Institute of Forestry and Conservation, University of Toronto, Toronto, ON, Canada.
PLoS One. 2023 Jul 18;18(7):e0288291. doi: 10.1371/journal.pone.0288291. eCollection 2023.
Declining tree health status due to pollutant impacts and nutrient imbalance is widespread in urban forests; however, chemical fertilizer use is increasingly avoided to reduce eutrophication impacts. Biochar (pyrolyzed organic waste) has been advocated as an alternative soil amendment, but biochar alone generally reduces plant N availability. The combination of biochar and either organic forms of N or Plant Growth Promoting Microbes (PGPMs) as biofertilizers may address these challenges. We examined the effects of two wood biochar types with Bacillus velezensis and an inactivated yeast (IY) biofertilizer in a three-month factorial greenhouse experiment with Acer saccharinum L. (silver maple) saplings grown in a representative urban soil. All treatments combining biochars with biofertilizers significantly increased sapling growth, with up to a 91% increase in biomass relative to controls. Growth and physiological responses were closely related to nutrient uptake patterns, with nutrient vector analyses indicating that combined biochar and biofertilizer treatments effectively addressed nutrient limitations of both macronutrients (N, P, K, Mg, Ca), and micronutrients (B, Fe, Mn, Mo, Na, S, and Zn). Biochar-biofertilizer treatments also reduced foliar concentrations of Cu, suggesting potential to mitigate toxic metal impacts common in urban forestry. We conclude that selected combinations of biochar and biofertilizers have substantial promise to address common soil limitations to tree performance in urban settings.
由于污染物影响和养分失衡，城市森林中树木健康状况普遍下降；然而，为了减少富营养化的影响，化肥的使用正日益被避免。生物炭（热解有机废物）已被提倡作为一种替代土壤改良剂，但生物炭本身通常会降低植物氮的有效性。生物炭与有机氮形式或植物生长促进微生物（PGPMs）的组合作为生物肥料，可能会解决这些挑战。我们在一个为期三个月的温室实验中，用 Bacillus velezensis 和一种失活酵母（IY）生物肥料研究了两种木质生物炭类型对 Acer saccharinum L.（糖枫）实生苗的影响，这些实生苗在一种具有代表性的城市土壤中生长。所有结合生物炭和生物肥料的处理都显著增加了实生苗的生长，与对照相比，生物量最多增加了 91%。生长和生理响应与养分吸收模式密切相关，养分载体分析表明，生物炭和生物肥料的组合处理有效地解决了大量营养元素（N、P、K、Mg、Ca）和微量元素（B、Fe、Mn、Mo、Na、S 和 Zn）的养分限制。生物炭-生物肥料处理还降低了叶片中铜的浓度，这表明有可能减轻城市林业中常见的有毒金属的影响。我们的结论是，选择合适的生物炭和生物肥料组合，对于解决城市环境中树木生长的常见土壤限制具有很大的潜力。
