非圆齿轮行星轮系传动的栽植机构参数优化与试验

为了进一步优化栽植嘴的轨迹、姿态及其挖出的穴口形状,提高钵苗移栽的立苗率,提出了基于两级非圆齿轮行星轮系传动的栽植机构组合设计思路,运用变性椭圆-共轭非圆齿轮、变性偏心圆-共轭非圆齿轮、变性巴斯噶蜗线非圆齿轮、变性傅里叶非圆齿轮和变性正弦非圆齿轮5类非圆齿轮副,组合设计了25种不同的栽植机构。建立了基于非圆齿轮行星轮系传动的栽植机构通用数学模型,并将通用数学模型代入旋转式钵苗栽植机构多目标优化模型,根据给定的栽植农艺条件,优化得到了满足理想栽植要求的栽植机构类型及其对应的机构参数。选取其中的偏心-椭圆齿轮行星轮系栽植机构与变性椭圆齿轮行星轮系栽植机构进行对比分析,结果表明运用多种非圆齿轮副进行组合设计的栽植机构具有优越性。根据优化得到的栽植机构类型及其对应的参数进行结构设计和样机研制,并进行了运动学高速摄像试验和模拟田间栽植试验。由高速摄像试验得到的轨迹、姿态、速度等指标和理论计算的对比分析,验证了通用数学模型的正确性;由模拟田间栽植试验可得本栽植机构立苗率较高,约为95%。     

新疆农田水利工程灌溉

通过分析当前新疆地区水利工程中存在的问题,总结出新疆实施水利工程灌溉的主要技术点。     

春伐桑树不同技术处理的试验初报(Ⅱ)——不同技术处理对夏秋季桑叶产质量的影响

在栽植密度一定且其它桑园管理措施一致的前提下,对春伐桑树不同技术处理与夏秋季桑叶产质量的关系进行了调查。结果是栽植密度每667 m2桑地面积1000~1200株、N∶P2O5∶K2O=10∶5∶5的施肥比例,每667 m2桑地面积留条7500~8000根,低干无拳式树形的组合,可适当提高幼虫生命力、茧层率和良卵率及实用孵化率,显著提高桑叶产量和全茧量、茧层量及产卵量。     

The Ecological Effects of Young Elm Trees Belt-Pumpkin Strip Intercropping System at the Agro-Pastoral Ecotone in Northern China

Young elm trees belt-pumpkin strip intercropping was studied to solve the actual problem of resource losses in the large barren area resulted from reconverting cultivated land into forest in the agro-pastoral ecotone in northern China. The final objective was to realize effective utilization of the barren land with both ecological improvement and economic development. Field experiments were conducted together with laboratory analysis. The results indicated that the soil moisture level was remarkably increased in young elm trees belt-pumpkin strip intereropping because the pumpkin vines covered the gap between pumpkin planting-furrow and elm trees belt. The water use efficiency of the intercropping system was increased by 23.7-163.3% as compared with the single cropping. Elm trees belt-pumpkin strip intercropping changed the sequential succession trend of the grasses growing in the gap of the pumpkin planting-furrow. The annual grasses become the dominant vegetation. The nutritive value as fodder and yield of the annual grasses were also increased remarkably. The biomass of pumpkin, elm trees and grasses under intercropping increased by 24.4, 28.4 and 144.4%, respectively, as compared with those under single cropping. The land use efficiency was increased by 132%. It was also indicated that the soil erosion from the intercropping land was not increased due to pumpkin plantation. The differences in the soil erosion among intercropped area, elm trees belt and pumpkin strip with single cropping were not remarkable. Therefore, it was concluded that young elm trees belt-pumpkin strip intercropping is an effective way to utilize the barren land between the young elm trees belt and realize synergistic enhancement of ecological benefit and economic profit.     

