以草本植物为原料的稀酸预处理及发酵研究

研究了杂交狼尾草和沙打旺2种草本植物在3种不同预处理方法及双酶糖化条件下葡萄糖和乙醇得率,评价其能源性差别.切短为对照组,处理组分别为粉碎,粉碎+1.5%硫酸,1.5%硫酸.测定处理前后纤维素、半纤维素和木质素的含量并分析SEM纤维结构图,采用SSF发酵工艺.结果表明,纤维素的含量分升高了1.29%～7.32%,半纤维素和木质素的含量分别降低了4.10%～11.98%、1.56%～3.00%.SEM纤维结构图网状纹理变得清晰.在pH4.8缓冲液体系发酵过程中,葡萄糖浓度缓慢增加,而乙醇浓度呈先增加后降低趋势,发酵后72 h出现峰值.加入果胶酶试验组的乙醇浓度值与对照组比高出0.18%～0.63%(P≤0.05).除粉碎+1.5%硫酸处理外,其它预处理方法提高了杂交狼尾革和沙打旺的纤维素、半纤维素酶解率和发酵转化率,且1.5%硫酸处理组的效果最好,杂交狼尾草的能源性好于沙打旺.     

Forage Yield and Sucrose Response of Rhodes and Ruzi Grass to Cutting Height and Cutting Frequency Under Irrigation

The development of irrigated pastures in the Sudan is still at its infancy. The present study determined the influence of 2 cutting heights (2.5 and 5.0 cm) and 4 cutting frequencies (4-, 6-, 8-, and 10-week) on forage yield as dry matter and forage sucrose of Rhodes grass ( Chloris gayana Kunth. cv. Massaba ) and Ruzi grass ( Brachiaria ruziziensis Germain et Everard cv. Congo Signal ) under irrigated conditions. Forage yield interactions involving species X cutting height X cutting frequency were significant. These yield interactions were attributed to differences in growth period and growth rhythm of the two species. On average, Rhodes exhibited a short growth period (13 months) compared to Ruzi grass (20 months). Forage yield and forage sucrose were, on average, superior in Ruzi compared to Rhodes grass. Forage yield and forage sucrose averaged 5.2 t ha⁻¹ and 7.2 % fw sucrose in Ruzi compared to 2.8 t ha⁻¹ and 6.9 % fw sucrose in Rhodes grass. Forage yield and forage sucrose of both species were negatively correlated with cutting frequency. The highest forage yield may be obtained at an 8-week cutting frequency in Rhodes (45.6 t ha⁻¹ yr⁻¹) compared to a 10-week cutting frequency in Ruzi grass (88 t ha⁻¹ yr⁻¹). Results suggest that very high forage yields as dry matter and forage sucrose of Rhodes and Ruzi grass may be possible under irrigated conditions in the Sudan at a cutting frequency of between 8 to 10 weeks.     

豆科牧草纳入耕作制的生态经济效益研究

在四川大足县生态农业试验区,通过对豆科牧草与粮作轮作、粮粮轮作和果园间种豆科牧草的生态经济效益研究,结果表明将豆科牧草纳入耕作制是旱地利用的新途径。     

黄河故道风沙区牧草控制风蚀效果的研究

通过野外测试与室内分析相结合的方法，对黄河故道风沙区种植牧草后的土壤风蚀特征进行了研究，结果表明：试验区土壤风蚀季相特征不同，以春季风蚀剧烈，而冬季次之。对照区年风蚀深度达5.2cm，与之相比，牧草种植小区年风蚀深度下降了69．62％～80．58％。不同牧草对风蚀的减弱程度不同，差异明显。种植牧草可增大地表粗糙度，降低近地表风速，风速降低幅度为30．17％～60．31％，达到防止风蚀的目的，并通过生物改良和阻滞堆积使细粒物质增多，增强抗蚀性。     

