我国茶园施肥现状与减施潜力分析

【目的】茶树是我国重要的经济作物之一，合理施肥是保证茶叶高产优质的重要措施，受茶树品种、采摘模式、栽培水平的影响，我国不同地区茶园间施肥量存在较大的差异。厘清我国茶园施肥现状，分析不同茶区施肥水平的差异，寻求差异化的减肥途径，对实现我国茶园化肥减施增效，促进茶产业可持续发展具有重要意义。【方法】依托国家茶产业技术体系试验站，本研究于2010—2014年期间在我国主要茶区调查了5000多个茶树种植单元，约占我国茶园总面积的5%。调查内容包括氮磷钾肥料品种、用量、施用时间、施用方式以及茶园面积、茶树品种、施肥成本等信息。根据肥料养分含量计算不同种植单元的氮磷钾养分投入量，有机养分替代比例，并以现行的茶园推荐施肥标准作为施肥评价依据，对不同区域茶园的施肥水平进行了评价。【结果】我国茶园的养分投入总量 (N + P₂O₅ + K₂O) 为796 kg/hm2，施用有机肥的茶园样本比例为46%，按纯养分计，茶园有机养分投入量平均占总养分投入量的15%。各省茶区年均养分投入量为N 281～745 kg/hm2、P₂O₅ 72～485 kg/hm2、K₂O 76～961 kg/hm2。参照目前的推荐肥料用量，我国有30%左右茶园存在化肥过量施用问题，其中山东、湖北、湖南、江西、四川、福建等地过量施肥问题较为突出。复合肥已成为茶园的重要肥料品种，80%的茶园施用的是等养分比例的复合肥，茶园中磷肥或者钾肥过量施用现象开始凸显，福建、江西、湖南等地过半茶园磷、钾养分投入过量。根据过量施肥茶园的现有施肥水平，通过总量控制和增加有机肥比例等途径，大约可削减30%～40%的化肥用量。【结论】我国30%的茶园化肥过量施用，80%的茶园施用的化肥氮磷钾比例不完全符合茶叶养分需求，有机肥养分所占比例偏低，只有15%。依据不同茶区养分具体管理方式、茶叶栽培特点以及土壤条件，因地制宜采取差异化的茶园化肥减施策略，大约可削减30%～40%的化肥用量。

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.