Biological Diversity in soil from Long-term Vertisol Experiments
Biodiversity vary widely in semi-arid soils as compared to other tropical soils due to the poor vegetation, which is the result of erratic and scanty rainfall. The treatment of soil by chemical fertilizers, biofertilizers not only enhances soil fertility but also enriches soil microbial life.
Biodiversity includes bacteria, fungi, actinomycetes, ants, mites, nematodes, etc. This project involves the study of biodiversity, influenced by the cropping systems in the long-term Vertisols BW 1 and BW 4 collected from ICRISAT, Patancheru, and Hyderabad.
Microbial and biological properties of the soil samples were analyzed to study the biological diversity under various cropping systems. Enumeration of microbes (bacteria, fungi, actinomycetes) was done by dilution plating technique, using appropriate media; microbial biomass carbon and microbial biomass nitrogen were determined by chloroform fumigation and incubation method, mineral nitrogen and net nitrogen mineralization were determined by measuring mineral N by steam distillation method. Nematodes were extracted by the modified Baermann technique.
Population of bacteria, fungi, actinomycetes, and nematodes were affected significantly by different cropping systems. The results showed that mean microbial population (9×105 cfu g-1 of soil) was high in the improved system when compared to the traditional system. Soil respiration (0.31µg C g-1 of soil), microbial biomass C (10.6 µg C g-1 of soil) and N (2.8 µg C g-1 of soil) were found to be more in the improved system than in the traditional system. This study enabled us to understand the synergistic interactions of soil biotic activity under improved system and traditional system.
The out come of this experiment necessitates further studies in exploiting the complex processes, which regulate the dual impacts of micronutrients and beneficial soil organisms to derive a technology for sustainable crop production.