It has been reported that phosphate solubilizing bacteria (PSB) are the most promising bacteria among the plant growth promoting rhizobacteria (PGPR); which may be used as biofertilizers for plant growth and nutrient use efficiency. Moreover, these soil micro-organisms play a significant role in regulating the dynamics of organic matter decomposition and the availability of plant nutrients such as nitrogen (N), phosphorus (P), potassium (K) and other nutrients. Through this study, the management of nutrient use efficiency by the application of PSB was targeted in order to make the applied nutrients more available to the plants in the rice (Oryza sativa) and yardlong bean (Vigna unguiculata) cultivation. Results have shown that the treatments with PSB alone or in the form of consortia of compatible strains with or without the external application of chemical NPK gave more germination index (G. I.) from 2.5 to 5 in rice and 2.7 to 4.8 in bean seeds. They also showed a higher growth in both shoot and root length and a higher biomass as compared to the control. This gives us an idea about the potentiality of these PSB strains and their application in rice and yardlong bean cultivation to get a better harvest index. Their use will also possibly reduce the nutrient runoff or leaching and increase in the use efficiency of the applied fertilizers. Thus, we can conclude that the NPK uptake and management can be improved by the use of PSB in rice and yardlong bean cultivation, and their application may be much more beneficial in the agricultural field.

The high-sulfur containing coalmine overburden (OB) dumping ground of the Tirap colliery under the northeastern coalfields in Assam, India, was reclaimed by phytoremediation techniques. Native plant species were planted with line and field methods and by amending with cow dung and unmined soil. In this study, the changes in microbial activity of the reclaimed mine OB wasteland of the Tirap colliery are examined. The enzyme activities of urease, dehydrogenase, and phosphatase were compared over time. Improvements in soil pH, bulk density, and water-holding capacity in the mine OB were found. After four years of reclamation, 1.01% of particles were soil sized (=0.255 mm grain size) with the maximum degradation in the mine OB grain sizes of −20 mm to +12 mm and of +25 mm. A 1,000-fold increase in microbial colony forming units (CFU) in the four years at the remediated site along with an increase in total DNA were evident for the mine OB reclaimed sites. The increase of microbial CFUs in the mine OB was related to a 100-to 2,000-fold increase in enzyme activity for the reclaimed areas. From this investigation, it can be concluded that the improvement of enzyme activities and the increase in microbial populations of reclaimed mine OB will yield information pertaining to the reclamation index of mine OB.