Influence of rhizosphere on soil fertility in different land use systems of Mizoram

Abstract

Land use change is an ecologically sensitive component of the tropical forest ecosystems affecting all components of the ecosystems. Changes in the ecosystem components significantly affect the fertility of the soil by altering rhizosphere structure, function and interactions. The present study focuses on soil fertility; bacterial communities; soil aggregate stability and magnitude of were the three most predominant phyla, totally accounting for more than 50% of all the sequences. NF showed the maximum abundance of Acidobacteria and Proteobacteria which decreased with the change in land use whereas OPP showed the least distribution of both Acidobacteria and Proteobacteria. Root exudation rate was high during the summer season in all the land use systems. RP showed the maximum annual root exudation rate and minimum in OPP. The roots of Hevea brasiliensis, Melocanna baccifera and Elaeis guineensis exuded more C in July and were followed in decreasing order by October, April and May. Exudation rates in Hevea brasiliensis were greater and were followed by Melocanna baccifera and Elaeis guineensis. Land use types and their management activities profoundly affected the soil properties thereby affecting the long term ecological sustainability. Conversion of natural forest to plantations strongly affected physical and chemical soil attributes, as well as the soil bacterial community. Bamboo forest, in the absence of management practices, act as efficient land use system in sequestering soil carbon. As the present study focuses on assessing the impact of conversion of natural forest and bamboo forest to rubber plantation, oil palm plantation and fallow land, the results obtained in this study may be useful in directing farming practices and policy-making process for sustainable land use in Mizoram.