施用不同pH改良剂对荔枝园酸性土壤性质及荔枝生长的影响

采集华南典型荔枝园酸性土壤pH(4.2±0.2)],分别在土壤中添加石灰（1 g/kg）、白云石粉（2 g/kg）和2个用量（0.625、4 g/kg）钙镁磷肥,以不添加改良剂为对照,进行土壤培养和荔枝盆栽试验,比较不同物质改良土壤的效果及对荔枝生长的影响。结果表明：施用pH改良剂均可不同程度提高土壤pH,影响土壤的大、中、微量元素养分有效性和酶的活性,土壤性质的变化与改良剂种类、用量及土壤属性本身有关;施用石灰、白云石粉和高量钙镁磷肥均能显著促进荔枝生长,其中石灰和白云石粉的综合作用优于高量钙镁磷肥,但施用低量钙镁磷肥抑制荔枝生长。建议石灰和白云石粉可用作荔枝园酸性土壤pH 改良剂,可否选用钙镁磷肥及其合理用量,则需根据土壤性质而定。

Effects of Soil pH Conditioners on Soil Properties of Acid Litchi Orchards and Litchi Growth

Typical acid soil from a litchi orchard was collected to conduct a soil incubation and a litchi pot experiment in a greenhouse to examine the response of soil attributes and litchi growth to soil pH conditioners, and to select suitable soil pH conditioners for litchi production. Lime (1 g/kg), dolomite (2 g/kg) and calcium magnesium phosphate (0.625 g/kg and 4 g/kg) were used respectively. The soils without conditioners were used as the control. The application of soil conditioners enhanced soil pH at different extents, and the influence on the availability of soil macro-, secondary and micro-nutrients, soil enzyme activities and litchi growth was associated with the type and use rate of conditioners and soil properties themselves. Generally, the usage of lime, dolomite and high dose of calcium magnesium phosphate obviously promoted the growth of litchi seedlings. Moreover, lime and dolomite exhibited better performance than calcium magnesium phosphate did with high dose. However, low dose of calcium magnesium phosphate inhibited litchi growth. It is suggested that lime and dolomite are practical soil pH conditioners in acid litchi orchards. The suitability of calcium magnesium phosphate as a soil pH conditioner and its proper use rate are dependent on the soil property of the target litchi orchard.