Robust needlegrass (Achnatherum robustum [Vasey] Barkw.) is a native perennial that has great promise for use in erosion control, restoration, and ornamental plantings. Seed dormancy can be a problem in developing new native grass cultivars, especially in species of Achnatherum and related genera. Germination response to a wide range of constant and alternating incubation temperatures is also a key parameter in interpreting seedbed ecology of potential planting material. Our purpose was to investigate the germination of robust needlegrass at 55 constant or alternating incubation temperatures from 0 through 40 C. Seeds of robust needlegrass germinate over a wide range of incubation temperatures with maximum observed germination over 75%. In terms of restoration ecology, this means that in contrast to many related grass species, severe seed dormancy is not a limiting factor in seeding technology. Optimum germination occurred with 15 to 20 C warm periods alternating with 0 to 20 C cool periods. The only constant temperature to produce optimum germination was 20 C. The highest germination occurred at what we consider moderate seedbed temperatures, but some germination occurred at 76 to 89% of the temperature regimes tested. DOI:10.2458/azu_jrm_v56i3_young
{"title":"Germination of seeds of robust needlegrass.","authors":"James A. Young, C. Clements, T. Jones","doi":"10.2307/4003813","DOIUrl":"https://doi.org/10.2307/4003813","url":null,"abstract":"Robust needlegrass (Achnatherum robustum [Vasey] Barkw.) is a native perennial that has great promise for use in erosion control, restoration, and ornamental plantings. Seed dormancy can be a problem in developing new native grass cultivars, especially in species of Achnatherum and related genera. Germination response to a wide range of constant and alternating incubation temperatures is also a key parameter in interpreting seedbed ecology of potential planting material. Our purpose was to investigate the germination of robust needlegrass at 55 constant or alternating incubation temperatures from 0 through 40 C. Seeds of robust needlegrass germinate over a wide range of incubation temperatures with maximum observed germination over 75%. In terms of restoration ecology, this means that in contrast to many related grass species, severe seed dormancy is not a limiting factor in seeding technology. Optimum germination occurred with 15 to 20 C warm periods alternating with 0 to 20 C cool periods. The only constant temperature to produce optimum germination was 20 C. The highest germination occurred at what we consider moderate seedbed temperatures, but some germination occurred at 76 to 89% of the temperature regimes tested. DOI:10.2458/azu_jrm_v56i3_young","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80369051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Resilience and the Behavior of Large-Scale Systems","authors":"A. Batabyal, L. Gunderson, Lowell Pritchard join","doi":"10.2307/4003824","DOIUrl":"https://doi.org/10.2307/4003824","url":null,"abstract":"","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85154540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-05-01DOI: 10.2458/AZU_JRM_V56I3_PARERA
C. Parera, M. Ruiz
The genus Adesmia (Fabaceae, Papilionoideae) is one of the scarce forage resources at high altitude and arid zones of South America. Its germination behavior has not been examined. Seeds of Adesmia subterranea "Cuerno de Cabra" were pretreated with sulfuric acid (1, 3, and 5 minutes soaking) and mechanical scarification to determine their impact upon dormancy and percentage and speed of germination. Treatments were evaluated under a range of constant temperatures (5 to 30 C) and 2 day/night cycles resembling the extreme environmental conditions of this species habitat. Water uptake and leachate conductivity were higher in the seeds scarified mechanically or with 5 minutes chemical scarification. These treatments also had the greatest total germination and rate at all temperatures in a petri dish germination test. However, in a cell tray experiment using a commercial substrate, the highest seedling emergence and rate were observed with chemical scarification (5 and 3 minutes). The high amount of leakage caused by the scarifications affected emergence in a non-sterile media. The results indicate that A. subterranea seeds have an impermeable seed coat which restricts water uptake, and the efficiency of sulfuric acid scarification to overcome seed coat impermeability and improve germination and emergence. DOI:10.2458/azu_jrm_v56i3_parera
