In Mediterranean countries forage crops and temporary grasslands are the most important supply even if severe moisture stress is common. In Italy, forage systems are various and differently located from North to South...In Mediterranean countries forage crops and temporary grasslands are the most important supply even if severe moisture stress is common. In Italy, forage systems are various and differently located from North to South of the mainland due to strong influence by rainfall distribution. Grasses and grazing cover 3.4 million ha of Italian utilized agricultural area （UAA） while alternated grassland and grass meadows cover 1.9 million ha. Most of grasslands are located in hilly and mountainous areas and are important for reducing erosion. Italy has a great longitudinal extension which accounts for a great variety of climate systems and soils： the northern regions have a humid subtropical climate and differ greatly from the south part that fits the Mediterranean climate profile. During the last 100/150 years the Italian climate has become warmer and drier showing an increase of erratic precipitation intensity. The future of breeding of forage grasses and legumes should be focused on higher nutrient use efficiencies and increased sustainability. New applications of genomics and bioinformatics will allow advanced breeding strategies. Over the past 15 years breeders have displayed a constant interest in forage species while a greater interest has risen in turfgrass varieties. Seed production of Italian herbages does not cover the requirements of the market. More specific value for cultivation and use （VCU） tests might be an effective means to improve the screening of candidate varieties. The goal is the selection of varieties able to withstand the stress of climate change, have better water and nitrogen use efficiency and resilience of vegetation cover.展开更多
Over-exploitation and rural growth have severely damaged native vegetations of Aravalli hills in Rajasthan, India. This study was conducted to evaluate the effects of different restoration practices （i.e., rainwater ...Over-exploitation and rural growth have severely damaged native vegetations of Aravalli hills in Rajasthan, India. This study was conducted to evaluate the effects of different restoration practices （i.e., rainwater harvesting （RWH） and planting of tree seedlings） on improve- ment in soil water and nutrients and growth and biomass of herbaceous vegetation. Contour trench （CT）, Gradonie （G）, Box trench （BT）, V-ditch （VD） and a control were imposed on 75 plots （each of 700 m 2 ） in natural slope gradient defined as 10%, 10% 20% and 20% slopes in 2005. Each plot had three micro-sites of 1-m 2 at up （USP）, middle （MSP） and lower （LSP） part of the plot for observation in 2008. The existed gradient （due to soil texture and topographic features） of soil pH, EC, SOC, NH 4 - N, NO 3 -N and PO 4 -P in June 2005 between 20% to 10% slopes were decreased in 2008 after applying RWH techniques. Such improvement in soil status promoted vegetation growth and biomass in higher slope gra- dients. Soil water, species diversity and herbage biomass increased from USP to LSP, and RWH techniques had positive role in improving SOC, nutrients, vegetation population, evenness and growth at MSP. Despite of lowest SWC, regular rain and greater soil water usage enhanced green and dry herbage biomasses in 10% 20% and 20% slopes, compared with 10% slope. The highest diversity in CT treatment was related to herbage biomass, which was enhanced further by highest concentrations of SOC and PO 4 -P. Further, CT treatment was found to be the best treat- ment in minimizing biomass variance in different slopes. Conclusively, soil texture and topographic features controlled soil water and nutrients availability. Rainwater harvesting techniques increased soil water storage and nutrient retention and also enhanced vegetation status and biomass by minimizing the effects of hillslopes. Thus depending upon the site conditions, suitable RWH technique could be adopted to increase herb- age biomass while rehabilitating the degraded hills.展开更多
