Tail liquid from amino acid fermentation could improve the uptake and utilization of water soluble fertilizer nitrogen by cherry tomato

Objectives Tail liquid from amino acid fermentation is rich in organic nutrients, and has been added into fertilizers as a kind of synergistic material in recent years. In this paper, the effects of amino acid fermentation tail liquid on fertilizer nitrogen utilization were studied using the ¹⁵N tracing technique.

Methods Cherry tomato was selected as test materials in a pot experiment. Base water soluble fertilizer (F) was prepared by mixing potassium pyrophosphate and potassium chloride (N-P₂O₅-K₂O ratio is 0-14-24); fertilizer (P) was made by adding ¹⁵N urea (¹⁵N abundance was 10.5%, N-P₂O₅-K₂O ratio is 18-14-24); the fermentation tail liquids of glutamic acid (H), lysine and threonine acids (B) and polyglutamic acid (S) were added with 200 g/L into fertilizer F and P, to form fertilizer FH, FB, FS, PH, PB and PS. For F based fertilizer experiment, all the fertilizer was applied at the same amount of urea, which was urea N 60 mg/kg soil. For the P based fertilizer experiment, all the fertilizer was applied in the same fertilizer amount. All the fertilizers were applied evenly at five growing stages of tomato. Tomato was harvested with three ear fruit, and the height, stem diameter, biomass, yield of cherry tomato were investigated. The total nitrogen content and ¹⁵N abundance in each part of plants and soils were analyzed.

Results 1) Addition of amino acid fermentation tail liquids could significantly improve the effect of fertilizer. Compared with base fertilizer P, fertilizer PH, PB and PS increased the plant height, stem diameter, above-ground weight, dry root weight and yields by 17.7%, 3.8%, 8.5%, 12.5% and 4.8%, respectively. 2) Addition of amino acid fermentation tail liquids could enhance the fertilizer nitrogen uptake, increase the accumulation of fertilizer nitrogen in leaf and fruit significantly, which ensured the apparent increase of the utilization of fertilizer nitrogen. Compared with fertilizer P, the averaged plant total nitrogen uptake, fertilizer nitrogen uptake, fertilizer nitrogen accumulation in leaf and fruit, and the utilization rate of fertilizer nitrogen under the new fertilizers PH, PB and PS, were increased by 8.1%, 9.9%, 18.2%, 8.0% and 9.9%, respectively.

Conclusions Water soluble fertilizer mixed with amino acid fermentation tail liquid could promote crop growth, yield and the uptake of fertilizer nitrogen. Therefore, the amino acid fermentation tail liquid could efficiently improve the uptake and utilization of water soluble fertilizer nitrogen by crop.