Enhancement of palatable perennial grasses by disturbance and seed addition in degraded native grasslands of the dry pampas in Central Argentina

2020 ◽  
Vol 34 (4) ◽  
pp. 445-459
Author(s):  
Gastón Puthod ◽  
Alejandro Loydi ◽  
Andrés García ◽  
Roberto A. Distel
1998 ◽  
Vol 76 (8) ◽  
pp. 1467-1475
Author(s):  
Lilia I. Lindström ◽  
María B. Mújica ◽  
Roberto M. Bóo

2009 ◽  
Vol 31 (4) ◽  
pp. 369 ◽  
Author(s):  
A. M. Bowman ◽  
Y. Alemseged ◽  
G. J. Melville ◽  
W. J. Smith ◽  
F. Syrch

Native grass-based pastures in the 400–600 mm rainfall zone of central NSW are an important basis for extensive grazing industries. However, over time they have been invaded by exotic weeds. This study aimed to evaluate several grazing strategies for the maintenance or improvement of native grasslands based on pasture productivity and species diversity. Seven grazing strategies, ranging from set stocking to permanently removing stock, were employed to evaluate the strategy that would best maintain a high proportion of desirable perennial grass species. Grazing treatments were evaluated based on their effects on pasture composition and on the density of selected key grass species such as Enteropogon acicularis (Lindl.) Lazar. (curly windmill grass). Managing the utilisation of the key desirable species E. acicularis combined with weed control was the most successful strategy in terms of increasing the density of the key species, although no treatment increased the proportion of desirable perennial grasses and desirable broadleaf species. This was followed by a ‘farmer’s choice’ strategy, which involved combining phosphorus fertiliser application, weed control and rest from grazing. In contrast, strategies that involved either a ‘summer lockup’ or ‘weed control’ alone performed poorly. It is concluded that native pastures in this region could be rehabilitated, and their productivity restored, by following strategies that provide rest from grazing, based on the utilisation levels of key, species combined with control of annual weeds.


Phyton ◽  
2014 ◽  
Vol 83 (1) ◽  
pp. 397-405
Author(s):  
Blazquez FR ◽  
DV Pel醗z ◽  
RJ ◽  
rioli ◽  
OR Elia

2011 ◽  
Vol 33 (1) ◽  
pp. 67 ◽  
Author(s):  
Y. Alemseged ◽  
R. B. Hacker ◽  
W. J. Smith ◽  
G. J. Melville

Thickening of native shrubs is a major problem in many ‘semi-arid woodlands’ as significant increase in shrub density is often negatively correlated with herbaceous vegetation and leads to reduced pasture production and soil erosion. This project aimed to test the hypothesis that temporary cropping (up to three crops in 15 years) consistently increases the density of native perennial grasses following the removal of shrubs. A total of 30 paddocks that had been cropped during the last 20 years were randomly selected using a satellite-based database that documented annual clearing and cropping history from 1987 to 2003. Paddocks were classified into four types based on clearing and cropping history and grazing management – not cleared (shrubs), regrowth (re-invaded by shrubs), set stocked (cropped and grazed), light/rotationally grazed (cropped and grazed). The responses of vegetation and soil (chemical and physical) properties to clearing and cropping were evaluated. Results indicated that ground cover, native perennial grass cover and standing dry matter were highest under light/rotationally grazed conditions. The shrub state represents a stable state within the Cobar pediplain brought about due to land-use change in the form of overgrazing and/or the removal of fire from the system. An alternative stable state was achieved as a result of disturbance in the form of clearing, cropping and grazing management thereby directly altering the shrub population. The resilience of this state is largely dependent on the grazing management system used and on the prevention of shrub from re-establishing while failure to control shrubs could lead to the re-emergence of the Shrub State. We conclude that native grasslands do regenerate following cropping after removal of shrubs. The importance of grazing management for restoring perennial ground cover following removal of shrubs and temporary cropping has been clearly demonstrated by the study.


2020 ◽  
Vol 51 (1) ◽  
pp. 90-98
Author(s):  
Blazquez Francisco Rubén ◽  
Daniel Valerio Peláez ◽  
Romina Jessica Andrioli ◽  
Omar Raúl Elia

2003 ◽  
Vol 43 (8) ◽  
pp. 843 ◽  
Author(s):  
D. L. Garden ◽  
N. J. S. Ellis ◽  
M. A. Rab ◽  
C. M. Langford ◽  
W. H. Johnston ◽  
...  

