【作者】 王得祥；

【导师】 杨改河； 雷瑞德；

【作者基本信息】 西北农林科技大学 ， 作物栽培与耕作学， 2001， 博士

【摘要】 在详细查阅、收集西北地区环境变化、人口、资源、农业及农村经济发展水平、植被建设模式、现有人工植被建设所依托的自然环境条件和技术措施、植被演替等现有资料的基础上，系统总结以往相关研究成果，结合对典型地区现有人工植被建成效调查分析，阐明在该生态环境脆弱地带实施退耕还林(草)的原则；分析总结退耕还林(草)急需解决的理论、技术问题及该地区退耕还林(草)、恢复生态环境的中、长期研究需求；首次提出退耕还林(草)功能区和功能群的概念，对西北地区的退耕还林(草)实践具有指导意义；通过分析西北地区自然环境基础和社会经济条件，阐明该区的自然环境、人口、经济发展水平对退耕还林(草)的支撑程度和限制程度；通过对该区环境演变、现状和植被建设的需求分析，阐明退耕还林(草)、植被建设的必要性、可行性和前景：根据西北地区自然分异规律，首次对西北地区退耕还林(草)类型进行区划，分析各类型区生态系统退化的状况及其所处阶段，阐述各类型区的基本特点和退耕还林(草)的途径，总结提出适宜西北不同区域的退耕还林(草)模式和适于该地区的一般模式；从政策、资金、人才、监督体系以及西北地区植被建设过程中的经验、教训等方面，分析讨论在退耕还林(草)植被恢复过程中必须注意解决的问题。 1．提出在退耕过程中(1)必须注意树草种的配置方式；(2) 强调“利他”与“自利”的统一；(3)要充分发挥市场机制的调节作用；(4)要按照耕地适宜性程度安排退耕还林还草的顺序；(5)应根据植物群落适应性的强弱确定各种配置模式的应用顺序；(6)应因地制宜原则，宜林则林、宜草则草、亦荒则荒；(7)应坚持生态目标与经济目标的协调统一；(8)遵循农业生态经济系统优化设计的特点。 2．提出了目前西北地区退耕还林(草)急需解决的科学问题即：(1)科学的总体规划；(2)西北地区自然环境基础与退耕还林(草)关系的研究；(3)西北地区环境与原生植被变迁的研究；(4)西北地区不同区域退耕还林(草)的适宜林草类型、途径等的研究；(5)西北地区退耕还林(草)保障措施的研究；(6)先进、实用科技成果的组装配套和推广；(7)生态效益补偿机制的研究和实施。 3．该区建设退耕还林(草)、生态环境领域研究重点是：(1)重视对西北地区退耕还林(草)与农业结构战略性调整的关系研究；(2)重视研究在生态脆弱地带，实施重大骨干性生态工程在退耕还林(草)、恢复生态环境中的必要性和迫切性。(3)重视研究不同区域自然环境条件、经济基础、资源现状、市场发育等对退耕还林(草)的影响。(4)重视研究加入世贸组织(WTO)所导致的对退耕还林(草)、重建生态环境的正负效应；(5)重视研究科技在退耕还林(草)、生态环境建设中的作用。 g 4．提出了今后长时期西北地区在退化生态系统恢复领域的研究需求为：（1）通过退耕还林还草措施治理西北地区环境的前景与重点治理区的选择问题；（2）坡耕地退耕还林还草与沟壑治理相结合的问题；（3）沙漠化治理与沙产业发展问题；（4）现有天然林的保护问题；（5）绿洲生态系统退化防治问题；（6）西北地区生态环境建设区划的理论基础问题；（7）通过恢复历史上不同类型天然植被的分布范围、界线，在相似的气候条件下进行类比，为确定未来植被恢复前景提供依据：（8）通过研究水分迁移规律，确定各种特定的水分平衡对于未来植被恢复前景的制约作用及其机理；（9）土地利用调整及退耕还林（草）科学问题研究；（10）宜林（草）地立地环境与林木（草）生物生态学特性偶合规律研究；门1）植被恢复与重建区域的划分及技术措施研究：（12）黄土高原地貌适度整形保持水土及其大规模退耕还林工程的可行性；（l）沙漠地区的固沙林带工程建设问题；（l）农业结构调整及自然资源优势产业价值（供应）链市场化培育基地建立； （l）可持续发展战略管理理论。 5．首次提出退耕还林（草）功能区和功能群的概念，并将其定义为主要环境问题、退耕还林（草）的方向和对策、区域后续发展对资源的需求、人类对环境的作用强度、区域的主导产业及其发展方向相似的社会、经济、生态复合体。在同一功能区内，由于退耕还林的措施、目标、未来产业发展方向以及地域差别，可以划分为若干个功能单元。据此，可将西北地区退耕还林（草）划分为农林复合经营区、水土流失治理区、畜牧业生产基地、遏止沙化区等9个功能区和相应的22个功能单元。以期对西北地区的退耕还林（草）实践具有指导意义。 6．通过分析自然环境基础，认为由地表起伏度RDLS、水资源、干燥度、森林面积、水土流失等方面来衡量的西北地区的生态环境限制度也明显高干全国其他地区和平均水平，植被恢复和生态环境建设难度很大。通过对该区目前土地利用现状分析认为中低产田构成了五省区耕地的主体，提高五省区农产品供给能力具有潜力?更多还原

