Nghiên cứu phương pháp ủ bokashi, compost và đánh giá chất lượng phân bón hữu cơ trên cải bó xôi (Spinacia oleracea L.)

Abstract

Raw materials of corn stalk and Japanese watercress at four volumetric ratios of 4:1, 3:1, 2:1, 1:2 were composted for 40 days using compost (PP compost) and bokashi (PP bokashi) methods. The quality of organic fertilizer products as solid (RComp) and liquid (LComp & LBoka) was analyzed for physico-chemical properties and initially evaluated for spinach (Spinacia oleracea L.) in a pot study. The single-factor experiment was arranged in a completely randomized design with seven treatments and three replications. The treatments differed in application rates, types and dilution of
liquid organic fertilizers. The PP compost had a thermophilic phase (t > 40^oC) lasting for 15 days, which was three times longer than the PP bokashi. Accordingly, RComp(2:1) had a high EC (electrical conductivity) value (3.8 mS/cm) and organic matter (77.7%), and macronutrient concentrations of total N, available phosphorus and potassium were 26.3 g/kg, 13.6 g P₂O₅/kg and 63.0 g K₂O/kg, respectively. Total aerobic plate counts in LComp(2:1) reached 2.5 × 107 CFU/mL. Meanwhile, L Boka(1:2) had an EC value of 19.8 mS/cm, and nutrient concentrations of total N, available phosphorus and potassium were 0.35 g N/kg, 0.09 g P₂O₅/kg and 9.93 g K₂O/kg, respectively. Total humic and fulvic acids in LBoka(1:2) reached 2,300 mg/kg. The results of the trial rate of 0.5 kg RComp/m² as a single or combined application with LComp(2:1) and LBoka(1:2) at diluted concentrations of total dissolved solids (TDS) 500 ppm gave a similar performance of plant heights, number of leaves, and yields of 1,278.9 - 1,425.7 g/m², and were significantly different from those of the control treatment (526.8 g/m²).