禾草混播人工草地早期主要杂草种子库研究

对土壤主要杂草种子库的动态变化进行了研究,结果表明:1)随土壤深度的增加种子含量呈下降趋势,绝大部分种子分布在0~15 cm的土壤中。2)在高寒地区种子繁殖植物种子库的输出主要发生在5-6月,种子库种子1龄时大量输出,3龄、4龄时输出很少。3)一年生或二年生杂草在3龄、4龄草地中几乎“消失”,并不是土壤中缺乏种子。4)种子库中种子的生活力除灰绿藜Chenopodium glaucum外均大于90%。5)人工草地早期出现的多年生杂草种子发芽率高。     

冀西北坝上地区豆禾混播草地建植第三年草地生产力变化研究

为持续研究冀西北坝上地区豆禾混播对草地产草量及其品质的影响,本试验在国家牧草产业技术体系张家口综合试验站选择建植3年的豆禾同行混播草地,测定其产量和品质。结果表明：紫花苜蓿＋无芒雀麦＋垂穗披碱草(MWP)按豆禾比3∶7混播时,年干草产量最高,达9 612.52 kg·hm^-2,较单播紫花苜蓿提高了11.40%,较单播禾草提高了56.64%~61.80%;豆禾混播以MWP3∶7,MW5∶5组合CP、CF含量最高,MW3∶7、MWP3∶7酸性洗涤纤维(ADF)和中性洗涤纤维(NDF)含量最低,均与单播禾草之间差异显著;且MW3∶7第1茬、MWP3∶7第2茬牧草相对饲喂价值(RFV)与相对牧草品质(RFQ)显著高于其他混播处理及单播禾草。综上所述,豆科与禾本科在混播比例为3∶7,5∶5时产量与品质显著提升,以紫花苜蓿＋无芒雀麦组合与紫花苜蓿＋无芒雀麦＋垂穗披碱草组合同行混播效果较好。     

巴西红壤单一禾本科草地和禾本科——豆科混播草地的氮循环

通过比较单一Ｂｒａｃｈｉａｒｉａｄｅｃｕｍｂｅｎｓ草地与Ｂ．ｄｅｃｕｍｂｅｎｓ－Ｃａｌｏｐｏｇｏｎｉｕｍｍｕｃｕｎｏｉｄｅｓ混播草地，笔者运用氮平衡和过程定位方法探讨了改良巴西萨利得斯放牧系统氮循环的主要途径，两种方法均表明单一禾本科草地土壤中流失的氮，可以通过引入豆科植物而得到补充，豆科植物在系统中的作用就是增加共生固氮和加强凋落物及根物质的净矿质化作用，增加土壤有效氮从而获得氮正平衡，后者的曩     

新疆半干旱地区不同种类混播草地的牧草产量和营养价值研究

提高混播草地的生产力和维持其营养价值对提高新疆半干旱地区放牧家畜生产力具有重要意义.本研究选择4种牧草,以单播为对照,设置豆禾两种牧草和3种牧草进行混播,分析混播草地生产力和牧草营养价值变化.结果表明:与单播相比,混播草地不仅具有明显生物量优势,而且牧草的酸性洗涤纤维和中性洗涤纤维含量更低,粗蛋白含量、干物质消化率、干...     

高寒地区多年生禾草混播草地杂草防除研究

对高寒地区多年生禾草混播草地一龄的杂草进行了化学药剂的防除试验。结果表明:2,4 D丁酯、杜邦巨星和甲黄隆的最佳剂量分别为1188g/hm2,4.27g/hm2和3.32g/hm2。在最佳剂量下杂草防除效果均超过90%。     

混播草地禾草及土壤主要养分变化研究

在干旱条件下研究了豆科、禾本科牧草混播草地禾草粗蛋白质含量以及土壤耕层主要养分的变化。结果表明，生长第４年混播草地禾草叶片的粗蛋白质含量比单播禾草提高１９．１％，茎的粗蛋白质含量提高１８．１％；生长第３年混播草地土壤０￣３０ｃｍ的有机质提高８．５％，全氮提高１３．３％，速效钾提高１６．２％，全磷降低４．８％。     

