6种臂形草属牧草品种比较试验

对Mulato臂形草、Mulato2号臂形草、热研3号俯仰臂形草、热研6号珊状臂形草、湿生臂形草、Abundance珊状臂形草6种臂形草属牧草进行品种比较试验。通过3a的观察测定,结果表明,6种臂形草均能适应试验区气候条件,热研6号臂形草和Mulato臂形草表现最优,产量分别达到33318kg／hm^2和32483kg／hm^2,营养期粗蛋白含量分别达到12．64％和11．77％。     

林草间作系统土壤微生物及其活性研究

试验对6年龄桉树人工林间作禾本科及豆科牧草后的土壤微生物进行研究,结果表明：间作牧草可显著提高林地土壤微生物的生物量、呼吸强度、硝化作用强度及纤维素分解作用强度,且均随着土层深度的加深而降低;其中以间作热研6号珊状臂形草、热研2号柱花草、GC1581柱花草和Mineirao柱花草的土壤微生物生物量最高;热研15号刚果臂形草、热研6号珊状臂形草、杂交臂形草、热研10号柱花草、Mineirao和GC1581的呼吸强度高于CK;热研11号黑籽雀稗、热研10号柱花草、GC1581和热研2号柱花草的硝化作用强度强于CK;热研9号坚尼草、杂交臂形草和热研6号珊状臂形草、热研10号柱花草和热研2号柱花草的土壤纤维素分解作用强度较强。     

桉树人工林间作禾本科牧草适应性筛选与评价

桉树人工林单一种植引起植被多样性减少、生物多样性下降是普遍存在的问题,间作成为恢复与重建桉树林下植被多样性的重要途径。桉树人工林下间作禾本科牧草综合评价结果表明,热研14号网脉臂形草、热研8号坚尼草、热研9号坚尼草、热研6号珊状臂形草等牧草产草量达215.89～475.42 kg/hm2,旱季牧草产量占年产草量的14.08%～17.51%,在极端干旱条件下仍保持一定的生长和生物量的积累,植株存活率达53.6%～76.6%,覆盖度达62.71%～90.42%。间作牧草在桉树行间形成良好的覆盖层,提高了林地植被覆盖度,植株存活率较高,促进植被多样性的形成,对增加桉树人工林的群落组成、形成多层次片层结构有积极意义。     

臂形草属种质苗期抗旱性鉴定研究

通过盆栽试验对臂形草属种质苗期进行干旱胁迫,分析测定胁迫不同时期叶片的相对电导率、游离脯氨酸含量、丙二醛含量、叶绿素SPAD值及叶片相对含水量。结果表明,在胁迫15 d时,各指标均存在差异。对这5项指标进行类平均法聚类分析,臂形草属种质可划分为2个抗旱级别,即强抗旱和弱抗旱种质,其中强抗旱臂形草种质包括CIAT26556珊状臂形草、网脉臂形草、热研6号珊状臂形草、CIAT6095刚果臂形草、CIAT16835珊状臂形草。强抗旱和弱抗旱臂形草种质在连续干旱胁迫时,相对电导率、游离脯氨酸含量、丙二醛含量均呈现上升的趋势,而叶绿素SPAD值及叶片相对含水量则呈现下降的趋势。而复水后,强抗旱和弱抗旱臂形草种质均有不同程度的恢复。     

热研14号网脉臂形草的选育

热研14号网脉臂形草是1991年10月从哥伦比亚国际热带农业中心首次引入,于1992￣1993年在网室和大田进行适应性观察,1994￣1996年进行品种比较试验,并于1996￣2003年进行区域性试验,1999￣2003年进行生产性试验。结果表明:热研14号网脉臂形草适应性强,具发达的匍匐茎,耐酸瘦土壤,能在pH4.5￣5.0的强酸性土壤和极端贫瘠的土壤上表现出良好的持久性和丰产性,在中等肥力和酸瘦土上具有较高的饲草产量,特别是热研14号网脉臂形草耐干旱和相对耐荫,在年降水750mm以上的热带、亚热带地区均可良好生长,在林下间作表现出良好的持续性;侵占性强,触地各节产生不定根,自然传播迅速,并能与飞机草等恶性杂草竞争;耐践踏、耐重牧,亲和力强,可与豆科牧草等混播建设草地持久、耐用。热研14号网脉臂形草适合草地建设、保持水土和果园间作。     

