Azuche, Hymenachne amplexicaulis (Rudge) Nees, Forage Genetic Resources for Floodplains in Tropical Mexico

Azuche Hymenachne amplexicaulis (Rudge) Nees is a C₃ grass native to tropical flooded areas in South and Central America with 2n = 2x = 24 chromosomes. During 2002 and 2003, the Graduate College for Agricultural Sciences (CP) and the Mexican Institute for Forestry, Agriculture and Animal Production Research (INIFAP) organized an expedition to collect the genetic diversity of this species within tropical Mexico, in order to preserve and study it under nursery conditions. The collection was performed from Puerto Vallarta to Tapachula on the Pacific and from Palizada, Campeche to Veracruz on the Gulf of Mexico coast, and also crossing sections through the Tehuantepec isthmus and through the Sierra Madre de Chiapas. Ninety sites were sampled, on each, 25 tillers were collected, tagged and stored in a commercial soil mix until establishment of individual plants within 6 l pots. The largest Azuche prairie observed had a 10 ha surface, with the grass limited to small surfaces of up to 0.25 ha. It was not found on places with salty water, even seasonally. The Pacific coastal side is less abundant in niches for this species. Producers’ experience indicated that this grass is beneficial for milk production compared with other forage grasses, mainly C₄, growing in flooded areas. Initial studies of genetic diversity showed wide morphological variation for sprouting ability, leaf width and length among samples. Azuche diversity showed good potential production attributes for farm and wild animals, under flooding tropical savanna conditions.     

同源四倍体高粱与约翰逊草杂交及其后代表现

本试验研究了高梁同源四倍体与约翰逊草边缘杂交的结实性及其后代表现。结果表明，四倍体高梁与约翰逊草正、反交均能结实，而且后代性关遗传较稳定后，具有强大的杂种优势，是一种很有希望的饲料作物。     

浅谈青海省饲草业现状及发展战略

本文对青海省饲草业发展现状进行了深刻阐述,分析、总结了现阶段饲草业发展中存在的突出问题,并结合本省实际,因地制宜地提出了全省饲草业今后的发展战略。     

湟源地区种植青玉米试验

湟源地区是青海省绵羊实行西繁东育的基地之一,但由于饲料资源不足而限制了绵羊繁育规模,我们通过种植青玉米的试验,结果表明,青玉米产量可达到6.50kg/m2,它将为解决绵羊饲料探寻出新的途径.     

调亏灌溉对多年生黑麦草光合特性的影响及阈值的确定

本研究以干旱半干旱区栽培面积较大的多年生黑麦草(Lolium perenne)品种"首相"和"潘多拉"为研究对象,使用人工控制灌水量的方法在生长季节使黑麦草经历"干旱胁迫-复水"的5个循环处理,研究其在不同调亏灌溉及复水处理下光合特性的变化趋势。结果表明,两个品种黑麦草叶片的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和PSⅡ原初光能转化效率(Fv/Fm)随着土壤相对含水量(RSWC)的降低而下降,当RSWC下限值不同时,各指标的下降程度不同,且复水后的恢复程度也不同。灌溉下限在RSWC为50%时,各指标变化幅度较小;灌溉下限在RSWC为40%时,两个品种黑麦草受害程度加大;灌溉下限在RSWC为20%时,两个品种黑麦草均受到严重伤害,复水后各指标不能完全恢复。两个品种比较,"首相"比"潘多拉"抗旱性强。说明调亏灌溉对多年生黑麦草具有明显的RSWC限制范围,品种之间表现不同,"首相"最佳灌溉RSWC下限为40%,"潘多拉"为50%。     

近40年玛曲地区牧草生长期蒸降差的变化特征

利用甘肃省玛曲县气象站1971-2010年的地面气象观测资料,根据Penman-Monteith模型计算了玛曲地区草地潜在蒸散量,并对近40年玛曲地区牧草生长期蒸降差的变化趋势进行了分析,发现近40年玛曲地区牧草生长期蒸降差以12.1mm·10a-1的趋势上升,其中牧草生长初期和末期蒸降差以3.5和11.2mm·10a-1的速度上升,牧草生长中期蒸降差呈略下降的趋势,下降速度为-2.6 mm·10a-1。20世纪90年代,由于潜在蒸散量增大和降水量减少,造成蒸降差增大,牧草生长期出现了水分亏缺现象。水分亏缺是导致玛曲草地退化和生态环境恶化的主要原因之一。     

