Effectiveness of Mycorrhiza on Soil Enzyme Activity, Nutrient Content and Fruit Quality of Dragon Fruit in Acidic Soil Conditions

Most soils in the eastern tropical region of India are moderately to strongly acidic and poor in available phosphorus and organic matter. Low soil fertility greatly affects the production of fruit crops such as dragon fruit, since the crop has high nutrient requirements due to the long fruiting period. Under these circumstances, arbuscular mycorrhizal fungi (AMF) can effectively improve nutrient availability and ensure quality fruit production. The present study is envisioned to assess the effectiveness of mycorrhiza on soil enzyme activity, shoot mineral profile and fruit quality attributes of dragon fruit. A composite native culture of Glomus was applied at 25, 50 and 100 g plant−1 along with two levels of P (25 and 50 g plant−1) in dragon fruit. Application of 50 g AMF with 25 g P (M50P25) significantly enhanced root colonization; activities of soil enzymes such as phosphatase, urease, dehydrogenase and fluorescein diacetate; and shoot nutrient content. Root colonization, soil enzyme activity and shoot nutrient content exhibited a significant correlation. Fruit weight, pulp content, pulp firmness, soluble solid contents, reducing sugar, sucrose, protein, ascorbic acid, betacyanin, phenol, flavonoid and antioxidant activity were also significantly higher under M50P25. Principal component analysis also exhibited proximity of M50P25 with soil enzyme activity, nutrient content and fruit quality attributes of dragon fruit. However, inoculation of 100 g AMF with 25 g P (M100P25) also exhibited prominence in influencing soil enzyme activity, nutrient uptake and the fruit quality of dragon fruit.