Pasture production under a series of Pinus radiata-pasture agroforestry systems in South-West Victoria, Australia

1995 ◽  
Vol 46 (6) ◽  
pp. 1285 ◽  
Author(s):  
JD Kellas ◽  
PR Bird ◽  
KN Cumming ◽  
GA Kearney ◽  
AK Ashton

Net pasture production has been monitored over time on an on-going Pinus radiata-pasture agroforestry experiment located at Carngham, Victoria. Established in 1983 by thinning a 2-year-old plantation, the study contains five treatments (systems): open pasture (no trees), 60 trees/ha, 200 trees/ha wide-spaced, 200 trees/ha 5-row belt and 1360 trees/ha. Net pasture production was only weakly affected by the proximity of trees in the 60 trees/ha and 200 trees/ha wide-spaced systems. However, in the 200 trees/ha 5-row belt system, pasture production was often significantly less within the tree zone and at 1.5 m from the tree edge compared with production at 10.5 m from the tree edge. While there was a trend for greater pasture production at 10.5 m and 18 m from the tree line than occurred in the open pasture system, the width of pasture adjacent to the 5-row belts was too narrow (36 m) to demonstrate any shelter benefit on pasture production. From 1990 to 1992, pasture production (kg ha-1) for each system was similar, although production tended to decrease with increasing tree stocking. Following the cessation of pruning (1992), pasture production was significantly reduced by increased tree stocking, such that pasture production in the 200 trees/ha wide-spaced and 200 trees/ha 5-row belt systems was 60% and 69% and 23% and 67% of open pasture in 1993 and 1994 respectively.

1995 ◽  
Vol 46 (6) ◽  
pp. 1299 ◽  
Author(s):  
PR Bird ◽  
PR Bird ◽  
JD Kellas ◽  
JD Kellas ◽  
GA Kearney ◽  
...  

Liveweight and greasy wool production data from young wethers were collected for the period autumn to early summer for the years 1986 to 1994 from an on-going Pinus radiata-pasture project at Carngham, Victoria. A plantation established in 1981 on a grazing property was thinned in 1983 to give trees spaced at: (i) no trees (a grazing control), (ii) 8 mx 12 m, (iii) 4 mx9 m, (iv) 4 mx3 m in a 5-row belt then a 10-row pasture gap, and (v) 2 mx3 m (original spacing). By 1989 the density of trees in these systems was slightly reduced by windthrow, animal damage and thinning to (ii) 60 trees/ha, (iii) 200 trees/ha wide-spaced, (iv) 200 trees/ha 5-row belt and (v) 1360 trees/ha. All trees in systems (ii), (iii) and (iv) had been pruned to 6 m by late 1992. The sheep stocking policy was initially based on a set 10 sheep ha-1. Since 1991 the stocking rate has been varied yearly in an attempt to maintain similar production per sheep. The pastures were re-sown in 1989 with perennial rye-grass and subterranean clover cultivars. Since 1991, wool production per ha from the 200 trees/ha wide-spaced system has been consistently less than in systems (i), (ii) and (iv). Wool production among systems differed significantly since 1992. Expressed as a percentage of wool production achieved on open pasture, the relative values for the agroforestry systems from 1990 to 1994 as follows.


