Elmer W H
Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven 06504.
Plant Dis. 2016 Dec;100(12):2507-2512. doi: 10.1094/PDIS-10-15-1196-RE. Epub 2016 Sep 15.
Asparagus can suffer from a crown and root rot caused by Fusarium oxysporum f. sp. asparagi and F. proliferatum. The disease is exacerbated when allelopathic toxins from old, rotting asparagus crowns are present in the soil. To minimize the damage from the replant problem, three strategies were examined: (i) biochar, (ii) application of earthworms (Lumbricus terrestris), and (iii) leaf mold to serve as a compost mulch and food source for earthworms. In a greenhouse, asparagus transplants were grown in soil amended with pathogen-infested asparagus residues or in nonamended soil, then both types of soil were augmented with biochar, earthworms, the combination of biochar and earthworms, or no treatment. Biochar increased arbuscular mycorrhizae (AM) colonization by 170% and reduced the incidence of root lesions by 57%; however, plant weight was not affected by any of the soil treatments and there were no significant interactions among the main effects. In the absence of infested asparagus residues, biochar reduced plant growth by 32%. Field plots that had severe crown and root rot, along with two other fields that had never been planted to asparagus, were planted with asparagus crowns and treated with leaf mold mulch, earthworms plus leaf mold mulch, biochar, or biochar plus earthworms plus leaf mold mulch. Untreated plots served as the control treatment. One year later, asparagus roots sampled from plots in the two new fields had a threefold increase in AM colonization when treated with biochar compared with control plots. Biochar did not increase yield over the duration of the 2012 to 2014 harvests when compared with that of the control plots. No soil treatment affected root colonization by AM in the field where Fusarium crown and root rot was severe. Compared with the untreated control plots, the leaf mold mulch treatment applied alone increased the marketable yields in each year of harvest. Combining leaf mold with earthworms provided no added benefit. Soil amendment with leaf mulch alone may hold promise for improving asparagus production in newly planted asparagus fields.
芦笋可能会遭受由尖孢镰刀菌芦笋专化型（Fusarium oxysporum f. sp. asparagi）和层出镰刀菌（F. proliferatum）引起的根颈和根腐病。当土壤中存在来自老化、腐烂芦笋根颈的化感毒素时，病害会加剧。为了将重茬问题造成的损害降至最低，研究了三种策略：（i）生物炭，（ii）投放蚯蚓（赤子爱胜蚓Lumbricus terrestris），以及（iii）用叶霉作为堆肥覆盖物和蚯蚓的食物来源。在温室中，将芦笋幼苗种植在添加了受病原体侵染的芦笋残体的土壤中或未改良的土壤中，然后在这两种类型的土壤中添加生物炭、蚯蚓、生物炭与蚯蚓的组合，或不进行处理。生物炭使丛枝菌根（AM）定殖增加了170%，并使根损伤发生率降低了57%；然而，植株重量不受任何土壤处理的影响，且主要效应之间没有显著的相互作用。在没有受侵染的芦笋残体的情况下，生物炭使植株生长降低了32%。对患有严重根颈和根腐病的田间地块，以及另外两块从未种植过芦笋的田地种植芦笋根颈，并分别用叶霉覆盖物、蚯蚓加叶霉覆盖物、生物炭，或生物炭加蚯蚓加叶霉覆盖物进行处理。未处理的地块作为对照处理。一年后，与对照地块相比，在两块新田地中，用生物炭处理的地块所采集的芦笋根中AM定殖增加了两倍。与对照地块相比，在2012年至2014年的收获期内，生物炭并未提高产量。在镰刀菌根颈和根腐病严重的田块，没有任何土壤处理影响AM对根的定殖。与未处理的对照地块相比，单独施用叶霉覆盖物处理在每年的收获中都提高了可销售产量。将叶霉与蚯蚓结合使用并没有带来额外的益处。仅用叶霉进行土壤改良可能有望提高新种植芦笋田的芦笋产量。
