| Tea is one of the main economic crops in China,and fertilization in tea gardens is a key measure to improve the yield and quality of tea.However,there are problems of unreasonable fertilization in tea gardens,including the imbalance between organic and inorganic caused by insufficient input of organic fertilizer,and the spatio-temporal contradiction between fertilizer nitrogen supply and nutrient demand of tea trees,which leads to the increase of nitrogen loss.The tea garden soil showed a trend of chemical degradation,biological degradation and physical degradation.Soil acidification,hardening and reduction of biota diversity were the main characteristics of soil ecological degradation,which were also the bottleneck restricting the improvement of tea yield and quality.With the implementation of the National Action Plan on Organic Fertilizer Replacement for Fruit and Veggie Tea,the study on the proportion and effect of organic substitution has attracted the attention of the academic community,and the matching of nutrient release patterns between organic fertilizers and chemical nitrogen fertilizers has become the focus of nitrogen management research in tea gardens.This study through different organic replacement ratio and urea nitrogen release model tea field experiment,researching alternative proportion and organic fertilizer nitrogen nutrient release patterns of tea production,quality,tea plant nutrient uptake and tea garden soil physical and chemical properties,in order to reasonable determine the proportion of organic alternative for tea tree and provide basis for organic fertilizer with chemical fertilizer is used rationally.The experiment has 9 treatments:CK（no fertilization）,TJ（conventional fertilization）,OM15-U（organic replacement of 15%U）,OM15-SU（organic replacement of 15%SU）,OM30-U（organic replacement of 30%U）,OM30-SU（organic substitute 30%SU）,OM50-U（organic substitute 50%U）,OM50-SU（organic substitute 50%SU）,OM75-U（organic substitute 75%U）,SU is ordinary urea and The sustained-release urea ratio is 6:4,and the main research results are as follows:（1）Organic fertilizer substitution and nitrogen nutrient release mode obviously affect the yield of tea fresh leaves.In terms of the annual fresh leaf output,the OM30-U treatment had the highest yield,which was 13.74%higher than that of the TJ treatment.Compared with the nitrogen nutrient release mode,the effect of the compatibility of common urea on the annual fresh leaf yield was better than that of slow-release urea.In the spring tea season,the output of OM75-U was as high as 5145.48kg·hm-2,an increase of 18.81%compared with TJ treatment,followed by OM30-U treatment,which increased by 16.11%compared with TJ treatment.From the perspective of the fresh leaf yield in the spring tea season,the effect of the nitrogen nutrient release mode is significantly affected by the organic substitution ratio.Under the conditions of low substitution ratios（15%and 30%substitution）,the yield of fresh leaves combined with ordinary urea is significantly higher than that of slow With the urea release compatibility mode,when the organic substitution rate was increased to 50%,the yield effects of the two nutrient release modes of nitrogen fertilizer were not significantly different（P>0.05）.In the summer tea season,the low-organic substitution slow-release nitrogen release mode treatment（OM15-SU）has a significantly higher yield effect than other treatments,with a maximum yield of 4,279.90 kg·hm-2,which is 41.51%higher than the TJ treatment.Other slow-release treatments The yield of nitrogen release mode treatment is lower,generally lower than that of ordinary urea treatment;while under the condition of compatibility of ordinary urea,under the condition of 50%organic substitution rate（OM50-U）,the yield of summer tea fresh leaves is as high as3544.65kg·hm-2Compared with TJ,the yield increased by 16.98%,followed by 30%organic substitution rate（OM30-U）,which increased by 10.38%compared with TJ treatment.（2）Organic fertilizer substitution and nitrogen nutrient release mode have obvious effects on tea quality.Organic fertilizers can replace chemical fertilizers to increase the content of amino acids,tea polyphenols,and water extracts in tea,and improve the quality of tea.In the spring tea season,the OM30-U treatment has the best effect of increasing the content of amino acids and tea polyphenols,which are increased by 0.1%and 0.5%respectively compared with the TJ treatment.Among them,under the normal urea nitrogen mode,the influence of the organic substitution ratio on it changes irregularly;Under the sustained-release urea nutrient release mode,the content of amino acids and tea polyphenols is the highest when treated with OM50-SU,and the content of tea polyphenols increases with the increase of the replacement rate.In the summer tea season,the amino acid content only increased by 0.28%and 0.55%in OM15-SU and OM50-U treatments;under the condition of common