Quality of ground water used for irrigation in Ujjain district of Madhya Pradesh, India.

The ground water samples collected from different tehsils of Ujjain district were analysed in the laboratory for electrical conductivity (EC), pH, cations (Na+, K+, Ca2+ and Mg2+) and anions (CO3(2-)), HCO3-, Cl- and SO4(2-)). The water samples were categorized as per criterion developed by Central Soil Salinity Research Institute, Karnal, Haryana, India. Out of 712 samples, 105, 144, 150, 84, 68, 111 and 50 samples belong to Ujjain, Mahidpur, Khachrod, Tarana, Barnagar, Nagda and Ghatia tehsils of the district respectively. 80% samples indicated good water quality at the district as a whole, whereas 14% were found saline (marginally saline (B1)-9%, saline (B2)-4%, high SAR saline (B3)-1%) and 6% as alkali (marginally alkali (C1)-5%, and alkali (C2)-1%) categories. In general, these waters were of Ca-Na-Mg type with the dominance of Cl followed by HCO3 and CO3 in case of good quality waters. The poor water quality belonged to categories of B1, B2, B3, C1 and C2, which were either having accumulation of salts (high EC) or high sodium adsorption ratio (SAR) and residual sodium carbonate (RSC). High significant negative correlation coefficient between pH and SO4-- was observed. The sodium (Na+) content showed significant positive correlation coefficient with EC. Similarly, HCO3- showed a significant positive correlation with RSC content. The ground water quality map of the district was generated using ERDAS-IMAGINE 8.7 Software showing different categories.

Edaphological characteristics of unweathered and weathered fly ashes from Gondwana and lignite coal.

Naturally weathered and unweathered samples of fly ashes produced from Gondwana and lignite coals were characterized for their edaphological properties. The particle size distribution in these fly ashes varied widely, and the percentage of [Formula: see text] size particles governed their water holding capacity. All fly ashes were noncoherent in the dry state and had lower particle density than quartz and mulite. The fly ashes were low in available N, but were sufficient in available P, K, Ca, Mg, S, Cu, Fe, Mn, Zn and B. Among the fly ashes, unweathered lignite fly ash was the richest source of K, Ca, Mg, S and Fe, while weathered lignite fly ash had the highest amounts of Mn, Zn and B. The pH of the fly ashes was closely related to the ratio of exchangeable Ca to exchangeable Al. The fly ashes were high in soluble salt, but were poor in cation exchange capacity. As an amendment to correct soil pH, the fly ashes had a poor buffering capacity. Weathering decreased the total Fe, available S and exchangeable Na percentages, but increased the organic C content of the fly ashes. Invariably, an excess of soluble salts and exchangeable Na could limit plant growth on fly ash dumps. Toxic levels of B and Al existed in only some fly ashes.