Pruned tea bushes secrete more root exudates to influence microbiological properties in soil

ABSTRACT

Pruning is adopted at 3–4 years interval as an agronomic practice during tea cultivation. It was hypothesized that biomass loss during pruning will imply stress on tea bushes. The aim of this study was to quantify changes in different parameters (labile organic carbon fractions, phosphatase activity, microbial biomass and microbial respiration) in tea rhizosphere due to pruning by collecting soil samples from the rhizosphere of ten of each pruned and un-pruned tea bushes. Hot-water extractable and dissolved organic C contents in rhizosphere soil of pruned tea were significantly (P ≤ 0.05) higher than those in the soil of un-pruned tea bushes. Analysis of phospholipid fatty acids (PLFA) revealed that the rhizosphere of pruned tea plants had higher population of Gram (+) and Gram (-) bacteria, fungi, actinomycetes and lower denitrifying bacterial population as compared to un-pruned tea plants. Activity of acid phosphatase enzyme in soil was also increased due to pruning. A separate study revealed that de-centering may induce production of up to 50% more labile organic carbon compounds by young tea as compared to un-pruned plants. Therefore, it could be concluded that pruned tea bushes secrete more root exudates to influence microbiological and biochemical properties in rhizosphere.

KEYWORDS:

• Pruning
• tea rhizosphere soil
• soil properties
• microbial characterization

Acknowledgement

Authors are thankful to the Director, TTRI, TRA, Jorhat for providing necessary facilities for conducting the experiment. Authors are also thankful to Mr. N. Sharma (Senior Manager), Mr. Varghese (Manager) and Mr. A. Dey (Assistant Manager) of Kolony Tea Estate for providing necessary ground support. The work was financially supported by Department of Science and Technology (DST), Government of India (DST/IS-STAC/CO2-SR-243/2015). Authors outsourced PLFA analysis from the Hyderabad-based Royal Life Sciences Pvt. Ltd., Secunderabad, India.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Department of Science and Technology (DST), Government of India [DST/IS-STAC/CO2-SR-243/2015].