Author(s):  
G.G. Cossens ◽  
M.F. Hawke

During the first 20 years of a Pinus radiata tree rotation, tree growth and pasture yield were assessed under a range of tree spacings at Invermay and Akatore, two coastal sites in Eastern Otago. Pasture yield in association with trees thinned to 100 stems per hectare (sph) was comparable to that from open pasture up to a tree age of 12 years. By the 19th year, however, pasture production declined to 63% of open pasture yield at Invermay and to 42% at Akatore. At 200 and 400 sph at Akatore, pasture yield was similar to that from open pasture at tree age 12 years but declined to 27% and 0% of open pasture yield respectively by year 20. At both Invermay and Akatore, the ryegrass and clover content of open pasture was relatively constant throughout the term of the trial. However, both the ryegrass and clover content of pasture beneath trees began to decline by tree age 12 years with a very rapid decline at Akatore in the number of pasture species at 200 sph by the 19th year. No pasture remained at 400 sph, after 19 years. Livestock carrying capacity with sheep on tree treatments at Invermay decreased from 100% of open pasture at year 6 to 60% by year 10. At Akatore, livestock carrying capacity averaged over the 20-year life of the trial was 4.1 stock units per hectare with a maximum of 8.1 stock units at a tree age of 8 years. Tree growth at both sites was similar, averaging between 1 and 1.1 m/year in height over 20 years, with trees at Invermay at 100 sph averaging 9% greater height and diameter growth than at Akatore. Increasing tree stocking from 100 to 200 to 400 sph at Akatore, resulted in increased tree height, but decreased diameter at breast height. A comparison of the East Otago trees with those in a similar trial at Tikitere (Rotorua) 900 km further north indicated that the southern trees were about 6 years later in their growth pattern by tree age 20 years. On both sites, soil pH tended to be lower in the presence of trees and was significantly lower than in open pasture by year 20. The results and comparisons with the Tikitere data suggest that, in an integrated agroforestry regime, there will be livestock grazing under the trees further into the tree rotation in Otago than in North Island sites. However, slower tree growth would result in a longer rotation time to harvest. Current recommendations to farmers are to plant trees on the less productive areas of the farm and adopt a tree stocking rate which fully utilises the site. Keywords: agroforestry, livestock, pasture, Pinus radiata, soil pH, tree stocking


2014 ◽  
Vol 12 (2) ◽  
pp. 165-182 ◽  
Author(s):  
Tertia Barnett ◽  
Maria Guagnin

This article examines the relationship between rock art and landscape use by pastoral groups and early settled communities in the central Sahara from around 6000 BC to 1000 AD. During this period the region experienced significant climatic and environmental fluctuations. Using new results from a systematic survey in the Wadi al-Ajal, south-west Libya, our research combines data from over 2000 engraved rock art panels with local archaeological and palaeoenvironmental evidence within a GIS model. Spatial analysis of these data indicates a correspondence between the frequency of rock art sites and human settlement over time. However, while changes in settlement location were guided primarily by the constraints on accessibility imposed by surface water, the distribution of rock art relates to the availability of pasture and patterns of movement through the landscape. Although the reasons for these movements undoubtedly altered over time, natural routes that connected the Wadi al-Ajal and areas to the south continued to be a focus for carvings over several thousand years.


2009 ◽  
Vol 49 (8) ◽  
pp. 654 ◽  
Author(s):  
Geoffrey Saul ◽  
Gavin Kearney ◽  
Dion Borg