【Abstract】 Based on reviewed literatures and collected data on environment change, population, resource, agriculture and agricultural economic development level, patterns of vegetation reconstruction in northwest China, on natural environment conditions and technical measures on which efforts in artificially reconstructing vegetation rely, and on vegetation succession,籶rinciples of restoring reclaimed land to forests or grasses (RRF) on fragile sites of ecological environment (EE) in northwest area were expounded. Theories and techniques as well as middle and long-time demands for research were analyzed and summarized. It is first time that the concept on function zones and units is put forward, which makes sense for practice of RRF in northwestern area. Supporting and limitation degree of natural environment, population, economic development level on RRF is clarified after an analysis of basis of physical environment and social economic conditions. Necessity, feasibility and prospect of RRF and reconstruction of vegetation were expounded after an analysis of environment change, present situation. It also first time that zones of RRF-types in northwestern area were classified according to laws of physical differentiation. Particularities and approaches to RRF were expounded and suitable patterns of structure for different sub-zones and general patterns for the entire zone were pointed out. Questions to which attention should be paid during RRF-efforts were discussed at a view of policies, investment, human power, control system and of experiences and lessons from reconstructing vegetation in northwestern area.1. It is pointed out that (1) much attention should be paid to the mixture patterns of grass and trees; (2) unification of "Benefits for others" and "Benefits for selves" should be emphasized; (3) market’s regulatory functions should be efficiently exerted; (4) priority of RRF should be arranged according to suitability of farmlands for forests or grasses, (5) priority of application of various models of pattern should be determined according to suitability of plant communities; (6)principle of "site adapted reconstruction of vegetation" should be strictly implemented, that is: seeking for truth, adapting for local sites, reforestating if it is suitable for trees, reconstructing with grass if grass is the best adapted landscape, leaving without any treatment if neither forest nor grass can establish; (7) principles of "coordinating and unifying ecological and economic targets" should be kept; (8)and optimal planning of ecological economic systems should be followed.2. Present urgent problems for RRF in northwestern areas are put forward: (l)overall plan on scientific research; (2) relationship between physical environment basis in northwestern area and RRF; (3) study on environment in northwestern area and change of original vegetation (4) Suitable forest and grass types and approaches to RRF of various zones in northwestern area. (5) Security measures for RRF in northwestern area (6) Assembly, matching and extension of advanced, practical research results; (7) study on and implementation of compensation mechanism for ecological benefits.3. Research emphasis on EE and RRF in this area is recommended: (1) take notice of studies on relationship between RRF in northwestern areas and strategic restructure of agriculture. (2)take attention to studies on necessity and urgency of realization of large key ecological projects as pioneer of RRF programs in some fragile ecosystems (3) take notice to study on effects of various physical environment conditions, economy, resources, market development on RRF (4) study on influence extent of international markets on agriculture in these areas after WTO, and their follow-up positive and negative effects on RRF and ecological environment construction (EEC); (5) pay attention to study roles of science and technology on EEC in northwestern area, particular attention to research, extension and application of techniques on EEC and RRF.4. Emphasis of future research更多还原