混播草地中豆科牧草的固氮作用

对混播草地中豆科牧草的固氮价值，影响豆科牧草固氮作用的主要因素，豆科牧草种的固氮能力及其固氮效益进行了综合探讨，指出应利用植物潜在的固氮价值更经济地进行草地生产。     

高寒地区禾草混播人工草地建植早期杂草群落动态变化研究

对高寒地区禾草混播草地第一至第四年的草地群落杂草进行了研究。发现:1.从一龄草地到四龄草地一年生杂草种类减少,杂草种类总数增加,且增加的杂草是多年生。一龄、二龄草地杂草种类相同,为一年生;三龄、四龄草地一年生杂草减少。2.从一龄草地到四龄草地组分种数量特征发生重大变化。一年生杂草在一龄时为优势种,第二年就退出优势地位,第三年开始多年生虽单种数量较少但种类增加,从而杂草在群落中的地位又发生变化或加强了发生变化的潜力。3.化学防除对第一、二年的草地群落结构和产量都有重大的影响;施肥抑制杂草侵入,利于维持草地稳定;放牧促进杂草侵入,使草地退化加速。4.覆盖播种防除杂草的效果变化较大;单播草地稳定性差,2、3、4组合混播草地杂草群落在三龄时差异不大,但草地产量依次递增。5.从一龄到四龄禾草混播草地杂草群落的变化出现了4个明显的时期:一年生杂草占优势时期、多年生目标禾草占优势时期、多年生杂草大量出现的时期和多年生杂草占优势时期。     

绵羊对两种混播草地采食强度的研究

用分蘖、分枝标记法估测了绵羊对多年生黑麦草＋白三叶和绒毛草＋白三叶两种混播草地的三个采自指标：采食率、采良量和采食强度。结果表明，绵羊对混播草地中多年生黑麦草和绒毛草的采食强度大于相应的白三叶；绵羊对多年生黑麦草的采食强度显著高于绒毛草，两种草地中白三叶草的被采食强度之间无显著差别。     

西藏地区不同牧草体外发酵特性研究

本文旨在利用体外产气法评定西藏地区不同牧草营养价值。选取西藏地区5种常见牧草,通过单因素试验设计,利用体外产气法评定5种牧草体外发酵48 h累积产气量、理论最大产气量(V_f)、初始产气速率(FRD_0)、达到最大产气量一半时所需时间(t_(0.5))、体外干物质消失率(IVDMD)、体外中性洗涤纤维消失率(IVNDFD)、p H、氨态氮(NH_3-N)浓度以及挥发性脂肪酸(VFA)产量。结果表明,体外发酵48 h后,苇状羊茅体外48 h累积产气量、V_f、FRD_0、IVDMD及甲烷(CH_4)、乙酸、丙酸、丁酸和总VFA产量均显著高于其他4种牧草(P0.05),但其体外发酵p H及乙酸/丙酸显著低于其他4种牧草(P0.05);紫花苜蓿体外NH_3-N浓度最高,显著高于其他4种牧草(P0.05)。综上分析,苇状羊茅体外发酵效果最佳,与其他试验牧草相比,更容易被瘤胃微生物降解利用。     

高寒地区暖季草场放牧牦牛的生产性能及其土壤养分变化

旨在通过不同放牧强度下高寒小嵩草(Alpine Kobresia parva(Nees)Wang et Tang ex Y.C.Yang)草甸和垂穗披碱草(Elymus nutans Griseb.)/星星草(Puccinellia tenuiflora(Griseb.)Scribn.et Merr.)高寒混播草地暖季草场植物初级生产力、土壤养分含量以及牦牛生产性能的研究,为草地合理利用提供有益的依据。结果表明:牦牛个体增重与放牧强度均呈线性关系;高寒小嵩草草甸暖季草场最适放牧强度为1.26头/hm²,垂穗披碱草/星星草混播高寒混播草地暖季草场的最适放牧强度是7.23头/hm²;放牧强度对高寒混播草地速效氮和速效磷的影响不显著,对速效钾的影响显著(P<0.05);随着放牧强度的提高,高寒小嵩草草甸土壤有机质、有机碳、全氮、全磷的含量呈减小趋势;当放牧强度分别达到1.07头/hm²,1.08头/hm²和1.22头/hm²时,0~5 cm,5~10 cm,10~20cm土壤速效氮含量依此达到最小;随着放牧强度的提高,高寒小嵩草草甸禾草和莎草的比例下降,可食杂草和毒杂草比例增加,而高寒混播草地垂穗披碱草的比例降低,星星草和杂类草的比例增加。     