蚕豆属(蚕豆科，凤蝶科)是南美洲高海拔干旱地区稀缺的牧草资源之一。其发芽行为尚未被研究。采用硫酸(浸泡1、3、5分钟)和机械刻蚀法对Adesmia subterranea“Cuerno de Cabra”种子进行预处理，测定其对种子休眠、发芽率和发芽速度的影响。在恒温(5至30℃)和类似于该物种栖息地极端环境条件的2个昼夜循环下对处理进行评估。机械刻蚀和化学刻蚀5 min的种子吸水性和渗滤液电导率较高。在培养皿发芽试验中，这些处理在所有温度下的总发芽率和发芽率都最高。然而，在使用商业基质的细胞托盘实验中，化学划伤(5分钟和3分钟)的出苗率和出苗率最高。在非无菌培养基中，由割伤引起的大量泄漏影响了出苗。结果表明，地下黄杨种子种皮不透水，限制了种子的水分吸收，硫酸刻蚀能有效地克服种皮不透水，促进种子萌发和出苗。DOI: 10.2458 / azu_jrm_v56i3_parera
{"title":"Adesmia subterranea Clos Germination Physiology and Presowing Treatments","authors":"C. Parera, M. Ruiz","doi":"10.2458/AZU_JRM_V56I3_PARERA","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I3_PARERA","url":null,"abstract":"The genus Adesmia (Fabaceae, Papilionoideae) is one of the scarce forage resources at high altitude and arid zones of South America. Its germination behavior has not been examined. Seeds of Adesmia subterranea \"Cuerno de Cabra\" were pretreated with sulfuric acid (1, 3, and 5 minutes soaking) and mechanical scarification to determine their impact upon dormancy and percentage and speed of germination. Treatments were evaluated under a range of constant temperatures (5 to 30 C) and 2 day/night cycles resembling the extreme environmental conditions of this species habitat. Water uptake and leachate conductivity were higher in the seeds scarified mechanically or with 5 minutes chemical scarification. These treatments also had the greatest total germination and rate at all temperatures in a petri dish germination test. However, in a cell tray experiment using a commercial substrate, the highest seedling emergence and rate were observed with chemical scarification (5 and 3 minutes). The high amount of leakage caused by the scarifications affected emergence in a non-sterile media. The results indicate that A. subterranea seeds have an impermeable seed coat which restricts water uptake, and the efficiency of sulfuric acid scarification to overcome seed coat impermeability and improve germination and emergence. DOI:10.2458/azu_jrm_v56i3_parera","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89009593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-05-01DOI: 10.2458/AZU_JRM_V56I3_OSEI
E. Osei, P. Gassman, L. Hauck, S. Neitsch, R. Jones, Jan Mcnitt, Heather E. Jones
Highly intensive stocking of dairy cattle on continuously grazed pasture coupled with liberal applications of commercial fertilizer can lead to increased losses of agricultural nutrients, which is a concern for water quality of receiving lakes and surface water resources. Integrated economic-environmental model simulations performed for the Lake Fork Reservoir Watershed in northeast Texas indicate that appropriate pasture nutrient management including stocking density adjustments and more efficient commercial fertilizer use could lead to significant reductions in nutrient losses. Soluble and organic P losses were predicted to decline by 54 and 13% relative to baseline conditions when manure P was assumed totally plant available (Low P scenario). The soluble and organic P loss reductions declined to 33 and 7% when only inorganic P was assumed plant available (High P scenario). Simulation of an N-based manure management plan resulted in the smallest predicted soluble and organic P loss reductions of 18 and 3%. Nitrogen loss predictions ranged from a 7% decline to a 1% increase for the 3 scenarios as compared to the baseline. The High P and Low P scenarios resulted in estimated aggregate profit reductions of 6 and 18% relative to the baseline. These profit declines occurred because the dairies had to acquire additional pasture land to accommodate the expanded area required for the P-based scenarios. In contrast, the N-based stocking density and nutrient management scenario resulted in an aggregate profit increase of 3% across all dairies. Variations in economic impacts were also predicted across farm sizes. DOI:10.2458/azu_jrm_v56i3_osei
