Effect of cutting frequency on the yield and quality of legumes and grasses under irrigation

Abstract

Four pasture legumes and seven grasses were subjected to a range of cutting frequencies during the 1980/81 season. A wide range of responses emerged, judged by both the dry matter and TDN yield responses of the different species. Whereas two cultivars of white clover and Ruanui ryegrass were most productive with frequent harvesting (every 2 to 4 weeks), kikuyu and Sirocco Phalaris responded well to a long interharvest interval (8 to 10 weeks). A number of pasture types, including lucerne, Currie cocksfoot, K31 fescue and Ariki ryegrass produced well at intermediate harvesting frequencies (6‐weekly) while in yet others (Kenland red clover and Seedmaster Phalaris) yield was not materially different over a wide range of cutting intervals in the range 6 to 10 weeks.     

Changes in blood composition of pregnant cows during the onset of hypomagnesaemia

Magnesium, calcium, phosphate, total protein and free fatty acid concentrations, and a lipase activity using p-nitrophenylpalmitate NP-C16) as a substrate, were determined in the serum of 15 pregnant Aberdeen Angus cows grazing a Phalaris tuberosa pasture with a tendency to induce tetany. A gradual decrease in magnesium concentrations, but no definite change in the other parameters, was observed when the results were plotted directly against the time of the experiment. When the results were plotted as a function of the stage of pregnancy or lactation of the animals, magnesium concentrations showed a more steady decrease which was associated with increases in calcium concentrations and, at the lowest magnesium concentrations, with increases in phosphate concentrations. Total proteins and free fatty acids remained fairly constant and the highest lipase activity was associated with parturition. The lowest magnesium concentrations in serum did not correspond with high levels of either lipase or free fatty acids. The hypomagnesaemia observed in this experiment was attributed to the high potassium:calcium and magnesium ratio in the pasture and to the physiological condition (pregnant and lactating) of the animals. None of the parameters evaluated in this paper would be more sensitive than serum magnesium levels for the early detection of the conditions that predispose grazing cattle to grass tetany.     

不同海拔区域威宁球茎草芦生长适应性研究

为明确威宁球茎草芦在贵州不同区域的生长适应性,2008—2011年以当地主栽培牧草法恩(Fawn)苇状羊茅以及宝兴鸭茅为对照,对威宁球茎草芦在不同海拔区域的生物学性状、生产性能、抗逆性等进行了为期3年的综合测定。结果表明:威宁球茎草芦较对照品种具有更高的生产性能和更强的适应性,鲜草产量显著高于对照法恩(Fawn)苇状羊茅与宝兴鸭茅,是贵州省四季均衡供草、建立永久性混播草地及治理石漠化的优良草种。     

镇江内江河漫滩草地植物群落演替过程中优势种间的竞争特性

在一定假设的基础上,通过对“替代试验法“公式的适当修正,来研究镇江内江河漫滩草地植被演替过程中的优势种群虉草和芦苇之间的竞争特性.结果发现:不同密度的混生状态下,二者均能利用不同的资源,表现出一定的共生关系,但二者之间竞争明显,虉草明显处于竞争劣势.在形态和生理表现上,处于劣势的虉草分枝数减少,高度增加,叶绿素含量和净光合速率降低.因此,在群落的演替过程中,芦苇种群必将替代虉草种群,成为演替下一阶段的优势种群.     

It is warm outside today: How temperature affects dairy cows’ willingness to be on pasture

The effect of Temperature Humidity Index (THI) on dairy cows’ willingness to be on pasture was examined. Information for 2 years regarding weather, milk production, and time for voluntarily passing a gate between the barn and pasture of cows milked with an automatic milking system was studied. When the THI exceeded 72 during the day, more cows spent time on pasture compared to when the THI was less than 72 (27.0% vs. 19.2% of cows on pasture, respectively). However, the time of day influenced the proportion of cows on pasture, and when the THI exceeded 72, more cows were on pasture at night and less during the afternoon compared to days when the THI was less than 72. In conclusion, even under Swedish conditions, THI might have an effect on cows’ behaviour. However, when the cows have free access to roughage and pasture, an increased THI does not affect milk production.     

