Abstract
Soil characteristics of vegetable fields in a semi-arid region at Tianjin City in China were studied. The fields planted with vegetables had a deep plow layer and good physical conditions for plant growth compared with the crop fields. In the vegetable field soils, organic matter, nitrogen and phosphate were accumulated in topsoils with continuous planting. Exchangeable Ca, Mg and Na in vegetable field soils were very high, but K was relatively low, so Ca/K and Mg/K ratios in the soils were extremly high compared with Japanese upland soils: Microflora in the vegetable field topsoils was poor except bacteria, especially fungi and actinomycetes which existed only a little in subsoils. The bacteria/fungi ratio of the vegetable field soils in Tianjin were much higher than those of the vegetable field soils in Kochi University. The 3 species of fungi, which have poor or rich saprophytic activities, grew well on the vegetable field soils after incubation in petri dishes. These results showed that almost all of the vegetable field soils in Tianjin had the ability of providing a nutrient source for microorganisms and it will be possible to develop good soil fertility by improving the manuring practices and environmental conditions.
