Criteria for land suitability evaluation in a small catchment on the Loess Plateau in China

This article describes some of the results of a land evaluation within the framework of a research project carried out in a small catchment on the Loess Plateau in northern China, which has long been exposed to land degradation from erosion. The project aimed to identify an approach for land use planning, combining participatory (land users) planning, land evaluation and soil erosion modelling. The results from this study were intended to provide the biophysical properties of importance to be used together with results from participatory approach (PA) studies and soil erosion modelling to construct scenarios for a more sustainable use of land. Land properties, which were restricting for agricultural cropping, were defined and values of each property were matched with the requirements for cropping. By defining the spatial distribution of critical properties, they could be combined to achieve compound suitability classes in each land unit for the chosen land use. Information was gathered from measurements and data searches as well as from farmers, using PA methods. Properties for which data and other information were available and which were considered to be relevant for the study included climate, soil water content, slope aspect, soil water storage capacity, rooting environment, tillage constraints, slope gradient, infiltration capacity, soil nutrients and flooding hazard. Each of the properties were discussed in relation to their influence on land suitability, primarily for agricultural crops. Whatever management changes were carried out to improve the productivity and sustainability in the project catchment, restrictions for agricultural production were large. The major constraints were water availability, nutrient availability and erosion hazard. The properties chosen for further use in suitability evaluation and scenario analyses were those having a significant spatial variability in the catchment: soil type, slope gradient and slope aspect. The results from this study are applied in other articles this issue. (C) 2003 Elsevier Science B.V All rights reserved.