“川草3号”虉草饲用价值初步研究

对3种牧草的饲用价值进行初步研究表明,"川草3号"虉草在鲜草产量、粗蛋白产量、茎叶比、鲜干比等方面均优于对照"川草2号"老芒麦和野生虉草;无论是在初花期还是盛花期,"川草3号"虉草的生物碱含量都显著低于对照野生虉草。     

Interaction of Grazing Muzzle Use and Grass Species on Forage Intake of Horses

The impact of horse preference and grass morphology on grazing muzzle effectiveness has not been investigated. The objective of this study was to determine the effectiveness of grazing muzzle use at reducing forage intake when horses grazed grasses with different morphology and preferences. The study was conducted in 2012 and 2013. Four horses were grazed in 2012, and three horses were grazed in 2013. Four species of perennial cool-season grasses were grazed in 2012 including Kentucky bluegrass (Poa pratensis L.), meadow fescue (Schedonorus pratensis Huds.), perennial ryegrass (Lolium perenne L.), and reed canarygrass (Phalaris arundinacea L.). In 2013, only Kentucky bluegrass and reed canarygrass were grazed because of winter kill of other species. Horses were allowed to graze a small pasture seeded with an individual species for 4 hours each day in June and August of 2012 and August and September of 2013. Horses grazed the same grass species for two consecutive days, one day with a muzzle and one day without. Before and after each grazing, a strip was mechanically harvested to determine initial and residual herbage mass. The difference was used to estimate forage intake. The effectiveness of a grazing muzzle was not affected by forage species (P ≥ .05). Use of a grazing muzzle decreased the amount of forage consumed by an average of 30% compared with not using a grazing muzzle (P < .0001). Results will aid horse owners and professionals in estimating forage intake of muzzled horses on pasture.     

西辽河平原不同生境草芦种群分株生长的可塑性

对西辽河平原天然草地两个生境草芦种群分株的高度、分株生物量、叶生物量、叶鞘生物量、茎生物量5个数量性状调查统计结果表明,不同生境间存在着极显著差异,分株在增高和增重上呈异速生长规律,且分株高度较高的草芦种群随高度的增加以茎增重为主,分株增重与各器官增重之间也呈较为稳定的异速生长规律;两个生境分株生物量分配均以叶的比重最大,在42.98%～50.47%之间.分株的高度与生物量之间非等比例增长的相关性规律是草芦种群适应环境的一种生长可塑性反应.     

洞庭湖湿地虉草替代大白菜对肉兔生产性能的影响

试验采用48只青年期(40～45日龄、体重约800 g)发育良好、健康无病的新西兰肉兔,随机分为4组:1组饲喂基础日粮,2～4组分别用占日粮5%,15%和25%的虉草Phalaris arundinacea代替日粮中等量的大白菜,试验期35 d.试验结果表明:各组间兔的日增重、屠宰率、料肉比等指标差异均不显著(P＞0.05),可见虉草代替大白菜不影响兔的生长,以15%的替代量的3组增重效果最佳,经济效益最好.     

虉草的研究进展

从生物生态学特性、饲用价值及影响因素、品种选育、栽培与利用等方面对国内外饲用虉草(Phalaris arundinacea L.)研究进行综述。虉草属生长高大、多叶、高产的多年生冷季型禾本科牧草,具有优良的农艺性状和较高的营养价值,其根系强大,既抗旱又耐湿耐寒;除了种子,还可以根茎或分株进行营养繁殖,乃至茎节也可生根并长出枝条;虉草群落一但建成其竞争力很强,并迅速形成单优势种群落;虉草的高生物碱含量影响其饲用价值,通过育种可降低其生物碱含量,提高消化率;虉草种子在成熟前易脱落,栽培品种最适采种期是开花后16—18 d,野生种群是11—13 d;虉草属是高度自交不育植物,在种子生产中仅有少量自交种子;其育种目标是在改善适口性的同时,提高种子保持能力以及种子和饲草产量;虉草具有持续高产和吸收氮素的能力,因此很适合施有机肥或氮肥;虉草可用于放牧、青贮和调制干草,年刈割3~4次,干物质生产效率最高,放牧时,要保持草层高度不超过30 cm,适宜留茬高度为7~10 cm。最后,对我国在虉草研究中亟待解决的问题进行了讨论。     

苇状羊茅种子需求和生产概况

从苇状羊茅Festuca arundinacea的生物学特性、种子需求现状、种子生产技术现状、研究进展等方面进行了简述,以便为苇状羊茅牧草种子生产技术进一步研究和利用提供参考.     