Avian Community Response to Grazing Intensity on Monoculture and Mixed Florida Pastures

Monoculture and mixed pastures in Florida provide habitat for a variety of resident and migratory bird species. The objectives of this study were to investigate the effects of grazing on vegetation structure and bird species richness and abundance in grazed monoculture and mixed pastures. Study pasture units were subject to four cattle grazing intensities: 0 = nongrazed (control), 15 = low, 20 = medium, or 35 = high animal units (AU) per pasture unit (no cattle, 1.3, 1.0, and 0.6 ha · AU^?1, on monoculture pastures and no cattle, 2.1, 1.6, and 0.9 ha · AU^?1, on mixed pastures). Monoculture pastures displayed a greater decrease in spatial heterogeneity of the vegetative community in the presence of grazing than mixed pastures. An increase in grazing intensity led to declines in total avian species richness and abundance and species richness within short-distance migrant, neotropical migrant, and permanent resident guilds on monoculture pastures. Declines in total species richness and abundance and neotropical migrant guild species richness and abundance were observed on mixed pastures subject to increasing grazing intensity. However, species richness within short-distance migrant and urban guilds and abundance within the grassland guild increased on this pasture type in the presence of grazing. Loss of spatial heterogeneity typically results in a lack of suitable habitat for birds that occupy the extremes of the vegetation structure gradient. This can lead to a loss of species richness and abundance. For the majority of avian guilds, a low grazing intensity of 1.3 ha · AU^?1 and 2.1 ha · AU^?1 on monoculture and mixed pasture, respectively, is recommended to maintain abundance. However, these grazing intensities may result in declines in species richness. Ultimately, if a range of avian species are to be supported on monoculture and mixed pastures, spatial heterogeneity of plant structure and composition must be maintained.     

Agrosilvopastoral Systems and Well-Managed Pastures Increase Soil Carbon Stocks in the Brazilian Cerrado

Agrosilvopastoral systems have been promoted as sustainable models that combine crops, livestock grazing, and forestry in the same area. We hypothesize that agrosilvopastoral systems can improve soil C and N stocks over time. Therefore, in this study, we aimed to evaluate the changes in soil C and N stocks after conversion of low-productivity pasture into well-managed pasture and agrosilvopastoral land in the Brazilian Cerrado. Soil samples were collected in 2016 and 2018 at 0–5, 5–10, 10–20, and 20–30 cm depths from the following areas: integrated crop-livestock-forest (ICLF), marandu grass (Brachiaria brizantha) monoculture (MAR), low productivity pasture of signal grass (Brachiaria decumbens) monoculture (PAST), and native vegetation (NV; “Cerrado”). The C and N content and stocks, ¹³C natural abundance, and C contents in the physical and chemical fractions of soil organic matter (SOM) were measured. The ICLF and MAR systems promoted faster recovery of soil C and N stocks at all soil depths compared with PAST. The C content of the free light fraction of SOM under the ICLF and MAR systems increased, reaching values similar to NV up to 20 cm. The C content was higher in the humin fraction at all depths in all areas, and for this measurement, the ICLF system performed remarkably compared with PAST at a depth of 5−10 cm. Our findings support the hypothesis that conversion of low-productivity pasture into agrosilvopastoral and actively managed pasture systems leads to improvements in soil quality and C and N stocks in the Brazilian Cerrado.     