海南农垦橡胶园生态系统养分的物质流分析

对俯仰臂形草(Brachiaria decumber)、网脉臂形草(B.dactylon)、刚果臂形草(B.ruziziensis)和杂交臂形草(B.Hybrid)4种臂形草种子的萌发期及幼苗期在不同盐浓度处理下的耐盐性进行了比较研究,试验结果表明在种子萌发期,刚果臂形草耐盐性较强,其次是网脉臂形草;在幼苗期,网脉臂形草的耐盐性大于刚果臂形草。     

优良热带牧草在云南元谋干热河谷区域试验研究

对15个热带优良牧草在云南元谋干热河谷进行区域试验研究。结果表明：参试的15个种质生长正常,生长季节产量高,耐热耐旱,是适应本区种植的优良牧草;牧草生物产量排在前3位的品种为杂交臂形草、热研8号坚尼草和热引19号坚尼草,产量分别是20.172、18.587和16.962t/hm2;15个种质生产性能排在前5位的依次为：研8号坚尼草、9号坚尼草、热研11号黑籽雀稗、9610雀稗、FSP2雀稗和10号狗尾草,它们品质优良,可在云南干热河谷区推广应用。     

云南干热河谷优良牧草的筛选

1999～2011年,针对云南干热河谷自然生态条件,从国内外收集、引进278份牧草资源。根据牧草种质植物学特征和生物学习性,开展了137份牧草资源调查,经生育期、营养价值、生产价值及抗逆性评价,筛选出热研4号王草、红象草、热研8号坚尼草、多花黑麦草、百喜草、新银合欢、木豆、热研2号柱花草、甘农3号紫花苜蓿、提那罗新诺顿豆等一批适应干热河谷种植、应用在本区生态养殖和生态环境建设的优良牧草。这些牧草表现出一定的速生性,生长季生物产量高。其中热带牧草抗逆性强,能够抵御干热河谷高温干旱生态环境;豆科牧草粗蛋白含量     

热研15号刚果臂形草的研究与利用

臂形草属[Brachiaria(Trinius)Grisebach]牧草是一种重要的放牧型牧草和水土保持植物,但原有品种已不能满足生产上的多样性需求,而热研15号刚果臂形草耐干旱,耐酸瘦土壤;侵占性强;耐践踏、耐重牧,与豆科混播亲和力强,适合草地建设、水土保持和果园田间;产量高,平均年产量达到209.87t/hm2·a,营养价值和饲用价值高,分别达14.12%和17.42%,具有良好的开发和利用价值。     

施氮水平对杂交狼尾草产量、品质和氮素吸收利用的影响

在大田种植情况下.研究4种施氮水平对杂交狼尾草产量、粗蛋白含量和氮素生产效率的影响,以及牧草产量、粗蛋白含量与施氮量和各种农艺性状的相关性.结果表明,施氮肥能显著提高杂交狼尾草的分蘖数、株高、产量和粗蛋白含量,N2、N4处理间分蘖数差异不显著,N3、N4处理间株高、干草产量和粗蛋白含量差异不显著.杂交狼尾草鲜草产量、干草产量、粗蛋白含量、分蘖数、株高和施氮量相互间都呈正相关,其中鲜草产量与施氮量、分蘖数和粗蛋白含量呈显著相关,与株高和干草产量呈极显著相关;干草产量与施氮量和分蘖数呈显著相关.与株高呈极显著相关:粗蛋白含量与施氮量也呈显著相关.杂交狼尾草在一定的施氮量范围内,随着施氮量增加.牧草的干物质积累总量、粗蛋白质产量和氮素积累总量也越多,而牧草的氮素干物质生产效率、干物质生产效率、粗蛋白质生产效率、氮素农艺效率和氮素表观回收率都逐渐降低.在施纯氮量为350～1 050 kg/hm2时,杂交狼尾草的氮素表观回收率为25.73%～45.12%,氮素回收率只有16.68%～20.35%.     