{"title":"Economic and environmental impacts of pasture nutrient management","authors":"E. Osei, P. Gassman, L. Hauck, S. Neitsch, R. Jones, Jan Mcnitt, Heather E. Jones","doi":"10.2458/AZU_JRM_V56I3_OSEI","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I3_OSEI","url":null,"abstract":"Highly intensive stocking of dairy cattle on continuously grazed pasture coupled with liberal applications of commercial fertilizer can lead to increased losses of agricultural nutrients, which is a concern for water quality of receiving lakes and surface water resources. Integrated economic-environmental model simulations performed for the Lake Fork Reservoir Watershed in northeast Texas indicate that appropriate pasture nutrient management including stocking density adjustments and more efficient commercial fertilizer use could lead to significant reductions in nutrient losses. Soluble and organic P losses were predicted to decline by 54 and 13% relative to baseline conditions when manure P was assumed totally plant available (Low P scenario). The soluble and organic P loss reductions declined to 33 and 7% when only inorganic P was assumed plant available (High P scenario). Simulation of an N-based manure management plan resulted in the smallest predicted soluble and organic P loss reductions of 18 and 3%. Nitrogen loss predictions ranged from a 7% decline to a 1% increase for the 3 scenarios as compared to the baseline. The High P and Low P scenarios resulted in estimated aggregate profit reductions of 6 and 18% relative to the baseline. These profit declines occurred because the dairies had to acquire additional pasture land to accommodate the expanded area required for the P-based scenarios. In contrast, the N-based stocking density and nutrient management scenario resulted in an aggregate profit increase of 3% across all dairies. Variations in economic impacts were also predicted across farm sizes. DOI:10.2458/azu_jrm_v56i3_osei","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87620344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-05-01DOI: 10.2458/AZU_JRM_V56I3_PICONE
L. Picone, G. Quaglia, F. García, P. Laterra
Changes in soil nutrient pools and microbial activity due to fire are important for understanding the availability of nutrients to plants. The objective of this study was to evaluate the effect of fire: 1) on size and seasonal dynamics of labile pools of C and N in a short-term after burning; and II) on chemical properties and microbial diversity immediately after fire, in a grassland with Paspalum quadrifarium Lam. Microbial biomass C and N tended to be higher in the burned (433 mg C kg-1 and 37 mg N kg-1) than in the unburned treatment (386 mg C kg-1 and 26 mg N kg-1). Both microbial biomass, decreased at the beginning of the growing season and then recovered at the end of the season. Levels of mineralizable C and N were similar in both treatments; however they showed different patterns of seasonal transformations. At initiation of plant growth, concentration of mineralizable C decreased while amount of mineralizable N increased; but the opposite occurred at the end of the growing season. Increases in microbial biomass coincided with low levels of mineralizable N and high concentrations of mineralizable C, suggesting a higher immobilization at the end of the season. Immediately after burning, organic C and N decreased by 11 and 7%, respectively. Mineral N was almost double, available P increased by 10 mg kg-1; but exchangeable bases, bacterial and actinomycetes population, and urease activity were not affected by burning. Fire can induce immediate changes to the soil; however, long-term studies will be required to evaluate the duration of the effect of fire on soil biological processes and nutrient transformations. DOI:10.2458/azu_jrm_v56i3_picone
火灾引起的土壤养分库和微生物活动的变化对了解植物的养分有效性具有重要意义。本研究的目的是评价火灾对燃烧后短期内碳、氮不稳定库的大小和季节动态的影响;(2)火后草地的化学性质和微生物多样性。燃烧处理的微生物生物量C和N (433 mg C kg-1和37 mg N kg-1)往往高于未燃烧处理(386 mg C kg-1和26 mg N kg-1)。两种微生物的生物量均在生长季开始时下降，在生长季结束时恢复。两种处理的可矿化C和N水平相似;然而，它们表现出不同的季节变化模式。在植物生长初期，可矿化碳浓度降低，可矿化氮量增加;但在生长季节结束时，情况正好相反。微生物生物量的增加与可矿化氮的低水平和可矿化碳的高浓度相一致，表明在季节结束时固定化程度较高。燃烧后，有机碳和氮分别下降11%和7%。矿质氮几乎翻倍，速效磷增加10 mg kg-1;但交换碱基、细菌和放线菌数量以及脲酶活性不受燃烧的影响。火能立即引起土壤的变化;但是，还需要进行长期研究，以评估火对土壤生物过程和养分转化影响的持续时间。DOI: 10.2458 / azu_jrm_v56i3_picone
