Conversa Giulia, Bonasia Anna, Lazzizera Corrado, Elia Antonio
Department of the Science of Agriculture, Food and Environment, University of Foggia Foggia, Italy.
Front Plant Sci. 2015 Jun 16;6:429. doi: 10.3389/fpls.2015.00429. eCollection 2015.
Peat is the most common substrate used in nurseries despite being a very expensive and a non-renewable material. Peat replacement with biochar could be a sound environmental practice, as it is produced from waste biomass, but evaluation of biochar as a potting substrate is needed. Ratios of peat:biochar of 100:0, 70:30, 30:70 (BC0, BC30, and BC70, respectively), two fertilizer rates (FERT1, FERT2), and arbuscular mycorrhizal fungi (AMF) inoculation were tested on potted Pelargonium plants. Plant growth, flowering, bio-physiological and nutritional responses, and root mycorrhization were evaluated. The BC30 mixture did not affect plant growth compared with pure peat. However, BC30 in combination with FERT2 treatment was more effective in enhancing nitrogen (N) and chlorophyll (CHL) leaf concentrations, and leaf and flower numbers. The BC70 mixture depressed plant growth, flowering traits, and root mycorrhization. Leaf N concentration was below the sufficiency range reported for Pelargonium growth. Leaf concentration of phosphorous (P) was adequate in pure peat and in BC30 but it dropped close to sub-optimal values in BC70. The pH value of the mixtures lowered P availability, though in BC30 the mycorrhizal activity could have allowed adequate P plant uptake. In BC70 plants, the deficiency of both N and P might be a reason for the observed growth reduction. The inoculation of the substrate with selected AMF improved plant growth (higher dry biomass, greater floral clusters, larger and more abundant leaves) and quality resulting in unstressed (lower electrolyte leakage and higher relative water content values) and greener leaves (low L(∗) and C(∗), high CHL content) and in more intensely colored flowers. We conclude that biochar can be applied in nursery/potted plant production provided that the proportion in the peat mixture does not exceed 30%. Furthermore, AMF inoculation contributed to achieving the best plant performance in 30% biochar amended medium.
泥炭是苗圃中最常用的基质，尽管它非常昂贵且不可再生。用生物炭替代泥炭可能是一种合理的环保做法，因为生物炭由废弃生物质制成，但需要对其作为盆栽基质进行评估。在盆栽天竺葵植株上测试了泥炭与生物炭比例为100:0、70:30、30:70（分别为BC0、BC30和BC70）、两种施肥量（FERT1、FERT2）以及接种丛枝菌根真菌（AMF）的情况。对植株生长、开花、生物生理和营养反应以及根系菌根化进行了评估。与纯泥炭相比，BC30混合物对植株生长没有影响。然而，BC30与FERT2处理相结合在提高叶片氮（N）和叶绿素（CHL）浓度以及叶片和花朵数量方面更有效。BC70混合物抑制了植株生长、开花性状和根系菌根化。叶片氮浓度低于报道的天竺葵生长充足范围。纯泥炭和BC30中磷（P）的叶片浓度充足，但在BC70中降至接近次优值。混合物的pH值降低了磷的有效性，不过在BC30中菌根活性可能使植株对磷的吸收充足。在BC70植株中，氮和磷的缺乏可能是观察到生长减少的原因。用选定的AMF接种基质可改善植株生长（更高的干生物量、更多的花簇、更大且更茂密的叶子）和品质，使叶片无胁迫（更低的电解质渗漏和更高的相对含水量值）且更绿（低L(∗)和C(∗)，高CHL含量）以及花朵颜色更鲜艳。我们得出结论，只要泥炭混合物中生物炭的比例不超过30%，生物炭就可应用于苗圃/盆栽植物生产。此外，接种AMF有助于在30%生物炭改良培养基中实现最佳植株表现。