The pathogenesis of the nervous syndrome of Phalaris aquatica toxicity in sheep

The clinical signs displayed by 96 sheep affected by the nervous syndrome of Phalaris aquatica toxicity and 10 normal sheep injected intravenously with the phalaris alkaloid, 5-methoxy dimethyltryptamine (dose range 0.01 to 5.0 mg/kg), were observed. The distributions of phalaris indole-like cytoplasmic pigments in nuclei of the brains and spinal cords of 9 naturally affected sheep were determined microscopically. Based on the relationship between clinical signs and the central nervous system nuclei involved in their production, the distribution of phalaris indole-like pigments, and the pharmacology of dimethylated tryptamines, it is suggested that the nervous syndrome induced by Phalaris aquatica results from a direct action of phalaris alkaloids upon serotonergic receptors in specific brain and spinal cord nuclei.     

Tryptamine alkaloid toxicosis in feedlot sheep

Tryptamine alkaloid toxicosis (Phalaris staggers) was diagnosed in feedlot sheep. Clinical signs of toxicosis, which were exacerbated by excitement, included gait abnormalities, muscular tremors, nystagmus, and convulsions. An estimated 8% of the most severely affected lambs had clinical signs of toxicosis. Gross lesions detected in the brain of affected lambs consisted of focal gray-green discoloration in the brain stem and thalamus; these areas had microscopic evidence of intraneuronal pigment accumulation. Brain specimens obtained at slaughter indicated that 60% of the lambs had lesions consistent with tryptamine alkaloid toxicosis. Tryptamine alkaloids were found in low concentrations in the feed. Lambs exposed to these feeds had higher death losses than those that were not exposed to the feeds. Cobalt concentration in the feed was higher than that previously reported to be associated with Phalaris staggers.     

氮磷钾配施对威宁球茎草芦鲜草产量及营养成份的影响

通过田间试验,探讨氮、磷、钾配施对威宁球茎草芦生物学性状、鲜草产量及植株营养成份的影响,并筛选出适宜的氮、磷、钾肥用量。结果表明:施肥处理比不施肥处理,其株高、分蘖数和鲜草产量最大增幅分别为13.21%、18.32%和56.87%。鲜草产量平均增产1 345.31 kg/667 m2,提高了34.24%;粗蛋白质含量随氮、钾肥施用水平的增加而提高,其中,NPK+1/2N处理的粗蛋白质含量最高达14.83%,提高了38.2%;经济效益每667 m2收入增加186.65～790.25元,提高88.62%～375.15%。     

川西北高寒牧区老芒麦和虉草青贮效果初步研究

为探讨川西北高寒牧区主推草种青贮效果,以收种后的老芒麦(Elymus sibiricns L.)和虉草(Phalaris arundinacea L.)为原料,对其叶围微生物进行计数,使用纤维素酶、蔗糖、尿素和乙酸作为添加剂,灌装青贮60 d后进行品质分析。结果表明:老芒麦和虉草附着的乳酸菌数量远低于霉菌、酵母菌和丁酸菌;蔗糖和尿素处理下,乳酸含量显著高于对照,氨态氮与总氮比值显著低于对照(P<0.05),能够改善老芒麦青贮饲料和虉草青贮饲料发酵品质;乙酸处理下,pH值、氨态氮与总氮比值显著低于对照,乙酸含量显著高于对照(P<0.05),能够改善老芒麦青贮饲料和虉草青贮饲料的发酵品质;纤维素酶对改善虉草青贮饲料发酵品质无显著影响。     