{"title":"Biological and chemical response of a grassland soil to burning.","authors":"L. Picone, G. Quaglia, F. García, P. Laterra","doi":"10.2458/AZU_JRM_V56I3_PICONE","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I3_PICONE","url":null,"abstract":"Changes in soil nutrient pools and microbial activity due to fire are important for understanding the availability of nutrients to plants. The objective of this study was to evaluate the effect of fire: 1) on size and seasonal dynamics of labile pools of C and N in a short-term after burning; and II) on chemical properties and microbial diversity immediately after fire, in a grassland with Paspalum quadrifarium Lam. Microbial biomass C and N tended to be higher in the burned (433 mg C kg-1 and 37 mg N kg-1) than in the unburned treatment (386 mg C kg-1 and 26 mg N kg-1). Both microbial biomass, decreased at the beginning of the growing season and then recovered at the end of the season. Levels of mineralizable C and N were similar in both treatments; however they showed different patterns of seasonal transformations. At initiation of plant growth, concentration of mineralizable C decreased while amount of mineralizable N increased; but the opposite occurred at the end of the growing season. Increases in microbial biomass coincided with low levels of mineralizable N and high concentrations of mineralizable C, suggesting a higher immobilization at the end of the season. Immediately after burning, organic C and N decreased by 11 and 7%, respectively. Mineral N was almost double, available P increased by 10 mg kg-1; but exchangeable bases, bacterial and actinomycetes population, and urease activity were not affected by burning. Fire can induce immediate changes to the soil; however, long-term studies will be required to evaluate the duration of the effect of fire on soil biological processes and nutrient transformations. DOI:10.2458/azu_jrm_v56i3_picone","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81312252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-05-01DOI: 10.2458/AZU_JRM_V56I3_MAJAK
W. Majak, L. Stroesser, Timothy J. Lysyk, J. Hall
Timber milkvetch (TMV, Astragalus miser Dougl. ex Hook var. serotinus) is widely distributed on rangelands in the southern interior of British Columbia, Canada. It synthesizes large quantities of miserotoxin, a glycoside that is toxic to cattle. Six grazing studies were conducted at Sixtyone Creek on the Cariboo Plateau during 1993 to 2000 to determine which class of livestock was most susceptible to TMV, to record clinical signs of poisoning under range conditions, and to determine the efficacy of protein supplements for the prevention of TMV poisoning. In vitro rates of TMV detoxification in rumen fluid were determined concurrently. Incidents of early, acute and chronic poisoning were documented using a total of 143 cows over the 6 year study. Older cows (more than 3-years old) and yearling heifers were less susceptible to TMV than lactating first-calf heifers, which showed acute signs of poisoning. A chronic syndrome was sometimes seen in second-calf heifers, especially during exertion. Heifers not previously exposed to TMV, such as those that were obtained from the prairie region of Alberta, were also more susceptible than cattle originating in B.C. with a known history of exposure to TMV. Each year, Hereford cows were divided into 2 groups, one of which received free-choice protein supplements in a molasses block, the other did not receive supplement and served as a control group during the 6-week grazing trial. The control group yielded 25 cases of TMV poisoning during the 6-year study, compared with 2 for the supplement group. However, the supplement increased rates of TMV detoxification (> 50%) in only 1 of the 5 years of testing. Native cattle yielded higher rates of TMV detoxification (> 25%) in 2 of the 5 years than introduced cattle. The innate capacity to transfer rumen microbial activity between cattle in close proximity and the natural enrichment of rumen microbial populations could elevate rates of detoxification regardless of supplement or origin. DOI:10.2458/azu_jrm_v56i3_majak
