| Camellia oleifera Abel is the main woody oil tree species in South China.However,due to extensive management,some of the oil tea forest is still in a low efficiency state,poor soil fertility,low yield and obvious size and year.Reasonable fertilization canimprove the soil environment,increase the number of microorganisms in the forest land,optimize the microbial community structure,and promote the growth of Camellia oleifera and improve economic benefits.Nitrogen is the most important element in the growth of Camellia oleifera.At present,there are few studies on the nitrogen forms and levels on the growth and rhizosphere soil environment of Camellia oleifera.Through the determination of growth index,chemical properties of rhizosphere soil,enzyme activity and soil micro generation,the study takes the two-year-old‘Gan Wu 2#'of Camellia oleifera seedling as the test material The effects of different fertilization combinations on the growth and soil environment of Camellia oleifera were analyzed.The purpose of this paper is to provide the best fertilization combination for the tea production.The main results are as follows:(1)Different forms of nitrogen and different levels of fertilization promoted the growth of ground diameter and shoot of Camellia oleifera seedlings;The growth ofCamellia oleifera seedlings treated with NH4+-N was the best,followed by CO(NH2)2-N,NO3—N was the worst.The ground diameter growth of AG(1.5g NH4+-N per plant)was the best of all treatments;the shoot growth of AZ(1g NH4+-N per plant)treatment had the best effect on shoot growth and total nitrogen content of Camellia oleifera leaves..(2)The results showed that different forms of nitrogen fertilizer could reduce the p H of Camellia oleifera rhizosphere soil,and there was no significant difference with CK(P>0.05);The content of hydrolytic nitrogen in XD(0.5g NO3--N per plant)was 128.7mg/kg higher than that in CK,which was the best among all treatments.The content of soilhydrolytic nitrogen in all treatments decreased after 90 days of fertilization.The soil total nitrogen content reached the maximum value under XZ treatment.After 45 days offertilization,the four treatments of AZ,AG,XG and ND treatments increased the content of soil available phosphorus.With the increase of fertilization time,the content of soilavailable phosphorus in CK treatment increased significantly,and was higher than that in other nitrogen treatments.The nitrogen fertilization of different forms had a inhibitioneffect on the total phosphorus content of soil,which was lower than CK treatment;After 45days of fertilization,the total potassium content of each treatment soil was lower than CK,but after 90 days of fertilization,the total potassium content of each treatment soilincreased,and XZ treatment was the highest;The results showed that AD(0.5g NH4+-N per plant)and NG(1.5g CO(NH2)2-N per plant)were the most significant effects on the promotion of soil available potassium content;The organic matter content of AG and XD treatment was lower than CK0.59 and 1.14 g/kg respectively,and the organic mattercontent of the other treatment soil was higher than CK.(3)NO3--N treatment inhibited the catalase activity in the rhizosphere soil of Camellia oleifera,and the catalase activity in AG treatment was the highest;AZ and AG treatments significantly promoted soil acid phosphatase,and increased by 4150?4218.68nmol/d/g.after 90 days of fertilization,respectively;Different fertilization treatments had no significant effect on urease activity;NO3--N treatment had no significant effect oninvertase activity,but AD and ND treatment had significant effect on invertase activity.(4)Combined with grey correlation analysis,AZ treatment(Application of 1g NH4+-N)was the best fertilization combination,followed by AD treatment(Application of 0.5gNH4+-N),NO3--N fertilization combination overall performance was poor,notrecommended as the selected nitrogen for Camellia oleifera seedling fertilization,only NG showed the best three levels of CO(NH2)2-N,such as choosing CO(NH2)2-N as thenitrogen for Camellia oleifera seedling fertilization,high concentration level was recommended.(5)Different forms of nitrogen and different levels of fertilization had significant effects on soil microorganism.NO3--N had a strong promoting effect on the bacterial richness in the rhizosphere soil of Camellia oleifera,followed by CO(NH2)2-N;the dominant phyla of soil microorganisms in the rhizosphere soil of Camellia oleifera were Actinobacteria,Proteobacteria and Chloroflexi.Soil environmental factors include soil p H,TN,TP,TK,AN,AP and AK,S-ACP,UE,CAT,S-SC which have related effects on soil bacterial community structure.Carbohydrate metabolism,amino acid metabolism,membrane transport and energy metabolism were the main functional genes of bacteria in the rhizosphere soil of Camellia oleifera... |
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