桂北柑橘园土壤化学性状研究

要 ：为了解桂北柑橘园土壤养分丰缺状况,2017年在桂北7个柑橘主产县(市)选取102个代表性柑橘园采集土壤样本,对pH、有机质和10种营养元素进行定量分析。结果表明,土壤pH变幅 3.95-8.02。其中,pH值处于强酸性(pH < 4.5)、酸性(pH值 4.5-5.5)和碱性(pH值 >7.3)范围的果园分别占总样本数的24.51%、48.04%和9.80%,大部分果园土壤pH值为强酸性和酸性,有64.70%的果园土壤pH值适宜或基本适宜(pH值4.5-7.0)柑橘生长,但仅有14.71%的果园土壤pH值适宜柑橘生长(pH值5.5-6.5)。土壤有机质含量丰富,适量及以上水平的比例达86.27%。果园土壤营养元素丰缺并存,失衡比较明显,其中,有效P和有效K含量不足(低量或缺乏)的比例分别为33.33 %和30.39 %,超标(高量或过量)比例分别为21.57%和23.53%；碱解N和有效Ca含量主要在适量范围,不足比例分别为36.27%和31.37 %；有效Fe和有效Mn含量丰富,超标比例分别为64.71%和55.89%；有效Mg、Zn、Cu和B含量不足比例较高,分别为59.80 %、92.16 %、56.86 %和50.98 %。桂北柑橘产区土壤养分限制因子主要为土壤酸化,有效Mg、Zn、Cu和B含量不足,生产上应注重调节土壤酸碱度,适度增施Mg、Zn、Cu和B肥。

Study on Soil Chemical Properties of Citrus Orchards in Northern Guangxi

In order to evaluate soil nutrient status of citrus orchards in northern Guangxi, 102 representative citrus orchards in 7 major citrus production counties in northern Guangxi were selected for collecting soil samples in 2017, and soil pH value, organic matter and 10 nutrient element contents were quantitatively analyzed. The results showed that the range of soil pH value was 3.95-8.02. Among them, strong acid (pH<4.5) soil occupied 24.51%, acid (pH 4.5-5.5) soil occupied 48.04%, alkaline (pH>7.3) soil accounted for 9.80%, and acid soil was the most widely distributed. There were 64.70% soil samples with suitable or appropriate pH value (pH 4.5-7.0) for citrus growth, but only 14.71% soil samples had pH value range (pH 5.5-6.5) suitable for citrus growth. The soil organic matter content was rich, the proportion of appropriate or above appropriate content levels reached 86.27%. Most of the analyzed citrus orchard soils were characteristics of rich and deficient of some elements, which indicated poor balance of soil element nutrient status. The proportion of soil effective P and K content below optimal range were 33.33 % and 30.39 %, respectively, and those above optimal ranges were 21.57% and 23.53%, respectively. The soil available N and effective Ca contents were mainly within the suitable level, however 36.27% and 31.37% were in insufficient level, respectively. The soil available Fe and Mn contents were rich, and 64.71% and 55.89% exceeded suitable level, respectively. The deficiency ratios of available Mg, Zn, Cu and B in soil were 59.80%, 92.16%, 56.86% and 50.98%, respectively. The limiting factors of soil nutrient in northern Guangxi citrus growing area were soil acidification as well as available Mg, Zn, Cu and B deficiency. A attention should be paid to adjusting soil pH, and moderately increasing the application of Mg, Zn, Cu and B fertilizers.