封育刈割放牧对草地植被的影响

通过年定位试验研究,比较全面地总结了在封育,刈割,放牧等不同条件的影响下,草地植牟群落结构和生物量的一系列变化,以及草地植被动态变化过程。     

草地雀麦刈割对坡地水土流失的影响

在自然降雨条件下,选择25°坡地种植草地雀麦,建立径流试验小区,并在抽穗期进行刈割处理,研究刈割后草地雀麦生物学特性变化及其对坡地水土流失的影响。结果表明:坡地种植草地雀麦,水土流失防治效果显著,可使25°坡地地表年径流量与土壤侵蚀模数达到6 781.7 m3/km2和36.4 t/km2.a,保水、固土能力为93.0%和99.9%。草地雀麦抽穗期刈割,对其固土能力影响不大,仍可保持93.8%,但对其保水能力影响显著,一定程度上可以增加坡面径流流失,使保水能力降低到53.9%。草地雀麦覆盖对坡地土壤侵蚀影响显著,抽穗期刈割草地雀麦,短期内可使坡面覆盖度下降,土壤侵蚀增加,但随着草地雀麦不断再生,覆盖度快速增加,达到76.7%以后,刈割与无刈割坡地的土壤侵蚀量差异不显著。草地雀麦覆盖度与土壤入渗率对坡地地表径流流失均有一定影响,抽穗期刈割,可使草地雀麦覆盖度减小,0~30 cm土层地下生物量与无刈割坡地相比,减少33.4%,土壤入渗率相应降低,地表径流有所增加。     

刈割对天山北坡草甸草原生物量的影响

[目的]以天山北坡羊茅+杂类草草甸草原为研究对象,研究刈割对草地生物量的影响,探讨地下生物量的形成规律。[方法]采用模拟放牧方式设置休牧、轻度放牧、中度放牧、重度放牧4个处理,测定分析草地生态系统生物量的变化。[结果]随着放牧强度的增大,草本生物量和凋落物逐渐下降,且下降幅度逐渐增大。与休牧相比,轻牧、中牧和重牧的草本生物量分别下降了27.51%,45.28%,65.05%。9月各处理地下生物量与6月相比分别增加了16.05%,13.07%,19.15%,19.08%,0—20cm土层的地下生物量占总地下生物量的85%,呈T型分布,向下递减趋势明显。[结论]放牧强度对植物地上生物量影响明显,表现为:休牧轻牧中牧重牧;季节变化中7月份地上生物量最大,显著高于9月;0—100cm土壤深度中各处理对地下生物量影响表现为:轻牧休牧中牧重牧;各处理下地下生物量的垂直分布变化趋势相同,即地下生物量集中分布在0—10cm土层,该层生物量占总地下生物量的70%,且随着土壤深度增加不断减少;季节变化中,地下生物量变化表现为:9月6月,各层生物量随土层深度的增加向下递减趋势明显。     

植被刈割对红壤酸度及有机无机复合状况的影响

在红壤地区自然植被（白茅）条件下,不同的刈割周期对土壤交换性盐基离子组成、土壤有机质、有机无机复合体、腐鱼质组成及铁、铝氧化物含量等均具有较大的影响。从１年刈割一次至６刈割一次处理,虽然土壤酸度的变化无明显规律,但土壤交换性钾、无定形铁、无定形铝、络合态铁的含量及铁活化度值均呈增加趋势,且土壤有机质和复合体的含量相应增高,松结态腐残质／紧结态腐殖质的比值亦增大,即腐残质的活性较强、质量较高,土壤肥     

芨芨草产量结构及刈割强度对其再生性影响的初步探讨

对芨芨草产量结构、刈割强度及其再生性的影响做了初步探讨，结果表明：(1)芨芨草的产量结构从基部到顶部呈下降趋势，在0～10cm，非同化器官的生物量远远大于同化器官的生物量，10cm以上同化器官和非同化器官生物量的差异不大；(2)留茬4cm的芨芨草日增长速率显著高于不留茬时的日增长速率。     

