Effects of Sewage Sludge Application on Plant Growth and Soil Characteristics at a Pinus sylvestris var. mongolica Plantation in Horqin Sandy Land

Abstract

The application of domestic sewage sludge (SS) may affect plant growth and soil quality through altering nutrient availability. However, the effect of SS application on the plant–soil system in sandy soils is poorly understood. In this study, we established SS application treatment plots (SL, 25 t ha−1) and control treatment plots without sewage sludge application (CK, 0 t ha−1). SS was applied to the soil surface of a Mongolian pine (Pinus sylvestris var. mongolica) plantation in Horqin Sandy Land, Inner Mongolia, China, to assess its potential effects on plants and soil. We analyzed tree growth performances (tree height, basal diameter, and diameter at breast height), understory traits (species diversity, coverage, and aboveground biomass), soil physical and chemical parameters (nutrient content, dissolved organic carbon, soil water content, bulk density, pH), and proxies of ecosystem services (soil organic carbon and total nitrogen stocks). The results showed that SS addition not only significantly increased soil nutrient contents, but also markedly enhanced aboveground productivity and plant coverage. Specifically, SS addition decreased soil bulk density and increased concentrations of soil organic carbon, total nitrogen, and total phosphorus and mineral nitrogen, and it also increased soil carbon and nitrogen stocks. Furthermore, the addition of SS significantly increased soil dissolved organic carbon contents and enhanced the fluorescence intensities of dissolved organic carbon components (humic acid-like and UV fulvic acid-like) in the topsoil (0–5 cm). This study provides evidence that SS is an acceptable, and possibly preferred organic fertilizer for improving the soil quality and tree–grass growth of Mongolian pine plantations.

Natural Bioactive Substances in Fruits of Aronia melanocarpa (Michx.) Elliott Exposed to Combined Light-Type, Chitosan Oligosaccharide, and Spent Mushroom Residue Treatments

“…Herbicide and controlled-release fertilizer (CRF) were suggested as solutions, but they present threats in terms of environmental safety affecting underground water quality [ 37 , 38 ]. Soil amendment using organic materials is a newly strategy that can improve soil porosity and increase availability [ 39 , 40 ]. Fresh spent mushroom residue (SMR) is a recommended organic amendment due to its purified composition, enriched nutrient residue, and wide accumulations [ 17 , 41 , 42 ].…”

Valorization of Textile Sludge and Cattle Manure Wastes into Fuel Pellets and the Assessment of Their Combustion Characteristics

“…Realizing the rich nutrient and carbon content in TWS, many researchers have investigated various methods, namely, anaerobic digestion, incineration, composting, pyrolysis, cocombustion, advanced oxidation, and blending with concrete. The mentioned methods/treatments were explored to produce renewable biogas, char, compost manure, bricks, fuel materials, and mineralization of their organic components. − Most of the conducted studies on TWS were on anaerobic digestion alone and/or in combination with other organic substrates, i.e., biogas production and nutrient-rich fertilizers for agriculture. , However, persistent heavy metals, dyes, and other chemical compounds in TWS are major constraints for its biological treatments, i.e., digestion, composting, and other thermal treatments, i.e., pyrolysis and incineration. − The direct combustion performance of TWS is weak due to the high content of inorganic materials, and for a similar reason, its heat content is poor. Moreover, studies on combustion/cocombustion performance and dynamics revealed the release of volatile organics in the medium temperature range of 200–300 °C and then unsustained combustion at higher temperature ranges due to significant inert/inorganic content. , Moreover, the cocombustion of TWS is an area that needs to be further explored, as TWS has a low heat calorific value and high volatile content, which could be optimized by compositing with other organic substrates (potential waste materials) to reduce the problems related to the low combustion efficiency of TWS and also help in solid waste reduction, detoxification, and energy recovery.…”