Identifying nutrient imbalances in pomegranate (Cv. Bhagwa) at different phonological stages by the diagnosis and recommendation integrated system

The diagnosis and recommendation integrated system (DRIS) approach was used to interpret nutrient analyses of leaf tissues from pomegranate cv. Bhagwa orchards grown in southwestern Maharashtra, India. The DRIS norms were established for three growth stages,viz. 50% flowering, fruit development and first harvesting of pomegranate. Various nutrient ratios were obtained from high-yielding population and were used to compute DRIS indices for diagnosing nutrient imbalances and their order of limitation to yield. Nutrient sufficiency ranges at 50% flowering derived from DRIS norms were 1.32–2.15% nitrogen (N), 0.18–0.24% phosphorus (P), 1.29–1.99% potassium (K), 0.64–1.20% calcium (Ca), 0.23–0.45% magnesium (Mg), 0.16–0.26% sulfur (S), 103.04–149.12 mg kg^?1 iron (Fe), 39.60–72.85 mg kg^?1 manganese (Mn), 15.99–26.10 mg kg^?1 zinc (Zn), 6.16–9.32 mg kg^?1 copper (Cu), 23.38–39.88 mg kg^?1 boron (B) and 0.29–0.47 mg kg^?1 molybdenum (Mo). Similarly, the sufficiency range at fruit development and first harvesting was developed for computing DRIS indices. The requirement of Fe, Mg, S, Zn and N by the pomegranate plant was higher at 50% flowering and fruit development stages. According to these DRIS-derived indices, 87.85, 73.83, 70.09, 69.16 and 65.42% orchards were deficient in Fe, S, Mg, Zn, and N, respectively, at 50% flowering, while 70.03, 66.36, 63.55, 61.68, and 68.22% orchards were found to be deficient in respective nutrients during the fruit development stage.     

Innovative soil management for sustainable pomegranate cultivation on skeletal soils

An innovative planting technique for pomegranate (Punica granatum L.) cv. Bhagwa in gravelly, shallow soils was standardized. Trapezoidal pits were dug in skeletal soils and filled with various types of soils, namely, gravelly, loamy, clayey, clayey mixed with sand and weathered rock. The clayey soil had the highest capacity to supply macronutrients (available N: 376.1, P: 47.1 and K: 761.6 kg/ha), and the loamy soil had the highest capacity to supply micronutrients (available Fe: 19.2, Cu: 8.1 and Zn: 1.83 ppm). The highest Mn (41.2 ppm), Zn (22.4 ppm), Cu (80.1 ppm) and chlorophyll (61.8) contents were observed in the leaves of plants grown in loamy soil. The highest number of hermaphrodite flowers was observed in loamy soil. Higher fruit quality in terms of higher juice content (49.3%), total soluble solids (TSS ) in fruit juice (15.7°B) and TSS :acid ratio (37.8) was produced in light‐textured soil. The highest fruit yield (4.28 t/ha) and cost‐benefit ratio (3.85) were obtained in clayey soil up to 0.60 m depth. This produced a 90.2% increase in yield, while total income was 147.4% higher than that obtained with weathered rock. However, when the pits were filled with clayey soils up to 1.20 m depth, disease prevalence increased, and yield was markedly reduced, to 2.25 t/ha. Thus, it may be concluded that skeletal soils could be used for pomegranate cultivation by refilling rhizosphere soil strata with clayey or loamy soil material up to 0.60 m depth.