Vol. 1, Issue 10, Part B (2015)

Abstract
Yamuna Biodiversity Park which located in semi-arid region of Delhi has a problem of soil salinity. The park has applied both phytodesalination and phytoremediation techniques to reclaim its saline soil. Many types of plants have been introduced and reintroduced to reduce the soil pH and salinity and to restore its nutrient content. The purpose of the work was to study the impact of spatio-temporal variation in plant communities on soil chemical properties. The vegetation sampling was conducted by selecting fifteen sampling plots sized 10×10 m2 to measure density, diversity, richness and abundance of plant species including trees, saplings and grasses and to measure girth at breast height of trees sized above 20 cm. Soil sampling was carried out using appropriate methods and equipments to measure soil temperature, moisture content, pH, salinity, electrical conductivity (EC), organic matter, nitrate and phosphate content. Results showed an inverse correlation between soil pH and sapling and grass density, while salinity and EC values were inversely correlated with plant diversity and species richness. Inverse correlation was also seen between soil organic matter and pH. Meanwhile, direct proportional relationship was found between soil nitrate and plant diversity and density, and between soil phosphate and plant diversity. Comparison to the earlier data gave spatio-temporal variation. Results showed many improvements in soil chemical properties during five-year period including soil pH, salinity, EC and soil nutrients including organic matter, nitrate and phosphate contents. This proved that phytoremediation technique by introduction/reintroduction of plant species has succeeded to reclaim the degraded saline soils and to restore soil nutrients.