不同牦牛放牧率下江河源区垂穗披碱草/星星草混播草地第一性生产力及其动态变化

江河源区2龄和3龄混播草地（垂穗披碱草＋星星草）牦牛放牧试验结果表明：在两个放牧季内，不同处理组的地上生物量开始阶段逐渐增加。之后逐渐下降。且随放牧率的增加同一时期地上生物量减小；2003年从7月20日开始、2004年从8月5日开始至9月20日，不同放牧率下同一时期的地上生物量差异显著（P〈0．05）；各放牧处理区2003年同一时期的地上生物量均高于2004年。且牧草生长季节地上平均生物量及其年度变化之间的差异显著（P〈0．05）。此外，不同放牧率下同一时期各土壤层地下生物量及其百分比组成、相同放牧强度下不同时期各土壤层地下生物量及其百分比组成均没有明显的趋向性变化；牧草生长季节地上平均生物量与放牧强度之间呈线性回归关系。0～30cm的地下生物量（包括活根和死根）与放牧强度之间呈二次回归关系；牧草生长季节地上与地下平均生物量之间呈二次回归关系，说明轻度放牧和中度放牧能刺激牧草的生长，具有补偿或超补偿生长的特点。     

草坪主要单子叶杂草防除

概述了目前草坪单子叶杂草的防除进展和存在的问题。明确主要恶性单子叶杂草的生物学特性和发生规律,提高草坪的管理水平、选择和培育适合当地生长的草坪草种,采用混播栽培管理措施和合理运用化学方法来综合防除单子叶杂草。创造有利于草坪草生长而不利于单子叶杂草生长发育的环境,使杂草在竞争中自然淘汰。     

Soil properties and plant production after short-term fallows in Senegal

Abstract. Field trials of vegetation modification were carried out to test the hypothesis that the management of key plant groups such as trees, perennial grasses and legumes would improve soil chemical properties in short-term fallows. Soil properties and plant production during a 4-year fallow period and millet yields after clearing were recorded at two sites representing dry and subhumid climates in Senegal, West Africa. During the four years of fallow, soil organic matter did not vary significantly at either site. A decrease in amounts of Olsen P, calcium and potassium in soil (0–10 cm depth) by 42–50% occurred at one site due to an effect of perennial grasses. The highest millet yields were measured in plots on which the largest amounts of biomass had been burnt after clear-cutting. These results confirmed that short-term fallows do not replenish soil organic matter and nutrient contents. The introduction of planted species did not arrest the decline in soil quality.     

干旱胁迫对不同禾本科牧草叶绿素荧光特性的影响

本试验以无芒雀麦、垂穗披碱草、老芒麦、细茎冰草为试验材料,研究了干旱胁迫处理下不同禾本科牧草的叶绿素荧光参数、叶片电导率和脯氨酸（Pro）含量变化的对比。结果表明：随着干旱胁迫程度的加剧,4种禾草初始荧光（Fo）和非光化学淬灭系数（qN）呈现逐渐上升趋势,而最大荧光（Fm）,潜在光化学效率（Fv/Fo）,最大光化学效率（Fv/Fm）和光化学淬灭系数（qP）呈现逐渐下降趋势。上述参数的变化幅度因材料抗旱性强弱而异,这种差异可作为简便评价禾草抗旱性强弱的鉴定指标,因此,运用隶属函数对不同禾草抗旱性进行评价分析,得出抗旱性强弱次序为：垂穗披碱草〉无芒雀麦〉细茎冰草〉老芒麦。     

刈割对三种热季禾本科牧草越冬的影响

本试验通过对毛花雀稗、纳罗克狗尾草和宽叶雀稗3种热季牧草在不同刈割频度下的越冬成活率的观测表明:毛花雀稗越冬力最强,受刈割频度和终刈时间的影响最小;纳罗克狗尾草次之;宽叶雀稗越冬力最弱,受刈割频度和终刈时间的影响最大.     

河北省平原农区牧草业发展现状及前景展望

分析总结了河北省平原农区牧草业的生产现状、研究水平和存在的主要问题 ,从节水农业、旱作农业、高效畜牧业发展以及国内外市场需求等方面阐述了牧草业的发展前景 ,提出了河北省平原农区牧草业发展的技术建议。