云雀(TMV)，黄芪。原钩虱(Hook var. sertinus)广泛分布于加拿大不列颠哥伦比亚省南部内陆的牧场。它合成了大量的米瑟罗毒素，一种对牛有毒的糖苷。1993年至2000年期间，在Cariboo高原的61 Creek进行了六项放牧研究，以确定哪一类牲畜最容易感染TMV，记录牧场条件下中毒的临床症状，并确定蛋白质补充剂对预防TMV中毒的功效。同时测定瘤胃液中TMV的体外解毒率。在为期6年的研究中，共记录了143头奶牛的早期、急性和慢性中毒事件。年龄较大的奶牛(3岁以上)和一岁的小母牛比哺乳期的小牛更不容易感染TMV，后者表现出急性中毒症状。第二胎小母牛有时会出现慢性综合症，尤其是在用力时。以前没有接触过颞叶病毒的小母牛，例如那些从阿尔伯塔草原地区获得的小母牛，也比原产于不列颠哥伦比亚省的有已知接触过颞叶病毒历史的牛更容易感染。每年将赫里福德奶牛分为2组，在为期6周的放牧试验中，一组在糖蜜块中自由选择补充蛋白质，另一组不补充蛋白质，作为对照组。在6年的研究中，对照组发生了25例TMV中毒，而补充组只有2例。然而，在5年的测试中，这种补充剂只增加了1年的TMV排毒率(50%)。本地牛在5年中有2年的TMV解毒率比引进牛高(约25%)。在邻近的牛之间转移瘤胃微生物活性的先天能力和瘤胃微生物种群的自然富集可以提高解毒率，无论补充或来源如何。DOI: 10.2458 / azu_jrm_v56i3_majak
{"title":"Toxicity and development of tolerance in cattle to timber milkvetch","authors":"W. Majak, L. Stroesser, Timothy J. Lysyk, J. Hall","doi":"10.2458/AZU_JRM_V56I3_MAJAK","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I3_MAJAK","url":null,"abstract":"Timber milkvetch (TMV, Astragalus miser Dougl. ex Hook var. serotinus) is widely distributed on rangelands in the southern interior of British Columbia, Canada. It synthesizes large quantities of miserotoxin, a glycoside that is toxic to cattle. Six grazing studies were conducted at Sixtyone Creek on the Cariboo Plateau during 1993 to 2000 to determine which class of livestock was most susceptible to TMV, to record clinical signs of poisoning under range conditions, and to determine the efficacy of protein supplements for the prevention of TMV poisoning. In vitro rates of TMV detoxification in rumen fluid were determined concurrently. Incidents of early, acute and chronic poisoning were documented using a total of 143 cows over the 6 year study. Older cows (more than 3-years old) and yearling heifers were less susceptible to TMV than lactating first-calf heifers, which showed acute signs of poisoning. A chronic syndrome was sometimes seen in second-calf heifers, especially during exertion. Heifers not previously exposed to TMV, such as those that were obtained from the prairie region of Alberta, were also more susceptible than cattle originating in B.C. with a known history of exposure to TMV. Each year, Hereford cows were divided into 2 groups, one of which received free-choice protein supplements in a molasses block, the other did not receive supplement and served as a control group during the 6-week grazing trial. The control group yielded 25 cases of TMV poisoning during the 6-year study, compared with 2 for the supplement group. However, the supplement increased rates of TMV detoxification (> 50%) in only 1 of the 5 years of testing. Native cattle yielded higher rates of TMV detoxification (> 25%) in 2 of the 5 years than introduced cattle. The innate capacity to transfer rumen microbial activity between cattle in close proximity and the natural enrichment of rumen microbial populations could elevate rates of detoxification regardless of supplement or origin. DOI:10.2458/azu_jrm_v56i3_majak","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76865393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many alfalfa (Medicago spp.) cultivars have limited ability to persist under grazing and therefore, a key step in incorporating alfalfa into pastures and rangelands is choosing a grazing tolerant cultivar. In this study, we evaluated the grazing tolerance of 16 alfalfa populations representing a range of potential grazing tolerance. Entries were transplanted on a rangeland site in July 1996 at the Northern Great Plains Research Lab in Mandan, N.D., USA and mob-grazed by cattle from 1997 to 2000. Plant survival, basal area, and stem numbers were recorded in the spring and fall of each year. At the final survival evaluation in May 2001, SCMF 3713 had the highest survival (90%), 'Vernal' had the lowest (23%) and 10 of the 16 entries had greater than 50% survival. A large decline in survival between September 2000 and May 2001 may be attributed to low temperatures in November and December of 2000. Entries such as 'Alfagraze', B-36 and Agripro ZG9415, which were developed in warmer climates, had the largest percentage drop in survival (43.0, 48.6, and 48.6 percentage points respectively) while SCMF 3713, 'Anik' and Alaska Syn A, developed in colder climates, had the least percentage point drops (2.8, 4.1, and 4.1 respectively). The ability to survive over winter contributed more to the different survival rates of these alfalfa populations than did any of the measured plant variables. Producers should know the origins of grazing tolerant alfalfa cultivars and consider selecting cultivars that have been tested in their area.
