[Assessment of soil fertility in Artemisia argyi planting areas in Qichun county based on minimum data set].

This study aims to explore the soil fertility in the main Artemisia argyi planting areas in Qichun county.To be specific, the soil physical and chemical properties in the main planting areas of A.argyi in Qichun county were analyzed.On this basis, 12 indexes were selected for principal component analysis(PCA) which was then combined with the norm value of each index and the correlation coefficients between the indexes to establish the minimum data set(MDS).The radar map was plotted to directly demonstrate the level of each index and the comprehensive level of the sampling sites.The comprehensive index model was used to calculate the soil fertility quality index(SFQI) of the total data set(TDS) and MDS(SFQI-TDS and SFQI-MDS, respectively), and linear regression of the two was performed.The results showed that the indexes that made up the MDS for soil fertility evaluation were pH, available potas-sium, available iron, available zinc, available manganese, available copper, and available magnesium.The radar map suggested the greatest difference in soil organic matter and smallest difference in available nitrogen among the 14 sampling sites.Moreover, the overall content of available phosphorus and available iron was high, while that of available nitrogen was the lowest.The SFQI-MDS which was yielded based on the weight of each index in MDS calculated with the norm value was more sensitive and the SFQI had stronger correlation with TDS-SFQI, which can better represent TDS-SFQI.SFQI-MDS was in the range of 0.298-0.784, with the average of 0.565 and variation coefficient of 18.38%.Caohe Town had the highest average SFQI-MDS.Clustering of SFQI-MDS value suggested that the soil fertility can be classified into 4 levels: level Ⅰ(SFQI ≥ 0.677) indicated excellent soil fertility, which accounted for 11.24%(mainly in Qingshi town, Balihu, and Zhangbang town); level Ⅱ(0.571≤SFQI≤0.680) meant good fertility, which made up 43.82%(mainly in Caohe town, Hengche town, and Pengsi town); level Ⅲ(0.466≤SFQI≤0.557) indicated average fertility, which took up 32.58%(mainly in Chidong town and Zhulin town); level Ⅳ(SFQI≤0.421) suggested poor fertility, which accounted for 12.36%(mainly in Guanyao town).It is recommended that nitrogen, potassium, magnesium, and calcium fertilizers should be increased and organic ferti-lizer should be applied for the cultivation of A.argyi in Qichun county to improve soil fertility and soil physical and chemical properties.