<span style="font-family:Verdana;">A grazing experiment was undertaken to assess the effects of two levels of herbage mass (HM) on herbage DM intake (DMI), fat and protein corrected milk yield (FPCM), ...<span style="font-family:Verdana;">A grazing experiment was undertaken to assess the effects of two levels of herbage mass (HM) on herbage DM intake (DMI), fat and protein corrected milk yield (FPCM), grazing behaviour, energy expenditure (HP), and methane emissions (CH</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">) of grazing dairy cows in spring. Treatments were a low HM (1447 kg DM/ha;LHM) or a high HM (1859 kg DM/ha;HHM). Pasture was composed mainly </span><span style="font-family:Verdana;">of</span><span style="font-family:;" "=""><span><span style="font-family:Verdana;"> cocksfoot (</span><i></i></span><i><i><span style="font-family:Verdana;">Dactylis glomerata</span></i><span></span></i></span><span><span style="font-family:Verdana;">) and lucerne (</span><i></i></span><i><i><span style="font-family:Verdana;">Medicago sativa</span></i><span></span></i><span style="font-family:Verdana;">), offered at a daily herbage allowance of 30 kg DM/cow, above 5 cm. Eight multiparous Holstein cows were used in a 2</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">×</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">2 Latin Square design in two 10-day periods. Despite the differences in pre-grazing HM between treatments, OM digestibility was not different (P = 0.28). Herbage mass did not affect DMI or FPCM. Grazing time was not different between treatments, but cows had a greater bite rate when grazing on LHM swards. However, HP did not differ between treatments. Daily methane emission (per cow), methane emission intensity (per kg FPCM) and methane yield (as percentage of gross energy intake) were not different. The lack of effect of the amount of pre-grazing HM on energy intake, confirms that the difference between HM treatments w</span><span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> beyond the limits that impose extra energy expenditure during grazing.</span>展开更多
Weed control is a crucial factor for maintaining establishment and herbage production in dwarf variety of late-heading type （DL） napiergrass （Pennisetum purpureum Schumach） in southern Kyushu, Japan. This study wa...Weed control is a crucial factor for maintaining establishment and herbage production in dwarf variety of late-heading type （DL） napiergrass （Pennisetum purpureum Schumach） in southern Kyushu, Japan. This study was aimed to verify the weeding-effect on dry matter （DM） production in the farm level and to examine the effect of several weed control, i.e. mixed sowing of annual setaria （abbreviated as S）, which has no regrowth ability after stem-elongation, paper-mulching （as P） and hand-weeding （as ＋W）, compared with no-weeding （as -W） on DM yield and quality of DL napiergrass in two years. Weed control practices significantly （P 〈 0.05） promoted several plant growth attributes in DL napiergrass, compared with no-weeding both in the farm and experimental levels. Paper-mulchidng （P-W or P＋S-W） had highest yields among several practices in both years. Setaria-sowing ha a partially mitigating effect of weed damage on DM production of DL napiergrass, while additive DM gain from setaria could compensate the yield decrease in DL napiergrass and reduce herbicide cost. Neither digestibility nor crude protein was affected by any weed control in either year. Thus, paper-mulching and annual setaria-sowing could be effective alternative practices for weed control of this species.展开更多
To reveal the seasonal dynamics of herbage intake, diet composition and digestibility and clarify the relationship of those with herbage nutrient and botanical composition of grazing sheep in Zhenglan Banner of Inner ...To reveal the seasonal dynamics of herbage intake, diet composition and digestibility and clarify the relationship of those with herbage nutrient and botanical composition of grazing sheep in Zhenglan Banner of Inner Mongolia, the n-alkane technique was used to test in sheep grazed during June, August and December. The results showed that the sheep mainly ate Fringed sagebrush, Stipa krylovii and Carex in proportions of 33.5,17.9 and 21.2%, respectively, in spring. In summer, the sheep consumed cleistogenes,Potentilla tanacetifolia, Thyme, etc; the intake of Fringed sagebrush, Carex and Stipa declined. In winter,Fringed sagebrush accounted for 50.1% of herbage intake, and the intakes of Cleistogenes and Stipa krylovii increased to 15.3 and 18.4%, respectively. Herbage intake by the sheep in spring was 1.8 kg DM/d, and digestibility was 71.4%. Herbage intake and digestibility decreased slightly to 1.7 kg DM/d and 68.4%during the summer, respectively and decreased significantly to 1.2 kg DM/d and 36.4% in winter. There were significant correlations between diet composition and CP content in winter, diet composition and botanical composition in summer. A highly positive correlation between herbage intake and digestibility was observed in grazing sheep.展开更多