urea compatibility,the content of tea polyphenols increased with the increase in the replacement ratio,and the content of tea polyphenols in the treatment of OM75-U The highest was 10.53%,an increase of 1.22%.Under the condition of compatible slow-release urea,only the OM15-SU treatment showed a tendency to increase the content of tea polyphenols.The content of tea water extract in spring and summer tea seasons increases with the increase in the proportion of organic fertilizer.When the replacement rate increases to50%,the content is the highest;in spring tea season,the content of OM50-U and OM50-SU treated water extracts is higher than TJ Increased by 2.62%and 2.77%respectively;in summer tea season,the content of OM50-U and OM50-SU treated water extracts increased by 2.20%compared with TJ,and the two nitrogen release modes had no significant effect on water extracts（P>0.05）).（3）The organic substitution ratio has a significant impact on the nutrient absorption of tea plants.In the spring tea season,OM15-U treatment had the highest nitrogen content,reaching 67.12 g·kg-1,and the nitrogen content increased by 19.71%compared with TJ,followed by OM15-SU treatment,which increased by 13.68%compared with TJ.Other treatments showed overall The nitrogen content of tea showed a downward trend with the increase of the organic substitution rate;the phosphorus content showed a downward trend,but there was no obvious regularity;the potassium content of fresh leaves was slightly higher than that of TJ when treated with OM30-SU and OM75-U,and other treatments All were lower than TJ treatment,showing irregular changes.In the summer tea season,the nitrogen content of tea treated with OM30-U was as high as57.11 g·kg-1,which was increased by 9.97%compared with TJ,followed by OM30-SU and OM50-SU;the potassium content of tea had a certain increasing trend with the increase of organic substitution ratio.Compared with TJ treatment,OM50-SU increased by 1.49 g·kg-1.In the spring tea season,OM15-U has the largest nitrogen absorption in the compatibility of urea,which is 24.08%higher than that of TJ treatment.On the whole,as the replacement rate increases,the nitrogen absorption shows a downward trend.Under the conditions of slow-release urea compatibility,OM30-The highest nitrogen absorption is in SU,10.07%higher than TJ.Phosphorus absorption showed an upward trend（except for OM15-U/SU treatment）,but there was no obvious regularity;the cumulative potassium absorption of OM75-U treatment was as high as 31.74 kg·hm-2,which was 20.31%higher than that of TJ,and no other treatments.The law changes.In the summer tea season,under the compatible conditions of slow-release urea,the absorption of nitrogen and potassium increases with the substitution rate,but the absorption decreases.The absorption of nitrogen and potassium of OM15-SU is the largest,with a significant difference;the absorption of phosphorus is only OM15-SU,OM30-U treatment is significantly improved compared with TJ treatment.（4）Different replacement ratios of organic fertilizer have obvious effects on the soil nutrient content of tea gardens.In the spring tea season,under the compatibility of ordinary urea,soil total nitrogen and alkali-hydrolyzable nitrogen content tend to increase under 50%replacement rate,and Olsen phosphorus content is the highest under30%replacement rate,and the difference is significant;under the condition of slow-release nitrogen compatibility,OM30-SU treatment significantly increased soil total nitrogen and alkali-hydrolyzable nitrogen content（P<0.05）,which increased by0.72g·kg-1and 96.71mg·kg-1compared with TJ treatment.At this time,the content of ammonium nitrogen and organic matter was also the highest.The compatibility of substitution and slow-release nitrogen models has obvious effects on soil nitrogen maintenance in spring tea season.In the summer tea season,the general urea compatibility treatment,the OM75-U treatment has the highest total nitrogen,ammonium nitrogen and organic matter content,which are increased by 25.10%,24.44%,and 17.78%respectively compared with the TJ treatment,and the ammonium nitrogen content increases with the increase in the replacement rate.However,the replacement rate increased,and the content of alkali-hydrolyzed nitrogen decreased.Only the OM50-U treatment Olsen phosphorus content increased;under the condition of slow-release urea compatibility,the total nitrogen content increased with the increase of the replacement ratio,and the total nitrogen,The content of ammonium nitrogen and organic matter is the highest,and the content of alkali-hydrolyzed nitrogen increases with the increase of the substitution rate.Only the OM30-SU treatment has an increase in the phosphorus content of Olsen.The compatibility of organic substitution and slow-release nitrogen has a significant effect on ensuring the nitrogen and phosphorus supply of summer tea. |
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