10 Jan 2014

Nutrient requirement by Shatang tangerine fruit and tree was determined

Shatang tangerine is an orange variety that grows in Guangdong province and is very sweet and popular in China. Due to its high profitability, its growing areas have extended very fast and farmers afford fertilizer and labor inputs to achieve high yield and quality. However, what and how much nutrients are required by the fruit was not well understood. To solve the problem, researchers from Guangdong Soil and Fertilizer Institute sampled three 7-year-old Shatang tangerine trees from a well-managed orchard at fruit maturity to analyze the total amount of nutrients supporting bumper harvest and the amount of nutrients removal by fruit. The results showed that to produce 100 kg fruit, the tree required 5.256 kg of N, 0.424 kg of P, 3.386 kg of K, 3.360 kg of Ca, 0.494 kg of Mg, 1.224 kg of S, 94.08 g of Fe, 24.22 g of Mn, 2.21 g of Cu, 16.40 g of Zn and 0.03 g of Mo. The nutrients removed by 100 kg of fruit were 1.000 kg of N, 0.106 kg of P, 0.854 kg of K, 0.274 kg of Ca, 0.094 kg of Mg, 0.144 g of S, 3.09 g of Fe, 0.65 g of Mn, 0.21 g of Cu, 1.00 g of Zn, 1.74 g of B and 5.4 mg of Mo. Requirement for macronutrients is in an order of N>KCa>S> MgP by the whole tree and N>K>Ca>S>P>Mg by the fruit, a very similar sequence. The least requirement is found for Mo by both tree and fruit. This finding is of great significance for soil scientists and horticulturists to fine tune their nutrient management program based on the past research.

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