The nutrient release kinetics of Polyhalite and its biological - PowerPoint PPT Presentation

IPI’s first symposium on Polyhalite 31 Oct. 2017, Sanya, Hainan The nutrient release kinetics of Polyhalite and its biological effect on tea growth and quality in China Kang Ni, Qunfeng Zhang, Jianyun Ruan Tea Research Institute, Chinese Academy of Agricultural Sciences 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Background China is the largest tea production country in the world (Area 2.8 M ha, 63%; 517 M ton, 42%) 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Background Beside N, K is also crucial in tea plantation  K increase fresh yield  Favors the accumulation of free amino acid and polyphenols  Tolerance of drought, frost and other stress (insects, fungal etc.) CK MOP SOP 30 50 350 (NPK-NP)/NP Spring tea Autumn tea 25 b b -1 ) 40 Relative yield increase (%) Free amino acid/Caffeine (g kg a -1 ) 20 300 Polyphenols (g kg b b b b N.S. 30 a a 15 N.S. 20 10 b b 250 5 a 10 0 0 200 Free Amino Acid Caffeine Polyphenols Free Amino Acid Caffeine Polyphenols 0 50 100 150 200 250 300 350 400 中国农业科学院茶叶研究所 -1 yr -1 ) K rate (kg K ha (Ruan et al., 2013) Tea Research Institute, CAAS

Background  Mg fertilization increase ~5% tea yield  Increase amino acid content in Green, Black and Oolong tea  Synergetic effect on K 120 40 Relative increase of amino acid content (%) Yingde Spring tea Autumn tea Relative yield of CK (%) 30 110 20 100 Year 1999 10 Year 2000 Year 2001 90 0 K150 K150+Mg35 K300 K300+Mg35 0 40 80 120 160 (Ruan et al., 1999) MgO (kg/ha) 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Background  Low CEC, acidic properties of soil plantation soil  Exch.K ranged 15.3~1031 mg/kg, ~75% less than 100 mg/kg  Exch.Mg ranged 10~80 mg/kg,~62% less than 45 mg/kg >80% of tea gardens in Yunnan, Jiangxi and Fujian in Mg deficiency (<45 mg/kg) K and Mg supply is crucial for sustainable of tea production 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Background Polyhalite application in tea plantation  Natural mineral  Four elements in one fertilizer (K, Mg, Ca, S)  Labor-cost saving (less separated fertilization)  Slow-release (lower solubility)  Without Cl toxicity  Mitigate soil acidification (Ca)  Surplus Ca addition (affect Mg uptake) • Ca>500 mg kg-1 reduce quality • Ca>2000 mg kg-1 harm the growth • Ca>5000 mg kg-1 seriously inhibit the growth 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Objectives 1. The K and Mg release of Polyhalite in tea plantation soil 2. The yield and quality effect of Polyhalite in green tea 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Questions 1. Does polyhalite has the slow-release nutrients in tea plantation soil? 2. Is there any advantage of Polyhalite on tea fertilization, compared with normal compound NPK? 3. Does addition of Ca by polyhalite have adverse effect on tea yield and quality? 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Laboratory leaching experiment 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Experiment design Code Explanations tr1 CK Control tr2 K K addition tr3 K+Mg K and Mg addition (zero Ca) tr4 PolyK Polyhalite addition as the K in tr3, high Ca input tr5 PolyMg+K Polyhalite addition as the Mg in tr3, and K added to the level in tr 4 tr6 PolyMg Polyhalite addition as the Mg in tr3, half Ca as tr4 tr7 K+Mg+Ca K and Mg as tr3, but medium Ca addition between tr3 and tr 5 K Mg Ca Code (mg kg-1 soil) (mg kg-1 soil) (mg kg-1 soil) tr1 CK 0 0 0 tr2 K 100 0 0 tr3 K+Mg 100 20 0 tr4 PolyK 100 40 141 tr5 PolyMg+K 100 20 72 tr6 PolyMg 51 20 72 tr7 K+Mg+Ca 100 20 35 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Leaching Experiment Soil pH 4.42 SOC 0.49% TN 0.07% 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Leaching experiment • Slow release of polyhalite 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Cumulative leaching • Less leaching of cations • High amount of anion of S (addition) 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

K and Mg in the soil layers (mg kg -1 ) 250 K 200 150 100 50 0 CK K K+Mg K+Mg+Ca PolyK PolyMg PolyMg+K top layer mid layer sub layer 80 Mg 60 • High content in Poly • Abundant in top layer 40 • Less downward 20 • Leaching reduction 0 CK K K+Mg K+Mg+Ca PolyK PolyMg PolyMg+K top layer mid layer sub layer

Pot experiment 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Pot experiment Code Explanations tr1 CK Control tr2 K K addition tr3 K+Mg K and Mg addition (zero Ca) tr4 PolyK Polyhalite addition as the K in tr3, high Ca input tr5 PolyMg+K Polyhalite addition as the Mg in tr3, and K added to the level in tr 4 tr6 PolyMg Polyhalite addition as the Mg in tr3, half Ca as tr4 tr7 K+Mg+Ca K and Mg as tr3, but medium Ca addition between tr3 and tr 5 处理 K Mg Ca CK 0.00 0.00 0.00 K 90.00 0.00 0.00 90.00 18.00 0.00 K+Mg 90.00 35.19 127.31 PolyK PolyMg+K 90.00 18.00 65.11 46.03 18.00 65.11 PolyMg 90.00 18.00 95.54 中国农业科学院茶叶研究所 KMgCa Tea Research Institute, CAAS

Pot experiment  Soil properties  pH 5.3, SOC 0.81%, TN 0.08%  Available P 0.6 mg/kg, Available K 71.9 mg/kg, Available Mg 26.6 mg/kg  Variety  Longjing 43 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Dry matter of young shoots • highest yield in polyK, high Mg input? 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Quality components • Polyhalite addition significantly increased amino acid content • CaSO4 addition reduced the amino acid and increase the polyphenols, but polyhalite showed less effect 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Field experiment 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Experiment design N1 N2 Comments （ 300 kg N ha -1 ） （ 500 kg N ha -1 ） - - -Mg NPK 50 MgO 50 MgO +Mg NPKMg 20 MgO + 20 MgO + +Foliar Mg NPKMg+F MgSO 4 .7H 2 O MgSO 4 .7H 2 O 50 MgO 50 MgO Polyhalite Poly 50 MgO 50 MgO Compound Compound 10 treatments 4 replicates Plot area: 56 m 2 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Field Trial 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

N300 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

N500 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Conlusion  Slow nutrient release of K, Mg and Ca in tea plantation soil  Polyhalite has potential in nutrient leaching reduction  Polyhalite slightly increased young shoot biomass  Polyhalite addition increased the amino acid content and reduce PP:AA in spring tea  Ca addition by polyhalite did not show adverse effect on autumn tea quality 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

Acknowledgements • Research group of Tea nutrition and physiology • ICL and IPI • Mr He Ming, Mr. Eldad Sokolowski and Dr. Li Guohua 中国农业科学院茶叶研究所 Tea Research Institute, CAAS

中国农业科学院茶叶研究所 Tea Research Institute, CAAS