Long-Term Production and Profitability From Grazing Cattle in the Northern Mixed Grass Prairie

Conventional wisdom among rangeland professionals has been that for long-term sustainability of grazing livestock operations, rangeland should be kept in high good to low excellent range condition. Our objective was to analyze production parameters, costs, returns, and profit using data generated over a 34-yr period (1969–2002) from grazing a Clayey range site in the mixed-grass prairie of western South Dakota with variable stocking rates to maintain pastures in low–fair, good, and excellent range condition classes. Cattle weights were measured at turnout and at the end of the grazing season. Gross income · ha^?1 was the product of gain · ha^?1 and price. Prices were based on historical National Agricultural Statistics Services feeder cattle prices. Annual variable costs were estimated using a yearling cattle budget developed by South Dakota State University agricultural economists. All economic values were adjusted to a constant dollar using the Bureau of Labor Statistics' Consumer Price Index. Stocking rate, average daily gain, total gain, net profit, gross revenue, and annual costs · ha^?1 varied among range condition classes. Net income for low–fair range condition ($27.61 · ha^?1) and good range condition ($29.43 · ha^?1) were not different, but both were greater than excellent range condition ($23.01 · ha^?1). Over the life of the study, real profit (adjusted for inflation) steadily increased for the low–fair and good treatments, whereas it remained level for the excellent treatment. Neither drought nor wet springs impacted profit differently for the three treatments. These results support generally observed rancher behavior regarding range condition: to maintain their rangeland in lower range condition than would be recommended by rangeland professionals. Ecosystem goods and services of increasing interest to society and associated with high range condition, such as floristic diversity, hydrologic function, and some species of wildlife, come at an opportunity cost to the rancher.     

Livestock Forage Conditioning Among Six Northern Great Basin Grasses

Studies of Anderson and Scherzinger's forage conditioning hypothesis have generated varied results. Our objectives were: 1) to evaluate late summer/early fall forage quality of crested wheatgrass (Agropyron desertorum [Fisch. ex Link] J. A. Schultes), bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Löve), Idaho fescue (Festuca idahoensis Elmer), bottlebrush squirreltail (Elymus elymoides [Raf.] Swezey), Thurber's needlegrass (Achnatherum thurberianum [Piper] Barkworth), and basin wildrye (Leymus cinereus [Scribn. & Merr.] A. Löve) from ungrazed paddocks and paddocks grazed at vegetative, boot, and anthesis; and 2) test hypotheses that postgrazing regrowth yields were correlated with soil moisture content when grazing occurred. Crop–year precipitation for 1997 and 1998 was 134% and 205% of average. Crude protein (CP) and in vitro dry matter digestibility (IVDMD) of ungrazed grasses displayed expected declines in quality. Among ungrazed grasses, late summer/early fall CP was 5.7% in 1997 and 3.6% in 1998; IVDMD was 47% and 41%, respectively. Late summer/early fall forage quality was elevated by vegetative, boot stage, or anthesis grazing. The phenologically youngest regrowth always ranked highest in CP and IVDMD. Among grasses, respective 1997 CP and IVDMD means were 9.0% and 55% for regrowth following anthesis grazing. No regrowth followed anthesis grazing in 1998, but CP and IVDMD means from boot stage treatments were 5.5% and 47%, respectively. With CP measures, a species by treatment interaction occurred in 1997, but species reacted similarly in 1998. Vegetative, boot stage, and anthesis grazing in 1997 caused respective late summer/early fall standing crop reductions of 34%, 42%, and 58%; and 34%, 54%, and 100% reductions in 1998. Forage conditioning responses were lower for bluebunch wheatgrass and crested wheatgrass than other grasses. Soil moisture content was a poor predictor of regrowth yields. Managed cattle grazing can successfully enhance late season forage quality.     

沿海滩涂地区不同栽培措施对禾本科牧草产量及品质的影响

为探讨沿海滩涂地区牧草高产栽培技术,以4种禾本科牧草为材料,研究了3种不同的栽培措施对不同饲草品种的饲草产量和品质的影响。结果表明: 覆秸秆与添加保水剂处理饲草的产量和叶/茎比显著高于对照(P<0.05)。同一品种,覆秸秆处理饲草的可溶性碳水化合物(WSC)、粗蛋白(CP)、干物质体外消化率(IVDMD)和体外可消化干物质产量最高,粗灰分(Ash)、酸性洗涤纤维(ADF)和中性洗涤纤维(NDF)含量最低,品质最好,其次是添加保水剂处理,对照最差。不同品种之间的饲草产量和品质差异显著(P<0.05),其中青贮玉米(Zea mays L.)和高丹草(Sorghum bicolor×Sorghum sudanese)表现较好。在沿海滩涂地区,覆秸秆和添加保水剂处理可以显著提高饲草产量,改善饲草品质,但不同品种之间产量和品质差异较大。     

