Influence of Sewage Sludge Dose on Physicochemical Characteristics of Soil and Productivity of Radish (Raphanus sativus L.)

Abstract

Sewage sludge, a byproduct of wastewater treatment, is a rich source of plant nutrients like nitrogen, phosphorus, potassium, magnesium, and iron. This makes it a potential fertilizer for agricultural use. However, sewage sludge also contains high concentrations of heavy metals that can accumulate in soil and potentially be taken up by plants. Additionally, it may harbor pathogens, posing health risks. This experiment, conducted at the College of Forestry SHUATS nursery in Allahabad, aimed to assess the impact of sewage sludge application on soil properties. The study involved applying varying rates of sewage sludge (9 kg/plot) to plots where the tuber crop radish (Raphanus sativus) was grown. A randomized complete block design with four replicates was used for the experiment. Soil samples were collected from a depth of 0-15 cm to analyze pH, electrical conductivity, organic carbon content, available nitrogen, available phosphorus, and available potassium. The results indicated a significant effect of sewage sludge on most soil properties. Notably, the application of sewage sludge increased soil nitrogen and phosphorus content. For example, soil nitrogen content rose from 127.4 kg/ha to 281.11 kg/ha with sewage sludge application, and soil phosphorus content increased from 15.3 kg/ha to 24.84 kg/ha. The study suggests that sewage sludge application in agriculture could be beneficial due to its ability to improve soil nutrient content and potentially enhance plant growth and yield. However, further research is needed to determine the long-term effects of heavy metal accumulation and potential pathogen contamination in the soil and harvested crops. A comprehensive risk assessment is crucial before widespread adoption of sewage sludge as a fertilizer.