Chronosequence variation in soil properties of sandstone quarry spoil surrounding  Aizawl, Mizoram and its impact on the growth of <i>Coriandrum sativum</i>

Sandstone quarrying is a major income-generating enterprise inAizwalCity of Mizoram, India. The by-product, sandstone dust, is dumped near the mining area, potentially affecting soil and water quality. The present study seeks to understand the soil development process over time by analyzing soil parameters in chronosequence, viz. fresh, 2-year, 4-year, 6-year, 8-year, 10-year, and 12-year-old dumps, and evaluating growth parameters of Coriandrum sativum (Coriander) in soils of different ages under greenhouse conditions. The soil moisture content of the soil increased with the age of the soil and freshly dumped sandstone quarry spoil had the highest levels of pH (7.7) and electrical conductivity (13.16 dS/m), which dramatically dropped to 5.4 and3.45dS/m, respectively, as the soil grew older. Other soil qualities, which included water-holding capacity, soil organic carbon (from 0.46%-0.78%), available nitrogen (from 38kg/ha-217.33kg/ha), and available potassium (from11kg/ha-22kg/ha) also improved with age. Although significant variation was observed in germination parameters among dumps of various ages, germination was not deterred in fresh dumps. Growth parameters improved as the soil matured, with maximum values observed at 12 the old dump. However, the slow development of coriander, even after 12 years, indicates that soil amendment techniques should be used to accelerate the recovery of plant attributes and eco-restoration of such sites.