许多苜蓿(Medicago spp)品种在放牧条件下的生存能力有限，因此，将苜蓿纳入牧场和牧场的关键步骤是选择耐放牧的品种。在这项研究中，我们评估了16个苜蓿群体的放牧耐受性，代表了潜在的放牧耐受性范围。1996年7月，在美国北达科他州曼丹的北部大平原研究实验室的一个牧场上移植了这些标本，1997年至2000年期间，它们被牛放牧。在每年的春季和秋季分别记录植株存活率、基面积和茎数。在2001年5月的最终生存评估中，SCMF 3713的生存率最高(90%)，‘Vernal’的生存率最低(23%)，16个条目中有10个的生存率大于50%。2000年9月至2001年5月期间的存活率大幅下降可能是由于2000年11月和12月的低温所致。在温暖气候下开发的“Alfagraze”、B-36和Agripro ZG9415等品种的存活率下降幅度最大(分别为43.0、48.6和48.6个百分点)，而在寒冷气候下开发的SCMF 3713、“Anik”和Alaska Syn A的存活率下降幅度最小(分别为2.8、4.1和4.1)。在这些紫花苜蓿种群中，过冬的能力比任何测量到的植物变量对不同存活率的贡献都更大。生产者应该了解耐放牧苜蓿品种的来源，并考虑选择在其所在地区经过测试的品种。
{"title":"Survival of 16 alfalfa populations space planted into a grassland.","authors":"J. Hendrickson, J. Berdahl","doi":"10.2307/4003816","DOIUrl":"https://doi.org/10.2307/4003816","url":null,"abstract":"Many alfalfa (Medicago spp.) cultivars have limited ability to persist under grazing and therefore, a key step in incorporating alfalfa into pastures and rangelands is choosing a grazing tolerant cultivar. In this study, we evaluated the grazing tolerance of 16 alfalfa populations representing a range of potential grazing tolerance. Entries were transplanted on a rangeland site in July 1996 at the Northern Great Plains Research Lab in Mandan, N.D., USA and mob-grazed by cattle from 1997 to 2000. Plant survival, basal area, and stem numbers were recorded in the spring and fall of each year. At the final survival evaluation in May 2001, SCMF 3713 had the highest survival (90%), 'Vernal' had the lowest (23%) and 10 of the 16 entries had greater than 50% survival. A large decline in survival between September 2000 and May 2001 may be attributed to low temperatures in November and December of 2000. Entries such as 'Alfagraze', B-36 and Agripro ZG9415, which were developed in warmer climates, had the largest percentage drop in survival (43.0, 48.6, and 48.6 percentage points respectively) while SCMF 3713, 'Anik' and Alaska Syn A, developed in colder climates, had the least percentage point drops (2.8, 4.1, and 4.1 respectively). The ability to survive over winter contributed more to the different survival rates of these alfalfa populations than did any of the measured plant variables. Producers should know the origins of grazing tolerant alfalfa cultivars and consider selecting cultivars that have been tested in their area.","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76410901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-05-01DOI: 10.2458/AZU_JRM_V56I3_SHORT
J. Short, J. E. Knight
Prescribed cattle grazing is often used to purposely enhance wildlife habitat. This study investigated the effects of fall cattle (Bos taurus) grazing intensity on elk (Cervus elaphus) and deer (Odocoileus spp.) forage in the following spring and summer. These effects were examined on rough fescue (Festuca scabrella Torr.) range on the Blackfoot Clearwater Wildlife Management Area in west central Montana. Cattle were grazed in enclosures during the fall of 1997 and 1998. A randomized complete block design with 5 replications of enclosures per year was used. Grazing levels were 0% removal (control), 50% removal, 70% removal, and 90% removal of herbaceous standing crop. To evaluate elk and deer forage, measurements were obtained in spring and summer on green grass standing crop, green forb standing crop, percent green vegetation, species richness, and plant species composition. There were no differences among grazing levels for plant species composition based on canopy coverage, species richness, and green forb standing crop variables ( P > 0.10). The 50% and 90% treatments reduced green standing crop in spring (P = 0.07) but not in summer (P > 0.10). Grazing treatments increased percent green vegetation (P < 0.01). Fall cattle grazing can be used as a wildlife habitat improvement tool to reduce unpalatable standing dead material. The 70% removal treatment was the most favorable for habitat improvement without degrading the range. DOI:10.2458/azu_jrm_v56i3_short
{"title":"Fall grazing affects big game forage on rough fescue grasslands.","authors":"J. Short, J. E. Knight","doi":"10.2458/AZU_JRM_V56I3_SHORT","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I3_SHORT","url":null,"abstract":"Prescribed cattle grazing is often used to purposely enhance wildlife habitat. This study investigated the effects of fall cattle (Bos taurus) grazing intensity on elk (Cervus elaphus) and deer (Odocoileus spp.) forage in the following spring and summer. These effects were examined on rough fescue (Festuca scabrella Torr.) range on the Blackfoot Clearwater Wildlife Management Area in west central Montana. Cattle were grazed in enclosures during the fall of 1997 and 1998. A randomized complete block design with 5 replications of enclosures per year was used. Grazing levels were 0% removal (control), 50% removal, 70% removal, and 90% removal of herbaceous standing crop. To evaluate elk and deer forage, measurements were obtained in spring and summer on green grass standing crop, green forb standing crop, percent green vegetation, species