六盘山叠叠沟华北落叶松人工林地上生物量的坡面变化

【目的】在降水有限、水分再分配明显的半干旱区山地坡面上,森林生物量通常表现出明显的坡向、坡位差异。便捷、精确地测算整个坡面的森林生物量目前还很困难。本研究旨在定量描述森林生物量的坡面变化规律及其空间尺度效应,为提高森林经营水平和实施精细化管理提供技术支持。【方法】在宁夏六盘山半干旱区的叠叠沟小流域,选择生长华北落叶松人工林的半阴坡和阴坡2个坡面,按坡位从上到下各设置了6块20 m×20 m的样地,调查各样地的立地条件及林分特征后,采用烘干法及六盘山区建立的生物量经验公式计算地上生物量;以"离开坡顶的水平距离"为尺度变量,定量描述地上生物量随坡面空间尺度增加而变化规律,及坡面上任意坡位处样地的地上生物量与坡面平均值的关系。【结果】研究区坡面上森林植被地上生物量存在明显的坡向、坡位差异;水分条件较差的半阴坡上的平均地上生物量(52.36 t·hm-2)比水分条件较好的阴坡低18.16%,但半阴坡上生物量的坡位间变幅(42.50 t·hm-2)比阴坡高14.71%,这说明半阴坡的坡面效应强于阴坡,并与土壤厚度及土壤水分条件差异有关;地上生物量的坡位变化在不同坡面上大致遵循相同的规律,都是由坡顶向下逐渐增大,至下坡处(半阴坡)或中下坡处(阴坡)达到最大,之后又逐渐减小,这主要受土壤水分在坡面上的再分配格局影响;研究区坡面上森林植被地上生物量(y,t·hm-2)随坡面空间尺度(x,m)增加而变化,阴坡表现为y=-2×10-7x3-8×10-5x2+0.121 9x+40.875(R2=0.999 8),半阴坡表现为y=2×10-7x3-7×10-5x2+0.067 5x+30.838(R2=0.995 7);距坡顶的水平距离每增加100 m,阴坡上的地上生物量坡段滑动平均值升高4.92 t·hm-2,半阴坡上为6.28 t·hm-2,即地上生物量的空间尺度效应在水分条件较差的半阴坡上要强于水分条件较好的阴坡;研究区坡面上任意给定坡位(X,m)与样地地上生物量与坡面平均值的比值(Y)的定量关系在半阴坡为Y=-7×10-8X3+4×10-5X2-2.2×10-3X+0.643 2(R2=0.932 1),在阴坡为Y=-1×10-8X3+1×10-6X2+3×10-3X+0.620 4(R2=0.973 9),以此可便捷和精确地确定整个坡面的森林生物量。【结论】半干旱区山地坡面上森林生物量呈先增加后减小的单峰型变化,与土壤水分的坡面再分配格局关系很大;采用"距坡顶的水平距离"为尺度变量可以很好地定量描述森林生物量沿坡变化规律及其空间尺度效应;基于以上工作可实现整个坡面生物量的便捷精确计算。     

四川省松潘县牦牛体表蜱、高原鼠兔携带巴尔通体和无形体的PCR检测与进化分析

旨在了解四川省松潘县牦牛体表蜱、高原鼠兔巴尔通体和无形体感染情况。采集牦牛体表的蜱和捕获高原鼠兔，对蜱进行形态学初步鉴定后，提取蜱和高原鼠兔脾总DNA，PCR扩增蜱16S rRNA、巴尔通体rpoB和无形体16S rRNA基因，对PCR产物阳性产物测序、比对及构建系统进化树，从而确定蜱种类及蜱和高原鼠兔感染巴尔通体和无形体的种类及感染率。结果显示：在松潘县进安乡、山巴乡、下八寨乡各采集到蜱102、97和131只，共计330只，经鉴定均为青海血蜱。蜱巴尔通体仅检出1种巴尔通体，与B.melophagi亲缘关系最近，进安乡、山巴乡和下八寨乡检出率分别为16.7%、8.2%和18.3%，其中下八寨乡检出率显著高于进安乡（P<0.05）；蜱源无形体进安乡、山巴乡和下八寨乡检出率分别为9.8%、12.4%和26.7%，下八寨乡检出率显著高于进安乡（P<0.01），检出的无形体均为1种，与牛无形体（A.bovis）亲缘关系最近；下八寨乡检出的鼠兔源巴尔通体与B.queenslandens亲缘关系最近，感染率为6.7%；进安乡、山巴乡和下八寨乡检出的鼠兔源巴尔通体与B.grahamii亲缘关系最近，感染率分别为8.7%、17.9%和13.3%，3个点检出率无显著差异；未定种Bartonella sp.（MN296294）和Bartonella sp.（MN296293）仅分别在进安乡和下巴乡检出；与蜱均检出无形体不同，高原鼠兔均未检出无形体。此外，蜱和高原鼠兔均未发现2种及2种以上病原混合感染。松潘县青海血蜱携带巴尔通体和无形体，高原鼠兔感染巴尔通体，且首次在高原鼠兔体内检测到疑似B.queenslandens的病原体，提示当地居民有感染这两类病原风险。     

