Dynamics of carbon, nitrogen and phosphorus concentration in soil microbial biomass under different land uses in Loess soil region of Pakistan
By: Sidra Munawar, Syed Moazzam Nizami, Tariq Mahmood, Muhammad Nawaz Chaudhary
Key Words: Soil microbial biomass, Land uses. Loess soil, Pothwar
Int. J. Biosci. 9(6), 318-329, December 2016.
Soil microbial biomass (SMB) assumed as gauge of biological quality as well as fertility. The quality and quantity of SMB is affected by different land uses. Therefore, the spatial variability of soil microbial biomass under three prominent land uses (agricultural land, grazing land and natural scrub forest) in the loess soil region of Pakistan was investigated. Overall, three hundred soil monoliths (100 from each land use) collected during 2014-15 from the loess soil region of Pakistan. Laboratory investigations were carried out for microbial biomass carbon, nitrogen and phosphorus (MBC, MBN & MBP) following standard protocols. The relationships were developed among land use pattern, soil microbial biomass and soil nutrients availability. The study revealed that the average value of MBC was 419 mg kg-1, 644 mg kg-1, and 749 mg kg-1 in agricultural land, grazing land and natural forests respectively. The mean value of MBN was 14.49, 11.99 and 109 mg kg-1, while MBP value was 5.49, 7.89 and 24.49 mg kg-1 in crop land, grass land and forest land respectively. A negative correlation was found between SMB (MBC, MBN and MBP) and pH and EC, while positive relationships was seen with TOC, NO3-N and available P. In the forest land sue the SMB and nutrients availability were maximum followed by grazing land and minimum in agricultural land use of the loess soil region. The study highlights the variation of concentration of microbial biomass C, N and P and is thought provoking for management of different land uses in this region.