【作者】 杨世琦；

【导师】 杨改河；

【作者基本信息】 西北农林科技大学 ， 作物栽培学与耕作学， 2003， 博士

【摘要】 西北地区是我国水土流失和土地沙化严重的地区之一，同时也是农村经济落后和农民收入较低的地区，是典型的生态赤贫和经济贫困的共生区。长期以来，由于对乱垦滥伐造成植被大面积破坏而疏于治理，导致自然灾害频繁发生，给西北地区和东中部区城的社会和经济发展造成了巨大损失，以退耕还林还草为途径，治理和改善西北地区生态环境已迫在眉捷。与此同时，我国农村也出现了经济发展滞缓、农民增收缓慢和农产品质量难以适应市需求等不合理现象也日趋突出，农业与农村经济结构的进一步调整也刻不容缓。 西北地区面对退耕还林草和农业结构调整两大重任，既要完成国家退耕还林还草的生态工程建设，又要实现农业与农村经济结构调整的重大突破，协调与处理退耕还林还草和农业结构调整之间的关系，推动西北地区生态环境改善和促进农业经济发展是西北地区全面发展面临的重要课题。本论文在对西北地区退耕坡地与退耕沙化地现状分析的基础上，研究确定了西北地区退耕还林区与退耕还草区，对完善西北地区退耕还林还草方案和实施具有重要的指导意义；在对西北地区农业结构和农村经济结构现状分析的基础上，研究提出了西北地区种植业结构、林业结构、牧业结构和农村经济结构的调整战略；同时提出了西北地区退耕还林还草工程技术保障体系及新时期西北地区农业结构调整的实施技术体系，形成了完善的西北地区退耕还林还草和农业结构调整研究的理论体系，在西北地区退耕还林还草和农业结构调整上取得了重要的研究结论和研究成果。 西北地区涉及退耕坡地和退耕沙化地共276.7万hm~2，占西北地区耕地面积的17.1％，退耕坡地主要在陕西和甘肃两省，退耕沙化地主要分布在新疆和宁夏两个自治区，退耕坡地占退耕面积的61.3％，其中陕西省占到退耕坡地的73.0％，退耕沙化地占退耕面积的38.7％，其中新疆自治区占退耕沙化耕地的80.3％。退耕还林还草涉及25°以下缓坡耕地梯田化面积527.5万hm~2，占西北地区耕地面积的47.7％。其中陕西省占33.3％，甘肃省占55.4％。 西北地区退耕还林还草以年降水量500mm为分界线，大于500mm的区域以还林为主，400～500mm区域以造灌木林为主，小于400mm还草为主。退耕还林还草要乔灌草三结合，用宫胁造林理论指导西北地区林草植被的恢复，还林主要面积在陕西省。林业结构调整要坚持的生态防护林为主，不低于60％，控制经济林不高于20％，要选择适地树种和草种，还林还草要树立植物群落思想，避免林、草品种单一化种植模式。 西北地区农业结构调整要体现科技调整、市场调整和优势调整特点，要协调好生l1...........~‘......目...............口..-日一，..........目...................口口..口.口.............口州..........目.......................态、经济和社会三效益之间的关系。在粮食发展问题上坚持稳总量求优质，总体上粮食目标定为人均300kg，西北地区保持退耕还林还草之前的粮食总产水平是能够实现的，要打破以粮为纲的农业结构调整思路，把发展农村经济，引导农民增收和提高农产品品质作为西北地区农业结构调整的核心内容，只要农民富裕了，就能从市场上购买口粮，自然就解决了粮食的问题，特别对于陕西、甘肃和青海三省，宁夏和新疆人均粮食接近400kgo 西北地区发展优质农作物要利用资源优势，合理布局，发展产业化，主要包括:新疆优质甜菜、棉花、葡萄、啤酒大麦和瓜果种植产业区，甘肃优质马铃薯、瓜果和啤酒大麦种植产业区，陕西优质苹果和优质小麦种植产业区，宁夏优质粳稻种植产业区，青海优质马铃薯和优质油菜种植产业区，西北地区高产优质玉米种植产业区，西北地区黄士高原优质小杂粮种植产业区，同时还要重视农产品安全问题。 西北地区牧业结构调整应分牧区牧业和农区牧业。牧区要加强草地和畜种改良建设，农区要加强饲草基地和畜禽改良建设，发展规模化和设施化养殖，农区和牧区都要向牧业产业化发展。西北地区农区牧业要发挥优势，合理布局，主要是陕西陕南生猪，关中肉牛和奶牛，陕北和渭北奶山羊养殖产业区，甘肃河西、陇南、天水和定西生猪，甘南、临夏、庆阳和河西肉羊，甘南肉牛，陇东奶牛养殖产业区，宁夏肉羊、奶牛养殖产业区，新疆奶牛、肉牛和肉羊养殖产业区，青海肉牛和肉羊养殖产业区，同时也要重视畜产品安全问题。 西北地区产业结构和农村经济结构调整要加快农村第一、二产业的发展，为农村第三产业发展提供发展基础，同时要引导和重视农村运输业、旅游业、餐饮、农业贸易和其它行业的服务业等。 西北地区还耕还林还草技术体系主要包括:经济补偿(贴)制度，生态移民工程，科技还林还草方案，依法退耕和依法保护林草，开发农村新能源技术体系，发展农村经济和引导农民增收的机制。农业结构调整技术体系主要包括:农业科技体系建设，农业市场体系建设，生态环境保护和建设技术体系，农业与农村教育体系建设，农业与农村综合体系建设。更多还原

