Abstract
The activity of amylase (AMY), arylsulphatase (ASA), β-glucosidase (GSA), dehydrogenase (DHA), acid-phosphomonoestarase (PHA) and protease (PRO) enzymes were analyzed in rhizospheric soils of broom grass, Thysanolaena maxima (TM) collected from fallow phases of 5 and 20 years Jhum cycles (F5 and F20, respectively) and their corresponding bulk soils. The activities of soil enzymes from rhizospheric soil of TMF5 were significantly higher relative to that of bulk soils and the rhizospheric soils from TMF20. The counts of rhizobacteria [0.74 ± 0.056 x 107 colony forming unit (cfu) g-1 soil] and root endophytic bacteria (0.083 ± 0.004 x 104 cfu g-1 roots) of TM from F20 fallow phase were higher compared to the counts of rhizobacteria and endophytic bacteria (0.27 ± 0.029 x 107cfu g-1 soil and 0.05 ± 0.008 x 104 cfu g-1 roots, respectively) of TM from F5 fallow phase. Altogether 63 isolates associated with TM were screened for multifaceted plant growth promoting (PGP) traits viz. production of pectinase and cellulase, IAA like substances, 1-aminocyclopropane-1-carboxylate deaminase (ACCD), N2-fixation, solubilisation of inorganic phosphorus (iP) from Ca3(PO4)2, AlPO4 and FePO4 and mineralization of organic phosphorus (Na-phytate). The PGP screening results indicated that the percent incidence of rhizobacteria and root endophytic bacteria for PGP traits was higher in F5 fallow phase as compared to F20 fallow phase. These results provided clear indication that TM plants play an important role in rejuvenating the biological activities (in terms of higher activities of enzymes in rhizospheric soils and greater population of beneficial rhizobacteria and root endophytes) in frequently burnt soils under shorter Jhum cycles.
Highlights
Shifting cultivation or locally known as Jhum cultivation is an age old and dominant agricultural practice in the hill states of North East India.[1]
It is considered to be well adapted to tropical climates and accessible to small farmers because of its low cost, degradation of land due to short Jhum cycle[2] it has become a major constraint in the soil productivity.[3]
The possible influence of slope gradient on soil attributes was confounded since, the present investigation aimed to study the effect of burning and the length of the fallow phases on soil biochemical attributes of rhizospheric soils of Thysanolaena maxima (TM) relative to bulk soils
Summary
Shifting cultivation or locally known as Jhum cultivation is an age old and dominant agricultural practice in the hill states of North East India.[1]. It was observed that after burning of Jhum sites of Nagaland, some of the weed species for example, Borreria hispida, Chromolaena odorata, Thysanolaena maxima and Ageratum conyzoides showed abundance growth in the starting of secondary succession of the vegetation.[4] weed infestation was carried out for agricultural practice, when Jhum cultivation sites were left for rebuilding of ecosystem, they again grew in abundance. In later stages of succession their dominance were replaced by shrubs or other woody plant varieties. As these weed species were pioneering the secondary vegetation, the soil-plant-microbe interactions associated with these ESP can be considered as most potential interaction among the other members of the plant community for rebuilding of the Jhum soil ecology
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
