Effect of different biological organic fertilizers on the growth of pineapple under continuous cropping and the heart rot

Abstract:

[Background] The soil-borne heart rot is common in pineapple production. [Objective] This paper aims to enhance the cultivation and disease prevention of pineapple under continuous cropping. [Methods] Soil was collected from the orchards with continuous pineapple cropping for pot experiment. With three substrates (coir, peat soil, rapeseed cake), biocontrol strains (Bacillus subtilis HL2, Streptomyces HL3), and commercial organic fertilizer, different biological organic fertilizers were prepared and the effect of them on the plant growth and heart rot of pineapple was investigated. [Results] Compared with CK (chemical fertilizer only), the biological organic fertilizers promoted the growth of pineapple plants, significantly increased the fresh weight (leaf, stem, root), dry weight (leaf, stem, root), and longest leaf length, and reduced the incidence of heart rot. Among the biological organic fertilizers, KC (80% organic fertilizer + rapeseed cake + HL2) demonstrated the best control effect, followed by KY (80% organic fertilizer + coir + HL2), KN (80% organic fertilizer + peat soil + HL2), and LY (80% organic fertilizer + coir + HL3) with the control rate of 83.5%, respectively. However, YJ (organic fertilizer only) showed the poor control effect. Correlation analysis showed that the content of the soil pathogen (Phytophthora nicotianae) was negatively correlated with actinomycetes, organic matter, and pH (p<0.001) but positively correlated with soil available potassium content (p<0.05) and the incidence (p<0.01). [Conclusion] In a word, the biological organic fertilizers promoted the growth of pineapple plants and decreased the incidence of heart rot. These results can serve as a reference for the healthy development of pineapple industry.