互花米草防治研究进展

互花米草因其在全球范围内日渐增长的负面影响而受到了极大的关注。对互花米草的入侵性以及防治与控制方面的研究已经成为近年来的一大热点,但始终没有找到彻底有效地控制互花米草扩散的途径。文章对互花米草自身的生物学特性所引起的入侵性以及其目前在世界范围内所带来的危害性进行了概述,从物理法、化学法、生物防治法等方面总结了国内外已有的关于互花米草防治技术的研究,对近期防治研究新成果——特别是利用无瓣海桑对互花米草进行植物替代的方法进行了介绍。进一步提出了现有技术的不足之处,并对如何加强防治互花米草的研究提出了一些建议。     

赤霉素(GA3)对八仙花花期及开花品质的影响

以八仙花为试验材料,研究了不同时间,不同浓度的赤霉素对八仙花的始花期、花径、开花数、枝长等的影响,结果表明:GA3可促进八仙花开花,浓度高开花早,可提前1-3天;250mg/L GA3明显增大八仙花花径,与对照比达到极显著水平;随着GA3浓度增加,八仙花的开花数和小花数都增加;不同时期对八仙花进行处理,也对八仙花提早开花有一定影响。对春、夏梢八仙花花期研究表明,夏梢八仙花观赏品质优于春梢八仙花,且夏梢八仙花种植周期短,更加经济,更利于广泛栽培。     

降雨对干旱半干旱地区土壤微生物影响研究进展

未来气候变化预示着降雨时间和数量的变化。降雨是干旱半干旱地区最重要的水分来源,降雨格局的变化将直接影响该区域生态系统的稳定性,而土壤微生物作为敏感指标多用来监测生态系统的稳定性。文中综述了降雨对干旱半干旱地区土壤微生物生物量、多样性的直接影响,以及其通过改变土壤水分、土壤空气和植被生长等对土壤微生物产生的间接影响,其中还可能伴随着其他因素的干扰,如土地利用方式、温度、海拔等。通过了解降雨格局变化对干旱半干旱地区土壤微生物的影响,可以更好地预测未来气候变化对该地区生态稳定性的影响。指出了降雨对干旱半干旱地区土壤微生物影响研究中存在的问题,并对未来研究进行了展望。     

Improvement of physical and hydraulic properties of desert soil with amendment of different biochars

Purpose

The objective of this study was to investigate the effects of amendment of different biochars on the physical and hydraulic properties of desert soil.

Materials and methods

Biochars were produced with woodchip, rice straw, and dairy manure at temperatures of 300 and 700 °C, respectively. Each biochar at 5% (w/w) was mixed with desert soil, and the mixtures were incubated for 120 days.

Results and discussion

The different biochar treatments greatly reduced soil bulk density and saturated hydraulic conductivity. Especially the rice straw biochar addition resulted in the lowest saturated hydraulic conductivities among the treatments. Biochar addition significantly increased water retention of desert soil at any suction. At the same suction and experimental time, the treatment with the rice straw biochar produced at the lower temperature resulted in higher water content than the other treatments. The biochar additions slightly enhanced formation of soil macro-aggregates in the early experimental time. However, the aggregate contents gradually decreased with time due to the lack of effective binding agents (e.g., soil organic matter and clay minerals).

Conclusions

The changes of hydraulic properties of desert soil were attributable to the biochar properties. The higher fine particle content, porosity, and surface hydrophilicity of rice straw biochars were the most beneficial properties to increase soil water retention and to reduce water flow in the desert soil. The improvement of hydraulic properties by biochar addition may provide a potential solution to combat desertification.

     

Ecological consequences of shrub encroachment in the grasslands of northern China

Landscape Ecology - Shrub encroachment is a critical environmental issue in arid and semi-arid landscapes. However, due to the complicated effects of shrub characteristics and environmental...     

夏秋蚕杂交组合“安05×安06”农村鉴定成绩

对安康市蚕桑研究所夏秋蚕杂交组合"安05×安06"进行了农村中试鉴定,结果表明:该杂交组合具有丰产性能相对稳定、抗病性强、茧丝质量优良的特点,适合安康蚕区夏秋季应用。