Evaluation of Native and Introduced Grasses for Reclamation and Production

Crested wheatgrass (Agropyron cristatum [L.] Gaertn.) and Russian wildrye (Elymus junceus Fisch.) are commonly used for reseeding in the more xeric Mixed Prairie of the Canadian prairies because they are perceived to be more productive than native species. However, they have been implicated in soil deterioration. The objectives of our study were to compare the aboveground net primary production and soil organic carbon (C) among monoculture communities of selected native grass species, crested wheatgrass, and Russian wildrye and to compare the native grass monocultures with their mixtures. In 1995, a 5-year study was initiated on Dark Brown Chernozemic (Typic Haploboroll) soil near Lethbridge, Alberta. Ten treatments consisting of monocultures of introduced and selected native species and mixtures of native species were established in a randomized complete block design with 4 replications. Aboveground net primary production and soil organic C were measured. Monocultures of 2 native species, green needlegrass (Stipa viridula Trin.) and blue grama (Bouteloua gracilis [H.B.K.] Lag. ex Steud.), were more productive than crested wheatgrass or Russian wildrye under both normal moisture and drought conditions. Monocultures of these native species also tended to be more productive than their mixtures. The western wheatgrass (A. smithii Rydb.) monoculture and the western wheatgrass–blue grama mixture experienced the greatest yield reduction as a result of drought. Treatment effects on soil organic C were not detected (P > 0.05) 5 years after seeding. Soils of the June grass (Koeleria macrantha [Ledeb.] J.A. Schultes f.) community had less (P < 0.05) macro-organic C than most other treatments.     

罗顿豆与3种多年生禾本科牧草的混播

在湘南红壤丘陵区以南非马唐(Digitaria smutsii)、索兰德狗尾草(Sorander bristlegrass)、扁穗牛鞭草(Hemarthria compressa)分别与罗顿豆(Lotononis bainesii)进行混播试验,以探明其最佳混播组合及其混播比率与混播方式。结果表明:本试验中,隔1行罗顿豆种2行南非马唐处理和隔2行罗顿豆种1行南非马唐处理是产草总量潜力较高的栽种模式,散栽50%罗顿豆和撒播50%索兰德狗尾草处理是粗蛋白产量潜力最高的栽种模式;罗顿豆与3种多年生禾本科牧草混播,相同处理下不同禾本科牧草总产量和粗蛋白产量差异明显,当罗顿豆和禾本科牧草用量各为正常用量的50%时,同一禾本科牧草条播与撒播处理对产草总量无显著影响;与禾本科牧草单播相比,次年相应混播处理均能提高牧草总产量和粗蛋白产量。     

不同牧草对五龙鹅生产性能和消化器官发育的影响

为了探讨日粮中不同牧草对五龙鹅生产性能的影响,选取3周龄健康、体重均一的五龙鹅仔鹅150只,随机分为5组,每组3个重复,每个重复10只鹅.5个组分别为对照组、籽粒苋组、苜蓿草组、皇竹草组、苦荬菜组,进行6周饲养试验后在8周龄末屠宰.试验结果表明:不同牧草日粮对五龙鹅的生产性能有一定的影响,苜蓿草组和苦荬菜组的平均日增重高于其他组(P＞0.05),苜蓿草组、籽粒苋组的饲料转化率显著优于苦荬菜(P＜0.05).屠宰试验表明:各组8周龄末屠宰性能的各项指标之间差异不显著(P＞0.05),但是苜蓿草组和籽粒苋组的屠宰性能指标有高于其他牧草组的趋势.不同牧草对五龙鹅的肌胃重有显著的影响(P＜0.05).综合分析得出,3～8周龄五龙鹅饲喂添加苜蓿草和籽粒苋的日粮有利于生产性能的发挥.     

甘肃马先蒿对五种禾草的化感潜力研究

为了探讨甘肃马先蒿（Pedicularis kansuensis）不同浸提液处理对几种禾草化感潜力的差异,本研究采用室内生物测定法,研究了甘肃马先蒿植株浸提液和粉末浸提液以及根区土壤浸提液对5种禾草种子发芽和幼苗生长的影响,旨在揭示甘肃马先蒿对人工草地退化的潜在作用,为退化高寒草甸恢复和人工草地的建植提供理论依据。结果表明：甘肃马先蒿不同浸提液处理对5种牧草种子萌发和幼苗生长均有不同的化感效应,总体而言,粉末浸提液对5种禾草的抑制作用比整株浸提液的抑制作用大。甘肃马先蒿整株浸提液和粉末浸提液对5种禾草种子发芽和幼苗生长的化感综合效应表现为：对青海中华羊茅（Festuca sinensis ‘Qinghai’）的化感潜力最大,对同德老芒麦（Elymus sibiricus ‘Tongde’）最弱,而根区土壤浸提液对同德老芒麦的化感潜力最大,对垂穗披碱草（Elymus nutans）最弱,对其它3种的作用介于两者之间。     

