Fertilization status and reduction potential in tea gardens of China

Objectives Tea is one of the main cash crops in China, balanced fertilization plays very important roles for the high yield and high quality tea production. Many factors including tea tree cultivars, plucking modes and management practices influence the nutrient requirements. The fertilization status was investigated in this paper. The potential and ways of reducing chemical fertilizer inputs were discussed for the sustainable development of tea industry in China.

Methods More than 5000 tea tree planting gardens, accounting for 5% of the total tea plantation areas across the 14 provinces of China, were surveyed from 2010 to 2014. The questionnaire included fertilizer types, rates, application time, application methods and tea garden areas, tea tree varieties, fertilization costs, and so on. The nutrient input and ratio of organic nutrients were calculated according to the nutrient contents and input amounts of a fertilizer product.

Results The total annual N + P₂O₅ + K₂O input in tea gardens of China was 796 kg/hm² in average. About 46% of the surveyed tea gardens applied organic fertilizers regularly and the organic nutrient amounts were about 15% of the total nutrient inputs. The average annual nutrient input was N 281−745 kg/hm², P 72−485 kg/hm² and K 76−961 kg/hm². According to the current recommendation, excessive fertilization was common in provinces of Shandong, Hubei, Hunan, Jiangxi, Sichuan and Fujian. About 30% of the surveyed tea gardens applied excessive chemical fertilizers. Compound fertilizers had become the main fertilizer type in the surveyed tea gardens. In 80% of tea gardens, the applied compound fertilizers had equal N-P₂O₅-K₂O ratios, which was not always suitable for the requirement of tea tree growth, and was the principle cause for excessive input of P and K, particularly in provinces of Fujian, Jiangxi and Hunan, where half of tea gardens showed excessive input of P and K. In the over-fertilized areas, 30%−40% of chemical nutrients could be decreased through balanced fertilization and increased input of organic fertilizers.

Conclusions Excessive application of chemical fertilizers is common in the tea gardens in China, and serious exceeding is over 30% of tea gardens area. Popularization of compound fertilizers with equal N-P₂O₅-K₂O ratios is responsible for excessive P and K input in 80% of the tea gardens. Organic nutrient only accounts for about 15% of the total nutrient input. About 30%−40% of current chemical fertilizer input could be reduced in the tea gardens through the increase of organic fertilizers and balanced fertilization, the practical reduction should be carried out according to the local situations in different area of China.