马尾松采伐迹地火烧黑炭对土壤营养元素含量的短期影响

以中亚热带33年生马尾松人工林采伐迹地为研究对象,分析了炼山1年后移除黑炭(B0)、单倍黑炭(B1)、双倍黑炭(B2)处理和未炼山对照(UB)土壤可提取态常量(P、K、Ca、Na、Mg)和微量(Al、Fe、Mn、Cu、Zn)元素含量及其比值的变化特征。结果表明:(1)黑炭输入量对土壤常量元素的影响因土层而异,在0—10 cm土层,B2土壤K、Ca和Mg含量显著高于B0土壤(P0.05),黑炭输入量对10—20 cm土壤常量元素含量没有影响(P0.05)。在0—10,10—20 cm土层,B2土壤速效P含量均显著高于UB土壤(P0.05)。不同黑炭输入量处理土壤速效P含量无显著差异(P0.05);(2)不同黑炭输入量处理土壤微量元素含量无显著差异(P0.05),但在10—20 cm土层,B2土壤Mn含量显著高于UB土壤(P0.05);(3)炼山没有显著影响土壤钠钾吸附比(SPAR)、Ca/Mg和Ca/Al。黑炭输入量对土壤Ca/Mg的影响因土层而异,在10—20 cm土层,B2处理土壤Ca/Mg显著高于B0和B1处理土壤Ca/Mg(P0.05),而在0—10 cm土层不同黑炭处理土壤Ca/Mg没有显著差异(P0.05)。因此,炼山产生的黑炭在短期内有助于提高土壤常量养分元素含量,并对于维持土壤结构稳定性具有积极意义,今后应持续监测黑炭对土壤养分的长期影响,从而完善炼山黑炭在人工林经营管理中的应用。

Short-term Effects of Black Carbon on Soil Extractable Nutrient Elements in a Pinus massoniana Plantation Subjected to Slash Burning

The objective of this study was to investigate the effects of fire-derived black carbon on soil extractable nutrient elements in subtropical plantations. Three levels of black carbon input were applied to the experimental plots (10 m×10 m) by removing charred materials across the plots two weeks after slash burning in a Pinus massoniana Lamb. plantation. The three levels of black carbon were:B0, in which all visible charred materials were carefully removed from the plot; B1, in which all charred materials were left in place on the forest floor; and B2, in which all charred materials removed from the B0 plots and the double quantities of charcoal inputs were added. Soil samples were collected from 0-10 and 10-20 cm depth 1 year after charcoal application or removal. The results showed that:(1) The impact of black carbon input on soil major nutrients varied with sampling depth. At 0-10 cm depth, the contents of potassium(K), calcium (Ca) and magnesium (Mg) in B2 soils were significantly higher than those in B0 soils (P<0.05), which differences were not observed at the 10-20 cm depth. Available phosphorus (P) contents in B2 soils were significantly higher than those in UB soils at both 0-10 cm and 10-20 cm depth (P<0.05). (2) The amount of black carbon input had no effect on soil minor nutrients (P>0.05). Double the quantities of black carbon input significantly increased manganese (Mn) content compared with the UB soils (P<0.05). (3) There was no significant differences of soil SPAR, Ca/Al, and Ca/Mg except for Ca/Mg at the 10-20 cm depth, where Ca/Mg in B2 soil was significantly higher than those in B0 and B1 soil(P<0.05). In summary, our findings highlighted the importance of black carbon to improve soil fertility and structural stability in subtropical plantations subjected to slash burning in the short term. Future research should focus on the long-term impacts of black carbon on soil nutrient availability in subtropical plantations subjected to slash burning.