Quality Indices and Optimum Levels of Nutrient in Fruits grown

on the Calcareous Soils of Iran[1]

Mohammad J. Malakouti

Professor of Soil Sciences, Tarbiat Modarres University and Director General, Soil and Water Research

Institute, Tehran-Iran

18^th World Congress of Soil Science, Philadelphia, Pennsylvania, July 9-15, 2006, USA

Abstract: Proper crop nutrition is of primary importance in achieving a sustainable agriculture. As a result of extensive investigations and analyzing more than 5000 leaf and fruit samples of apple, vineyard, citrus, almond, pomegranate, olive and pistachio orchards under different management systems during a five year period, the average values for critical levels of nutrient concentrations were determined. The experimental data showed that a balanced application of fertilizers by foliar sprays or in manure pits significantly improved the yield and quality of fruits of the selected trees. 

The desirable nutrient concentration for apple tree leaves were nitrogen 2.20-2.30; phosphorus, 0.15; potassium 1.80-2.00; calcium 1.80-2.20; magnesium 0.40; sulfur 0.35 percent; and iron 100-150; manganese 70-100; zinc 40-60; copper 10-15; boron 30-70 and molybdenum 1-2 mg/kg. The desired nutrient concentrations for apple fruits were as follows: nitrogen 40; phosphorus 12; potassium 150; calcium 7.0; magnesium 5.0; iron 0.20; manganese 0.10; zinc 0.10; copper 0.10; and boron 0.5 mg per 100 gr of fresh fruit; similarly, other quality indices for apple fruit included: dry matter 16%; texture hardness to be in excess of 3 kg per cm²; total sugars 14 g and total acidity (malic acid) 0.5 g in 100 ml of fruit juice, Brix 14, pH 4; the ratios N/Ca less than 10; K/Ca less than 20; and of Ca/Mg 1.4.

The experimental data showed that the fertilizer treatments significantly affected the nutrient concentrations in leaves and fruits. There were significant differences in the concentrations of phosphorus, potassium, iron, manganese, copper and boron in grape leaves and grapes sampled from the different regions mainly due to the amendments of the soils physicochemical properties as well as the different orchard management practices. Statistical analysis indicated that the concentrations of potassium and zinc in grapes had significantly increased with treatments. Extensive investigations and data analysis indicated the desirable nutrient concentration for grape leaves to be nitrogen 2.80; phosphorus 0.25; potassium 1.90; calcium 2.50; magnesium 0.60; and sulfur 0.40 percent; iron 150; manganese 110; zinc 35; copper 15; boron 40 and molybdenum 1-2 mg per kg. The desirable nutrient concentration for fresh grapes were determined to be nitrogen 120; phosphorus 10; potassium 200; calcium 15; magnesium 10; iron 0.30; manganese 0.10; zinc 0.10; copper 0.05; and boron 0.50 mg per 100 gr of fresh fruit; and for raisins they were: nitrogen 50; phosphorus 15; potassium 170; calcium 18; magnesium 16; iron 0.40; manganese 0.30; zinc 0.20; copper 0.05; and boron 0.50mg per kg.

The desirable leaf nutrient concentration for northern orange tree leaves to be nitrogen 2.60-2.80; phosphorus; 0.15; potassium 2.50-3.0; calcium 2.00-2.20; magnesium 0.60; and sulfur 0.30 per cent; iron 100-150; manganese 75-100; zinc 40-60; copper 7-15; boron 50-75; and molybdenum 1-2 mg per kg; and for orange fruit to be nitrogen 150; phosphorus 15; potassium 200; calcium 40; magnesium 12; iron 0.20; manganese 0.10; zinc 0.10 copper 0.05 and boron 0.40 mg per 100g of the fresh fruit.

The desirable nutrient concentration for almond tree leaves were determined to be nitrogen 2.20; phosphorus 0.15; potassium 1.90; calcium 1.80; magnesium 0.40 percent; and for iron 100; manganese 70; zinc 40; copper 10 and boron 50 mg per kg; and for almond fruits the desirable nutrient concentration are: nitrogen 125; phosphorus 475-550; potassium 150-1000; calcium 2450-350; magnesium 275-300; iron 4.5-5.5; manganese 2.5-3.5; zinc 3.5-4.0 and copper 1.0-1.5 mg per 100g of the fresh almond fruit.

The desirable nutrient concentration for pomegranate leaves were determined to be nitrogen 2.25; phosphorus 0.15; potassium 1.70; calcium 1.90; magnesium 0.50 percent; and for iron 110; manganese 40; zinc 30; copper 10 and boron 70 mg per kg. the desirable nutrient level for pomegranate fruit were determined to be nitrogen 170; phosphorus 8; potassium 260; calcium 3; magnesium 3; iron 0.30; manganese 0.40; zinc 0.15; copper 0.12 and boron 0.15 mg per 100g of the fresh fruit. The desirable nutrient concentration for olive tree leaves were determined to be nitrogen 2.80; phosphorus 0.25; potassium 1.90; calcium 2.50; magnesium 0.60 and sulfur 0.40 percent; and for iron 150; manganese 110; zinc 35; copper 15; boron 40 and molybdenum 1-2 mg per kg. the desirable nutrient concentration for olive fruits for canned were determined to be nitrogen 6; phosphorus 3; potassium 9; calcium 94; magnesium 4; iron 3; manganese 0.25; zinc 0.25 and copper 0.20 mg per 100g of the fresh fruit.

The desirable nutrient concentration for pistachio leaves were determined to be nitrogen 2.00, phosphorus 0.12; potassium 1.60; calcium 2.50; magnesium 0.50; and sulfur 0.40 per cent; iron 110; manganese 50; zinc 40; copper 12; boron 50 and molybdenum 2mg per kg, and for pistachio nuts to be: nitrogen 3.20; phosphorus 0.62; potassium 1.50; calcium 0.04; magnesium 0.14; iron 65; manganese 10; zinc 0.12 and copper 0.07 mg per kg.

Keywords: Desirable nutrient concentration in leaf and fruit; Apple (Malus dometica L.); Grapes (Vitis vinifera L.); Orange (Citrus sinensis); Tangerines (Citrus reticulata); Almonds (Prunus amygdalus); Pomegranate (Punica granatum); Olives (Olea europea) and Pistachios (Pistacia vera L.).