Abstract:Based on an 18-year experiment with different planting patterns in Quzhou County of Huabei Plain, the farmland soils under the conventional cultivation, pollution-free cultivation and organic planting conditions were used to investigate the effects of planting patterns on soil micro morphological characteristics. Soil samples under the three planting conditions were collected and then soil thin sections were made. Soil micro morphological characteristics in soil thin sections were segmented from cross plain light photographs by image analysis. Results showed that the three soils were quite similar in mineral composition under three planting patterns. Their coarse granules were mainly formed of quartz and feldspar, but there was somewhat difference in size and shape of particles. The soil matrix and soil aggregates were well developed and soil organic matters were increased by about 25% under the organic planting condition, compared with conventional cultivation. The organic planting led to the highest soil pore area and soil surface porosity was up to 32%, the bulk density was the lowest with value of 1.19g/cm3 and the organic matter was the highest of 22.67g/kg. Under the conventional cultivation condition, the bulk density of topsoil was 1.30g/cm3, the organic matter was 18.42g/kg, the soil surface porosity was 30%, and soil structure was tight and under-developed. Under the pollution-free cultivation condition, the development degree of soil structure was bigger than that under the conventional cultivation condition, but it was less than that under organic planting condition. Therefore, soil structure was loose and well developed under the organic cultivation condition for plant growth.
