琯溪蜜柚园土壤钙素养分分析

Analysis of soil calcium nutrition of Guanxi pomelo orchard

【目的】测定并分析福建省平和县琯溪蜜柚叶片和蜜柚园土壤中交换性钙的含量水平,探讨土壤交换性钙含量的影响因素,为蜜柚钙素养分的调控提供参考依据。【方法】采集312个蜜柚园的蜜柚叶片和土壤样品及28个树龄逾15 a的蜜柚园不同土层的土壤样品,分析叶片和土壤中交换性钙的含量及其相互关系,研究土层深度、土壤理化性质对交换性钙含量的影响情况。【结果】312个蜜柚园的蜜柚树叶片钙的平均含量为3.11%,其中,钙含量等级属于低量(<3.0%)、适量(3.0%~4.9%)和高量(>4.9%)的叶片样本比例分别为46.80%、52.24%与0.96%。蜜柚园土壤中交换性钙的含量为16.70~2203.74 mg·kg^(-1),平均含量为274.60 mg·kg^(-1),有84.62%的土壤样本中交换性钙的含量低于500 mg·kg^(-1),土壤交换性钙含量与叶片钙含量之间呈极显著正相关,说明土壤交换性钙是蜜柚树体钙素养分的重要来源。土壤交换性钙含量随着土层深度的增加而降低,随着土壤有机质含量的增加而提高。相关性分析结果表明,土壤交换性钙含量随着土壤pH值、阳离子代换量(CEC)、碱解氮与速效钾含量的增加而提高,却随着土壤有效硫含量的增加而下降,其与土壤速效磷的关系如下:当土壤速效磷含量<450 mg·kg^(-1)时,土壤交换性钙含量随着速效磷含量的增加而提高;当土壤速效磷含量>450 mg·kg^(-1)时,土壤交换性钙含量随着土壤速效磷含量的增加而下降。【结论】平和县蜜柚园土壤交换性钙含量普遍偏低,土壤酸化、保肥性能差及养分不平衡是土壤钙素缺乏的主要原因。生产上应深施石灰性物质以提高土壤pH值,补充钙素养分,还应重视有机肥的施用和平衡施肥。

【Objective】With the aim to provide evidence for calcium nutrition regulation of Guanxi pomelo in Pinghe county Fujian province,calcium content in leaves,soil exchangeable calcium content and its influencing factors were studied.【Method】Leaf and soil samples from 312 pomelo orchards and soil samples from soil profiles of 28 pomelo orchards with planting years more than 15 years were collected.The relationship between soil exchangeable calcium content and calcium content in leaves,the effects of soil depth and soil physicochemical properties on soil exchangeable calcium content were studied.【Result】The average calcium content in leaves was 3.11%of 312 pomelo.The calcium content in leaves was classified into the low(<3.0%),the moderate(3.0%-4.9%)and the high(>4.9%)levels,which were 46.80%,52.24%and 0.96%,respectively.Soil exchangeable calcium content in 312 pomelo orchards was in a range of 16.70 mg·kg^(-1) to 2203.74 mg·kg^(-1),with average of 274.60 mg·kg^(-1).The percentage of soil samples with soil exchangeable calcium content below 500 mg·kg^(-1) was 84.62%.The results showed that soil exchangeable calcium content was significantly positive correlated with calcium content in leaves,indicating that soil exchangeable calcium was the important calcium source for pomelo tree.Soil exchangeable calcium content decreased with soil depth and increased with soil organic matter content.The correlation analysis showed that soil exchangeable calcium content was significantly positively correlated with soil pH,soil cation exchange capacity(CEC),alkali-hydrolyzable nitrogen and available potassium,but significantly negatively correlated with soil available sulfur content.The relationship between soil exchangeable calcium content and available phosphorus varies with the change of available phosphorus.When the soil available phosphorus content was less than 450 mg·kg^(-1),soil exchangeable calcium content increased with the increase of available phosphorus.When the soil available phosphorus content was higher than 450 mg·kg^(-1),the exchangeable calcium content decreased with the increase of available phosphorus.【Conclusion】Soil exchangeable calcium content of pomelo orchards in Pinghe county is generally deficient.Soil acidification,low soil fertility retention capacity and nutrition imbalance are the causes of soil calcium deficiency.Deep application of liming materials to improve soil pH and soil calcium supply is strongly recommended.Moreover,attention should be paid to balanced fertilization and increased application of organic fertilizer.