Seasonal Timing of Fire Alters Biomass and Species Composition of Northern Mixed Prairie

Fire plays a central role in influencing ecosystem patterns and processes. However, documentation of fire seasonality and plant community response is limited in semiarid grasslands. We evaluated aboveground biomass, cover, and frequency response to summer, fall, and spring fires and no fire on silty and clayey sites in semiarid, C₃-dominated grassland. The magnitude of change in biomass between years was greater than any differences among fire treatments. Still, differences existed among seasons of fire. Summer fire reduced non-native annual forb frequency (3% vs. 10% ± 2%) and Hesperostipa comata, reduced native annual forbs the first year, increased Poa secunda and bare ground, and increased Vulpia octoflora the second year. Fall fire increased grass biomass (1224 vs. 1058 ± 56 kg ? ha^? 1), but fall fire effects were generally similar to those of summer fire. Spring fire effects tended to be intermediate between no fire and summer and fall fire with the exception that spring fire was most detrimental to H. comata the first growing season and did not increase bare ground. All seasons of fire reduced litter, forb biomass, and frequency of Bromus japonicus and Artemisia spp., and they reduced H. comata, V. octoflora, and native annual forbs the first year, but increased basal cover of C₃ perennial grasses (2.2% vs. 0.6% ± 0.4%). Fire during any season increased dominance of native species compared with no fire (6.6% vs. 2.0% ± 1.0% basal cover) and maintained productivity. Seasonal timing of fire manipulated species composition, but increased C₃ perennial grass cover and native species dominance with fire during any season indicated that using fire was more important than the season in which it occurred. In addition, fire effects on the vegetation components tended to be counter to previously observed effects of grazing, suggesting fire and grazing may be complementary.     

三峡地区奶牛牧草引种栽培试验报告

由于政府的优惠政策和龙头企业的驱动,夷陵区奶牛发展速度较快,但也面临一系列问题,其中最突出的问题之一就是“草”,饲草资源不足,质量低劣,优质青绿饲草供应严重短缺,已成为制约奶牛产业发展,影响奶牛效益的主要因素。为此,我们根据“三峡奶业关键技术研究与产业化技术集成示范项目”牧草与饲料作物生产技术研究与产业化开发课题的要求,开展本项试验,通过试验,筛选适合夷陵区推广种植的“当家”草种。1试验内容与方法1.1试验地点试验区分别设在夷陵区小溪塔街办官庄村、龙泉镇水府庙村、鸦鹊岭镇龙潭村、雾度河镇普垭村,除普垭村为海拔300…     

贵州地方优良禾本科牧草抗病性初步研究

2004-2006年对发生在贵州地方优良禾本科牧草上的锈病、禾草云斑病和褐斑病进行田间调查,经统计分析和新复极差检验,结论是贵州地方草种对3种病害的抗性显著优于引进品种.     

不同基肥对弃荒地牧草产量和质量的影响

在贪瘠的弃荒地使用不同组合的基肥探讨对牧草产量和质量的影响。结果表明,在相同的肥水管理条件下,以“复合肥 牛粪 石灰”基肥组合(A处理),可使多花黑麦草(特高)、多年生黑麦草(保利)的年产草量分别比“猪粪 牛粪 石灰”的基肥组合(B处理)提高10.6%和29.2%,差异显著(p<0.05);粗蛋白质、粗脂肪、粗灰分分别有所提高;粗纤维、无氮浸出物有所降低。     

基于转录组测序的牧草分子标记开发研究进展

转录组测序是一种获得生物组织或细胞几乎所有转录本的高通量测序技术,测序所得的基因编码序列可用于研究植物在不同条件下的基因表达、调控方式及后续的功能基因发掘与遗传进化分析。随着分子标记技术的快速发展,转录组测序数据也可作为标记开发的重要来源,为牧草开展种质资源遗传多样性评价、遗传变异分析、居群结构研究和育种提供有效工具。本文综述了基于转录组测序的牧草分子标记如EST-SSR和SNP的开发及应用现状,以期为牧草分子标记开发提供重要参考。     

