampling of root exudates. Weevil infestation significantly reduced foliar biomass and total N and C contents and impaired N-fixation. The C:N ratios of the infested plants were significantly increased compared with those of uninfested seedlings. The most abundant amino acids in the exudates were aspartic acid and serine. Keywords: nitrogen fixation, Sitona spp., root exudates, white clover.

Productivity and pasture intake of defaunated crossbred sheep flocks

2000 ◽  
Vol 40 (5) ◽  
pp. 655 ◽  
Author(s):  
R. S. Hegarty ◽  
C. Shands ◽  
C. Harris ◽  
J. V. Nolan
Keyword(s):  
White Clover ◽  
Dry Matter ◽  
Apparent Digestibility ◽  
Preferential Selection ◽  
Rapid Spread ◽  
Selection For

From a flock of pregnant crossbred ewes, 63 were established as protozoa-free by treatment with alkanate 3SL3 and 64 ewes were maintained as controls. The controls included 20 ewes, which had been defaunated and subsequently re-inoculated with protozoa. After lambing, both flocks were grazed in a 6-paddock rotation until weaning at 20 weeks of age. Defaunated ewes were heavier than control ewes throughout lactation and had a higher urinary allantoin concentration than the control ewes. Intake and apparent digestibility of pasture dry matter by ewes did not differ between groups although these estimates were confounded by differences in pasture composition between the paddocks used. Both groups selected a diet with digestibility approximately 10% units higher than the bulk digestibility of pasture on offer. Control ewes selected a higher proportion of white clover in their diet than was available in the pasture (24% v. 2%) but defaunated ewes did not exhibit preferential selection for clover. Lambs from defaunated ewes were heavier at birth, remained heavier until weaning and grew more wool than lambs from control ewes. Contamination of fauna-free ewes and lambs with protozoa was first observed at weaning and protozoa were detected in 41 out of 60 lambs, 4 weeks after contamination was first detected. Study of defaunated ewes returned to a flock of untreated ewes confirmed rapid spread of contamination into defaunated ewes with small entodiniomorph protozoa establishing first.

Quantitative digestion by sheep of carbohydrates, nitrogen and S-methyl-L-cysteine sulphoxide in diets of fresh kale (Brassica oleracea)

1984 ◽  
Vol 102 (2) ◽  
pp. 479-486 ◽  
Author(s):  
T. N. Barry ◽  
T. R. Manley ◽  
S. J. Duncan
Keyword(s):  
Amino Acids ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Metabolizable Energy ◽  
Water Soluble ◽  
Amino Acid Supplementation ◽  
Total N ◽  
Dimethyl Disulphide ◽  
Ruminant Diets ◽  
Predicted Values

SummaryApparent digestibility of forage kale (cv. Maris Kestrel) was compared with that of mixed perennial ryegrass (0·85) and clover (0·15) herbage in two experiments. In a third experiment measurements were made of the partition of digestion between the reticulo-rumen and post-ruminal regions of the digestive tract in sheep fed kale, using intra-ruminal infusion of inert ruthenium phenanthroline and chromium-EDTA markers and time sequence sampling from the duodenum. Results in Expt 3 were compared with predicted values for a range of ruminant diets, including digestion of fresh perennial ryegrass and white clover.In Expts 1 and 2 the ratio of readily fermentable to structural carbohydrate (CHO) was much higher in kale (2·6–3·2) than in mixed ryegrass and clover herbage (0·6), and showed little difference between kale leaf and stem components. Apparent digestibilities of organic matter (OM), cellulose and hemicellulose were 80–90% for kale diets, varied little with changes in leaf/stem ratio, and were generally slightly higher than for mixed ryegrass and clover herbage. Calculated metabolizable energy (ME) concentrations were 12·0 and 11·7 MJ ME/kg D.M. for kale and mixed ryegrass and clover respectively.Despite large intakes of water-soluble CHO and pectins in kale-fed sheep in Expt 3, duodenal flows were small and respectively 92 and 98% of the total amounts digested were digested in the rumen. Ruminal cellulose digestion (95% total digested) was as predicted for normal ruminant diets, but less hemicellulose was digested in the rumen (71% total digested) than predicted. Total N flow at the duodenum was 5 g/day less than N intake, and respectively 27 and 66% of the N apparently digested was accounted for as total N absorption from the rumen and post-ruminal absorption of NAN. Calculated absorption of amino acids from the small intestine was less for the kale diet (14% ME intake) than for diets of fresh perennial ryegrass and white clover (20% ME intake). Possible reasons are that 10% more of the OM ingested was digested in the rumens of sheep fed kale than was predicted, that the ratio of dietary total N/100 g digestible OM was much less for kale (3·7) than for perennial ryegrass and white clover (5·6) diets, and that protein formed a lower proportion of the total N in kale diets (75%) than in diets of ryegrass and clover (90%). Despite 3·3 g of S-methyl-L-cysteine sulphoxide (SMCO) being consumed per day, none was detected in either rumen or duodenal contents or in faeces.In was concluded that complete conversion of SMCO to dimethyl disulphide occurred in the rumen, that dimethyl disulphide may have caused the depression in ruminal digestion of hemicellulose, and that the digestion products of kale are deficient in absorbed amino acids relative to other forms of energy, thus explaining responses to essential amino acid supplementation in lambs grazing kale.

scholarly journals Analysis of N2O emissions and isotopomers to understand nitrogen cycling associated with multispecies grassland swards at a lysimeter scale

