| Tea is an economic perennial,mainly distributed in the subtropical region of China.Fertilization is an important production measure to provide nutrients for the growth and development of tea trees.Rational fertilization can not only increase tea production,but also improve soil fertility to a certain extent.However,to pursuit high yields,tea farmers excessively applied chemical fertilizers in the current agricultural production,which causing the reduction of tea quality and soil fertility in tea gardens,and even environmental pollution.Therefore,exploring the effects of organic fertilizers instead of chemical fertilizers on the yield and quality of tea and soil fertility in different main tea-producing regions would provide a scientific theoretical basis for the high-yield and high-quality tea production and soil fertility improvement,which is important for the sustainable development of tea industry.This research was carried out in five typical tea gardens,which are subordinated to three major tea areas,namely Jiangnan tea area—Jurong,Jiangsu(model of hand picking single buds to produce famous green tea)and Liyang(model of hand picking one bud and one leaf to produce white tea),Southwest China tea area-Yunnan Dadugang(machine-picked model to produce Pu’er tea)and Sichuan Pujiang(hand-picked + machine-picked model to produce famous green tea),South China tea area-Fujian Fu’an(machine-picked model to produce bulk tea).A total of 7 treatments were set up in the field test,namely no fertilization treatment(CK),conventional fertilization treatment(CF),optimized fertilization treatment(T1),commercial organic fertilizer replacement treatment(T2),biological organic fertilizer replacement treatment.(T3),substitution of commercial organic fertilizer and combined application of wood vinegar liquid foliar fertilizer(T4),substitution of commercial organic fertilizer and combined application of amino acid foliar fertilizer(T5).The best organic fertilizer substitution measure of different tea gardens were determined by measuring tea yield,tea quality,soil physical and chemical properties and economic benefits.The main findings were as follows:1.Replacing some chemical fertilizers with organic fertilizers can increase the yield of tea by increasing the bud weight and germination density of spring tea,thereby increasing the economic benefits of tea gardens.Compared with conventional fertilization,the substitution of commercial organic fertilizer,bio-organic fertilizer and commercial organic fertilizer in combination with foliar fertilizer in Jurong and Liyang,Jiangsu province in the Jiangnan tea area significantly increased the germination density.The best organic fertilizer substitution was different from different production models in five tea gardens.Compared with conventional fertilization,in Jurong tea plantation,commercial organic fertilizer substitution and combined application of wood vinegar liquid foliar fertilizer was the best measure,which increased the yield of green tea by 42% and the economic benefit increased by 62%;In Liyang tea plantation,the measure of commercial organic fertilizers substitution and combined application of amino acid foliar fertilizers had the best effect,which significantly increasing production by 76% and economic benefits by 73%;In Yunnan Dadugang tea plantation,the effect of commercial organic fertilizers substitution and combined application of amino acid foliar fertilizer treatment was the best,which significantly increased the yield by 22% and the economic efficiency by 20%;In the Pujiang tea plantation,the effects of organic fertilizer substitution had not significant differences with conventional fertilization treatment;In Fujian Fu’an tea plantation,bio-organic fertilizer substitution treatment was the best measure,which significantly increased production by 36%and economic efficiency by 15%.There was no significant difference in tea quality among the fertilization treatments in Dadugang tea plantation in Yunnan and Pujiang tea plantation in the southwest tea region.2.Replacing some chemical fertilizers with organic fertilizers has improved the quality of tea in different tea gardens to varying degrees.Compared with conventional fertilization,in the Jurong tea plantation,commercial organic fertilizer substitution and combined application of wood vinegar foliar fertilizer treatment significantly increased the content of tea water extract by 16%,while the treament of organic substitution and combined application of amino acid foliar fertilizer significantly increased the amino acid content of tea by 9%;In Liyang tea plantation,Jiangsu province,the substitution of commercial organic fertilizers and combined application of amino acid foliar fertilizers significantly increased the amino acid and water extract content of tea by 31% and 18%,respectively.Moreover,the caffeine content of bio-organic fertilizers was significantly increased by 42%.In the tea plantation of Fu’an,Fujian,the content of amino acids and water extracts in tea leaves under bio-organic fertilizer substitution treatment was significantly increased by 40% and 31%,respectively.3.Replacing some chemical fertilizers with organic fertilizers increased the content of available nutrients in tea plantation soils.Compared with conventional fertilization,in the Jurong tea plantation,Jiangsu province,the content of total nitrogen and available potassium under commercial organic fertilizer substitution and combined application of foliar fertilizers treatment significantly increased by 14% and 30%,respectively;in Liyang tea plantation,Jiangsu,commercial organic fertilizer substitution and combined application of foliar fertilizers significantly increased soil organic carbon content by 35%.In the southwest tea plantation of Yunnan Dadugang tea plantation,the bio-organic fertilizer substitution significantly increased soil available phosphorus content by 38%;in the Pujiang tea plantation,Sichuan,the available phosphorus and available potassium content in soil was the highest under the conventional fertilization treatment.In the tea plantation of Fu’an,Fujian,the South China tea area,the bio-organic fertilizer substitution significantly increased the available phosphorus and organic carbon content by 64% and 17%,respectively.The regression analysis suggested that there were significant correlations between soil physicochemical properties and tea yield(except for the tea gardens in Pujiang,Sichuan).In addition,organic substitution in tea gardens among different areas significantly increased the partial productivity and the agronomic utilization efficiency of nitrogen fertilizers.In summary,organic substitution in five typical tea gardens reduced 36% chemical nitrogen fertilizer input and ensured tea yield and quality at the meanwhile.There are differences in the best substitution measure for tea gardens with different production models.By comprehensively estimating tea green yield,quality,economic benefits and soil fertility and other indicators,we recommended to use commercial organic fertilizer substitution and combined application of foliar fertilizer with wood vinegar in the Jiangnan tea area,Jurong tea plantation,Jiangsu;In Liyang tea plantation,Jiangsu,it is recommended to use commercial organic fertilizer substitution and combined application of amino acid foliar fertilizer;In the southwest tea area of Yunnan Dadugang tea plantation,it is recommended to use commercial organic fertilizers substitution and combined application of amino acid foliar fertilizers;In the Pujiang tea plantation in Sichuan,the proportion of organic replacement should be appropriately reduced.It is recommended to use bio-organic fertilizer as an alternative to tea plantation in Fu’an,Fujian,in the South China tea area. |
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