如何做好犬舍卫生消毒工作

许多病毒、病菌侵入犬机体后无论发病与否,都可能通过尿液、粪便排毒,有的长期排毒,所以有犬活动的地方,基本都有病毒(菌)存在,为了防止病毒(菌)传播,我们应对犬集中活动的地方进行消     

青贮中心在石漠化地区草地畜牧业中的作用

针对石漠化地区生境破碎、地理单元小而多、养殖场规模较小且较为分散、难以实现青贮池配套的问题,简要分析了石漠化地区发展草地畜牧业的意义,以及发展中存在的问题,提出草地畜牧业发展的突破点,即建立青贮中心,分配所属区域的养殖场。从石漠化地区构建青贮中心的技术可行性以及效益分析出发,深入挖掘构建青贮中心和集约化农场对石漠化地区发展草地畜牧业的重大意义。     

SNPs Screening and Bioinformatics Analysis of SIM1 Gene in Congjiang Pigs

In this study, Congjiang pig was served as a research object, crossbred pigs (Congjiang pig×boar), outside crossbred pigs (Duroc×Landrace×Yorkshire) as controls.Using DNA pools and direct sequencing detected polymorphism of 7 exons, part of introns and 3'untranslated region (3'-UTR) sequences of SIM1 gene for three groups.Bioinformatics software predicted what impact polymorphic loci had to mRNA secondary structure and protein primary, secondary structure of SIM1 gene.The results showed that 12 SNPs were screened in SIM1 gene of three groups, C77T located in exon 5, T29186C and A29195C located in intron 9, C63T and C225T located in exon 10, and C107T, A426G, T583C, A586C, A605C and A615C located in exon 11, G267T located in 3'-UTR. C77T, T29186C, A29195C, C63T, C225T, C107T and G267T were silent mutations, A426G, T583C, A586C, A605C and A615C were missense mutations.The five missense mutations respectively led to isoleucine (Ile) into valine (Val), leucine (Leu) into proline (Pro), glutamate (Glu) into alanine (Ala), glutamic (Glu) into aspartic (Asp), asparagine (Asn) histidine (His), and according to online software forecast, mRNA secondary structure and protein primary, secondary structure of SIM1 gene changed in mutations before and after.     

丙酸镁对西门塔尔牛瘤胃液pH和氨态氮浓度的影响

选用4头3.5岁、体况良好(500±20)kg的中国西门塔尔牛阉牛,采用4×4拉丁方设计,研究日粮添加丙酸镁(100g/d)、丙酸(87g/d)和氧化镁(24g/d)对西门塔尔牛瘤胃液pH和氨态氮(NH3-N)浓度的影响。结果表明:日粮添加丙酸镁、丙酸和氧化镁后,0h各组间pH差异不显著(P0.05),3h、6h丙酸镁和丙酸组pH较对照组和氧化镁组显著降低(P0.05),9h丙酸镁组pH与其他三组差异不显著(P0.05),丙酸镁组和丙酸组pH平均值较对照组和氧化镁组显著降低(P0.05);0h和9h各组间瘤胃液NH3-N浓度差异不显著(P0.05),3h和6h丙酸镁组瘤胃液NH3-N浓度显著低于其他组(P0.05),丙酸镁组瘤胃液NH3-N浓度平均值显著低于其他组(P0.05)。本试验条件下,日粮中添加丙酸镁可降低西门塔尔牛瘤胃液pH和NH3-N浓度。