The Yabello rangeland is a semi-arid area in Borana, Ethiopia that is facing great degradation challenges. Increasing infestation of vegetation cover, over grazing and high seasonal variation have significantly affect...The Yabello rangeland is a semi-arid area in Borana, Ethiopia that is facing great degradation challenges. Increasing infestation of vegetation cover, over grazing and high seasonal variation have significantly affected the herbage composition and biomass in the Yabello rangeland. This study focused on assessing the effect of vegetation cover, grazing and season on both herbage composition and biomass in the Yabello rangeland. An experiment was conducted using randomized plots of 1m×1m. Sites were selected based on vegetation cover type and grazing variation, and seasonal impacts were also assessed. Data on herbage composition, height and mass with respect to those parameters were analyzed using SAS statistical software version 9.1(SAS Institute, 2001) and Microsoft Excel. A total of 26 grass species were recorded and Chloris roxburghiana Chrysopogon aucheri and Chrysopogon aucheri grass species showed the highest average single species cover height and biomass production, for all the sites among all parameters. As a result, those grass species are highly recommended for the rehabilitation of degraded rangeland in the study area. This study also showed that vegetation cover type grazing and seasonal variation were the key factors in determining herbage species composition, height and biomass production. Finally, we recommended that sustainable management which controls bush vegetation cover and balances grazing levels is essential for sustainable herbage production and biodiversity conservation in the area.展开更多
Background:Tall fescue is sensitive to sowing depth and,in the Pampas region of Argentina,its sowing is often delayed from autumn(average air temperature 18.5℃)to winter(average air temperature 10.0℃).Since tall fes...Background:Tall fescue is sensitive to sowing depth and,in the Pampas region of Argentina,its sowing is often delayed from autumn(average air temperature 18.5℃)to winter(average air temperature 10.0℃).Since tall fescue is sensitive to the sowing depth,and temperature determines the emergence period,this study aimed to evaluate the effect of sowing depth at different times on seedling emergence and herbage yield.Methods:Two field experiments were carried out in Pergamino,Buenos Aires province,Argentina,to evaluate a summer‐active tall fescue at two sowing times and five sowing depths.The emergence of seedlings and the herbage yield in the year of sowing were determined.Results:Seedling emergence was maximal when sown at 1.2–1.5 cm depth and at 230 growing degree days(GDD)in early autumn and 257 GDD in winter.In both years and sowing seasons,herbage yield was positively related to the number of seedlings at maximum emergence.Conclusions:No differences in seedling emergence were observed between the autumn and winter sowings,and the emergence of tall fescue was well explained by the thermal time.The concept of“critical depth”was determined as the sowing depth at which the greatest seedling emergence and forage yield are achieved.展开更多
Feed-animal balance is the key technique on the grassland ecosystem management,and attracts widespread attention in the world.Many studies have been conducted by former researchers,and most of their efforts were inten...Feed-animal balance is the key technique on the grassland ecosystem management,and attracts widespread attention in the world.Many studies have been conducted by former researchers,and most of their efforts were intended to keep the balance of feed-animal.However,there are still much more issue needed to be studied in details on the face of grassland degeneration and animal husbandry sustainable development.The author analyzed the feed-animal balance research progress,including the concept of stocking rate and its practical management techniques,especially on the stocking rate calculation methods.In addition,the social and economy effects on feed-animal balance were also discussed during the progress of improving the development of pastoral economy.In order to achieve feed-animal balance more effectively,it was concluded that the focus must be shift from only on animal number to the grassland quality,and it's necessary to strengthen market tax control.展开更多
