水保所知识产出(1956---)知识库

鉴于黄土髙塬沟壑区县域—农户尺度上资源-人口-粮食及环境间矛盾凸显，以长武县土地利用、社会经济统计以及农户调查资料为基础，对长武县2009年土地利用结构特征进行定量分析；采用机制法分析了退耕还林（草）工程实施前后的长武县粮食潜力和安全问题演变；基于结构方程研究了农户尺度农业资源、产业态势、经济效益和土地利用的数量/结构间的关系及其响应规律；基于县域尺度，对1949～2008年来长武县农业生态经济系统的耦合进行探索。为该区农业生态和区域经济系统持续稳定发展、粮食安全等问题提供理论依据和科技支持。主要结论有：
1）长武县2009年土地利用总体特征为：以林地-耕地为景观基质，林地-耕地-园地-未利用地为组合类型，以农用地为主，土地利用程度较低。人口密度与土地利用程度显著相关，居民工矿用地区位优势一定程度上体现了土地利用结构。黄土高塬沟壑区土地利用没有直接反应经济水平，有待于进一步调整和优化土地利用现状。 2）长武县退耕还林（草）前后的1993年到2009年可实现粮食潜力总量下降了7.8%，而实际粮食生产总量增产了4.0%，潜力实现率由61.58%增至68.59%。17a间，主要粮食作物播种面积减少了27.8%，单产平均提高44.1%，而人口增长了12.5%，人均播种面积下降了35.9%，人均粮食产量由320.1 kg减少至296.0 kg，下降了7.5%。粮食潜力机制法分析显示，温度和土地有效系数的提高是促进可实现粮食潜力增加的主要因素。耕地减少是限制粮食增幅的直接原因，单产提高是促进增产的主要因素。耕地减少、人口增加是该区粮食安全的核心问题，粮食单产的提高是维持该区粮食安全稳定的保障。 3）基于农户调查资料建立的土地利用结构方程模型和农业生态经济系统耦合的结构方程模型研究表明：
（1）产业态势和经济效益具有共变关系，其相关性系数为0.74，二者对农户土地利用均表现为负影响，路径系数分别为-0.14和-0.37。农户层次的产业态势和经济水平对种植业的发展起抑制作用，农户层次上经济水平的提高和产业态势的发展必然导致种植业地位的下降。土地利用和农业资源路径系数为0.51，农户层次土地利用水平的提高有助于发挥农业资源的价值。。 （2）农户层次上农业生态经济系统耦合分析表明，耦合状态和产业态势经济效益的路径系数分别为0.57、0.61，经济效益对产业态势路径系数为0.81，农业资源对耦合状态路径系数为0.13，对耦合状态的发展有促进作用。农户层次农业生态经济系统耦合结构模型体现了农业生态系统和农业经济系统相互制约、相互促进，螺旋式上升发展的发展机制。 4）县域尺度农业生态经济系统耦合规律研究表明，1949～2008年，长武县农业生态经济系统的发展经历了―粗放式传统农业阶段-农业机械化进程阶段-前现代化农业协调发展阶段‖3个历史时期，与国家宏观经济政策调控效应基本吻合，系统耦合在―协调发展‖和―极限发展‖间经历了两起两落的急剧变化过程。1955～1961年、1984～1992年，长武县农业生态经济系统处于极限化耦合态势；1962～1965年、1981～1983年，为纠正前阶段宏观政策后的快速过渡期；1949～1954年、1966～1980年为生态系统与经济系统的低水平协调发展阶段；1993年以后，农业生态经济系统经过螺旋式发展，进入高水平协调发展阶段。目前，长武县农业生态经济系统有突破协调发展水平，并向极限化发展的潜在危险。良好的农业政策和外部环境能够促进农业生态经济系统在协调发展的水平上稳定发展，反之，容易出现系统相悖发展的局面。 综上所述，长武县土地利用现状有待于进一步调整和优化；农户尺度及县域尺度分析均表明：土地利用和经济效益间无直接关系，解决县域粮食安全问题需要提高粮食单产；农户层次经济效益的提高需要经营规模化和产业化；县域尺度农业生态经济系统关系目前处于协调发展状态，但存在相悖的风险，因此在经济快速发展的同时，必须重视生态环境建设。
关键词：土地利用结构特征；农业生态经济系统；耦合；粮食潜力与安全；长武县；黄土高塬沟壑区

Considering the contradictions among resources, population and grain are becoming more and more serious, the issues of response of agriculture eco-economic system to land use changes was investigated on county scale in Loess Plateau Gully Area, by taking data such as land use data, social economic statistics data and peasant household survey data. These were land use changes and characteristics of land use structure, potential grain productivity and security under the background of ―Grain for Green‖ policy, land use and agro-ecolomic system coupling in household scale and agro-ecolomic system coupling degree in1949-2008 on county scale were analysed, and the results are as follows: Based on the understanding of connotation of land use structure, this study investigated land use structure characteristics Changwu county in 2009, by selecting quantitative indices combined with GIS technology. The main feature of land use structure in the county could be generalized as: arable land and forest land patches constitute landscape matrix, regional land combination type comprises forest land, arable land, garden plot and unused land. The plateau-gully-slope morphological pattern of Loess Plateau provided a natural foundation of land use structure in the country. There was mighty significant correlation between population density and land use degrees. Land use structure was embodied by location advantage of residents, industrial and mining land to some extent. Land use structure in Loess Plateau didn’t reflect economic levels, land use status should be adjusted and optimized in this region.