【Abstract】 Northwest China is one of the serious places with soil erosion and desertification, a typical place with environment deficit and economic recession, where farmers’ income remains at a low level due to economic draggling in rural area. Being unreasonable reclamation and deforestation with neglect of rehabilitation for a long time, vegetation is widely destroyed so that results in frequently natural disasters and prevents social progress and economy development in Northwest China, also in Middle and East China. It is an urgent task to improve ecological environment by way of returning farmland to forestry or pasture (RFFP) in Northwest China. Simultaneously, increasingly irrational situations come up in the rural area, such as economic stagnation, earnings increased slowly, and quality of farm products difficult to meet market needs, thus it is necessary to readjust agricultural structure and rural economic structure.To achieve social overall development in Northwest China, it is a significant study to accomplish the project of RFFP as well as to make a breakthrough on regulation of agriculture structure and rural economic structure, to harmonize relations between RFFP and regulation of, to advance ecological environments and improve rural economic development in Northwest China. The article drew conclusions and obtained useful fruits on RFFP and regulation of agriculture structure in Northwest China, as follows: Based on analysis of situations of returned slope farmland and desertification land present, the study defined ranges of returning farmland to forest as well as that of returning farmland to grassland, what contributes guidance to carrying out the project of RFFP in Northwest China. Based on analysis of agriculture structure and rural economic structure, and the research put forward strategies for structure regulation on planting, forestry, stockbreeding and rural economy. Through above study, the study brought forward technique safeguards systems on the project of RFFP and applicable technique systems on regulation of agriculture structure at the new time in Northwest China, which make research rich andmake theory perfect; furthermore it is more practical on RFFP and regulation of agriculture structure.In Northwest China, returned slope farmland and returned desertification land involved 2,767,000 hm2, which is 17.1% of farmland there. Returned slope farmland is mostly in Shaanxi and Gansu, which is about 61.3% of returned farmland and Shaanxi reaches 73.0%. Returned desertification land mainly distributes in Xinjiang and Ningxia, which is 38.7% of retimed farmland and Xinjiang reaches 80.3%. The area of RFTFOP concerning farmland with flat gradient below 25 for terrace is 5,275,000 hm2, which is 47.7% of farmland in the Northwest of China, and 33.3% in Shaanxi, 55.4% in Gansu.Precipitation of 500mm per year is boundary for RFTFOP in Northwest China. The farmland where precipitation is more than 500mm, or between 400-500mm, or below 400mm, correspondingly, is returned to forestry, to shrubbery and to pasture. Under instruction of Miyawakis Theory, the vegetation for reoccupying must be mixing vegetation of arbor, shrubbery, and pasture in Northwest China. It is in Shaanxi that the majority area for returning farmland to forestry. Regulation of forestry structure emphasizes on forestry protection for environment, with selecting suitable tree seedling and grass seeds, and forming views of plant community to avoid single species of tree seedling and grass seeds. Forestry protection for environment should not be below 60%, and economic forestry no more than 20%.In Northwest China, regulation of agriculture structure contains the regulation of Sic-tech, market and advantage resources and coordinates the relationship of ecological, economic and social benefits in Northwest China. On the issue of foodstuff, targets aim to stabilize gross output and guarantee fine-quality and fulfill that per capita foodstuff is 300kg what can maintain the previous level. To abolish conventional ideas that f更多还原