耕地

Cultivated land quality was assessed by BP neural network in Dazu County, Chongqing. The assessment results showed that paddy lands were mainly of the second-grade and third-grade, while dry lands were mainly of the first-grade and second-grade. It illustrated the high natural quality of the cultivated land, but the natural quality only reflected land natural characteristics. Therefore, influence coefficient was used to modify natural quality index based on the investigation to households. At the same time, by using the household income as the value of cultivated land, the impact of natural quality and investment structure on the value were further discussed. The results showed that trinomial equation and binomial equation were fitted to reflect the relationship between natural quality and income.

该文采用BP神经网络模型对重庆市大足县耕地自然质量进行评价，发现研究区水田自然质量等级以二等地和三等地为主，旱地以一等地和二等地为主，耕地自然质量总体偏高；但耕地自然质量仅仅是耕地自然属性的反映，因此在基于对研究区农户行为调查的基础上，采用"影响力系数"对耕地自然质量进行修正，并将农户收益作为耕地质量货币化价值的表现，进一步讨论了耕地自然质量和农户投资结构对这种价值的影响以反映对耕地质量的影响。

This article detailedly expatiated upon the principles, contents and methods of cropland classification; it analyzed the necessity to combine the work of cropland classification with GIS technology, summarized the attributions of ARC/INFOand some other related softwares; it established the technologic route of cropland classification supported by GIS, by a case study in Liwu Town,Li County Hebei Province, this article expatiated the practicable mechanism of combining the function of ARC/INFO with the work of cropland classification, and put forward some new ideas and approaches of utilizing GIS: this paper put forward the idea of coding the polygons in the basic graphic database such as soil map and land use map according to their attributes, and put forward the detailed coding project; based on the code databases, it expatiated upon the detailed approaches to create single梖actor map and output the final classification map; it put forward the principles and the method of creating classification units in the environment of GIS, that is how to keep the lines of soil polygon, the border of districts and the important objects such as residential areas, banks of rivers and roads ,and how to overlap single梖actor soil map and land use map, and to delete some vector lines of the overlapped map appropriately; it detailed the methods of creating mathematic model of classification coefficients in the environment of computer, and used FOXPRO6.0 programs to realize the automation of calculating coefficients; it represented the method of plotting the final map by overlapping various coverages according to the code tables and lookup tables, the process of outputting the cropland classifying map was finished by program.

本文法对耕地等别划分的原则、内容及方法作了较详细的阐述，介绍了多系数综合修正法的耕地等别计算方法及其具体应用和AHP的确权方法；分析了耕地等别划分工作与地理信息系统技术相结合的必要性，简要介绍了地理信息系统软件ARC／INFO及其他相关软件的功能特点，制定了地理信息系统支持下耕地等别划分的技术路线，通过对河北省蠡县蠡吾镇的实证研究，重点阐述了ARC／INFO及相关数据库软件与耕地等别划分结合的有效机制及GIS应用的一些新思想、新方法：提山了对土壤图和土地利用现状图等基础图形数据库进行特征编码的思想和具体的编码方案，阐述了基于与图形库相链接的特征编码表，单因素图提取、成果图的输出的具体实现方法；提出了GIS环境下耕地单元划分的原则和方法，即在保留土壤因素图斑界线、行政界线和重要地物等的原则下，将土壤单因素图和土地利用现状图进行拓扑叠加，对叠加图中的矢量线进行适当的删除；阐述了在计算机环境下，耕地分等参数计算模型建立的方法，并用FOXPRO6.0语言程序实现了参数计算的自动化；阐述了根据图形库特征编码表和建立绘图符号查找表，按不同图层叠加绘制成果图的方法，该过程用命令程序实现耕地等别图的输出。

Soil physico-chemical properties and variability in space and time in tillaged-layer of paddy, dry field and vegetable field in different physiognomic areas were analyzed. The variation characteristics for various soil nutrient elements in the three different types of farmland before and after twenty years were explored and compared.

不同区域间表现出江汉平原及鄂中丘陵区，高产田面积大(占70％以上)，而鄂东沿江丘陵区中低产田所占比例大(占75％以上)。20年间不同区域耕地地力变化表现出，丘陵区耕地面积大幅减少，耕地质量明显下降；平原区耕地面积虽有所减少，但减幅不大，耕地数量和质量保持基本稳定。2。

Analysis of the archives data of Hetian region during the Republic of China showed that this time water resources basically maintained on a stable level, and it was not the decisive factor to the waste of local big area tilth, but the essential factor actually restricted the population quantity, the reclamation wasteland scale and the overall cultivated area level in all the counties.

地区人口增长过多引发对地区耕地面积的需求扩大，同时引起对耕地灌溉水量的增长需求扩大，由此呈现出农田灌溉水不足的表象，造成地区人口、耕地水平与水资源承载力相互关系的失调；即影响和田地区耕地撂荒的关键是当地水资源总量与人口规模、耕地面积总水平的平衡关系，突破这个平衡就必然引起耕地的撂荒或生态环境劣化；而诱发耕地大面积撂荒的自然因素也与过度垦荒有一定程度的关系。

Recent studies indicate land fiscalization is one of the important reasons for land decrease.

