云南玉溪柑橘园土壤养分状况与分布特征

在云南省玉溪市华宁南盘江低热河谷区、华宁山地丘陵区、元江干热河谷区和新平山地丘陵区4个柑橘生态区,选取一个月内未施肥的101个代表性柑橘园采集土壤进行分析。结果表明:玉溪柑橘园土壤pH变幅在3.98～8.07,52.48%的土壤p H基本适宜柑橘生长,14.85%的土壤pH适宜柑橘生长;土壤有机质匮乏,59.40%的土壤低于15 g/kg。土壤碱解氮、有效磷、钾、钙、镁、铁、锰、锌、铜、硼的平均含量分别为78.64、53.95、273.15、3240.37、233.39、23.21、43.82、5.67、2.89、0.50mg/kg。总体上,土壤碱解氮和有效硼含量不足(低量和缺乏),比例分别为78.22%和66.34%;有效钾、钙、锰和铜含量以超标(高量和过量)居多,比例分别为64.36%、51.48%、56.44%和83.17%;有效磷、铁、锌含量以丰富(适宜、高量和过量)为主,比例分别为67.31%、75.24%和88.12%;有效镁不足、适宜和超标的果园各占约1/3。在土壤养分状况的区域特征方面,华宁优于新平,新平优于元江。土壤pH与有效钙、镁含量的正相关性极显著,与有效锰、铜含...

Characteristics of Soil Nutrients and Frequency Distribution of Yuxi Citrus Orchards in Yunnan

Soil samples were collected from 101 typical citrus orchards in 4 main citrus-planting areas of Yuxi City in Yunnan Province, and nutrient contents were measured. The 4 main citrus-planting areas are Nanpanjiang low-heat valley, Huaning hill and mountainous area, Yuanjiang dry-hot valley area and Xinping hill and mountainous area. The results showed that soil pH ranged from 3.98 to 8.07, 52.48% soil samples with sub-suitable pH for citrus growth and only 14.85% soil samples with pH suitable for citrus growth. Soil organic matter (SOM) was deficient and 59.40% soil samples were insufficient in SOM content. The average contents of available N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B were 78.64, 53.95, 273.15, 3 240.37, 233.39, 23.21, 43.82, 5.67, 2.89 and 0.50 mg/kg, respectively. In general, the insufficient proportions (deficiency and low grades) of available N and B were 78.22% and 66.34%, respectively. The exceeding proportions (high and excessive grades) of available K, Ca, Mn and Cu were 64.36%, 51.48%, 56.44% and 83.17%, respectively. Meanwhile, 67.31%, 75.24% and 88.12% of samples were abundant (suitable, high and excessive grades) in available P, Fe and Zn contents, respectively. The insufficient, suitable and exceeding proportions of available Mg were all about 1/3. As to the regional differences of soil nutrient status, Huaning was best, followed by Xinping and Yuanjiang, Nanpanjiang was worst. There were extremely significant positive correlation between soil pH with available Ca and Mg, and significant negative correlation between soil pH with available Mn and Cu. SOM was significantly positively correlated with most other soil nutrients. In conclusion, for fertilization management of citrus orchard, attention should be paid to adjust soil pH, increase the application of N, B and organic fertilizer, moderately reduce the application of K and P fertilizers, while reasonably control the application of Ca, Mn and Cu fertilizers.