Two pasture systems were compared at five on-farm sites across south-western Victoria between 1990 and 1996. The ‘typical’ pasture treatment mimicked the pasture and grazing management common in the region, with volunteer annual-based pastures fertilised with around 5 kg/ha phosphorus (P) each year. The ‘upgraded’ pasture treatments were resown to phalaris, perennial ryegrass and subterranean clover, and higher rates of fertiliser (13–25 kg P/ha.year) plus other nutrients were applied. Both pastures were set stocked with the participating farmers breeding ewes. Stocking rate was an emergent variable on each plot. The stocking rate on the typical treatments was based on normal farm practise. Initially, the stocking rate of the upgraded pastures was 15% higher than for the typical pastures and increased over time depending if the ewes in the upgraded pastures were heavier than those in the typical pastures. Measurements included soil fertility, pasture production, nutritive value and composition, and animal production. Net annual pasture production of the upgraded pastures was 10 500 kg/ha compared with 8700 kg/ha for the typical pastures. This average difference (18%) between the treatments was greatly influenced by the large advantage (40%) of the upgraded pasture in the wet year of 1992. Upgraded pastures had higher pasture production than typical pastures in spring but the reverse occurred in autumn. In a separate small plot experiment, the response of each pasture to higher P fertiliser applications was tested. In autumn and winter, there was a significant interaction between pasture type and P rate, with higher responses on the upgraded pastures. In spring, both pastures responded to increased P applications but the upgraded pastures were more responsive at all P rates. The upgraded pastures contained significantly higher legume content (30–50%) than the typical pastures (10–20%). The proportion of sown perennial grasses in the upgraded pasture declined from around 30 to 10% after 6 years displaced by annual grasses and broad-leaf weeds. Herbage from upgraded pastures had significantly higher crude protein content (2–7 units) and digestibility (1–10 units) than the typical pastures with the difference between the treatments increasing over time. The set stocking policy used in this experiment is likely to have exacerbated the decline in sown perennial grasses and implementation of some form of strategic or rotational grazing may have improved persistence. The experiment also highlights the importance of selecting perennial grasses able to cope with the local environment and grazing conditions. Despite the decline in perennials, these results show significant potential to improve pasture productivity and quality in south-western Victoria.


Soil Research ◽  
2008 ◽  
Vol 46 (3) ◽  
pp. 203 ◽  
Author(s):  
G. A. Thomas ◽  
D. N. Orange ◽  
A. J. King

An experiment was conducted on a Kandosol in south-west Queensland from 2001 to 2005 to determine the effects of fallow management practices and crop and pasture rotations on soil properties and crop production. In April 2004, infiltration measurements were made using a rainfall simulator at the end of a 6-month fallow period following harvest of crop phases (wheat under reduced tillage and zero tillage, chickpea under zero tillage) and following termination of pasture phases (2-year legume and grass + legume leys) with herbicide application and zero tillage during the fallow period. Measurements were made at 3 surface cover levels in each treatment: (i) where crop or pasture dry matter was cut at ground level and removed to approximate 0% cover, (ii) at existing cover percentage, and (iii) where wheat straw was added to give 100% cover. In a separate study to monitor water infiltration, the movement of bromide applied to the soil surface in November 2003 was monitored in the soil profile to 1.5 m soil depth in April 2004 and February 2005. Mean cumulative infiltration after 100 mm rainfall over 1 h was 35, 42, and 69 mm (l.s.d. P = 0.05, 6) with 0%, existing, and 100% cover, respectively, and was greater following wheat (52 mm) than following chickpea (39 mm) under zero tillage (l.s.d. P = 0.05, 13). Short-term pasture leys did not appear to improve infiltration characteristics of the soil under the conditions of this study. In the rainfall simulator study, mean drainage of water below 1.5 m soil depth was 8.5% of applied rainfall. In the bromide tracer study, only ~12% of the applied bromide could be accounted for in the 0–1.5 m soil depth 15 months after application. Rainfall received during this period was similar to the long-term mean amount. Results demonstrate the importance of surface cover in increasing rainfall infiltration on this soil, thereby potentially improving soil water storage for crop and pasture production and reducing the risk of runoff and soil erosion. However, the relatively rapid movement of water and solutes through the soil profile has implications for possible adverse effects of drainage to lower parts of the landscape and for nutrient leaching below the root-zone, decreasing the availability of soil and applied nutrients to crops and pastures.


