Evaluation of substrate dynamics for integrated nutrient management under high density planting of guava cv. Sardar.

A field experiment was carried out with different treatment combinations of organic manures (FYM @ 25 and 50 kg, vermi-compost @ 5 kg and organic mulch 10 cm thick per plant), inorganic fertilizers (full dose of recommended NPK, 50% dose of recommended NPK), bio-fertilizers (Azospirillum, Azotobacter, Pseudomonas flourescence Aspergillus niger etc.) and foliar spray of micronutrients on eight-year-old guava trees cv. Sardar under high density planting. The results revealed that the application of 50 percent dose of recommended NPK + 50 kg FYM + 250 g Azotobacter (T7) significantly increased the canopy volume (201.42 m3), fruit weight (153.30 g), TSS (14%), ascorbic acid (198.30 mg/100 g pulp), reducing sugar (4.77%), total sugars (8.10%), leaf nitrogen (1.40%), phosphorus (0.46%), potassium (1.17%) contents and fruit yield (28.95 kg per plant). Nitrogen, phosphorus and potassium content of the leaf were positively correlated with fruit yield. Further, regression analysis revealed that fruit weight (r2 = 0.914) dominantly influenced the fruit yield and leaf nitrogen content also influenced (r2 = 0.499) fruit yield significantly. The combined application of 50 percent dose of recommended NPK + 50 kg FYM + 250 g Azotobacter (T7) gave significantly higher fruit yield plant−1 (28.95kg) with higher B: C ratio (2.53:1).