This study aimed to evaluate the effect of two rest intervals on structural sward characteristics and productive performance of beef heifers reared on Campos grassland managed on rotational grazing. The treatments wer...This study aimed to evaluate the effect of two rest intervals on structural sward characteristics and productive performance of beef heifers reared on Campos grassland managed on rotational grazing. The treatments were two intervals between grazing of 375 and 750 DD (degree days), based on thermal cumulative sum for leaf expansion of native grasses belonging to two functional groups. The experimental design was a randomized complete block design with two treatments and three replications. The tested animals were beef heifers with initial age of 12 months and average weight of 185.2 ± 17.4 kg. Measures in the pasture were: herbage mass, mass of green leaf blades, stem mass, dead material mass and green leaf allowance. The 750 DD rest interval presented higher herbage mass (24%), higher green herbage mass and 19% more leaves in the canopy. This rest interval also presents a high proportion of dead material and stems in the sward structure. In the other way, the 375 DD rest interval presents better chemical characteristics, with 20% more crude protein in the hand plucking samples. Heifers’ dry matter intake was similar between the rest intervals (2.04% of live weight) and the bite mass was also similar (0.22 g DM per bite) but the animal performance was higher in the 375 DD rest interval. The stocking density showed similarity between treatments with an average of 875 kg/LW/ha. The live weight gain per area was higher in 40 kg/LW/ha (P = 0.117) for 375 DD rest interval, reaching 251 kg/LW/ha produced over the 149 experimental days. Based on these results, we can conclude that the treatment of shortest interval between defoliation gave the highest gain individual animals in warm seasons.展开更多
The aim of this study was to compare the area production and grazing behavior of single- and twin-rearing ewes kept on a mixed Italian ryegrass/white clover pasture. The herbage allowance was maintained at 12 kg DM/10...The aim of this study was to compare the area production and grazing behavior of single- and twin-rearing ewes kept on a mixed Italian ryegrass/white clover pasture. The herbage allowance was maintained at 12 kg DM/100kg live weight during the experiment, by continuous variable stocking management for 112 days (4 periods of 28 days). We measure the live weight gains, the area production and the body condition score of ewes and lambs. Animal behavior was observed on four occasions during which we evaluated whether the lambs were grazing near to or far from their mother. Live-weight output from the ewes and lambs, and net output (ewes and lambs) were calculated. Results showed that being irrespective of birth type, ewes had similar mean daily weight gains, although ewes with twin lambs presented a mean lower body condition score. Ewes live weight output/ha did not differ significantly among birth types, but twin lambs produced 98.2 kg (45%) more live weight gain/ha. Total net live-weight output (ewes + lambs) was 121.5 kg greater for twins than for singles. Ewes with twin lambs spent more time grazing and ruminating. Lambs increased the time they spent grazing in each successive period. Single lambs spent significantly longer time grazing within 12 m of their dams (near grazing). Analysis of far grazing times by the broken line method showed that growing lambs rapidly increase the time spent far grazing up to a live weight of 20.3 kg in both birth types, which occurs at 95.3 and 115.9 days of age for single and twins, respectively. The results indicate that twin lambs are more productive than singles, when evaluated per area unit of pasture.展开更多
Background:Feed is the most costly input for US ruminant livestock production systems,and increasing the utilization efficiency of irrigated forage systems can improve system profitability.This study assessed the prod...Background:Feed is the most costly input for US ruminant livestock production systems,and increasing the utilization efficiency of irrigated forage systems can improve system profitability.This study assessed the production,utilization,and quality of 22 intensively managed perennial grasses and legumes.Methods:Forages were cultivated as monocultures under irrigation and subjected to mob stocking or similarly frequent and intense mowing for 2 years at 6‐week intervals