柳枝稷和坚尼草的耐镉性初步研究

为了探究镉污染条件下开发能源植物的可行性,以高生物量黍属能源植物柳枝稷和坚尼草为材料,温室中苗期水培试验,分别对柳枝稷外源施加浓度为0,0.5,5,10,20,50,100μmol/L镉(Cd),对坚尼草施加浓度为0,2,5,7.5,10μmol/L Cd,从形态、生长生理等角度,分析两种能源草对镉的响应。结果表明:随Cd浓度的增加,柳枝稷和坚尼草生物量和根伸长量均下降,Cd浓度为50μmol/L时,柳枝稷根鲜重减少达显著水平(P0.05)。而坚尼草则在Cd浓度为2μmol/L时,根和地上部分总鲜重减少达显著水平。相比于对照,Cd浓度为2μmol/L时,坚尼草的根伸长量已下降96.3%,而柳枝稷在5μmol/L Cd时根伸长量才降低55.0%,柳枝稷的耐镉性高于坚尼草。经20μmol/L镉处理,柳枝稷的地上部镉浓度达40mg/kg,生物量下降了45%。不同浓度的镉处理下,镉在柳枝稷体内的迁移指数为5.9%~14.2%,柳枝稷可以在Cd污染条件下被开发为能源和修复植物种植。此外,实验还发现,在根平均直径为0~1mm范围内,柳枝稷的总根长、根表面积和根体积与镉积累呈显著负相关,与迁移指数呈显著正相关(P0.05),该结果说明,细根在植物的镉吸收积累和转运中可能起着非常重要的作用。     

沂蒙山区果园生草技术

果园生草技术已成为较为先进的水果园土壤管理方法之一,是果园土壤管理制度一次重大变革。果园生草能够改善土壤理化性状、提高有机质含量、调节果园的微生态环境、增强土壤抗侵蚀能力等。本文通过简单介绍34个果园人工和自然生草培肥地力的生产实践,整理了适合沂蒙山区果园的生草模式和技术,提出了临沂市水果园人工生草选择黑麦草、紫花苜蓿、鼠茅草,自然生草以马唐、狗尾草、荠菜等为宜。生草园需做好肥水、刈割等管理环节,实现树、草的营养良性循环,以园养园。     

Effects of grass hay proportion in a corn silage‐based diet on rumen digesta kinetics and digestibility in dairy cows

In this study, we aimed to evaluate the effects of six levels of orchardgrass hay (GH) proportion (0%, 10%, 20%, 30%, 40% or 50% of dry matter) in finely chopped corn silage (CS)‐based diets on digesta kinetics of CS and GH in the rumen. Six non‐lactating, rumen‐cannulated Holstein cows were used in a 6 × 6 Latin square design. Ruminal digesta kinetics was measured by ruminal dosing of feed particle markers (dysprosium for CS, erbium for GH) followed by fecal sampling. The increase of GH proportion had a quadratic effect (P < 0.01) on total tract digestibility of neutral detergent fiber (NDF) and acid detergent fiber. The proportion of GH did not affect the particle size distribution of rumen digesta, total weight of dry matter or NDF in the rumen. The rates of large particle size reduction in the rumen for CS tended to increase linearly with increasing GH proportion (P = 0.077). A quadratic effect (P < 0.05) was found with increasing the GH proportion for the ruminal passage rate of small GH particles, but not for CS particles. The results suggested that associative effects between CS and GH could be generated on rumen digesta kinetics when cows were fed a CS‐based diet with an increased proportion of GH.     

南方席草生产机械化现状及发展趋势

席草生产在南方部分县(市、区)是农业支柱产业之一。本文在论述席草生产机械化现状，分析其存在问题和近期发展趋势的基础上，提出了加快席草业机械化发展需要采取的对策。