The effects of application of superphosphate and grazing on production and botanical composition of native grasslands were investigated at 3 locations in the high rainfall zone of south-east Australia. These studies were conducted as part of the Sustainable Grazing Systems Key Program, which investigated various aspects of grassland productivity and sustainability between 1996 and 2001. Grasslands in this study either had high contents of Themeda australis or Austrodanthonia spp., or were based on a degraded Austrodanthonia spp. grassland with a high content of annual and weedy species. All sites used increasing levels of superphosphate application (nil, low, medium and high) as treatments, with clover being added in some treatments at 1 site, and herbicide in 1 treatment at another site. Grazing (sheep) was continuous at 1 site (with stocking rates matched to pasture productivity) and intermittent at other sites, with grazing being dictated by available herbage between defined trigger points. Climate was monitored and changes in soil P, herbage mass, botanical composition, ground cover and sheep production recorded. Changes in composition resulting from the treatments varied between sites. At the continuously grazed Austrodanthonia spp. site, there was a decline in native perennial grasses throughout the experiment and an increase in exotic annual grasses in spring where superphosphate was applied. The grassland at the T. australis site remained relatively stable, which may have been due to the limited amount of grazing applied. The degraded Austrodanthonia�spp. grassland showed wide seasonal fluctuations in annual species. There were no clear effects of treatments at the latter 2 sites. Sheep production increased with increased superphosphate application at the continuously grazed Austrodanthonia spp. site, but there was little effect at the other 2 sites. Recommendations are made for sustainable management of native grasslands depending on their current botanical state.


2013 ◽  
Vol 35 (4) ◽  
pp. 385 ◽  
Author(s):  
Daniel V. Peláez ◽  
Romina J. Andrioli ◽  
Omar R. Elia ◽  
Eliana E. Bontti ◽  
María A. Tomas ◽  
...  

The study was undertaken to quantify the effect of different controlled fire frequencies on foliar cover, density, individual basal area, and mortality of the most common perennial grass species in the semi-arid rangelands of the southern Caldenal in central Argentina over a 20-year period. Cover of bare soil was also assessed. The study comprised three fire treatments: (i) high fire frequency (controlled burns every 3–5 years; HFF); (ii) low fire frequency (controlled burns every 8 years; LFF); and (iii) unburned control (C). Fire treatments, regardless of frequency, induced an increase in foliar cover and density in desirable grasses, no changes in intermediate grasses, and a decrease in undesirable grasses. Individual basal area tended to be higher for desirable grasses and lower for intermediate and undesirable grasses when subject to fire. Most of the species under study exhibited higher mortality rates in the HFF treatment than in the LFF and C treatments. The results of the study suggest that recurrent controlled burns of moderate intensity may favour the herbage production of desirable perennial grasses. This, in turn, assuming appropriate grazing management, may have a beneficial impact on livestock production. Nevertheless, given the effects of fire on the cover of bare soil and mortality of grasses, further research is needed in order to determine the appropriate fire frequency in terms of rangeland sustainability.


2008 ◽  
Vol 45 (6) ◽  
pp. 435-447 ◽  
Author(s):  
Carlos A. Busso ◽  
Andrea Bolletta ◽  
Andrea C. Flemmer ◽  
Tomás Montani

1998 ◽  
Vol 76 (8) ◽  
pp. 1467-1475 ◽  
Author(s):  
Lilia I Lindström ◽  
María B Mújica ◽  
Roberto M Bóo

The most important economic activity on the Caldenal rangelands in central Argentina is cattle raising in cow-calf operations. It is known that grasses are the bulk of the diets and a previous study provided detailed information on the epidermal structures of the most important grass species in the region. The objective of this work was the elaboration of a key to facilitate the microhistological analysis of esophageal, fecal, and ruminal samples. The key allows for the identification of eleven perennial grass species from epidermal characteristics of the blades, sheaths, and stems. The most important epidermal characteristics relevant to microhistological identification are illustrated for each species.Key words: leaf and stem epidermis, Gramineae, microhistological key, perennial grasses, Caldenal.


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