Study On Improvement Of Acid Soil In Tea Garden By Bamboo-Biochar Based Organic Fertilizer

Affected by human factors and self-factors,the acidification of tea garden soil is becoming more and more serious.Acidification will lead to soil compaction and fertility reduction,which will inhibit the growth of tea trees,affect the quality of tea,and cause certain environmental problems.Therefore,the acidification of tea gardens has a strong practical significance in production.In this study,the pot experiment and the field experiment were used respectively to explore the effects of different amounts of bamboo biochar on the improvement of acidified soil in tea gardens.The pot experiment was carried out with three different acidification tea garden soils in Chishou Township,Songyang County(tea planting period of 2 years,pH 4.78,S1;15 years,pH 3.95,S2;25 years,pH 3.01,S3),by studying the amount of different bamboo biochar(B0,B1,B2,B3 and B4,5 kinds of treatment,bamboo biochar application amount is 0,0.64,1.28,2.56 and 5.12 g bamboo biochar powder/kg soil).The effect of growth was to screen out the optimum amount of bamboo biochar under different acidified soil types.The field experiment was conducted with the tea plantation of Datuo Town,Suichang County.We set 4 different treatments:CK(7.5t/hm2 commercial organic fertilizer),T1(1.25 t/hm2 bamboo biochar powder+7.5t/hm2 commercial organic fertilizer),T2(1.80 t/hm2 bamboo biochar powder+7.5t/hm2 commercial organic fertilizer),T3(2.25 t/hm2 bamboo biochar powder+7.5t/hm2 commercial organic fertilizer).The differences of soil physical and chemical properties,soil enzyme activities,soil microbial community structure and tea quality under different treatments were analyzed.The results showed that:(1)The pot experiment showed that the application of bamboo biochar would improve the growth and physiological characteristics of tea,but the difference of soil acidification degree and bamboo biochar content would affect the improvement effect of bamboo biochar.In the soil with short cultivation period and low acidification(S1),there was no significant difference in plant height of tea seedlings between 5 different bamboo biochar dosages.However,with the increase of soil acidification degree,bamboo biochar significantly promoted the high growth of tea seedlings.Compared with the non-applied bamboo biochar control,in the moderately acidified soil(S2),B3 treatment significantly increased the plant height of tea seedlings.The increase was 28.48%(p<0.05),B4 treatment increased plant height by 19.87%(p<0.1);in highly acidified soil(S3),B2 treatment increased plant height by 17.14%(p<0.05),B3 significantly increased by 24.87%(p<0.01)and B4 significantly increased by 13.81%(p<0.1).It indicates that when bamboo biochar consumption is low,it has little effect on the growth of tea tree plant height,while B3 consumption has a good effect on acidified soil improvement and can promote the plant height of tea tree to some extent,while when bamboo biochar consumption is high(B4),the improvement effect decreases.There was no significant difference in the effect of different amounts of bamboo biochar on tea leaf area(p>0.05),but the number of leaves treated with B3 in S2 soil and B4 in S3 soil were significantly higher than those treated with control(p<0.05)(2)Field experiments showed that bamboo biochar combined with organic fertilizer had a certain effect on soil microbial community structure and soil enzyme activity.T2 treatment had the best effect and was beneficial to the improvement of soil microbial community.From the perspective of total PLFA and microbial community structure,the total PLFA in T2-treated soil and the PLFA content of bacteria,fungi,actinomycetes,gram-negative bacteria and gram-positive bacteria in the soil increased significantly(p<0.05)The total amount of soil PLFA in T1 and T3 treatment did not change significantly.However,compared with CK,the PLFA content of actinomycetes 10Me16:0 and 10Me 17:0,common bacteria 15:0 and 18:0,and fungi 18:2?6c were significantly increased in T1,T2 and T3 treatment(p<0.05).Soil enzyme activity also responded to the addition of bamboo biochar.The activity of sucrase increased under the treatment of T1,T2 and T3(p<0.05),while the activity of acid phosphatase decreased significantly(p<0.05).No significant difference in soil urease between treatments(p>0.05).Compared with the control group,there was no significant difference in soil enzyme index of T1 and T2,but the soil enzyme index of T3 treatment was significantly higher than CK(p<0.05).Compared with CK,soil pH was significantly increased under T2 and T3 treatment,and other soil physicochemical properties(CEC,organic matter,available phosphorus.hydrolyzed nitrogen and available potassium)did not reach significant levels between treatments(p>0.05).The application of bamboo biochar is beneficial to increase the content of tea polyphenols.Tea polyphenols increased significantly in T2 treatment(p<0.05),and increased significantly in T1 and T3 treatment at the level of 0.1The combination of bamboo biochar and organic fertilizer can improve the acidic soil of tea garden and improve the tea quality.The comprehensive comparison showed that the treatment effect of B3 in pot experiment was better,while that of T2 and T3 in field experiment was better.