報告書番号

V11035

タイトル（和文）

省エネルギー植物生産技術の開発(4)－レタス連続栽培における肥料成分の削減－

タイトル（英文）

Reducing fertilizer in continuous hydroponic culture of lettuce

概要 （図表や脚注は「報告書全文」に掲載しております）

植物工場の水耕栽培では、温室効果ガス排出量削減のために作物の収穫量を損なうことなく必要最小限の肥料を処方することが求められている。当所では、今までに肥料分の吸収特性に基づく新しい水耕液調整法を明らかにした。しかし、本方法が、農業生産において多用されるNFTによる連続栽培に適用できるかは不明であるため、代表的な水耕栽培作物であるレタスの水耕液組成を作成し、NFT連続栽培への適用可能性を検討した。最初にレタスの肥料の吸収特性を整理し、それを基に作成した水耕液を用いて、NFT連続栽培を行った。その結果、当所で開発した新しい水耕液調整法はNFTによる連続栽培に適用でき、従来の処方よりもさらに減量化が行える可能性を示すことができた。

概要 （英文）

Lately plant factories with low CO2 emission have attracted considerable attention. It is claimed to reduce fertilizer in hydroponic culture used in the plant factories in view of reducing CO2 emission. We presented new methods to make a formula for hydroponic solution based on the characterization of fertilizer absorption in a previous report. It is unknown whether the method is acceptable for continuous NFT (Nutrient film technique) culture because the method was made for 1 time culture. To clarify that the method was useful for the continuous culture, we characterized the absorption of fertilizer of lettuce (Lactuca sativa) using DFT (Deep flow technique) culture system. First, we measured Yield and absorption of fertilizer with lettuces grown in the Enshi solution diluted by 0.1 -0.5 times. The yield of lettuce grown in the solution diluted by 0.2 times or under was lower in comparison to lettuce grown in the solution diluted by 0.3 times or more. The absorption of fertilizer was characterized into three groups. The first was that the addition and absorption of fertilizer was almost same (NH4-N). The second was that the addition corresponded to the absorption in the solution diluted by0.3 times or under (NO3-N, PO4-P, K). And the third was that the absorption did not depend on the addition (Mg, Ca). Second, we made a new formula of fertilizer for continuous NFT (Nutrient film technique) culture. Lettuces were harvested 21 times during the continuous hydroponic culture. The concentration of culture solution was kept low. Furthermore, yield and quality of lettuces grown in the new formula solution are comparable to those of lettuces grown in the regular solution. In conclusion, we show that the new method is applicable to the continuous culture and the possibility of reducing fertilizer in hydroponic culture.

報告者

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