祁连山北坡3个季节性牧场夏季的土壤呼吸

以祁连山北坡高寒灌丛化草甸和高寒草原为对象,测定比较夏季、冬季和春秋季牧场的夏季土壤呼吸特征及与其影响因素之间的关系,为牧场碳汇管理提供依据。以高山灌丛化草甸为主的夏季牧场日均土壤呼吸速率(Rs)为0.26μmol·(m~2·s)~(-1),以高寒草原为主的冬季和春秋季牧场日均Rs分别为0.24和0.19μmol·(m~2·s)~(-1)。随放牧增强,冬季牧场Rs减小,春秋季和夏季牧场Rs增加。冬季牧场Rs与土壤含水量(soil mosture,SM)显著正相关(P0.05),Rs与放牧率(stocking rate,SR)和土壤温度(soil temperature,Ts)显著负相关(P0.05);春秋季牧场Rs与SR、光合有效辐射(photosynthetically awailable radiation,PAR)、Ts显著正相关(P0.05);春秋季牧场Rs与SM和群落盖度(community coverage,C)显著负相关(P0.05)。结构模型方程表明,冬季牧场放牧率通过Ts对Rs的负向间接作用最强,SM对Rs正向的直接作用次之;春秋季牧场群落盖度对Rs负向直接作用最大,放牧率对Rs正向的直接作用次之。冬季牧场Rs可分别由Rs=0.436-0.012Ts+0.018SM(R2=0.911,P=0.038)和Rs=0.707+0.002SR-0.02Ts(R2=0.775,P=0.037)估测;春秋季牧场可由Rs=-0.239+0.003PAR-0.001C(R2=0.979,P=0.004)估测。     

夏季飞来昆虫对放牧牛摆尾行为的影响

本研究选择黑毛和牛种牛4头作为实验牛。从2000年8月至10月，在0.8ha的实验牧草地进行了实验。实验结果表明：飞来昆虫消化的季节，飞来昆虫对放牧牛摆尾行为的影响可能存在个体飞来昆虫不仅引起牛的体表护理行为，还可能导致心理上的应激。     

免耕改良退化人工草地试验

为改善退化人工草地优质牧草生长条件,对杂草、蛴螬危害引发的退化草地,进行低成本免耕改良试验.结果表明:化学除杂、全日制放牧免耕补播与常规法(耕作重播)均能改善人工种植牧草生长环境,杂草、蛴螬数量明显降低;两种免耕补播比常规法重播成本分别降低54.1%,64.3%;改良草地优质牧草覆盖度、组分、产草量均有显著提高.     

盐胁迫对虉草种子萌发与幼苗生理生化的影响

采用0(CK)、50、100、150、200和250 mmol/L 6个NaCl浓度梯度,对6份虉草(Phalaris arundinacea)材料的种子萌发和幼苗生长2个阶段进行盐胁迫处理。通过对种子的发芽率、鲜质量、苗高、根长、脯氨酸含量、丙二醛和叶绿素含量等生理化指标的测定,观测其在盐胁迫下的一系列生理生化反应。结果表明,低NaCl浓度对种子萌发及幼苗生长这2个阶段的影响较小,随着NaCl浓度的增高,种子发芽率、根长、鲜质量、苗长、叶绿素含量逐渐降低,脯氨酸含量显著增加,丙二醛含量呈先降低后增加的趋势。6份虉草材料在种子发芽和幼苗生理变化上均表现出不同的耐盐能力,Zxy06p 2449、Zxy06p 1904耐盐能力较强,其次为Zxy06p 2380、Zxy06p 2633,Zxy06p 2262和Zxy06p 1916的耐盐性较差。     

不同草地利用方式对河北坝上天然草地植物群落特征的影响

本研究以坝上天然草地植物群落为研究对象,分析了不同草地利用方式(打草场、冬牧地、公牧地)对植物群落的数量特征、物种组成、功能群特征及物种多样性的影响.结果表明:冬牧地的群落高度、物种数及物种多样性指数均最大,打草场的群落盖度显著大于放牧地(冬牧地和公牧地)且其地上生物量与冬牧地没有显著差异,同时打草场物种多样性指数与冬...