不同品种冬小麦再生生长对刈割干扰的响应

为探究不同熟性冬小麦品种库源分配对刈割的响应,在温室控制条件下,选取陇东地区常用的中熟(‘宁麦5号’和‘陇育4号’)和晚熟(‘西峰27号’和‘陇育1号’)冬小麦品种,测定不同品种冬小麦不刈割(对照)以及分蘖期刈割(留茬2 cm)后再生生长早期叶面积指数,花期和成熟期的物质分配构成。研究结果表明:不同熟期冬小麦刈割再生后的叶面积指数、光合产物分配均有所不同。刈割后再生生长早期,4个品种叶面积指数较未刈割均显著下降;再生至花期中熟品种‘宁麦5号’和‘陇育4号’的叶面积指数仍显著降低27%和17%,晚熟品种‘西峰27号’略降低6%,‘陇育1号’则上升7%。中熟品种‘宁麦5号’和‘陇育4号’再生至花期地上生物量降低18%和11%,晚熟品种‘陇育1号’上升13%;各品种再生至花期地下生物量较未刈割均呈下降趋势,并且中熟品种的下降幅度小于晚熟品种,但晚熟品种在成熟期出现增加趋势,‘陇育1号’显著增加26%。再生至花期中熟品种各部分可溶性碳水化合物含量均降低,而晚熟品种‘陇育1号’各部分可溶性碳水化合物含量增加2%~12%。可见晚熟品种‘陇育1号’再生至花期可溶性碳水化合物含量及干物质向叶、穗分配增加,资源再分配、源库协调能力强,为后期籽粒产量形成奠定了良好的基础,较中熟品种更适于在分蘖期利用青饲草、成熟期收获籽粒的利用方式。     

不同资源条件下刈割对植物再生能力的影响

以甘南地区高寒草甸中10种常见植物为对象,通过田间模拟试验,对不同生长期内的植物个体进行不同程度的刈割、施肥处理,以探讨不同资源条件下刈割对植物再生能力的影响.结果表明:多数情况下,适口性较好的植物的补偿能力较高,适口性较差的补偿能力较低.垂穗披碱草、燕麦、多枝黄芪、矮嵩草在高资源条件下的生物量补偿程度低于低资源条件,金花苜蓿、珠芽蓼、中华羊茅、獐牙菜、细叶亚菊及藏蒲公英则相反;中华羊茅、细叶亚菊、珠芽蓼在高资源条件下繁殖部分的补偿程度较高,其余7种则相反.不同资源条件下10种植物在总生物量、现存生物量方面的补偿能力排序一致,说明综合补偿指数能较好地反映刈割后植物在总生物量、现存量方面补偿能力的种间差异.本研究结果说明不同资源条件下,生存对策是影响植物再生能力的主要因素,且综合补偿指数可以更客观地反映植物的再生特点.     

水生植物刈割对生态沟渠中氮、磷拦截的影响

本研究选用生态沟渠中水生美人蕉、铜钱草、黑三棱、穗花狐尾藻和灯心草作为试验植物,通过比较刈割区和未刈割区底泥样和植物样氮、磷含量及水样氮、磷去除率,分析刈割措施对生态沟渠拦截氮、磷效果的影响。结果表明,5种植物(300 m2)2次刈割试验共带走全氮11.889 kg和全磷1.099 kg;其中,不同植物收获全氮表现为水生美人蕉(7.686 kg)>穗花狐尾藻(1.501 kg)>铜钱草(1.128 kg)>灯心草(0.974 kg)>黑三棱(0.601 kg),收获全磷表现为水生美人蕉(0.433 kg)>穗花狐尾藻(0.233 kg)>黑三棱(0.191 kg)>铜钱草(0.134 kg)>灯心草(0.109 kg)。刈割管理还可以提高沟渠底泥中氮、磷的去除率(黑三棱除外)。与未刈割区相比,刈割提高底泥全氮和全磷的去除率次序分别为穗花狐尾藻(20.73%)>铜钱草(20.00%)>灯心草(16.05%)>水生美人蕉(4.86%)>黑三棱(9.72%)和灯心草(20.69%)>铜钱草(16.67%)>水生美人蕉(4.55%)>穗花狐尾藻(0.00%)>黑三棱(16.00%)。刈割后的水体氮、磷去除结果也说明植物刈割可以提高水生植物对氮、磷的净化效果。因此,植物刈割管理既能直接转移出沟渠中的营养物质,也提高了沟渠底泥和水体中氮、磷的去除效率。     