Effect of six-weekly harvests on the yield, chemical composition and dry matter degradability of Panicum maximum and Stylosanthes hamata in Nigeria

The dry matter (DM) yield and degradability of 6‐week‐old harvests of tropical forages were measured over a season. The forages were nitrogen‐fertilized Guinea grass (Panicum maximum, NFG), unfertilized Guinea grass (UFG), Verano stylo (Stylosanthes hamata,VS), a Guinea grass–Verano stylo mixture (GSM) and Guinea grass in the grass–Verano stylo mixture (GGSM). Six‐week‐old forages were made possible through a cutting regime, which produced four harvests in the growing season. The DM yields of the forages differed significantly (P < 0·001) and showed a significant reduction (P < 0·01) across the season. Crude protein and neutral‐detergent fibre concentrations were significantly (P < 0·01) different between the forages but there was no difference between harvests. The DM degradability of the forages at all harvests were significantly (P < 0·001) different with differences in the soluble fraction (a), degradable fraction (b), potential degradability (PD) and effective degradability (ED), but rate of degradability (c) did not show any significant difference between the forages. Significant (P < 0·01) differences were found between harvests for b and PD, and for the interaction between forage and harvest for b, PD and ED but were not found for the a and c fractions. Both the PD and ED values of all the forages fell with advancing harvests. Although the 6‐week‐old harvests of forage were found not to influence the characteristic reduction in yield of tropical grasses over time, it is concluded that such a management system could be used to obtain forage of relatively high nutritive value during the growing season.     

套种不同牧草的果园土壤对磷的吸附与解吸特性

采用恒温培养法研究了蜜柚果园自然生草和套种不同牧草后土壤对磷的吸附和解析特性。结果表明：果园土壤对磷的等温吸附、吸附量-解吸量曲线分别与常规的Langmuir方程、二次函数方程吻合。几种牧草果园土壤的最大吸附磷量依次为：圆叶决明＞百喜草＞自然生草CK、平托花生＞宽叶雀碑;供试的5种土壤中,人工生草的果园土壤对磷的解吸率均小于自然生草,表明人工生草能改善果园土壤对磷的缓冲能力。     

An evaluation of the hygienic quality in single‐species hays and commercial forages used in equine nutrition

Pulmonary diseases such as recurrent airway obstruction have become a major concern in the horse industry. Airborne dust, including aeroallergens from forages, is suspected to be the main factor in its aetiology. Hypothesizing that grassland flora could affect hay hygienic quality, and therefore have implications for the respiratory health of horses, we compared five single‐species hays (Trifolium repens, Lolium perenne, Alopecurus geniculatus, Poa trivialis and Holcus lanatus). Multi‐species hay from Normandy, and different commercial forages (single‐species haylage, multi‐species haylage, Crau hay and hay from Swiss mixing), chosen to represent current horse forages, were also investigated. Dust, moulds, pollens and endotoxins were different among forage types, while mycotoxins were not detected in any of the forage types. Holcus lanatus hay was the dustiest among the single‐species hays but also the least contaminated by moulds. A particular mould profile was associated with each plant species. The four commercial forages appeared to have a better hygienic quality than the multi‐species hay. Among commercial forages, the single‐species haylage was the least dusty but also the most contaminated by moulds. Overall the results suggest that the hygienic quality of equine forages could be improved by an appropriate choice of grassland species.     

