scholarly journals Development of a grass measurement optimisation tool to efficiently measure herbage mass on grazed pastures

2020 ◽  
Vol 178 ◽  
pp. 105799 ◽  
Author(s):  
D.J. Murphy ◽  
B. O' Brien ◽  
M.D. Murphy
Keyword(s):  
Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1214
Author(s):  
Hendrik P. J. Smit ◽  
Thorsten Reinsch ◽  
Pieter A. Swanepoel ◽  
Ralf Loges ◽  
Christof Kluß ◽  
...  

Nitrogen fertilization, irrigation and concentrate feeding are important factors in rotational pasture management for dairy farms in South Africa. The extent to which these factors affect environmental efficiency is subject to current and intense debate among scientists. A three-year field study was conducted to investigate the yield response of different N-fertilizer treatments (0 (N0), 220 (N20), 440 (N40), 660 (N60) and 880 (N80) kg N ha−1 year−1) on grazed pastures and to calculate the carbon footprint (CF) of milk produced. Excessive N-fertilization (N60 and N80) did not increase herbage dry matter and energy yields from pastures. However, N80 indicated the highest N-yield but at the same time also the highest N surpluses at field level. A maximum fertilizer rate of 220 kg ha−1 year−1 (in addition to excreted N from grazing animals) appears sufficient to ensure adequate herbage yields (~20 t DM ha−1 year−1) with a slightly positive field-N-balance. This amount will prevent the depletion of soil C and N, with low N losses to the environment, where adequate milk yields of ~17 t ECM ha−1 with a low CF (~1.3 kg CO2 kg ECM−1) are reached. Methane from enteric fermentation (~49% ± 3.3) and N2O (~16% ± 3.2) emissions from irrigated pastures were the main contributors to the CF. A further CF reduction can be achieved by improved N-fertilization planning, low emission irrigation techniques and strategies to limit N2O emissions from pasture soils in South Africa.


Pedobiologia ◽  
2011 ◽  
Vol 54 ◽  
pp. S131-S137 ◽  
Author(s):  
Nicole L. Schon ◽  
Alec D. Mackay ◽  
Ross A. Gray ◽  
Maria A. Minor
Keyword(s):  

1980 ◽  
Vol 31 (5) ◽  
pp. 967 ◽  
Author(s):  
JJ Lynch ◽  
JB Donnelly

The effect of windbreaks was studied in an experiment in which sheep were grazed continuously at 15, 30 and 37.5 ha-1 for five years. The paddocks were either square or rectangular in shape with fences of sheet iron or wire. In the square paddocks the sheet iron fences acted as a windbreak providing protection for plants and animals. In the first two years when rainfall was well below average, sheep in sheltered paddocks at 37.5 sheep ha-1 had marginally higher production than sheep in the other treatments, while at 15 sheep ha-L the productivity of the sheltered sheep was markedly higher. During the remaining three years, there were no large differences between treatments in herbage or animal production at the lowest stocking rate, while at the highest stocking rate sheep in sheltered paddocks had substantially higher production than those in unsheltered treatments. At 30 sheep ha-1 there was also increased plant and animal productivity from sheltered paddocks during the last two years of the experiment. This experiment is one of the first to show the effect of a windbreak on grazed pastures. The results indicate that shelter may have an important place in increasing pasture and animal production in the temperate areas of Australia.


BMC Ecology ◽  
2018 ◽  
Vol 18 (1) ◽  
Author(s):  
M. G. Bacher ◽  
O. Fenton ◽  
G. Bondi ◽  
R. E. Creamer ◽  
M. Karmarkar ◽  
...  

1989 ◽  
Vol 113 (1) ◽  
pp. 81-86 ◽  
Author(s):  
M. J. M. Hay ◽  
J. L. Brock ◽  
V. J. Thomas

SUMMARYDensities of physiologically independent plants of white clover were studied in New Zealand in pastures stocked at 22·5 ewes plus lambs/ha by set stocking, rotational grazing or a combination of both systems. Plants were sampled once a month for 1 year (1984/85) by taking turves and washing out the plants. Numbers of growing points and stolon dry weight per plant were obtained. At each sampling fifty, 50 mm diameter pasture plugs were taken from each sward and growing point density and stolon mass/m2 of white clover were measured. The density of white clover plants in the swards was estimated on the basis of both stolon dry weight and number of growing points.The two estimates gave similar results. There was a trend of lowest densities in set-stocked pastures (334/m2), intermediate densities in combination management pastures (431/m2) and highest densities in the rotationally grazed pastures (553/m2). The overall mean density of white clover plants was 439/m2 and the range was 193–811/m2.The structure of swards under the three systems of grazing differed and this was considered to contribute towards the variation in density of white clover plants in the various swards.


1997 ◽  
Vol 77 (4) ◽  
pp. 669-676 ◽  
Author(s):  
J. D. Popp ◽  
W. P. McCaughey ◽  
R. D. H. Cohen

A 4-yr experiment was conducted (1991 to 1994) near Brandon, MB, to determine the effects of grazing system (continuous and rotational) and stocking rate [light (1.1 steers ha−1); heavy (2.2 steers ha−1)] on the productivity, botanical composition and soil surface characteristics of an alfalfa (Medicago sativa L.; approximately 70%), meadow bromegrass (Bromus biebersteinii Roem & Schult.; 25%) and Russian wild ryegrass [Psathyrostachys juncea (Fisch.) Nevski; 5%] pasture. Grazing season length was shorter (P < 0.05) for cattle in continuously compared with rotationally stocked pastures in 1991, while in 1993 and 1994 it was shortest (P < 0.05) in heavily stocked continuously grazed pastures. Carrying capacity (steer days ha–1) was greater (P < 0.05) in heavily stocked rotationally grazed pastures compared with other treatments in 1991, 1993 and 1994. In 1992, it was greater (P < 0.05) in heavy than light stocking rate treatments for both rotationally and continuously grazed pastures. Cattle usually gained more (P < 0.05) per day (kg d−1) and during the season (kg hd−1) at light than at heavy stocking rates, while total liveweight production (kg ha−1) was greater (P < 0.05) at heavy than at light stocking rates. Forage production and disappearance did not differ (P > 0.05) within grazing systems and stocking rates from 1991 to 1993, but in 1994, production and disappearance were greater (P < 0.05) at heavy than at light stocking rates. Mean seasonal herbage mass available and carry-over were greater (P < 0.05) in lightly stocked pastures than heavily stocked pastures from 1991 to 1994. After the first year of grazing, the proportion of alfalfa increased (P < 0.05), while grasses declined (P < 0.05) within all grazing treatments. In subsequent years, a trend was observed, where alfalfa declined and grasses increased in all pastures, except those stocked heavily and grazed continuously, which by 1994 had the greatest (P < 0.05) percentage of alfalfa. As years progressed, increases (P < 0.05) in basal cover concurrent with declines in bare ground were recorded on all grazing treatments, while litter cover often did not differ (P > 0.05) within either grazing system or stocking rate, except in 1992, when basal cover was lowest (P < 0.05), while litter cover was greatest (P < 0.05) on lightly stocked continuously grazed pastures compared with other treatments. Stocking rates were a key factor to optimizing individual animal performance and/or gain per hectare on alfalfa grass pastures, however differences in the effect of continuous and rotational stocking on pasture productivity were minimal. Key words: Alfalfa, grazing, stocker cattle, production


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