Temporal and spatial distributions of soil nutrients in Hani terraced paddy fields, Southwestern China

摘要

Hani terraced paddy fields are one of the most important ways for agricultural products and greatly influence regional landscapes in mountainous areas of Southwestern China. However, the knowledge of soil nutrient conditions from Hani terraced paddy fields is limited. This paper investigates such soil nutrient parameters as organic matter (OM), total nitrogen (TN), total phosphorus (TP), available phosphorus (AP), total potassium (TK), available potassium (AK) of four sampling sites of paddy fields under special geographical environment and agricultural technology, and compares the differences of soil nutrients related to spatial patterns and temporal periods. Correlation analysis is performed to analyze the impact of environmental factors on soil nutrients, as well as the relationships between soil nutrient parameters and altitude, slope direction, gradient and distance from village. The results show that there were some differences separately in the content of soil nutrients such as OM, TN, TP, AP, TK and AK. The AK and AP levels are lower in the fallow period than that in the tillage period, only OM level in the fallow period is higher than that in the tillage period; TN, TK, TP levels are nearly similar in the tillage and the fallow period. Unlike great differences in two periods, soil nutrient content in the ridge of fields is identical basically with the content in the corresponding paddy fields. Correlation analysis shows that soil nutrients of AK, TP, TN and OM have distinctive negative correlations with distance from villages, while AP and TK display a slight fluctuation.