between May and September.Twenty‐two grasses and legumes were randomly assigned to adjacent 1.5‐m‐wide×9‐m‐long split subplots within each whole plot of eight replications,and the eight replications were grouped into four pairs,with the two replications per pair randomly assigned to defoliation either by grazing or mowing.Results:Seven mostly warm‐season grasses did not persist following the first defoliation,and accumulation for three legume species could be evaluated only twice in Year 1.For the 12 remaining forage species defoliated four times in both years,defoliation management did not affect dry matter accumulation or removal,but utilization was 10%greater under grazing than mowing(p=0.0031).Conclusions:Under 6‐week‐long rest periods,numerous irrigated cool‐season grasses and temperate legumes were tolerant of repeated mob grazing.展开更多
文摘In Mediterranean countries forage crops and temporary grasslands are the most important supply even if severe moisture stress is common. In Italy, forage systems are various and differently located from North to South of the mainland due to strong influence by rainfall distribution. Grasses and grazing cover 3.4 million ha of Italian utilized agricultural area （UAA） while alternated grassland and grass meadows cover 1.9 million ha. Most of grasslands are located in hilly and mountainous areas and are important for reducing erosion. Italy has a great longitudinal extension which accounts for a great variety of climate systems and soils： the northern regions have a humid subtropical climate and differ greatly from the south part that fits the Mediterranean climate profile. During the last 100/150 years the Italian climate has become warmer and drier showing an increase of erratic precipitation intensity. The future of breeding of forage grasses and legumes should be focused on higher nutrient use efficiencies and increased sustainability. New applications of genomics and bioinformatics will allow advanced breeding strategies. Over the past 15 years breeders have displayed a constant interest in forage species while a greater interest has risen in turfgrass varieties. Seed production of Italian herbages does not cover the requirements of the market. More specific value for cultivation and use （VCU） tests might be an effective means to improve the screening of candidate varieties. The goal is the selection of varieties able to withstand the stress of climate change, have better water and nitrogen use efficiency and resilience of vegetation cover.
文摘Over-exploitation and rural growth have severely damaged native vegetations of Aravalli hills in Rajasthan, India. This study was conducted to evaluate the effects of different restoration practices （i.e., rainwater harvesting （RWH） and planting of tree seedlings） on improve- ment in soil water and nutrients and growth and biomass of herbaceous vegetation. Contour trench （CT）, Gradonie （G）, Box trench （BT）, V-ditch （VD） and a control were imposed on 75 plots （each of 700 m 2 ） in natural slope gradient defined as 10%, 10% 20% and 20% slopes in 2005. Each plot had three micro-sites of 1-m 2 at up （USP）, middle （MSP） and lower （LSP） part of the plot for observation in 2008. The existed gradient （due to soil texture and topographic features） of soil pH, EC, SOC, NH 4 - N, NO 3 -N and PO 4 -P in June 2005 between 20% to 10% slopes were decreased in 2008 after applying RWH techniques. Such improvement in soil status promoted vegetation growth and biomass in higher slope gra- dients. Soil water, species diversity and herbage biomass increased from USP to LSP, and RWH techniques had positive role in improving SOC, nutrients, vegetation population, evenness and growth at MSP. Despite of lowest SWC, regular rain and greater soil water usage enhanced green and dry herbage biomasses in 10% 20% and 20% slopes, compared with 10% slope. The highest diversity in CT treatment was related to herbage biomass, which was enhanced further by highest concentrations of SOC and PO 4 -P. Further, CT treatment was found to be the best treat- ment in minimizing biomass variance in different slopes. Conclusively, soil texture and topographic features controlled soil water and nutrients availability. Rainwater harvesting techniques increased soil water storage and nutrient retention and also enhanced vegetation status and biomass by minimizing the effects of hillslopes. Thus depending upon the site conditions, suitable RWH technique could be adopted to increase herb- age biomass while rehabilitating the degraded hills.
