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The large volume changes behaviour of expansive soil in contact with water is considered a threat for superstructure due to unavoidable settlement, when used as a foundation base. In order to control the volume changes and to improve the soil properties to meet the challenges during the post construction stages, addition of industrial by-products have become a recent trend in civil engineering field. This paper outlines the characteristics changes of the expansive soil, which is treated by red mud (RM) and phosphogypsum (PG) with varying percentages simultaneously. After amendment, the expansive soil is altered from highly compressible (CH) clay to medium compressible silt (MI). The optimum insertion of the by-products increases the maximum dry density (ρdmax) and the compressive strength value by 4.42% and 295.42%, respectively, with respect to the parent soil. It is also noticed that the reduced value of swelling pressure (Ps) makes the treated soil suitable for strip footing due to possession of low uplift pressure. An attempt is made to validate the compaction characteristics data through the grey relational analysis (GRA) to facilitate further experimental programmes. The microstructural analyses are conducted by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) to support the experimental investigations. [ABSTRACT FROM AUTHOR]

A correction to the article "Integrating farm with bio-based practicesfor food security and sustainability" that was published in the June 2015 issue is presented.

Since the 1960s, agricultural production in India has been enhanced significantly due to extensive use of fertilizers, improved seeds, plant protection chemicals and irrigation. But increased crop production has accelerated the removal of plant nutrients from the soil by almost four times over the last two decades, constraining the quality of soil resources. The Agricultural Training Centre (ATC), Ramakrishna Mission Ashrama, Narendrapur, has been trying for decades to tackle the problem through trials and experimentation, in collaboration with the farmers in the villages. Bio-intensive farming is one of the options to keep the agricultural production system friendly with overall natural ecosystem as well as generate enough production for sustainability of the farm household. As a pilot project, the ATC implemented the concept in three villages of Ruppur Gram Panchayat of Birbhum district, West Bengal, through 50 households. Here chemical agriculture was highly preferred in spite of decreasing net return per unit area. The impact of the project shows considerable reduction of some chemicals, increasing trend for conservation of natural resources, generation of self-employment as well as sustainable income of the farm house holds. [ABSTRACT FROM AUTHOR]