表格

以几种海南常见的乡土地被植物为对照,对目前国内屋顶绿化应用较为广泛的佛甲草、垂盆草进行耐旱性研究。综合各项生理指标,供试品种的耐旱性如下：佛甲草＞垂盆草＞钝叶草＞热研12号平托花生＞细叶结缕草＞狗牙根＞大叶油草＞南美蟛蜞菊。     

Variation in forage yield and quality of three cruciferous catch crops grown in southern England

Cruciferous catch crops are an important source of forage, particularly in sheep systems, but due to their late sowing date, commonly July or early August, soil moisture is often a limiting factor in crop establishment and subsequent growth, causing wide variations in yield from year to year. Crops of stubble turnip ( Brassica campestris ssp. rapifera ), forage rape ( B. napus ssp. biennis ) and fodder radish ( Raphanus sativus ) were grown at Hurley between 1969 and 1977. Fodder radish was the most variable in dry matter (DM) yield, while stubble turnip was the most stable. Both DM yields and in vitro digestibilities rose during the autumn, reaching a maximum in mid-December for stubble turnip and forage rape, and in mid to late November for fodder radish. Yield and digestibility subsequently declined. The N concentrations of the forages exhibited a contrary trend, reaching minimum values at about the time of the highest DM yields. The gradual changes in crop quality suggest that the crops are well suited to grazing utilization, in which management is simplified if crop quality shows little variation.     

Differences in tolerance to infertile acid soil stress among germplasm accessions and genetic recombinants of the tropical forage grass genus,Brachiaria

Several Brachiaria species are the most widely grown forages in tropical America. A field study was conducted during two seasons (1994, wet and 1995, dry) in a medium-textured Oxisol at Carimagua, Colombia. The main objective of the study was to evaluate genotypic variation in plant attributes for tolerance to low fertility, acid soil stress conditions (pH 4.9) among germplasm accessions and genetic recombinants of Brachiaria. The entries included 43 genetic recombinants selected from a breeding population, four parental accessions and an additional eight germplasm accessions. Small amounts of fertilizer were applied at establishment (kg ha⁻¹: 40 N, 20 P, 20 K, 14 Ca, 12 Mg and 12 S). A number of plant attributes including forage yield, leaf area, shoot nutrient composition and shoot nutrient uptake were measured during both seasons. Significant genetic variation was observed in several plant attributes such as leaf area, shoot nutrient content, nutrient partitioning to leaves, shoot nutrient uptake, and forage yield in both seasons. Forage yield ranged from 59 to 343 g plant⁻¹ in the wet season and 5 to 174 g plant⁻¹ in the dry season. Correlation between forage yield and shoot nutrient uptake indicated the importance of nutrient acquisition, particularly of phosphorus (r=0.90; P<0.0001), for adaptation to infertile acid soil stress. Two genetic recombinants (BRN093/3009, FM9201/1873) were productive when grown under infertile acid soil stress in both wet and dry seasons. But, neither of these two recombinants is highly resistant to xylem-feeding insects known as spittlebugs (Homoptera: Cercopidae). One spittlebug-resistant genetic recombinant (BRN093/1371) exhibited several desirable attributes such as superior leaf area and leaf biomass, greater N content in leaves, and greater partitioning of N and P to leaves that could contribute to adaptation and persistence in these soils. This recombinant is being utilized in a breeding program to develop superior Brachiaria lines.     

Factors affecting digestibility of temperate forages from seminatural grasslands: a review

Abstract To indicate possibilities for the use of forages from seminatural grasslands in ruminant production systems, a literature study to describe the nutritive value of those forages was carried out. In species‐rich grasslands, the digestibility of forages is usually lower than the digestibility of forages produced by grasslands used for intensive production. There is also more variation within a species‐rich sward, because of different stages of maturity of the individual species and because of likely variations in digestibility among forage species independent of stage of maturity. Moreover, the presence of dicotyledonous species may have a positive or negative effect on digestibility. In forages from seminatural grasslands, the relationship between chemical composition and digestibility differs from that of Lolium perenne, which is often used as a research standard. Therefore, predictions of the digestibility of species‐rich forage can be inaccurate. The relationship between in vivo and in vitro digestibility may also be different from the relationship that is common for L. perenne. In some cases, the in vivo digestibility is higher than the in vitro value, as calibrations are based on L. perenne. Therefore, the quality of forages from seminatural grasslands might be higher than predicted, and this may increase the scope for practical use of this kind of forage in ruminant nutrition systems.