不同干燥方法对生姜粉物理性质的影响

采用离心喷雾干燥、热风干燥、远红外干燥、真空冷冻干燥对安徽临泉产新鲜生姜进行干燥制粉，研究干燥制粉后的生姜粉的物理性质。结果表明：喷雾干燥的生姜粉容重较高，而得率、水合能力、吸油能力以及感官性能都是最差的；远红外干燥的生姜粉得率和容重最高，水合能力、吸油能力及感官性能较好；热风干燥的生姜粉水合能力最好，而得率、容重、吸油能力和感官性能都仅次于远红外干燥的姜粉；真空冷冻干燥的生姜粉得率和水合能力居中，容重最低，吸油能力和感官性能最好。     

苜蓿草粉对45#钢磨损性能的影响

以苜蓿草粉为磨料在磨料磨损试验机上采用二次正交旋转回归试验法分析了磨料粒度、转速和载荷3个条件因素对45#钢磨损量的影响规律,确定了磨损试验的最佳条件。在该条件下考察了苜蓿草粉对2种不同热处理的45#钢的软磨料磨损行为,用扫描电子显微镜对磨损表面形貌进行观察。结果表明,影响45#钢磨损性能的3因素由大到小依次为转速、磨料粒度和载荷;亚温淬火比退火的45#钢的耐磨性好;苜蓿草粉磨料对45#钢表面的磨损是软、硬磨料共同作用的结果。退火45#钢的软磨料磨损以多次塑性变形萌发的低周期疲劳剥落为主要磨损机制,淬火45#钢则以显微切削为主要磨损机制。     

The productivity and energy potential of alfalfa,fodder galega and maize plants under the conditions of the nemoral zone

This study aimed to investigate the productivity of two C3 legumes – alfalfa (Medicago sativa L.) and fodder galega (Galega orientalis Lam.) – and the feasibility of their use as renewable energy resources. Maize (Zea mays L.), a well-established bioenergy crop belonging to the C4 plant group, was used as a baseline in comparison. Field trials were conducted at the Institute of Agriculture at the Lithuanian Research Centre for Agriculture and Forestry during the period 2012–2013. The perennial forage legumes were grown without mineral or organic fertilizers. The maize was grown (a) without and (b) with nitrogen fertilizers. The perennial forage legumes were harvested three times per growing season. Carbon (C), nitrogen (N) and sulphur (S) contents of biomass were determined by using a dry combustion method. The calorific value of biomass was determined by a combustion method using an IKA bomb calorimeter. The largest share of the total annual yield of biomass of perennial forage legumes was obtained from the first cut and amounted to 54% and 57% for alfalfa and fodder galega, respectively. The S content of biomass was similar in all crops investigated, but the N content was higher in perennial forage legumes. Biomass C content did not differ between the crops, but the C:N ratio was widely varied – from 28–35 in fertilized maize, to 16–17 in alfalfa and 15–16 in fodder galega. This study showed that alfalfa and fodder galega can be grown as energy crops under less intensive management; however, the specific chemical composition of biomass should be considered before choosing the most appropriate conversion process.     

