华南荔枝园土壤性质调查与分析

采集华南荔枝主产区荔枝园土壤样本470个,根据第二次全国土壤普查土壤养分分级指标对土壤性质进行评价,并对各产区土壤性质进行对比,进一步探讨土壤性质之间的关系。结果表明,华南荔枝园土壤普遍酸性强,90%以上果园土壤为酸性和强酸性。土壤阳离子交换量整体处于低水平,保水保肥能力弱。土壤有机质、碱解氮、速效钾及有效钼含量处于中低水平,交换性钙和镁及有效硼处于低水平,而有效磷、有效锌含量适中,有效硫和有效铜含量丰富。整体上荔枝园土壤养分肥力偏低且不均衡。不同产区土壤养分肥力差异较大。海南产区土壤有机质、碱解氮、有效磷和有效锌含量最高;云南产区速效钾、交换性钙、交换性镁、有效铜含量明显高于其他产区,而有机质、有效磷、有效硫、有效钼含量最低;广东产区则土壤有效硼含量最高。Pearson相关分析结果显示,土壤多种性质之间关系密切。其中,pH和交换性钙、交换性镁均呈极显著正相关关系（P<0.01）;交换性钙和交换性镁之间,有效铜和有效锌之间,速效钾与交换性钙之间均为极显著正相关（P<0.01）。针对华南荔枝园土壤酸性强及养分不均衡的问题,建议重视土壤pH改良,加强有机肥的施用,合理施用氮、磷、钾肥,并增加钙、镁、硼肥。

Investigation and Analysis on Soil Properties of Litchi Orchards in South China

470 soil samples were collected from litchi orchards in main production areas in South China. According to the Soil Nutrient Classification Norms of the Second National Soil Survey, the soil nutrient fertility status of the litchi orchards was evaluated, and the main nutrient contents in different provinces were compared. The relation among soil properties was investigated as well. The results showed that soils in most of the litchi orchards in South China were in low pH, with more than 90% of them of being acid (pH 4.5-5.5) and highly acid (pH<4.5). Generally, soil cation exchange capacity of litchi orchards was low and weak in water and nutrient holding capacity. The content of soil organic matter, alkali-hydrolyzable nitrogen, available potassium and available molybdenum was in lower medium levels, while soil exchangeable calcium, exchangeable magnesium and available boron were deficient, and available phosphorus and zinc were in medium values. However, soil available sulfur and copper were abundant in litchi orchards. On the whole, soil nutrient fertility in litchi orchards was low and unbalanced. Soil nutrient fertility in different production areas were variable. Soil organic matter, alkali-hydrolyzable nitrogen, available phosphorous, copper and zinc in Hainan province were higher than those in all other production areas in South China. Soil available potassium, exchangeable calcium and magnesium, and available copper in Yunnan Province ranked the highest in all production areas, however, soil organic matter, available phosphorus, sulfur and molybdenum were the lowest. Totally, soil available boron in Guangdong Province ranked first in all the production areas. Pearson correlation analysis showed that close relation among soil properties was observed. Among them, soil pH was positively correlated to soil exchangeable calcium and magnesium, respectively (P<0.01). Positive correlation was found between exchangeable calcium and exchangeable magnesium, and between available copper and zinc, and between available potassium and exchangeable calcium as well (P<0.01). Owing to the universally low soil pH and unbalanced soil nutrient fertility, great attention should be paid to soil pH improvement and application of organic fertilizer. Meanwhile, proper combination of nitrogen, phosphorous and potassium fertilizers and supplement of calcium, magnesium and boron fertilizers need to be highlighted.