Effect of soil fertility and nutrient availability in rhizosphere on Citrus (Citrus reticulata) yield

An experiment was conducted to find out the availability of nutrients in rhizosphere of Nagpur mandarin (Citrus reticulata Blanco) orchards, experiencing different levels of productivity during 2012–2013. Soil samples were collected and analysed for various soil fertility related parameters. The soil pH was slightly alkaline due to moderately calcareous soil, pH, and electrical conductivity being within a safe limit. The pH, EC, organic carbon and calcium carbonate varied from 7.12 to 7.74, 0.280 to 0.531 dS m⁻¹ at 25° C, 0.70 to 0.89 per cent and 2.47 to 3.60 per cent, respectively in rhizosphere soil. Available nitrogen and phosphorus were low. It varied from 128.57 to 178.75 and 8.28 to 13.9 kg/ha, available potassium and available sulphur ranged from 313.6 to 571.2 kg/ha and 5.824 to 8.064 kg/ha, respectively. In micronutrient, DTPA-Fe, DTPA-Mn, DTPA-Cu and DTPA-Zn, ranged from 11.3 to 16.7, 5.71 to 9.34, 3.28 to 5.30 and 0.38 to 0.62 mg/kg. These limits showed large-scale zinc deficiency, whereas other micronutrients like Fe, Mn and Cu were in optimum limit.