Response of nutrient supplementation through organics on growth, yield and quality of pomegranate

- Nutritional requirement of pomegranate could be fulfilled with the exclusive use of organic sources.
- Organic sources viz. farmyard manure, poultry manure and green manuring with sun hemp could be harnessed for effective organic production of the pomegranate.
- It also increased microbial load 3-4 folds, which translate into higher soil fertility and nutrient uptake by the plants.
- It also reduced incidence of most devastating bacterial blight disease of pomegranate.

The study was carried out on pomegranate (Punica granatum L.) cv. 'Bhagwa' to investigate efficacy of organics on plant nutrient uptake, growth behaviour, fruit yield and quality attributes, disease incidence and soil health. Organic nutrient sources, namely, farm yard manure (FYM), vermicompost (VC), poultry manure (PM), and insitu green manuring (GM) through sun hemp (Crotalaria juncea L.), exsitu GM through Glyricidia (Gliricidia sepium), Karanj (Pongamia pinnata) and neem (Azadirachta indica), and recommended dose of inorganic fertilizers against control were evaluated. The results revealed significant decrease in soil pH and electrical conductivity and substantial increase in soil organic carbon content in all organic manuring treatments over control. Application of FYM had the highest availability of most of the nutrients (P: 64.4 and K: 578.7 kg ha−1; Cu: 15.1, Zn: 2.30 and Mn: 8.4 ppm) in the soil. Three years pooled data showed that the highest P (0.182%), K (1.06%) and Fe (176.7 ppm) contents in the leaves were supplied by PM, while N (2.33%) was by FYM. Although, during first year, vegetative growth of the plants was better in inorganic fertilizers than other treatments, second year onwards it was increased significantly in FYM, VC and GM with sun hemp treatments. Maximum fruit yield was obtained with the application of PM (3.96 kg tree−1) followed by FYM (3.86 kg tree−1). All of the organic manuring treatments resulted in improved fruit quality characteristics viz. fruit juice content, juice acidity, TSS and TSS: acid ratio as compared to inorganic fertilizers. Organic manuring with neem recorded the lowest disease index (5.84) on plants. Similarly, increased microbial load in the rhizosphere soil in terms of P. fluorescence (20.3 × 10−4 cfu g−1) and Azotobacter chroococcum (17.4 × 10−3 cfu g−1) population was recorded in FYM. A. niger (13.6 × 10−4 cfu g−1) and PSM (15.6 × 10−5 cfu g−1) activity was higher in GM with Karanj and Sun hemp, respectively.