文摘<span style="font-family:Verdana;">A grazing experiment was undertaken to assess the effects of two levels of herbage mass (HM) on herbage DM intake (DMI), fat and protein corrected milk yield (FPCM), grazing behaviour, energy expenditure (HP), and methane emissions (CH</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">) of grazing dairy cows in spring. Treatments were a low HM (1447 kg DM/ha;LHM) or a high HM (1859 kg DM/ha;HHM). Pasture was composed mainly </span><span style="font-family:Verdana;">of</span><span style="font-family:;" "=""><span><span style="font-family:Verdana;"> cocksfoot (</span><i></i></span><i><i><span style="font-family:Verdana;">Dactylis glomerata</span></i><span></span></i></span><span><span style="font-family:Verdana;">) and lucerne (</span><i></i></span><i><i><span style="font-family:Verdana;">Medicago sativa</span></i><span></span></i><span style="font-family:Verdana;">), offered at a daily herbage allowance of 30 kg DM/cow, above 5 cm. Eight multiparous Holstein cows were used in a 2</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">×</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">2 Latin Square design in two 10-day periods. Despite the differences in pre-grazing HM between treatments, OM digestibility was not different (P = 0.28). Herbage mass did not affect DMI or FPCM. Grazing time was not different between treatments, but cows had a greater bite rate when grazing on LHM swards. However, HP did not differ between treatments. Daily methane emission (per cow), methane emission intensity (per kg FPCM) and methane yield (as percentage of gross energy intake) were not different. The lack of effect of the amount of pre-grazing HM on energy intake, confirms that the difference between HM treatments w</span><span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> beyond the limits that impose extra energy expenditure during grazing.</span>
文摘Weed control is a crucial factor for maintaining establishment and herbage production in dwarf variety of late-heading type （DL） napiergrass （Pennisetum purpureum Schumach） in southern Kyushu, Japan. This study was aimed to verify the weeding-effect on dry matter （DM） production in the farm level and to examine the effect of several weed control, i.e. mixed sowing of annual setaria （abbreviated as S）, which has no regrowth ability after stem-elongation, paper-mulching （as P） and hand-weeding （as ＋W）, compared with no-weeding （as -W） on DM yield and quality of DL napiergrass in two years. Weed control practices significantly （P 〈 0.05） promoted several plant growth attributes in DL napiergrass, compared with no-weeding both in the farm and experimental levels. Paper-mulchidng （P-W or P＋S-W） had highest yields among several practices in both years. Setaria-sowing ha a partially mitigating effect of weed damage on DM production of DL napiergrass, while additive DM gain from setaria could compensate the yield decrease in DL napiergrass and reduce herbicide cost. Neither digestibility nor crude protein was affected by any weed control in either year. Thus, paper-mulching and annual setaria-sowing could be effective alternative practices for weed control of this species.
基金supported by the Modern Agroindustry Technology Research System(CARS-39)grant from the Chinese Ministry of Agriculture
文摘To reveal the seasonal dynamics of herbage intake, diet composition and digestibility and clarify the relationship of those with herbage nutrient and botanical composition of grazing sheep in Zhenglan Banner of Inner Mongolia, the n-alkane technique was used to test in sheep grazed during June, August and December. The results showed that the sheep mainly ate Fringed sagebrush, Stipa krylovii and Carex in proportions of 33.5,17.9 and 21.2%, respectively, in spring. In summer, the sheep consumed cleistogenes,Potentilla tanacetifolia, Thyme, etc; the intake of Fringed sagebrush, Carex and Stipa declined. In winter,Fringed sagebrush accounted for 50.1% of herbage intake, and the intakes of Cleistogenes and Stipa krylovii increased to 15.3 and 18.4%, respectively. Herbage intake by the sheep in spring was 1.8 kg DM/d, and digestibility was 71.4%. Herbage intake and digestibility decreased slightly to 1.7 kg DM/d and 68.4%during the summer, respectively and decreased significantly to 1.2 kg DM/d and 36.4% in winter. There were significant correlations between diet composition and CP content in winter, diet composition and botanical composition in summer. A highly positive correlation between herbage intake and digestibility was observed in grazing sheep.
