放牧强度对高寒草地产草量及羊体质量增加的影响

以托云牧场高寒草地为研究对象,通过设置3个放牧样地,一个对照样地,研究不同强度放牧对草地地上生物量的影响以及在不同放牧压力下羊体质量增加的效果。结果表明,1）托云牧场是以银穗草（Leucopoa albida）、羊茅（Festuca arioides）、点地梅（Androsace umbellata）和棘豆（Oxytropis falcatae）为优势种的高山草地;2）高寒草地地上生物量较低,禁牧区7月地上生物量（干物质）仅830 kg·hm-2;3）放牧活动对地上生物量有较大影响,重度放牧能显著降低牧场地上生物量;4）以羊体质量增加值为评价指标,该高寒牧场在载畜量为1.05羊单位·hm-2时能获得较好的体质量增加效果。     

盐胁迫对4种禾本科牧草种子萌发和幼苗生长的影响

通过NaCl溶液(0、1.5、3.0、6.0、9.0g/L)处理4种禾本科牧草种子,测定了种子萌发和幼苗生长有关指标。结果表明:美洲狼尾草较耐盐,在9.0g/L盐溶液处理下比其它品种维持了高的发芽率、发芽指数、活力指数,并且其相对值高,以及较高的相对苗长和根长,盐处理显著提高几种牧草幼苗质膜相对透性,总体上降低胚乳的利用速度和利用效率。     

Impact of molybdenum on the copper status of red deer (Cervus elaphus)

AIM: To determine the effect of increasing molybdenum (Mo) intakes on serum and liver copper (Cu) concentrations and growth rates of grazing red deer (Cervus elaphus).

METHODS: Molybdenum- and Cu-amended fertilisers were applied to six 1.1-ha paddocks in a 3 × 2 design. Three levels of Mo were applied on two paddocks at each level in mid April (designated Day 1); levels were: none (control), 0.5 (medium) and 1.0 (high) kg Mo/ha as sodium molybdate. In late May (Day 39), two levels of Cu (none and 3.0 kg Cu/ha, as copper sulphate) were applied to each of the three levels of Mo-treated paddocks. Pasture Mo, Cu and sulphur (S) concentrations were measured at about fortnightly intervals. In late June (Day 74), ten 6-month-old red deer hinds were placed on the six experimental pastures, and serum and liver Cu concentrations were monitored at about monthly intervals for 102 days. The hinds were weighed on four occasions during the trial.

RESULTS: Mean pasture Mo concentrations on Day 56 were 2, 4.6 and 11.3 mg/kg dry matter (DM) for the untreated control, medium and high Mo-treated pastures, respectively. Pasture Cu concentration was 95 mg/kg DM on Day 59, 53 mg/kg DM on Day 90, and 9 mg/kg DM by Day 153. Mean S concentration in pasture was 3.3 (range 3.03–3.45) g/kg DM. Copper application to pasture had no significant effect on serum and liver Cu concentrations in deer so data were pooled within Mo treatment. Mean initial (Day 74) serum Cu concentration was 9.2 µmol/L. In the deer grazing the control Mo pasture, this increased to 10.3 µmol/L on Day 112, before decreasing to 6.4 µmol/L on Day 176. In deer grazing the medium and high Mo-treated pastures, mean serum Cu concentrations were 3.8 and 3.9 µmol/L, respectively, on Day 112, and 2.5 and 3.3 µmol/L, respectively, on Day 176. Mean initial (Day 74) liver Cu concentration was 131 µmol/kg fresh tissue. In the deer grazing the control Mo pasture, this declined to 120 and 52 µmol/kg on Days 112 and Day 176, respectively. In deer grazing the medium and high Motreated pastures, liver Cu concentrations decreased to 55 and 52 µmol/kg fresh tissue, respectively, on Day 112, and 21 and 20 µmol/kg fresh tissue, respectively, on Day 176. Mean serum and liver Cu concentrations were not significantly different between deer grazing the medium and high Mo-treated pastures, and were lower (serum p=0.003, liver p<0.001) in those groups than in deer grazing the untreated control pastures. No clinical signs of Cu deficiency associated with lameness were observed. Deer grazing pastures that had Mo concentrations >10 mg/kg DM had lower (p=0.002) growth rates (100 vs 130 g/day) than those on pastures containing <2.4 mg Mo/kg DM.

CONCLUSION: Increasing pasture Mo concentrations from 2 mg/kg DM to ≥4.6 mg/kg DM significantly reduced serum and liver Cu concentrations in grazing deer. Reduced growth rate was observed at pasture Mo concentrations >10 mg/kg DM.     