richness, and plant species composition. There were no differences among grazing levels for plant species composition based on canopy coverage, species richness, and green forb standing crop variables ( P > 0.10). The 50% and 90% treatments reduced green standing crop in spring (P = 0.07) but not in summer (P > 0.10). Grazing treatments increased percent green vegetation (P < 0.01). Fall cattle grazing can be used as a wildlife habitat improvement tool to reduce unpalatable standing dead material. The 70% removal treatment was the most favorable for habitat improvement without degrading the range. DOI:10.2458/azu_jrm_v56i3_short","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77179708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bottlebrush squirreltail [Elymus elymoides (Raf.) Swezey] and big squirreltail [E. multisetus (J. G. Smith) Burtt Davy] are short-lived perennial bunchgrasses found on rangelands from the Pacific Coast to the Great Plains and from Canada to Mexico. They are highly variable species with several subspecies described for bottlebrush squirreltail. In many rangeland communities, bottlebrush squirreltail is the transitional dominant native grass in secondary successional communities. There is considerable interest in using squirreltail species in rangeland restoration seedings, but problems with seed collection (disarticulating rachis) have kept seed prices very high. Recently, grass geneticists have begun to develop lines of squirreltail for release as pre-varietal germplasm. Our purpose was to compare the germination at a wide range of constant or alternating temperatures of squirreltail seeds from developmental lines and material collected from native stands. Big and bottlebrush squirreltail seeds (caryopses) germinated over a wide range of temperatures. Seeds of bottlebrush squirreltail produced from the same stand in 3 different years had remarkably similar germination temperature profiles. The greatest variation in germination among accessions occurred at very cold and cold categories of seedbed temperatures. These differences may be very significant in the establishment of seedlings in the field. There was no one temperature regime that always supported optimum germination for all of the squirreltail accessions tested. The regimes most frequently supporting optimum germination were 15/20 and 15/25 C. The seeds of big and bottlebrush squirreltail tested do not have the ecological amplitude of seeds of the competitive exotic weed cheatgrass (Bromus tectorum L.), but they come close. DOI:10.2458/azu_jrm_v56i3_young2
{"title":"Germination of seeds of big and bottlebrush squirreltail","authors":"James A. Young, C. Clements, T. Jones","doi":"10.2307/4003819","DOIUrl":"https://doi.org/10.2307/4003819","url":null,"abstract":"Bottlebrush squirreltail [Elymus elymoides (Raf.) Swezey] and big squirreltail [E. multisetus (J. G. Smith) Burtt Davy] are short-lived perennial bunchgrasses found on rangelands from the Pacific Coast to the Great Plains and from Canada to Mexico. They are highly variable species with several subspecies described for bottlebrush squirreltail. In many rangeland communities, bottlebrush squirreltail is the transitional dominant native grass in secondary successional communities. There is considerable interest in using squirreltail species in rangeland restoration seedings, but problems with seed collection (disarticulating rachis) have kept seed prices very high. Recently, grass geneticists have begun to develop lines of squirreltail for release as pre-varietal germplasm. Our purpose was to compare the germination at a wide range of constant or alternating temperatures of squirreltail seeds from developmental lines and material collected from native stands. Big and bottlebrush squirreltail seeds (caryopses) germinated over a wide range of temperatures. Seeds of bottlebrush squirreltail produced from the same stand in 3 different years had remarkably similar germination temperature profiles. The greatest variation in germination among accessions occurred at very cold and cold categories of seedbed temperatures. These differences may be very significant in the establishment of seedlings in the field. There was no one temperature regime that always supported optimum germination for all of the squirreltail accessions tested. The regimes most frequently supporting optimum germination were 15/20 and 15/25 C. The seeds of big and bottlebrush squirreltail tested do not have the ecological amplitude of seeds of the competitive exotic weed cheatgrass (Bromus tectorum L.), but they come close. DOI:10.2458/azu_jrm_v56i3_young2","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79289083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-03-01DOI: 10.2458/AZU_JRM_V56I2_BESTELMEYER
B. Bestelmeyer, Joel R. Brown, K. Havstad, R. Alexander, G. Chavez, J. Herrick
