Studies on utilization of sewage waste water for greening wastelands through afforestation

Abstract

One of the major burning problems in urban areas is the disposal of sewage water, which degradesthe environment, and as well as creates health hazards to human beings. One opening to this bottleneckis that this sewage water could be diverted for irrigation purpose especially for afforestation purpose.Sewage water provides nutrients and using it for irrigation has been found to enrich soil, improveuptake of plants and ameliorate degraded soils. It was found that sewage water irrigated tree speciesrecorded maximum height and basal diameter when compared to bore well water irrigation. It showedthat it boosted the growth of tree species. Hence the utilization of sewage water as irrigation waterfor tree crops is the one of best option for increasing biomass and protecting environment deteriorationfrom deforestation of land and water by sewage water.

In this context, a field experiment was conducted at sewage farm and the following tree species viz.,Eucalyptus tereticornis, Tectona grandis, Casuarina equisetifolia, Azadirachta indica and Acacianilotica were planted and irrigated with sewage water at 2 weeks interval. The same 5 species werealso planted near the sewage farm and irrigated with bore well water. The growth parameters viz.,height and basal diameter were recorded at periodical interval. The results revealed that the heightand basal diameter of all the five selected tree species were higher under sewage water irrigationwhen compared to bore well water irrigation. The results inferred that at 3 MAP, the percent increasein height and basal diameter respectively was 15 % and 18 % for Casuarina equisetifolia, 39 % and 20 % for Tectono grandis, 17 % for Acacia nilotica. 24 % and 20 % for Azodirachta indica, 23 %and 18 % for Eucalyptus tereticornis over bore well water irrigation. At 6 MAP, the percent inheight and basal diameter was 7 % each for Casuarina equisetifolia, 13 % and 6 % for Tectonagrandis, 13 % and 6% for Acacia ni/otica, 15 % and 9 % for Azadirachta indica, 14 % and 12 %for Eucalyptus tereticornis under sewage water irrigation over bore well water irrigation.At 9 MAP, the increase in height and basal diameter was 8 % each for Casuarina equisetifolia, 9 %and 6 % for Tectona grandis, 12 % and 9 % for Acacia nilotica. 10 % and 4 % for Azadirachtaindica, 21 % and 11 % for Eucalyptus tereticornis over bore well water irrigation. At 12 MAP.increase in height and basal diameter was 7 % and 4 % for Casuarina equisetifolia, 7 % and 4 %for Tectona grandis, 6 % and 4 % for Acacia nilotica, 47 % and 4 % for Azadirachta indica, 8 %and 7 % for Eucalyptus tereticornis over bore well water irrigation. At 15 MAP under sewagewater irrigation, the percent increase was 4% each for Casuarina equisetifolia, 5 % and 3 % forTectona grandis, 6 % and 5 % for Acacia nilotica, 7 % and 5 % for Azadirachta indica, 10 % and8 % for Eucalyptus tereticornis over bore well water irrigation.

From the study, it was found that sewage water can be better used for raising tree plantation onrelatively unferti le wastelands through afforestation, urban forestry plantation, social forestry plantationto safeguard the planet earth from global warming, severe drought, adverse climatic condition, pollution etc.