金华市适宜种植牧草的引种效果试验

随着金华市奶牛饲养量的不断增加和饲养水平的不断提高，奶牛养殖户越来越认识到青绿饲料的重要性。由于金华地区耕地较少等原因，优质牧草不论数量上还是品质上都落后于周边奶牛业发达地区，明显影响着金华奶牛饲养水平和牛奶的品质。为解决优质牧草短缺现象，笔者进行了部分牧草新品种的引种试验。     

贵州野生禾本科牧草引种驯化试验

在贵州省境内不同生态环境条件下采集的３２属８７种优良野（逸）生禾本科牧草，经种植观察，于１９９２～１９９６年对升圃的１９份材料在栽培条件下经过几代种子繁殖和人工选择，各个材料的开花期，种子成熟期等性状渐趋一致，并基本稳定。再生能力强，叶量增多。鲜草产量在３４ｔ／ｈａ～８７ｔ／ｈａ范围内。种子产量８５ｋｇ／ｈａ～２８１６ｋｇ／ｈａ。拔节期粗蛋白质含量８．８３％～１８．９３％。     

冰草属牧草硝酸还原酶的活性与其产量营养的关系

试验选择7种冰草属牧草为研究对象,测定硝酸还原酶的活力,并与大田栽培试验的同种牧草生产性能、营养成分测定结果进行分析,证明硝酸还原酶的活力作为生理指标之一可以正确的反应牧草品种的品质和产量,是一项筛选优良牧草品种的重要的生理指标,为禾草施氮提供了科学依据.     

高寒地区栽培牧草化感效应缓解初探

为研究探讨土壤微生物对化感效应的潜在作用,以高寒草地生态修复常用牧草为研究对象,通过室内生物学实验,测定种子发芽率及幼苗的苗高、根长和干重,计算分析化感综合效应。结果显示：以未灭菌土壤U100为基质的5种牧草种子发芽率均为最高,完全灭菌土壤U0的均为最低,不同比例未灭菌土壤U75,U50和U25则因牧草种子的不同而表现出不同差异;幼苗生长方面,‘青海’垂穗披碱草(Elymus nutans ‘Qinghai’)、‘同德’老芒麦(Elymus sibiricus ‘Tongde’)和‘青海’中华羊茅(Festuca sinensis Qinghai)幼苗苗高随灭菌土壤增加而减小;5种牧草幼苗的根长均在U100处理下最长;幼苗干重的变化趋势同苗高相似。未灭菌土壤对5种牧草的影响主要表现在根系生长和干重方面。研究证明在幼苗生长阶段土壤微生物对根系生长至关重要,土壤微生物能缓解化感效应提高种子发芽率,但对不同物种的影响存在差异。     

丛枝菌根对牧草与草地生态系统的重要作用及其研究展望

丛枝菌根是草地生态系统的重要组成部分,其对系统的重要作用日益引起人们的广泛关注.为促进相关研究,本文综述了丛枝菌对牧草养分吸收、抗逆性、生长发育以及对草地生态系统中牧草间竞争与共存、群落结构调节、提高草地生产力等的重要作用.针对我国当前相关的研究:即主要牧草进行菌根共生特性与菌根依赖性的调查研究、菌根对牧草竞争的影响研究、高效菌种筛选与接种应用技术的开发研究、对草地生态系统进行丛枝菌根综合效应的研究、菌根对牧草竞争的影响研究、草地管理与菌根效应相互关系的研究、丛枝菌根对退化草地植被恢复的作用研究、污染草地土壤菌根修复的研究、草地丛枝菌根资源库的建立等进行了展望.     

国外栽培牧草品种资源的引种研究

总结了１９８３年至１９９０年“中澳合作项目———云南省牲畜和草场改良项目”期间从国外引进的优良牧草１２５个种共计６８１个栽培品种分别在云南七个不同气候带条件下的引种试验。试验通过１２个指标的观测,筛选出优良的牧草种２３个共计５０个栽培品种,并对筛选出的优良品种的定性及定量指标作详细介绍,以利于生产推广。     

中美耐盐禾草建植和产量试验

对选自中国和美国的28份多年生耐盐禾草在内蒙古河套灌溉区盐渍荒地上进行的建植和产量试验结果表明,在表土含盐量为0.54%～0.72%、pH值为8.9～9.4的盐渍土中,引自美国的高薄冰草品种Tyrell、Jose、Largo、Alkar和中国的野大麦生长良好,建植率为57%～80%,干草产量为4700～6900kg/hm2;美国的阿尔泰赖草Prairieland、卡氏赖草Logon's、细披碱草Pryor、San Luis、西方牧冰草Rosana、Barton、Arriba、杂交偃麦草RS-Hoffman、RST-hybrid以及中国的羊草LECH2等品种/材料也可建植成功,并获得较高的牧草产量.