[Characteristics and distribution pattern of farmland patch in river valley in middle and low Taihang mountain area--a case study in Yanzhi River in Fuping County, Hebei Province].

Based on the investigations in the main valley of Yanzhi river in Fuping county of Hebei Province, the characteristics and distribution patterns were analyzed. The results indicated that farmland patches were distributed in the whole valley, except the headstream reach. With the increase of human disturbances, the proportion of farmlands increased along the river from upstream to downstream, while in natural landscapes, the environmental heterogeneity and fragmentation of farmlands decreased. The area of Yanzhi river valley totaled 2297.09 hm2, mainly composed by farmland. There were 117 farmland patches mainly distributed along the riverbank in the valley, totalling 1027.78 hm2 and occupying 44.74% of the valley, which were very well irrigated, but always endangered by flood. The farmland patches were not symmetrically distributed along river, with 57.17% of farmland located on the left side of bank. The width of farmland patch presented an increasing trend, with a remarkable variation. The farmland patches were mainly strip-shape.