基金The Funding Source Science and Technology Partnership Program,Ministry of Science and Technology of China(KY201702010)The China-Africa Joint Research Center Project of the Chines Academy of Science(SAJC201610).
文摘The Yabello rangeland is a semi-arid area in Borana, Ethiopia that is facing great degradation challenges. Increasing infestation of vegetation cover, over grazing and high seasonal variation have significantly affected the herbage composition and biomass in the Yabello rangeland. This study focused on assessing the effect of vegetation cover, grazing and season on both herbage composition and biomass in the Yabello rangeland. An experiment was conducted using randomized plots of 1m×1m. Sites were selected based on vegetation cover type and grazing variation, and seasonal impacts were also assessed. Data on herbage composition, height and mass with respect to those parameters were analyzed using SAS statistical software version 9.1(SAS Institute, 2001) and Microsoft Excel. A total of 26 grass species were recorded and Chloris roxburghiana Chrysopogon aucheri and Chrysopogon aucheri grass species showed the highest average single species cover height and biomass production, for all the sites among all parameters. As a result, those grass species are highly recommended for the rehabilitation of degraded rangeland in the study area. This study also showed that vegetation cover type grazing and seasonal variation were the key factors in determining herbage species composition, height and biomass production. Finally, we recommended that sustainable management which controls bush vegetation cover and balances grazing levels is essential for sustainable herbage production and biodiversity conservation in the area.
基金Instituto Nacional de Tecnología Agropecuaria,Grant/Award Number:PNPA1126073。
文摘Background:Tall fescue is sensitive to sowing depth and,in the Pampas region of Argentina,its sowing is often delayed from autumn(average air temperature 18.5℃)to winter(average air temperature 10.0℃).Since tall fescue is sensitive to the sowing depth,and temperature determines the emergence period,this study aimed to evaluate the effect of sowing depth at different times on seedling emergence and herbage yield.Methods:Two field experiments were carried out in Pergamino,Buenos Aires province,Argentina,to evaluate a summer‐active tall fescue at two sowing times and five sowing depths.The emergence of seedlings and the herbage yield in the year of sowing were determined.Results:Seedling emergence was maximal when sown at 1.2–1.5 cm depth and at 230 growing degree days(GDD)in early autumn and 257 GDD in winter.In both years and sowing seasons,herbage yield was positively related to the number of seedlings at maximum emergence.Conclusions:No differences in seedling emergence were observed between the autumn and winter sowings,and the emergence of tall fescue was well explained by the thermal time.The concept of“critical depth”was determined as the sowing depth at which the greatest seedling emergence and forage yield are achieved.
基金The National Special Research Fund for Non-Profit Sector."Carrying Capacity and Livestock in Different Places"(200903060)"Re-search and Demonstration of Resources Optimization in Family Farmland"(201003019)+1 种基金"Research and Demonstration of Nurture of Natural Grassland and Used Technology in Semi-arid Farmland"(201303060)National Forage Industry Technological System(CARS-35)
文摘Feed-animal balance is the key technique on the grassland ecosystem management,and attracts widespread attention in the world.Many studies have been conducted by former researchers,and most of their efforts were intended to keep the balance of feed-animal.However,there are still much more issue needed to be studied in details on the face of grassland degeneration and animal husbandry sustainable development.The author analyzed the feed-animal balance research progress,including the concept of stocking rate and its practical management techniques,especially on the stocking rate calculation methods.In addition,the social and economy effects on feed-animal balance were also discussed during the progress of improving the development of pastoral economy.In order to achieve feed-animal balance more effectively,it was concluded that the focus must be shift from only on animal number to the grassland quality,and it's necessary to strengthen market tax control.