Effects of organic solid cattle manure application on nutritive value of winter cereal forages

Nutritive value of winter cereal forages is one of interested subjects of farmers for animal feeding. Field experiments were established in 2007–2008 and 2008–2009 growing seasons in northeast Turkey to investigate the effect of organic solid cattle manure application (0, 10 and 20 Mg ha^?1 yr^?1) on nutritive value of three annual cereals for forage. The winter cereal forages were: wheat (Triticum aestivum L.), oat (Avena sativa L.) and rye (Secela cereale L.). ADF (acid detergent fiber), NDF (neutral detergent fiber) CP (crude protein), nitrogen, phosphorus, potassium, sulfur, calcium, copper, iron, magnesium, manganese, sodium, zinc and boron (N, P, K, S, Ca, Cu, Fe, Mg, Mn, Na, Zn and B) concentrations were researched in this study. Wheat had the highest CP, N, Ca, Cu, Na and Zn concentration, whereas oat had the lowest ADF and NDF and the highest K, Fe and Mn concentrations. The greatest Mg and P concentrations were determined in rye. Organic solid cattle manure applications had no effect on N and CP contents, but it decreased ADF and NDF contents. However, in most cases it positively affected the P, B, Cu, Fe, Mg and Na concentrations, whereas it decreased K, Ca, Mn and Zn concentrations. The results showed that wheat and oat are more nutritive species than rye in terms of animal feeding and the organic solid cattle manure, in some cases increased the nutritive values of wheat, oat and rye under organic agriculture conditions.     

黄颡鱼的含肉率及肌肉营养价值研究

采用常规方法测得广西桂江黄颡鱼的含肉率为 83.88% ;每 1 0 0 g肌肉 (干样 )中含粗蛋白85.96g,粗脂肪 5.0 4 g,粗灰分 5.57g,氨基酸总量为 70 .2 1 g,必需氨基酸含量 2 7.39g,含钙 39.58mg,磷 1 87mg,铜 0 .33mg,锌 5.33mg,铁 4 .75mg,锰 3.0 3mg,硒 74 7.0 6μg。综合分析结果认为 ,广西桂江的黄颡鱼是营养价值较高的优质鱼类     

外源甘氨酸对镉胁迫下苜蓿幼苗生长和氧化损伤的影响

以苜蓿为试验材料,分析了甘氨酸处理对幼苗镉(Cd)毒害缓解的生理机制。Cd毒害降低了苜蓿幼苗超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,导致幼苗出现氧化伤害,如丙二醛(MDA)含量升高,伊文斯蓝(Evans blue)染色加深。甘氨酸处理提高了苜蓿幼苗SOD和CAT活性,降低了MDA的累积,减少了氧化伤害。Cd毒害还降低了幼苗硝酸还原酶(NR)活性,外源甘氨酸处理则显著提高其NR活性。施用NR抑制剂钨酸钠降低了苜蓿幼苗的NR活性,同时抵消了甘氨酸对Cd胁迫幼苗的生长缓解作用。表明甘氨酸通过提高苜蓿幼苗的抗氧化能力和NR活性,从而提高幼苗对Cd胁迫的耐受性。     

沼渣营养价值及沼渣源饲料和其生产的猪肉重金属残留分析

对牛粪、玉米秸秆作为发酵原料生产沼气的发酵残留物--沼渣的营养价值及沼渣源配合饲料和沼渣源配合饲料生产的猪肉的重金属残留进行了分析.结果表明,风干沼渣中干物质、粗蛋白、粗脂肪、粗灰分、粗纤维含量分别为857.7mg·g-1、99.0mg·g-1、34.9mg·g-1、10.7mg·g-1、252.7mg·g-1;重金属元素镉、铅、铜含量分别为18.48P,g·kg-1、42.50μg·kg-1、20.80μg·kg-1,汞未检出.对照组、沼渣Ⅰ组、沼渣Ⅱ组饲料中镉、铅、铜、汞的含量均低于国家饲料卫生标准;猪肉中重金属镉、铅、铜含量对照组、沼渣Ⅰ组、沼渣Ⅱ组分别为0.033mg·kg-1、0.044mg·kg-1、0.058mg·kg-1,0.268mg·kg-1、0.364mg·kg-1、0.393mg·kg-1,5.555mg·kgM-1、7.180mg·kg-1、8.404mg·kg-1,汞均未检出.沼渣作为猪饲料源利用有一定的潜力,以2%～10%在饲料中添加不会引起猪肉重金属镉、铅、铜、汞含量超标.     