2013 ◽  
Vol 92 (1) ◽  
pp. 66-99 ◽  
Author(s):  
Christopher A. Whatley

This article responds to and is designed as a counterweight to recent work on political history in early-modern Scotland in which Jacobitism has been persuasively portrayed as a strongly supported movement over time rather than an episodic cause. Building upon recent research on the Union of 1707 which demonstrated the degree of principled and consistent support there was for closer union with England within a British polity, the paper seeks to show that there was a clearly identifiable ideological basis to anti-Jacobitism in Scotland. The term, however, is best understood as the Revolution or, even better, the Whig interest, not least as the principles upon which anti-Jacobitism were based pre-dated the Revolution of 1688–9 and the emergence of Jacobitism. The Revolution, it is argued, had many more supporters, and from a wider geographical area, than has generally been assumed in accounts which focus largely on the south west of Scotland. Support took various forms, ranging from prayer through public campaigning to the taking up of arms. It is also clear that support for Whig principles was not only long-standing but also grew over the period examined. What is underlined is that Scotland was a deeply fissured nation, the principal divide owing much but not everything to religion and differing perspectives on the nature of monarchical authority and the role of parliament.


2006 ◽  
Vol 54 (5) ◽  
pp. 459 ◽  
Author(s):  
Kamaljit Kaur ◽  
David J. Midmore ◽  
Rajesh K. Jalota ◽  
Nanjappa Ashwath

Land clearing in Queensland is often practised to enhance pasture production, and hence, increase financial returns from beef production. The benefits of clearing have been quantified in terms of short-term gains in pasture yield but have not adequately accounted for possible medium- or longer-term impediments that may be attributed to clearing. Therefore, impacts of clearing and the subsequent sowing of exotic grasses such as Cenchrus ciliaris L. on pasture composition and production were studied. To achieve this, paired sites were selected representing cleared and uncleared pastures across three different times since clearing (i.e. 5, 11–13 and 33 years since clearing) for the three dominant tree communities of central Queensland (i.e. Eucalyptus populnea F.Muell. (poplar box), E. melanophloia F.Muell. (silver-leaved ironbark) and Acacia harpophylla F.Muell. ex. Benth. (brigalow)). The results demonstrated that species diversity declined with clearing and sowing of exotic pastures. Species diversity and pasture production were negatively related. Although pasture yield was 2–3 times greater 13 years after clearing of E. populnea and A. harpohylla, the gains in pasture yield were not consistent over time, yields being only 1.5 times greater after 33 years of clearing. In E. melanophloia, an increase in the yield of only 1.5–1.8 times occurred 5 years after clearing compared with uncleared pastures, whereas 33 years after clearing, yield was 3/4 of that in uncleared pastures. The initial gains in pasture yield were accompanied by a loss of plant diversity that may affect ecosystem functions such as nutrient cycling or soil mineralisation, and the longer-term production gains.


1998 ◽  
Vol 18 (8-9) ◽  
pp. 575-582 ◽  
Author(s):  
B. J. Miller ◽  
P. W. Clinton ◽  
G. D. Buchan ◽  
A. B. Robson

2016 ◽  
Vol 88 (2) ◽  
pp. 973-982 ◽  
Author(s):  
LUÍS C.R. SILVA ◽  
SEBASTIÃO A. MACHADO ◽  
FRANKLIN GALVÃO ◽  
AFONSO FIGUEIREDO FILHO

ABSTRACT Bracatinga (Mimosa scabrella Bentham) is an important pioneer tree species in Ombrophylous Mixed Forest of Brazil and is widely used as an energy source. In traditional agroforestry systems, regeneration is induced by fire, then pure and dense stands known as bracatinga stands (bracatingais) are formed. In the first year, annual crops are intercalated with the seedlings. At that time the seedlings are thinned, then the stands remain at a fallow period and cut at seven years old. The species is very important mainly for small landowners. We studied the understory species that occur naturally during the succession over several years in order to manage them rationally in the future and maintain the natural vegetation over time. Three to 20 year-old Bracatinga stands were sampled between 1998 and 2011. All tree species with diameter at breast height (DBH) ≥ 5 cm were measured.The floristic evolution was assessed with respect to Sociability Index, the Shannon Diversity Index and the Pielou Evenness Index. Graphs of rank/abundance over different age groups were evaluated using the Kolmogorov-Smirnov test. We identified 153 species dispersed throughout the understory and tend to become aggregated over time.


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