丘陵山区耕地质量的空间格局分析

耕地质量的时空分布特征在人类活动的诱导下发生巨大变化，研究耕地自然质量向耕地经济质量转变的过程及其空间分布格局，拓宽了耕地质量的研究内涵。以重庆市合川区为例，将农用地分等定级的斑块数据与农户调查相结合，应用“影响力系数”获取修正后的耕地质量指数，从真正意义上反映土地的现实生产能力，并进一步采用空间自相关分析的方法讨论其空间分布格局。研究发现，利用影响力系数修正后的耕地质量等级指数能够真实反映土地生产能力，农户对耕地投入产出水平使耕地自然质量呈现下降的趋势，新获取的质量等级系数具有经济学意义；水田和旱地的质量等级分布存在非常显著的空间正相关关系。高质量的水田斑块与高质量的水田斑块相邻，低质量的水田斑块与低质量的水田斑块相邻，旱地图斑也遵循该分布规律，总体上空间分布集聚现象显著。

SPATIAL PATTERN ANALYSIS BASED ON MODIFIED CULTIVATEDQUALITY GRADES IN HILLY AREA

The temporal spatial distribution of cultivated land quality had brought about great changes under inducement by human activities. Studies on the process of cultivated natural quality alteration to economic quality could expand research connotation of land quality.Taking Hechuan City in Chongqing for example,patch data based on agricultural land classification and gradation and influence coefficient were used to obtain adjusted quality indices.Influence coefficient was used to modify natural quality index based on the investigation to households,and this influence coefficient made adjusted quality indices economization.It turned out that the farmers’ input output made cultivated land natural quality reduced.Meanwhile,spatial autocorrelation analysis was used to reflect the spatial agglomeration of farmland by GeoDA.The results showed that modified quality grades reduced compared with natural quality grades;the distribution of adjusted quality grade of paddy land and dry land had remarkable positive correlation in space.That is to say,high quality paddy field was adjacent to high quality paddy field,and also low quality paddy field was adjacent to low quality paddy field.The distribution of dry land also followed the same rule,and concentration phenomenon was obvious.