苜蓿干燥特性试验研究

该文在薄层干燥试验台上研究了苜蓿的干燥特性。试验结果为：干燥温度越高,苜蓿的干燥速度越快。试验确定了临界干燥速度与干燥温度间的方程,定量分析了苜蓿干燥速度与干燥温度间的关系。运用量纲分析方法,得到干燥动力学常数K与初始含水率M_o,样品质量G,干燥温度T,介质流速v,茎秆长度l的经验公式,可以准确分析和评价苜蓿在各种条件下的干燥特性。     

Soil carbon pool and effects of soil fertility in seeded alfalfa fields on the semi-arid Loess Plateau in China

The dynamics of the soil organic carbon pool and soil fertility were studied in soils with different number of growing years of alfalfa (Medicago sativa L.) in the semiarid Loess Plateau of China. The soil water content and soil water potential decreased and the depth of desiccated layers grew with the number of growing years of alfalfa. The soil organic C (SOC) cannot be enhanced on short timescales in these unfertilized and mowed-alfalfa grasslands in the topsoil, but the light fraction of organic C (LFOC), soil microbial biomass C (MBC) and microbial biomass N (MBN) all increased with the number of growing years. When alfalfa had been growing for more than 13 yr, the soil MBC increased slowly, suggesting that the MBC value is likely to reach a constant level. SOC, soil total P (STP), available P (AvaiP) and the ratio of SOC to soil total N (C/N) all decreased monotonically with the growing years of alfalfa up to 13 yr and then increased. SOC was significantly positively correlated with STP, AvaiP, soil total C (STC) and soil total N (STN) (R=0.627**, 0.691**, 0.497*, 0.546*, respectively). MBC and LFOC were significantly positively correlated with the number of growing years of alfalfa (R=0.873*** and 0.521*, respectively), and LFOC was more sensitive to vegetation components, degree of cover and landform than to the number of years of growth. SOC showed a significant negative correlation with LFOC/SOC and MBC/SOC (R=−0.689**, −0.693**, respectively). A significant positive correlation exists between MBC and soil inorganic C (SIC). LFOC, MBC, LFOC/SOC and MBC/SOC were all significantly positively correlated with each other. Therefore, practices that involve water-harvesting technologies and add residues and phosphate fertilizer to soils should be promoted to improve soil nutrients and hydration and to postpone the degradation of alfalfa grasslands under long-term alfalfa production.     