贵州高寒山区不同牧草混播组合效果试验

为提高贵州高寒山区人工草地的生产能力,2018—2020年在威宁彝族回族苗族自治县塔山村开展牧草混播组合试验。A组：20%威宁球茎草芦+40%雅晴多年生黑麦草+20%海发白三叶+20%瑞德红三叶;B组：20%威宁球茎草芦+50%安巴鸭茅+30%海发白三叶;C组：30%法恩苇状羊茅+40%雅晴多年生黑麦草+30%三得利紫花苜蓿;D组：40%安巴鸭茅+30%雅晴多年生黑麦草+30%三得利紫花苜蓿;E组：40%威宁球茎草芦+30%雅晴多年生黑麦草+30%海发白三叶。随机区组设计,连续3年对牧草的产量和营养成分进行测定,第3年取混合样对营养成分进行分析。结果：A、E组牧草产量显著高于B、C、D组(P<0.05);A、C、E组各年度间组分变化不大,稳定性较强;A、D、E组的粗蛋白含量较高,均超过16%。结论：A、E组适宜作为贵州高寒山区的人工草地混播组合。     

Grazing Protection Influences Soil Mesofauna in Ungrazed and Grazed Riparian and Upland Pastures

The influence of grazing protection caused by streambank fencing on soil mesofauna density is unknown. Our objective was to determine if grazing protection (ungrazed vs. grazed), location (upland vs. riparian pasture), and seasonal (spring vs. fall) treatment effects associated with streambank fencing had a significant influence on soil mesofauna distribution and density. We collected five intact soil cores (0–5 cm depth) in June and October of 2012 from within four treatments consisting of ungrazed and grazed riparian and upland pastures associated with streambank fencing along an 800-m reach of the Lower Little Bow River in southern Alberta, Canada. Soil mesofauna were extracted and densities of Acari (mites) taxa, Collembola (springtails) taxa, and other mesofauna were determined. Grazing protection resulted in a significant (P ≤ 0.05) negative response of Astigmata mite densities for the upland pasture, and a positive response for Oribatida mites and total Collembola, and Hypogastruridae and Onychiuridae springtails for both pastures. Location and season had a significant influence on Acari and Collembola taxa, but the effects were dependent on interaction effects. We conclude that grazing protection influenced certain soil mesofauna in pastures associated with streambank fencing, and this may influence decomposition of soil organic matter, nutrient cycling, and soil structure in associated pastures.     

修剪频率对混播草坪土壤呼吸特征的影响

以草地早熟禾(Poa pretensis)和高羊茅(Festuca arundinacea)混播草坪为研究对象,采用开路式土壤碳通量测量系统Li-8100对不同修剪频率下草坪的土壤呼吸昼夜变化特征进行研究,旨在探讨修剪对城市草坪土壤呼吸特征的影响。结果表明:草坪在1周修剪1次、2周修剪1次和常规修剪(对照)这3种情况下,其土壤呼吸速率昼夜变化均呈单峰曲线模式,且3种情况下草坪土壤呼吸速率日最高值均出现在12:00-14:00,而日最低值出现的时间不一;从草坪土壤日呼吸总量来看,6月与7月草坪在1周修剪1次处理、2周修剪1次处理和对照之间差异均不显著,8月草坪在1周修剪1次处理下与对照之间差异不显著,而两者与草坪2周修剪1次的处理之间差异显著(P<0.05);从整体来看,3种情况下草坪的土壤呼吸速率均与5 cm土层地温成显著正相关(P<0.05),与其他温度指标的相关性因不同月份和不同处理而不同,而草坪土壤呼吸的Q₁₀值的大小基本上都随着土层深度增加而增加。     

虉草人工草地的生长动态研究

对虉草人工草地的株高、生长速率、种群密度、种群出生率和地上生物量动态进行了研究,结果表明:虉草种群出生率呈现多峰型周期性变化,整个生长季出现3次峰值,以拔节-抽穗期种群出生率最高(41.77%);株高生长曲线呈单峰型,孕穗-开花期生长速率最大(3.17cm/d),盛花期后生长速率递降;株高与叶片数的季节变化动态均呈"S"型曲线;随草地年龄增加,地上生物量和种群密度呈现逐渐上升的趋势,表明试验期内虉草种群仍处于增长期。     

鹅放牧散养与果园杂草控制的研究

旨在探索“果园—鹅”共作处理的果园控草模式。该模式对梨园杂草的田间均度和密度均产生显著影响,打碗花、野苋等鹅喜食杂草的降幅明显,而蛇莓、朝天委陵菜等杂草则大幅增加;夏季成年梨园每667m2放养10只四季鹅,可以达到鹅采食量与杂草生长量的相对平衡。