Abstract:【Objective】As of 2022, the total area of fruit cultivation in Liandu District was 5247 hectares with an annual production of 119,064 tons, accounting for one-third of the total fruit production in Lishui City. Four varieties are mainly cultivated, including citrus, peach, prune and loquat, accounting for 91.06% of the fruit cultivation area in Liandu District. Previous surveys have shown that most orchards exhibit inadequate nutrient management practices. High application of chemical fertilizers, low application of organic fertilizers, and low application of medium and trace elements fertilizers are common, and these have led to soil nutrient imbalance, soil acidification and soil sloughing in orchards, which have seriously hindered the growth and development of fruit trees, resulting in reduced yields and lower quality. To comprehensively assess soil fertility and provide a scientific basis for soil management strategies, soil nutrient data covering peach, citrus, bayberry, and loquat soil were collected and analyzed in the study.【Methods】A total of 58 orchards were surveyed, encompassing 26 peach orchards, 17 citrus orchards, 9 prune orchards and 6 loquat orchards located within Liandu District. In total, 75 soil samples were collected from fruit-growing bases, comprising 33 samples from peach orchards, 18 from citrus orchards, 16 from prune orchards, and 8 from loquat orchards. Soil samples were collected from representative fruit trees. The systematic sampling method was employed to collect 5 to 6 independent samples from the 0~30 cm plough layer near the drip line of the canopy. Sample point coordinates were recorded using GPS, and the orchard's terrain conditions, fertilizer management, and yield were investigated. Soil samples were naturally dried, and stones, plant debris, animal residues were removed before mixing and sieving. The key parameters selected for diagnosing soil nutrient abundance and deficiency included soil bulk density (BD), soil pH, cation exchange capacity (CEC), total water-soluble salts (TS), soil organic matter (SOM), total nitrogen (TN), alkaline hydrolyzed nitrogen (AN), available phosphorus (AP), available potassium (AK), exchangeable calcium (Ca), exchangeable magnesium (Mg), available sulfur (S), available iron (Fe), available manganese (Mn), available copper (Cu) and available zinc (Zn). The differences in soil fertility among the four orchards were conducted by principal component analysis and cluster analysis in this study.【Results】The soil bulk density of the four orchards in our study ranged from 1.21 to 1.26 g∙cm-3. The soil pH of the four orchards was below 5.5, indicating a strongly acidic condition. In 66.67% of the citrus orchards and 68.75% of the prune orchards, the soil pH was below 4.5. In 84.85% of the peach orchards, the soil pH was below 5.5. Additionally, the soil pH of all loquat orchards was below 6.0, classifying them as acidic. The cation exchange capacity of the four orchards varied from 15.26 to 15.53 cmol∙kg-1. The average concentration of total water-soluble salts across the four orchards was below 1 g∙kg-1. Soil salinization was observed in certain areas. Soil organic matter, total nitrogen, alkali-hydrolyzed nitrogen, available phosphorus and available potassium generally categorized between levels III and I. Soil organic matter levels were classified as level IV in 12.12% of peach orchards, 11.11% of citrus orchards, and 6.25% of prune orchards. Total nitrogen levels in 3.03% of peach orchards were classified as level V. Alkali-hydrolyzed nitrogen was classified as level VI in 5.56% of citrus orchards, whereas 6.06% of peach orchards and 5.56% of citrus orchards was level IV. Available phosphorus levels were categorized as level IV in 6.06% of peach orchards, while 12.06% of peach orchards was level IV. In 12.5% of prune orchards, available potassium was classified as level IV, whereas 12.12% of peach orchards ranged between level IV and V. The levels of exchangeable calcium, magnesium, available sulfur, iron, manganese, copper and zinc were sufficient for orchard growth in all orchards. However, some loquat orchards exhibited deficiencies in manganese and copper. The overall soil fertility ranking was as follows: loquat orchard > citrus orchard > peach orchard > bayberry orchard, which based on the principal component composite scores. The results from the cluster analysis indicated the combined soil fertility scores in the following order: loquat orchard, peach orchard > prune orchard > citrus orchard, allowing the four orchards to be categorized into three groups. The soil fertility quality of both loquat and peach orchards was classified as first class, whereas bayberry orchard were classified as second class and citrus orchard as third class.【Conclusion】Our study demonstrated that loquat orchards exhibited high levels of soil nutrients typically, while citrus orchards was low. Overall, the orchards soil was characterized by high acidity, and some specific areas was salinization. Soil organic matter, total nitrogen, alkaline hydrolyzed nitrogen, available phosphorus and available potassium were abundant, however, some orchards soil exhibited deficiencies in medium and trace element. In the future, it is recommended to increase the application of organic fertilizers, reduce the application of acidic chemical fertilizers, and pay attention to the application of medium and trace elements fertilizers, apply quicklime or soil conditioners to neutralize soil acidity. Moreover, selecting fertilizer scientifically can help minimize the accumulation of salt ions, enhancing the level of soil fertility in orchards.
PDF （）