天然草场助推式间歇排种器的设计、分析与试验

为解决禾本科草种细长,千粒质量小,流动性差,易缠绕等造成的禾本科草种排种困难的问题,设计助推式间歇排种器。该排种器主要由种箱、种盒、护种轮、种刷、推种板、连杆和曲柄构成。工作时,通过曲柄转动,驱动推种板往复移动实现充种、清种、护种的排种过程。排种过程为主动排种,改变以往依靠种子自身重力和流动性实现被动排种的情况。根据排种器设计要求,确定影响工作性能的相关参数,并进行排种量稳定性试验。试验结果表明:排种器单次排种量为0.137 5g,满足禾本科草种排种量要求;试验过程中,排种器充种顺利,无草种堵塞和架空现象;排种器排种量稳定性变异系数为5.5,符合GB/T 25421—2010要求。     

不同种植年限苜蓿地土壤理化性状

本研究分析了半干旱区不同种植年限苜蓿(Medicago sativa)地土壤理化性状。结果表明,随着苜蓿种植年限的增加,0-100 cm土层土壤容重出现不规律的波动,苜蓿地土壤容重值整体偏大;土壤有机质随种植年限的增加而增大,随土层深度增加而显著减小(P<0.01),并且在种植5年的苜蓿地中提高最明显,在种植8年的苜蓿地中最低。各年限苜蓿地均表现出土壤有机质的“表聚性”。在一定的种植年限范围内,种植苜蓿对土壤有机质具有累积作用;土壤全氮含量随苜蓿种植年限的增长表现为先增大后减小的趋势,随土层深度的加深而逐渐减小,种植苜蓿4年时土壤全氮含量最大,8年时苜蓿地土壤全氮含量最低,并且土壤全氮含量主要集中于0-40 cm土层,全氮显著累积作用于表层土壤;土壤硝态氮随着苜蓿种植年限的增加而先增加后减小,随着土层的加深而逐渐降低,表层土壤对土壤硝态氮有累积作用,并且与苜蓿种植时间长短有显著相关性(P<0.05)。而铵态氮含量在剖面上变化不大,与苜蓿生长年限没有显著相关性(P>0.05)。今后需从栽培苜蓿草地的管理措施上深入探讨栽培苜蓿地的最佳种植和利用年限。     

人工草地绵羊系统优化研究Ⅳ人工草地划区轮牧罗姆尼怀孕母羊群体采食量研究

人工草地划区轮牧条件下,牧草生长旺季罗姆尼(Romney)怀孕母羊羊群采食量与怀孕日龄间呈显著正相关,回归方程Y=0.003 2X+0.853 7,r=0.949 5;但霜冻到来后采食量与怀孕日龄间呈显著负相关,回归方程Y=-0.007 3X+1.784 1,r=-0.985 1.     

近红外光谱技术在天然草地牧草营养价值评价中的应用及展望

近红外光谱技术(NIRS)是近几十年迅速发展的测试分析技术,由于准确、高效、无损等检测优势,在牧草营养价值评价领域得到广泛应用,但是在天然草地牧草方面应用较少。快速、实时评价天然草地牧草营养价值,为研究天然草地营养供给和营养载畜量提供基础数据,对草地畜牧业生产具有重要意义。文章阐述了近红外光谱技术的基本原理和特点,介绍了直接法和间接法评价牧草营养价值,分别从常规营养成分、矿物元素、抗营养成分、营养物质消化率4个层次综述近红外光谱技术在2个方法中的应用,并做出展望,以期建立基于NIRS技术的天然草地牧草营养价值数据库,为天然草地的科学管理和合理利用发挥重要作用。     

微灌技术对环湖区退化人工草地的影响

旨在采用微灌技术对环湖区混播人工草地进行节水灌溉试验的观测研究,探索环湖区人工草地对灌溉条件响应,为环湖区混播人工草地管理和持续高效利用提供参考依据。采用光伏扬水系统进行微喷灌节水灌溉试验,调查群落结构,计算地上和地下植物量。研究表明：植物群落多样性、均匀度、生态优势度指数均为灌溉区大于对照区;水分充足条件下能促进植物茎叶的生长,而干旱有利其根部的发育;灌溉可有效提高环湖区人工草地的优良牧草产量。可见水分的增加抑制了退化草地指标种生长,有利于草地恢复,环湖区人工草地对灌溉条件具有较好响应。     

Effects of silvopastoral areas on milk production at dual-purpose cattle farms at the semi-humid old agricultural frontier in central Nicaragua

In extensive cattle production systems, the composition of grazing areas may significantly influence productivity. In dual-purpose cattle production systems in the lowland tropics, pasture lands with trees, so-called silvopastoral areas, are considered as being important, particularly to facilitate the management of crossbred European native cattle. The aim of the study was to quantify the effects of silvopastoral areas on production at dual-purpose cattle farms in the semi-humid lowlands of central Nicaragua. The relationships between seasonal milk production and herd data, and the proportions of land use types were examined for 74 farms by stepwise regression analysis.