研究结果表明：①土地财政与耕地数量之间存在相互反馈作用；②土地财政是导致我国耕地数量减少的重要原因，其影响的弹性系数为-0.01；③土地财政对耕地保护具有正反两方面作用：一方面，土地财政刺激地方政府形成城市扩张冲动，导致耕地数量减少；另一方面，土地财政带来土地开发整理增加耕地面积的大幅增加，降低耕地减少速度；④经济、人口和城镇化等社会经济因素也是导致我国耕地数量减少的重要原因。

Results showed that:(1) soil loss from plough tillage was as much as 3~8 times that from no-tillage; the aerodynamic roughness lengths under plough and no-tillage were 0.032, 0.417, respectively.(2) No-tillage soil contained more clay and fine sand in the 0-10cm topsoil layer than the plough tillage soil. In the 0-5 and 5-10cm soil depth, the bulk density, soil hardness and soil moisture were more under no-tillage than plough tillage. Especially, the soil hardness in 0-5, 5-10 and 10-20cm under no-tillage were as much as 4.7, 2.8 and 3.8 times, respectively.

研究结果表明：翻耕农田土壤风蚀量是免耕地的3~8倍，翻耕地和免耕地的地表粗糙度分别为0.032和0.417；与翻耕地相比，免耕地表层0~10cm土壤粘粒和粉粒含量较多；免耕地土层0~5cm和5~10cm的土壤容重、坚实度和土壤水分都大于翻耕地，其中0~5cm、5~10cm和10~20cm土层土壤坚实度分别是翻耕地的4.7、2.8倍和3.8倍。

At last, the cultivated land spatial protection strategy by leveling and districting is put forward. Such as emphasis on the quality protection of cultivated land, protecting eco-landscape function, increasing the exploitation of reserve resource, reducing non-agricultural cultivated land occupation, strengthening the policy management, etc. Then such policy is put forward as promoting and improving the compensation system of cultivated land, carrying on the balance between quantity and quality of cultivated land.

最后，作者提出了分区的耕地空间保护策略，并提出耕地保护不仅要保数量，更要保质量，要加强保护长江三角洲地区耕地的生态景观功能、在生态环境允许的情况下，加大滩涂等后备资源的开发与培育、促进土地的节约集约利用，减少非农建设对耕地资源的占用等耕地保护重点以及提出促进完善耕地占用补偿机制及实施耕地占补平衡的数量质量平衡控制等耕地保护政策。

On the basis of numeral material and field investigations, this paper analyses the natural condition of cultivated land, social and economic condition of cultivated land, stages of cultivated land utilization, productive potentiality of cultivated land, and studies on the agriculture with regional features, intensive faming of cultivated land, a grand gathering of faming, plan faming, taking part in WTO, witch tightly related to the necessary and important of quality utilization of cultivated land.

本研究在大量收集资料和实地调查的基础上，对福建省耕地利用的自然条件、社会和经济条件、耕地利用阶段、耕地生产潜力等进行分析研究。从特色农业、耕地集约经营与规模经营、耕地计划利用、加入WTO等方面探索耕地优化利用的必要性和重要性，寻找适合福建省不同区域耕地优化利用的途径，提出区域耕地优化利用的模式。

By analyzing the cultivated land data from different sources in different phases after 1949,the paper considers the statistics with more errors happens during 1960-1985.According to the systematic data on land use gathered in the 1996 survey,based on reverse deduction of the cultivated land area from 1986 to 1996,and deduction of the cultivated land area from 1960 to 1985 by stages by employing yield of grain,this paper redescribed the actual changing trend and character of Chinese cultivated land and analyzed the driving force of the policy relative to cultivated land to cultivated land area change.

针对该问题，论文对1949～2003年不同时期不同来源的耕地数据系列进行分析，认为统计数据存在问题较多的时期为1960～1985年，并采用粮食产量对耕地面积进行了分时期的反演，对于1986～1996年间的耕地数量则按照全国土地利用详查统一到1996年的结果再进行反推，由此重新刻画建国以来中国耕地资源数量变化的趋势和特征，并结合不同时段耕地相关政策对耕地数量变化的驱动作用进行分析。

By analyzing the cultivated land data from different sources in different phases after 1949,the paper considers the statistics with more errors happens during 1960-1985.According to the systematic data on land use gathered in the 1996 survey,based on reverse deduction of the cultivated land area from 1986 to 1996,and deduction of the cultivated land area from 1960 to 1985 by stages by employing yield of grain,this paper redescribed the actual changing trend and character of Chinese cultivated land and analyzed the driving force of the policy relative to cultivated land to cultivated land area change.

针对该难题，论文对1949～2003年不同时期不同来源的耕地数据系列进行分析，认为统计数据存在问题较多的时期为1960～1985年，并采用粮食产量对耕地面积进行le分时期的反演，对于1986～1996年间的耕地数量则按照全国土地利用详查统一到1996年的结果再进行反推，由此重新刻画建国以来中国耕地资源数量变化的趋势和特征，并结合不同时段耕地相关政策对耕地数量变化的驱动作用进行分析。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。