Soil and Leaf Nutritional Studies and Status of Healthy and Declined Mandarin Orchards

Abstract

The present investigation was carried out to determine soil and leaf nutritional status of some typical healthy and declined mandarin orchards of Amravati District (M.S) during 2016-19.Total twenty five representative surface and depth wise soil and leaf samples from healthy and declined mandarin orchards were collected and analyzed various nutrients in plant as well as leaf samples. The data analysis showed that total nitrogen content in healthy and declined mandarin orchards from surface soils varied from 0.045 to 0.093 % and 0.015 to 0.37% respectively. The available nitrogen, phosphorus and potassium content of healthy orchards surface soils varied from 200.0 to 265.7 kg ha-1 , 22.0 to 35.3 kg ha-1 , 320.0 to 665.0 kg ha-1 and in declined orchards it varied from 130.4 to 203.5 kg ha-1 , 17.8 to 21.3 kg ha-1 , 360.0 to 744.4 kg ha-1 respectively. The exchangeable calcium and magnesium together constitute more than 80% of exchange complex. The exchangeable calcium, magnesium and sulphur content in healthy orchards surface soils varied from 26.34 to 30.22 cmol (p+ ) kg ha-1 , 11.71 to 16.92 cmol (p+ ) kg ha-1 , 0.27 to 0.90 kg ha-1 and in declined orchards it varied from 29.00 to 31.98 cmol (p+ ) kg ha-1 , 12.07 to 13.71 cmol (p+ ) kg ha-1 , 0.36 to 0.69 kg ha-1 respectively. Micronutrients status of orange orchards showed that available copper, zinc, iron and manganese in healthy orchards surface soils varied from 2.20 to 5.60 ppm, 0.50 to 0.79 ppm, 4.50 to 6.29 ppm, 12.61 to 18.11 ppm and in declined orchards it varied from 1.90 to 2.48 ppm, 0.35 to 0.46 ppm, 3.40 to 5.00 ppm, 8.10 to 12.24 ppm respectively. Findings revealed that total nitrogen, available nitrogen, phosphorus, sulphur, zinc and manganese content found more supporting in healthy orchards than declined ones. Depth wise distribution showed that total nitrogen, available nitrogen, phosphorus and copper showed decreasing trend with the soil depth. The leaf nutrient content in the plant showed that nitrogen, phosphorus and potassium content in leaf of healthy orchards varied from 2.35 to 2.55%, 0.14 to 0.17%, 0.82 to 1.00% and in declined orchards it varied from 1.75 to 2.00%, 0.10 to 0.13%, and 0.84 to 1.70% respectively. Calcium, magnesium and sulphur content in healthy orchards varied from 3.00 to 3.90%, 0.60 to 0.74%, 0.21 to 0.19% and in declined orchards it ranged from 2.40 to 3.15%, 0.33 to 0.74%, and 0.19 to 0.23% respectively. Results pertaining to micronutrient showed that iron; manganese, copper and zinc in healthy orchards varied from 105.6 to 140.6 ppm, 21.72 to 34.62 ppm, 29.40 to 35.96 ppm, 30.45 to 39.18 ppm, and in declined orchards it varied from 70.66 to 100.00 ppm, 20.38 to 27.67 ppm, 21.72 to 26.05 ppm, and 17.24 to 25.00 ppm respectively. Results showed that a healthy orchard has significantly higher content of nutrient than declined orchards except potassium content