2020 ◽  
Author(s):  
Conor Bracken ◽  
Gary Lanigan ◽  
Karl Richards ◽  
Saoirse Tracy ◽  
Christoph Müller ◽  
...  
Keyword(s):  
Nitrogen Cycling ◽  
White Clover ◽  
Block Design ◽  
N Uptake ◽  
Soil Microbial Communities ◽  
N Cycling ◽  
N2o Emissions ◽  
Total N ◽  
Transformation Pathways ◽  
Grass Growth

&lt;p&gt;Nitrous oxide (N&lt;sub&gt;2&lt;/sub&gt;O) is a potent greenhouse gas associated with nitrogen fertiliser inputs to agricultural production systems. Minimising N&lt;sub&gt;2&lt;/sub&gt;O emissions is important to improving the efficiency and sustainability of grassland agriculture. Multispecies grassland swards composed of plants from different functional groups (grasses, legumes, herbs) have been considered as a management strategy to achieve this goal. Numerous soil nitrogen transformation pathways can lead to the production of N&lt;sub&gt;2&lt;/sub&gt;O emissions. These transformation pathways are regulated by soil microbial communities and the environmental conditions and management practices that impact on them. Much research has been carried out on N cycling and N&lt;sub&gt;2&lt;/sub&gt;O emissions from predominantly grass monoculture systems. However, there is a lot yet to understand about how agricultural grasslands with diverse plant communities influence soil N cycling and N&lt;sub&gt;2&lt;/sub&gt;O emissions. A lysimeter experiment was set up as a completely randomised block design and carried out over a full year to investigate N&lt;sub&gt;2&lt;/sub&gt;O production, and nitrogen cycling associated with four sward types. The swards four swards were: perennial ryegrass (PRG, Lolium perenne); PRG and low white clover (PRG + LWC, Trifolium repens); PRG and high white clover (PRG + HWC); PRG, WC and ribwort plantain (PRG + WC + PLAN, Plantago lanceolata) managed at 250, 90, 0, and 45 kg N ha&lt;sup&gt;-1&lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;, respectively. Fertiliser N was applied by syringe as urea in splits at suitable timings to meet grass growth demands. N&lt;sub&gt;2&lt;/sub&gt;O fluxes were measured using a static chamber technique and additional samples were taken after the final flux sample to measure the associated N&lt;sub&gt;2&lt;/sub&gt;O isotopomers using a novel Cavity Ring Down Spectroscopy technique. Leachate volumes were measured on a weekly basis and composite monthly samples were used to determine the total amount of N leached from each treatment over the full year. Herbage was harvested on a monthly basis to measure DM yield (kg DM ha&lt;sup&gt;-1&lt;/sup&gt;), total N (%) and N yield (kg N ha&lt;sup&gt;-1&lt;/sup&gt;).This work reports on the N&lt;sub&gt;2&lt;/sub&gt;O emissions and N leaching associated with the four sward treatments and related these N losses to the treatments DM yields and N uptake as an estimation of the efficiency of these differing grassland management strategies. N&lt;sub&gt;2&lt;/sub&gt;O isotopomer measurements were used to indicate N transformation pathways driving N loss over the growing season particularly around periods of peak N&lt;sub&gt;2&lt;/sub&gt;O emissions.&lt;/p&gt;

Effects of afforestation with Eucalyptus grandis on soil physicochemical and microbiological properties

Soil Research ◽  
2012 ◽  
Vol 50 (2) ◽  
pp. 167 ◽  
Author(s):  
Danju Zhang ◽  
Jian Zhang ◽  
Wanqin Yang ◽  
Fuzhong Wu
Keyword(s):  
Soil Fertility ◽  
Soil Properties ◽  
Agricultural Land ◽  
Soil Layer ◽  
Western China ◽  
Stand Age ◽  
Arable Soils ◽  
Total N ◽  
Over Time ◽  
Microbiological Properties

It is generally believed that plantations of Eucalyptus bring about a decrease in soil fertility. Soil physicochemical and microbiological properties were measured across a range of E. grandis plantation ages (1–10 years) in south-western China to determine whether and how eucalypt afforestation of agricultural land affected the soil fertility. The results indicate that afforestation with E. grandis caused changes in soil properties with soil depth, and the changes were dependent on the stand age. Soil bulk density decreased significantly, but water-holding capacity increased significantly with time. Soil organic matter content, C : N ratio, and soil microbial biomass C and N concentrations showed an initial phase of decline and then increased significantly over time in the upper soil layers of E. grandis plantations aged from 1 to 4 or 5 years. Soil pH in E. grandis plantations did not change significantly with stand age or soil layer. Cation exchange capacity in the upper soil layer of E. grandis plantations increased significantly over time. Total exchangeable bases and base saturation in the soil decreased significantly with depth and with increasing plantation age. Furthermore, E. grandis afforestation of arable soils had no significant effects on total N, total P, and available P contents. The requirements of the trees, understory microenvironmental conditions, and allelopathic effects might play important roles in the dynamic changes of soil physicochemical and microbiological properties. The results demonstrate the progressive development of processes that lead to the restoration of soil fertility following E. grandis afforestation of arable soils. However, most of the properties measured for the afforested soils resembled the properties of arable soils and did not resemble those of the soil of control forests. Thus, reversion of soil properties in the study plantations is likely to require a considerable period of time. Long-term research is needed to understand changes in the soil properties resulting from afforestation with Eucalyptus and to predict future trends.

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