秸秆热解气化工程生态价值量估算方法研究

秸秆热解气化工程是一项高质消纳秸秆资源的生态生产工程,工程项目将秸秆资源转换产出"气、炭、油、液",实现了秸秆资源的生态价值,对我国农业领域落实国家节能减排任务具有重要实践意义。准确估算秸秆热解气化工程的生态价值量,提供系统全面的定量评价指标体系与计算方法,是有效推动农业绿色发展的重要科学依据。本研究基于生态价值理论中的二分法理论,对秸秆热解气化工程生态价值量的构成进行分析,得出秸秆热解气化利用项目主要产生的生态效益资产由减排效益资产与废弃资源商品化资产共同构成。据此,建立了秸秆热解气化工程生态价值量估算总公式,即:秸秆热解气化工程生态价值量(V_(PE))=秸秆热解气化工程减排效益货币价值(V_(EB))+秸秆资源产品经济价值(V_(RC))。在计算过程中,选取生命周期分析(LCA)法计量秸秆热解气化工程项目的净减排量,并借助二氧化碳影子价格将净减排量进行货币化,得到工程减排效益资产(V_(EB));而后,计算出通过生态生产项目实现的秸秆资源产品经济价值(V_(RC));最终,将V_(EB)与V_(RC)加总,得到秸秆热解气化工程生态价值量(V_(PE))。本研究在方法构建的同时,采用文献调研法对各个计算环节所需参数的选取进行了分析与对比,提供了计算过程所需的参数体系。本研究在方法研究与参数研究一体化研究过程中,力图在以下3个方面取得实质性的突破和创新:一是不仅局限于从减排效益视角进行分析与研究,系统全面构建秸秆热解气化工程项目生态价值量估算模型。二是明确将项目生态"潜在价值"合理转化为市场"真实价值",以货币价值形式对秸秆热解气化项目生态效益进行计价衡量。三是本研究在终端能源产品替代减排量估算研究过程中,考量了不同技术工艺水平和产品的能源转换率对温室气体排放的影响。     

基于CVM的闽江河口湿地生态系统非使用价值评价

以东亚—澳大利西亚候鸟迁徙路线上重要的驿站——闽江河口湿地为例,运用支付卡式条件价值评估法（CVM）,对该湿地生态系统的支付意愿进行面对面的问卷调查。共发放支付卡式CVM问卷500份,回收有效问卷482份,估算出闽江河口湿地生态系统的算术平均支付意愿值为151.16元/a,累计频度中位数为56.36元/a,支付意愿值相对分布频度曲线基本呈单调递减分布;考虑到本文目的是核算闽江河口湿地生态系统的经济价值,并为相关部门提供科学决策,因此,采用算术平均值计算其非使用价值,其值为5.01亿元/a;Spearman秩相关系数分析表明支付意愿与收入水平、受教育程度、年龄、性别和职业呈显著相关关系。     

The effect of suppression treatments on the uptake of 15N by intercropped corn from labeled alfalfa (Medicago sativa)

In greenhouse experiments, we examined the N transferred to intercropped corn from ¹⁵N-labeled alfalfa shoot residue and intact roots in an undisturbed soil system in response to two different suppression treatments and complete killing of alfalfa. The alfalfa treatments included complete killing (glyphosate only), glyphosate injury + cutting, and cutting only, with alfalfa shoot residue returned to the soil surface in all three treatments. Corn was planted in each pot following application of the treatments. When alfalfa was suppressed by glyphosate injury + cutting, corn had recovered 12% of the alfalfa N by 8 weeks of growth, but with cutting only, N recovery by corn was reduced to 4.0%. The completekill treatment resulted in 8% recovery by corn of alfalfa N. In all treatments, most of the alfalfa-N remained in the soil organic pool. A second experiment tested a cutting only treatment with ¹⁵N-labeled alfalfa residue returned to the soil surface. The ¹⁵N-labeled alfalfa residue contributed 4.1% of N to corn during the 8-week growth cycle. Twice as much ¹⁵N was found in the active microbial biomass pool in the two treatments with live intereropped plants compared to the monoculture treatments with complete killing (non-intercropped) and the control treatment of alfalfa regrowth only. An analysis of the change in the ¹⁵N content of the undisturbed alfalfa roots from just before the suppression until 8 weeks later suggested that approximately 80% of the root ¹⁵N was lost from the plant suppressed by cutting. This corresponds to 28% of the total N released from the alfalfa. The results suggest that the degree of legume suppression was a key factor in the availability of legume N to the second crop. When the two species were intercropped, more of the N available from legume residues went to plant uptake and microbial biomass and was not stabilized as quickly in the soil organic pool. Appropriate management schemes must be designed to increase N availability to the second crop without yield reduction. These studies suggest severe suppression is necessary; if successful, more of the N can be maintained in active pools.