排序方式： 共有8条查询结果，搜索用时 15 毫秒
1
1.
2.
兴国县飞播马尾松林多功能经营评价 总被引：1，自引：0，他引：1
根据2009年江西省兴国县森林资源二类调查数据,以飞播马尾松林为研究对象,通过对森林多功能经营内涵的探讨,从兴国县飞播马尾松林功能定位与林种结构现状出发,采用理论分析与专家咨询相结合的方法,构建了由水土保持功能、水源涵养功能、用材功能3个方面共13个指标组成的多功能经营评价指标体系,并运用模糊综合评判法从林分尺度分另别对兴国县飞播马尾松林各小班和林分多功能经营总体状况进行评价.结果表明:兴国县1 894个飞播马尾松林小班中,多功能经营状况优等级的小班160个,中等级的小班665个,差等级的小班1 069个;兴国县飞播马尾松林林分多功能经营总体上处于差等级.制约其森林多功能充分发挥的主要限制因子为林下植被盖度低、树种结构单一和林分蓄积生长率低. 相似文献
3.
4.
中国农作物秸秆综合利用潜力研究 总被引：20，自引：14，他引：20
针对秸秆分区布局规划不完善,导致地区性、季节性、结构性秸秆过剩,资源浪费与环境污染问题突出,研究秸秆综合利用规划理论,提出"一主多元、农用优先"秸秆综合利用途径。中国秸秆综合利用潜力总量8.76亿t,比2015年增加利用量1.56亿t,其中秸秆肥料化、饲料化和能源化利用量分别增加8 722.4万t、5 122.3万t和1 720.1万t。通过肥料和饲料化利用,可直接和间接替代化肥潜力氮肥(N)1 481.6万t、磷肥(P2O5)419万t、钾肥(K2O)1 885.1万t,节本增效节约化肥成本约685.9亿元(折合98.5元/t秸秆);通过能源化利用,可替代煤炭等化石能源5982.4万t(标准煤),可减排二氧化碳1.5亿t、二氧化硫448.7万t、氮氧化物224.3万t,烟尘4068万t,经碳排放交易经济效益可达20.25亿元(折合16.9元/t秸秆),环境和经济效益显著。 相似文献
5.
Summary Developed countries need to promote alternatives to crops produced in excess (such as cereals), and cultivation with limited environmental impact. Hemp (Cannabis sativa L.) is a potentially profitable crop, fitting into sustainable farming systems. Interest in new fibre crops is in fact increasing, to find alternatives to a high-input crop such as cotton, or to relieve the pressure of the paper industry on remaining natural forests. Besides, innovative applications are provided by hemp in renewable raw materials (oils from seeds and essential oils or secondary metabolites from inflorescences for food, cosmetic or pharmaceutical industry; straw and hurds for the building industry and for energy production). The development of more specialized hemp plants, needs a better understanding and control of metabolism. Since the renewed interest for this crop is increasing all over the world, it is important to update the knowledge on this crop, to understand whether it is a really sustainable, alternative and economically rewarding crop, and what contribution plant breeding, agronomical practice, and processing techniques are making, or could further make, to improve the relevant traits. The symposium Hemp: perspectives for advanced utilization, held in Bologna (Italy) on March 2004, was an opportunity to update the research carried out in different fields. 相似文献
6.
本文从环境保护、生产成本、技术研发、行业联系及政策扶持等方面探讨了我国当前苎麻生产的形势与问题,从天然纤维需求、苎麻特性及农业资源区划等角度分析了苎麻产业的发展前景,并从种植区域布局、机械化生产、清洁化脱胶、多用途及政策等方面重点提出了推动该产业发展的建议。 相似文献
7.
Paolo Ranalli 《Euphytica》2004,140(1-2):121-131
Summary Hemp is a multi-use crop, able to provide fiber, cellulose, seeds and seed oil, cannabinoid, and biomass. Integrating many agroindustrial chains, Cannabis is considered a crop model in which insights into specific metabolic pathways and biosynthetic processes are valuable for improvement of the plant for all sets of industrial derivatives. In this review the hemp breeding status is elucidated and many aspects are focused: (i) recovering, maintenance and characterization of genetic resources; (ii) widening of germplasm and genetic variability; (iii) marker-assisted selection and development of breeding programs; (iv) sexual differentiation; (v) monitoring of THC content. Modern hemp varieties for fiber and other specific end uses have been developed and new varieties are entering production. The scenario for the breeding advances in hemp relies on basic and applied research which provides insights to identify a strategy for the design of modified plants with enhanced performance. This is accounted by the dissection of traits into components and the modification of single steps of the related metabolic pathways. These advances are provided by genomic techniques and are able: (i) to identify key genes encoding enzymes and regulatory factors participating in cannabinoid, fiber and oil biosynthesis; (ii) to identify the mode of regulation of these genes; (iii) to characterize the function of the selected genes through higher, lower or specific expression incited by specific promoters. The identification of molecular markers for specific traits, gathered in a saturated linkage map, will have a remarkable impact on hemp breeding. The advances in basic and applied research make it possible to design methods for the identification of superior parents and cross combinations and the development of selection schemes that rely on less labour-intensive and time-consuming methods. 相似文献
8.
1