ABSTRACT

Plant nutrient deficiencies can reduce crop development and yields and can be especially problematic in high-yielding intensive crop production systems and when organic materials are used as the only source of nutrients. Aqueous extracts used in organic agriculture, such as compost – or vermicompost-tea, often have deficiencies in macro-nutrients and ionic imbalances. However, when organic materials are used as fertilisers, they are often applied in combination with plant growth promoting bacteria (PGPB), which can improve the availability of the nutrients. In this study, PGPB were used as a tool to facilitate the nutrition of horticultural crops without using synthetic fertilisers. Three bacterial species (Azotobacter vinelandii (AV), Bacillus megaterium (BM) and Frateuria aurantia (FA)) were tested as (i) inoculated to an aqueous vermicompost extract and (ii) applied directly by fertigation to the growing medium in two tomato production cycles. The results showed that it was possible to obtain a balanced nutrient solution, with adequate concentrations of the main nutrient ions, from an aqueous and aerated solution made from vermicompost, without the addition of PGPB. In the second trial, the inoculation with PGPB to the growing substrate for tomatoes fertigated with vermicompost tea, resulted in significant increases in the yield and quality of the tomato fruit, increased nutrient assimilation by the plants and increased enzymatic activity in the growing substrate.

摘要

植物营养缺乏会降低作物的发育和产量，并且在高产集约化作物生产系统中以及当有机材料被用作唯一的营养来源时尤其成问题。有机农业中使用的水提取物，例如堆肥或蚯蚓堆肥茶，通常缺乏大量营养素和离子失衡。然而，当有机材料用作肥料时，它们通常与植物生长促进细菌（PGPB）结合使用，这可以提高养分的利用率。在这项研究中，PGPB 被用作在不使用合成肥料的情况下促进园艺作物营养的工具。三种细菌（Azotobacter vinelandii (AV)、Bacillus megaterium (BM) 和Frateuria aurantia (FA)) 被测试为 (i) 接种到水性蚯蚓粪提取物和 (ii) 在两个番茄生产周期中通过施肥直接施用于生长介质。结果表明，在不添加 PGPB 的情况下，可以从由蚯蚓粪制成的水和充气溶液中获得具有足够浓度的主要营养离子的平衡营养液。在第二个试验中，将 PGPB 接种到用蚯蚓茶施肥的番茄的生长基质上，显着提高了番茄果实的产量和质量，增加了植物对养分的吸收，并提高了生长基质中的酶活性。