State-and-transition models have received a great deal of attention since the introduction of the concept to range management in 1989. Nonetheless, only recently have sets of state-and-transition models been produced thatcan be used by agency personnel and private citizens, and there is little guidance available for developing and interpreting models. Based upon our experiences developing models for the state of New Mexico, we address the following questions: 1) how is information assembled to create site-specific models for entire regions, 2) what ecological issues should be considered in model development and classification, and 3) how should models be used? We review the general structure of state-and-transition models, emphasizing the distinction between changes among communities within states (pathways) that are reversible with changes in climate and "facilitating practices" (e.g. grazing management), and changes among states (transitions) that are reversible only with "accelerating practices" such as seeding, shrub control, or the recovery of soil stability and historical hydrologic function. Both pathways and transitions occur, so these models are complementary. Ecological sites and the climatically-defined regions within which they occur (land resource units) serve as a framework for developing and selecting models. We illustrate the importance of clearly delineating ecological sites to produce models and describe how we have dealt with poorly-delineated sites. Producing specific models requires an understanding of the multiple ecological mechanisms underlying transitions. We show how models can represent and distinguish alternative and complementary hypotheses for transitions. Although there may be several mechanisms underlying transitions, they tend to fall within discrete categories based upon a few, fundamental ecological processes and their relation-ships can be readily understood. A knowledge of mechanisms is closely related to the use of ecological indicators to anticipate transitions. We conclude that models should include 1) reference values for quantitative indicators, 2) lists of key indicators and descriptions of changes in them that suggest an approach to a transition, and 3) a rigorous documentation of the theory and assumptions (and their alternatives) underlying the structure of each model.
{"title":"Development and use of state-and-transition models for rangelands.","authors":"B. Bestelmeyer, Joel R. Brown, K. Havstad, R. Alexander, G. Chavez, J. Herrick","doi":"10.2458/AZU_JRM_V56I2_BESTELMEYER","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I2_BESTELMEYER","url":null,"abstract":"State-and-transition models have received a great deal of attention since the introduction of the concept to range management in 1989. Nonetheless, only recently have sets of state-and-transition models been produced thatcan be used by agency personnel and private citizens, and there is little guidance available for developing and interpreting models. Based upon our experiences developing models for the state of New Mexico, we address the following questions: 1) how is information assembled to create site-specific models for entire regions, 2) what ecological issues should be considered in model development and classification, and 3) how should models be used? We review the general structure of state-and-transition models, emphasizing the distinction between changes among communities within states (pathways) that are reversible with changes in climate and \"facilitating practices\" (e.g. grazing management), and changes among states (transitions) that are reversible only with \"accelerating practices\" such as seeding, shrub control, or the recovery of soil stability and historical hydrologic function. Both pathways and transitions occur, so these models are complementary. Ecological sites and the climatically-defined regions within which they occur (land resource units) serve as a framework for developing and selecting models. We illustrate the importance of clearly delineating ecological sites to produce models and describe how we have dealt with poorly-delineated sites. Producing specific models requires an understanding of the multiple ecological mechanisms underlying transitions. We show how models can represent and distinguish alternative and complementary hypotheses for transitions. Although there may be several mechanisms underlying transitions, they tend to fall within discrete categories based upon a few, fundamental ecological processes and their relation-ships can be readily understood. A knowledge of mechanisms is closely related to the use of ecological indicators to anticipate transitions. We conclude that models should include 1) reference values for quantitative indicators, 2) lists of key indicators and descriptions of changes in them that suggest an approach to a transition, and 3) a rigorous documentation of the theory and assumptions (and their alternatives) underlying the structure of each model.","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84339849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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