In this study, the data of agricultural meteorology in Changwu County in 1993 and 2009 were used to evaluate the grain productivity potentiality. The farmland area and its geographical distribution in 1993 and 2009 were used to check the farmland change and the grain security in the county. The potential productivity for each meterological factor limitation level for main grain plants and the degree of potentiality exploited was calculated using mechanism methodology. Compared with 1993, the achievable potential productivity in 2009 reduced by 7.8%, while the actual grain productivity increased by 4.0%, so the fulfilling rate of the potential natural productivity increased from 61.58% in 1993 to 68.59%Considering the contradictions among resources, population and grain are becoming more and more serious, the issues of response of agriculture eco-economic system to land use changes was investigated on county scale in Loess Plateau Gully Area, by taking data such as land use data, social economic statistics data and peasant household survey data. These were land use changes and characteristics of land use structure, potential grain productivity and security under the background of ―Grain for Green‖ policy, land use and agro-ecolomic system coupling in household scale and agro-ecolomic system coupling degree in1949-2008 on county scale were analysed, and the results are as follows: Based on the understanding of connotation of land use structure, this study investigated land use structure characteristics Changwu county in 2009, by selecting quantitative indices combined with GIS technology. The main feature of land use structure in the county could be generalized as: arable land and forest land patches constitute landscape matrix, regional land combination type comprises forest land, arable land, garden plot and unused land. The plateau-gully-slope morphological pattern of Loess Plateau provided a natural foundation of land use structure in the country. There was mighty significant correlation between population density and land use degrees. Land use structure was embodied by location advantage of residents, industrial and mining land to some extent. Land use structure in Loess Plateau didn’t reflect economic levels, land use status should be adjusted and optimized in this region.
In this study, the data of agricultural meteorology in Changwu County in 1993 and 2009 were used to evaluate the grain productivity potentiality. The farmland area and its geographical distribution in 1993 and 2009 were used to check the farmland change and the grain security in the county. The potential productivity for each meterological factor limitation level for main grain plants and the degree of potentiality exploited was calculated using mechanism methodology. Compared with 1993, the achievable potential productivity in 2009 reduced by 7.8%, while the actual grain productivity increased by 4.0%, so the fulfilling rate of the potential natural productivity increased from 61.58% in 1993 to 68.59%Analysis on scale of county and peasant household didn’t reflect economic efficiency. The way to solve grain security needs improvement of per capital grain yield. To improve economic efficiency, management should be aimed at scale and industrialization. Appropriate agricultural policies and a better external environment can promote the stable development of the agricultural eco-economic system in a harmonious level, otherwise, a retrogressive system may be expected.
Key Words: land use structure characteristics, agro-ecolomic system, coupling, grain productivity and security, Changwu county, Loess Plateau Gully Area