Effects Of Nitrogen Fertilizer Management On Tea Yield And Quality And Soil Fertility In Tea Garden

The effects of different nitrogen application rates and different organic nitrogen fertilizer instead of chemical nitrogen fertilizer on tea yield and quality and soil fertility were studied in order to provide theoretical basis for reasonable guidance of nitrogen application management in tea gardens.In Meitan and Guiding tea producing areas of Guizhou,each set 5 nitrogen gradients:N0(0 kg·hm^-2),N1(150 kg·hm^-2),N2(300 kg·hm^-2),N3(600 kg·hm^-2),N4(900 kg·hm^-2)and 7 organic nitrogen replacement fertilizer nitrogen modes:T1（CK no fertilizer）,T2（100%chemical nitrogen fertilizer）,T3（80%chemical nitrogen fertilizer+20%organic nitrogen fertilizer）,T4（60%chemical nitrogen fertilizer+40%organic nitrogen fertilizer）,T5（40%chemical nitrogen fertilizer+60%organic nitrogen fertilizer）,T6（20%chemical nitrogen fertilizer+80%organic nitrogen fertilizer）,T7（100%organic nitrogen fertilizer）,The effects of nitrogen application rate on tea yield and quality,nitrogen use efficiency,cost-benefit and soil nutrients were analyzed.The results show that:（1）In Meitan tea garden of Guizhou,the yield of fresh leaves and dry tea increased first and then decreased with the increase of nitrogen application rate,and N2(300 kg·hm^-2)treatment was the highest,which significantly increased by 55.06%and 61.91%compared with N0 treatment without nitrogen application,respectively.Compared with N4(900 kg·hm^-2)treatment,they increased by 9.51%and 7.31%,respectively.Nitrogen content,nitrogen accumulation,contribution rate of nitrogen fertilizer,agronomic utilization rate of nitrogen fertilizer and apparent utilization rate of nitrogen fertilizer were the highest in the treatment of N2(300 kg·hm^-2).N2(300 kg·hm^-2)treatment had the lowest phenol-ammonia ratio.The highest tea yield and net yield were N2(300 kg·hm^-2)treatment.In Guiding tea garden of Guizhou,the yield of fresh leaves and dry tea was the highest in N3 treatment(600 kg·hm^-2).N3(600 kg·hm^-2)treatment had the highest nitrogen contribution rate and physiological nitrogen utilization rate.N2(300 kg·hm^-2)nitrogen treatment had the lowest phenol-ammonia ratio.The highest tea yield and net yield were N3treatment.（2）Soil organic matter,alkali-hydrolyzed nitrogen and available potassium increased first and then decreased with the increase of nitrogen application rate in Meitan tea plantation,and the highest values were found in N2(300 kg·hm^-2)treatment,which increased by 21.84%,19.46%and 28.65%,respectively,compared with N0 treatment without nitrogen application.Compared with N4(900 kg·hm^-2)treatment,they increased by 25.86%,22.55%and 89.78%,respectively.Soil organic matter,total nitrogen and alkali-hydrolyzed nitrogen increased first and then decreased with the increase of nitrogen application rate in Guiding tea plantation,and N2(300 kg·hm^-2)treatment was the highest.（3）In the experiment of different organic nitrogen replacing fertilizer nitrogen,T3（80%chemical nitrogen fertilizer+20%organic nitrogen fertilizer）treatment had the highest yield of fresh leaf and dry tea in Meitan tea garden,which significantly increased by 21.53%and 24.80%compared with T2（100%chemical nitrogen fertilizer）treatment.Compared with T7（100%organic nitrogen fertilizer）treatment,it was significantly increased by 73.82%and 66.61%.Nitrogen accumulation,contribution rate of nitrogen fertilizer,agrologic utilization rate of nitrogen fertilizer,partial productivity of nitrogen fertilizer and apparent utilization rate of nitrogen fertilizer were the highest in T3（80%chemical nitrogen fertilizer+20%organic nitrogen fertilizer）treatment.The content of tea polyphenols in T3（80%chemical nitrogen fertilizer+20%organic nitrogen fertilizer）treatment was lower.T3（80%chemical nitrogen fertilizer+20%organic nitrogen fertilizer）treatment had the highest yield and net yield of tea.T4（60%chemical nitrogen fertilizer+40%organic nitrogen fertilizer）treatment had the highest yield of fresh leaves and dry tea in Guiding tea garden in Guizhou.The highest nitrogen accumulation,nitrogen contribution rate,nitrogen agronomic use efficiency and nitrogen apparent use efficiency were found in T4（60%chemical nitrogen fertilizer+40%organic nitrogen fertilizer）treatment.T5（40%chemical nitrogen fertilizer+60%organic nitrogen fertilizer）treatment showed a lower content of tea polyphenols and phenol-ammonia ratio.T4（60%chemical nitrogen fertilizer+40%organic nitrogen fertilizer）treatment had the highest yield and net yield of tea.（4）The contents of total nitrogen and available phosphorus in Meitan tea plantation first increased and then decreased with the increase of organic nitrogen replacement ratio,and T3（80%chemical nitrogen fertilizer+20%organic nitrogen fertilizer）treatment was the highest,which increased by 13.44%and149.54%compared with T2（100%chemical nitrogen fertilizer）treatment,respectively.Compared with T7（100%organic nitrogen fertilizer）treatment,they increased by 58.00%and 311.12%,respectively.In Guiding tea plantation,the contents of soil organic matter,total nitrogen,alkali-hydrolyzed nitrogen,available phosphorus and available potassium were the highest under T4（60%chemical nitrogen fertilizer+40%organic nitrogen fertilizer）treatment.In conclusion,the theoretical nitrogen application rate of N2(300 kg·hm^-2)in Meitan tea plantation and N2～N3(300～600 kg·hm^-2)in Guiding tea plantation can improve soil nutrient content and nitrogen efficiency,and thus increase tea yield and quality,and increase cost and benefit.In Meitan tea plantation,20%organic nitrogen replaced fertilizer nitrogen ratio,and 40%organic nitrogen replaced fertilizer nitrogen ratio in Guiding tea plantation were better combined application models of organic fertilizer in tea plantations.