ABSTRACT

To facilitate sustainable agriculture in the acidic soil in the southern region of China, reducing inorganic fertiliser in combination with an alkaline humic acid fertiliser amendment (HAFA) was investigated on key physicochemical properties of acid growth media and cherry tomato growth. Five treatments were established: 100% rate of the local conventional inorganic fertiliser, reduced application of inorganic fertiliser (30, 50, and 70% inorganic fertiliser application, w/w) combined with HAFA, and an unfertilised treatment as the control. HAFA increased medium pH by 0.39–0.75 compared with the 100% inorganic fertiliser treatment. In addition, medium organic matter and acid phosphatase, invertase, and polyphenol oxidase activity increased significantly following amendment. In addition, increased plant height, stem diameter, root length, leaf Soil and Plant Analysis Development values, plant biomass accumulation, and nutrient uptake were observed under 30–50% inorganic fertiliser treatment in combination with 1.0–1.4 mL of HAFA. Greater transfer factor ratios of N, P, and K were observed following amendment. Reducing inorganic fertiliser proportions did not significantly alter fruit shape index, single-fruit weight, or fruit quantity per plant. The benefits of HAFA were obvious, significantly increasing fruit ascorbic acid and lycopene concentrations, sugar-acid ratio, and yield.