文摘This study aimed to evaluate the effect of two rest intervals on structural sward characteristics and productive performance of beef heifers reared on Campos grassland managed on rotational grazing. The treatments were two intervals between grazing of 375 and 750 DD (degree days), based on thermal cumulative sum for leaf expansion of native grasses belonging to two functional groups. The experimental design was a randomized complete block design with two treatments and three replications. The tested animals were beef heifers with initial age of 12 months and average weight of 185.2 ± 17.4 kg. Measures in the pasture were: herbage mass, mass of green leaf blades, stem mass, dead material mass and green leaf allowance. The 750 DD rest interval presented higher herbage mass (24%), higher green herbage mass and 19% more leaves in the canopy. This rest interval also presents a high proportion of dead material and stems in the sward structure. In the other way, the 375 DD rest interval presents better chemical characteristics, with 20% more crude protein in the hand plucking samples. Heifers’ dry matter intake was similar between the rest intervals (2.04% of live weight) and the bite mass was also similar (0.22 g DM per bite) but the animal performance was higher in the 375 DD rest interval. The stocking density showed similarity between treatments with an average of 875 kg/LW/ha. The live weight gain per area was higher in 40 kg/LW/ha (P = 0.117) for 375 DD rest interval, reaching 251 kg/LW/ha produced over the 149 experimental days. Based on these results, we can conclude that the treatment of shortest interval between defoliation gave the highest gain individual animals in warm seasons.
文摘The aim of this study was to compare the area production and grazing behavior of single- and twin-rearing ewes kept on a mixed Italian ryegrass/white clover pasture. The herbage allowance was maintained at 12 kg DM/100kg live weight during the experiment, by continuous variable stocking management for 112 days (4 periods of 28 days). We measure the live weight gains, the area production and the body condition score of ewes and lambs. Animal behavior was observed on four occasions during which we evaluated whether the lambs were grazing near to or far from their mother. Live-weight output from the ewes and lambs, and net output (ewes and lambs) were calculated. Results showed that being irrespective of birth type, ewes had similar mean daily weight gains, although ewes with twin lambs presented a mean lower body condition score. Ewes live weight output/ha did not differ significantly among birth types, but twin lambs produced 98.2 kg (45%) more live weight gain/ha. Total net live-weight output (ewes + lambs) was 121.5 kg greater for twins than for singles. Ewes with twin lambs spent more time grazing and ruminating. Lambs increased the time they spent grazing in each successive period. Single lambs spent significantly longer time grazing within 12 m of their dams (near grazing). Analysis of far grazing times by the broken line method showed that growing lambs rapidly increase the time spent far grazing up to a live weight of 20.3 kg in both birth types, which occurs at 95.3 and 115.9 days of age for single and twins, respectively. The results indicate that twin lambs are more productive than singles, when evaluated per area unit of pasture.
基金supported by the Utah Agricultural Experiment Station,Utah State University,and approved as journal paper number 9783approved by the Utah State University Institutional Animal Care and Use Committee as Protocol 1130.
文摘Background:Feed is the most costly input for US ruminant livestock production systems,and increasing the utilization efficiency of irrigated forage systems can improve system profitability.This study assessed the production,utilization,and quality of 22 intensively managed perennial grasses and legumes.Methods:Forages were cultivated as monocultures under irrigation and subjected to mob stocking or similarly frequent and intense mowing for 2 years at 6‐week intervals between May and September.Twenty‐two grasses and legumes were randomly assigned to adjacent 1.5‐m‐wide×9‐m‐long split subplots within each whole plot of eight replications,and the eight replications were grouped into four pairs,with the two replications per pair randomly assigned to defoliation either by grazing or mowing.Results:Seven mostly warm‐season grasses did not persist following the first defoliation,and accumulation for three legume species could be evaluated only twice in Year 1.For the 12 remaining forage species defoliated four times in both years,defoliation management did not affect dry matter accumulation or removal,but utilization was 10%greater under grazing than mowing(p=0.0031).Conclusions:Under 6‐week‐long rest periods,numerous irrigated cool‐season grasses and temperate legumes were tolerant of repeated mob grazing.
