Assessing the impact of composted municipal solid waste on soil physical properties and corn (Zea mays) yield in a temperate agroecosystem.

Project Abstract

This study investigates how composted municipal solid waste (CMSW) amendments influence soil physical properties and corn (Zea mays) yield within a temperate agroecosystem, aiming to optimize sustainable waste recycling while maintaining or enhancing crop productivity. A randomized complete block design with four CMSW application rates (0, 10, 20, and 30 tons per hectare) and four replication blocks was established on a loamy soil to capture short- and medium-term effects on soil structure, moisture dynamics, bulk density, porosity, aggregate stability, infiltration rate, and water-holding capacity across a full growing season. CMSW was characterized for organic carbon, total nitrogen, CN ratio, trace metals, and phytotoxic compounds to assess potential risk factors; compost maturity indices, such as C/N ratio and respiration activity, were monitored to determine bioavailability and stabilization status. Soil physical properties were measured at multiple intervals pre-application, post-incorporation, mid-season, and at harvest. In parallel, corn growth and productivity were tracked, including emergence rate, vegetative biomass, phenological development, tasseling, grain filling, and final grain yield and kernel quality. Soil microbial activity and community structure were analyzed using phospholipid fatty acid profiling and 16S rRNA gene sequencing to elucidate CMSW-induced changes in the rhizosphere microbial milieu and their relation to nutrient cycling and soil aggregation. Nutrient fluxes, mineralization rates, and leaching potential were assessed through lab incubation and a lysimeter-based drainage study to understand the fate of nitrogen and phosphorus under CMSW amendments. The research also evaluated environmental and agronomic trade-offs, including ammonia volatilization, nitrate leaching, heavy metal input thresholds, and potential impacts on soil biodiversity. Statistical analyses employed mixed-effects models to account for block design and temporal variation, complemented by structural equation modeling to unravel causal pathways linking CMSW characteristics, soil physical properties, microbial activity, nutrient dynamics, and maize yield components. Results indicated that CMSW application improved soil porosity, reduced bulk density, and enhanced saturated hydraulic conductivity, with the most pronounced effects at 20 t/ha. Infiltration and water-holding capacity increased, reducing susceptibility to drought stress during critical grain-filling stages. Improved aggregate stability correlated with higher microbial activity and a shift toward a more diverse microbial community, which supported accelerated nitrogen mineralization and synchronized phosphorus availability with crop demand. Grain yield showed a significant positive response at 10 and 20 t/ha, with kernel weight and starch content marginally affected at 30 t/ha due to subclinical salinity indicators and trace metal accumulation approaching recommended thresholds. The study identified a soil- and CMSW-specific optimum rate (approximately 20 t/ha) that maximizes physical soil improvements and yield benefits while maintaining environmental safeguards. These findings contribute to sustainable waste management strategies by demonstrating a viable use of CMSW as a soil amendment in temperate agroecosystems, informing guidelines for rate, timing, and monitoring to optimize soil health, crop productivity, and environmental resilience.

Project Overview

What This Project Is About

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A plain-language look at how adding composted municipal waste to soil might change how the soil behaves physically (like its texture, water retention, and structure) and how it affects the growth and yield of corn in a temperate farming area. The project compares soils with composted waste to untreated soils to see if the waste improves or harms soil quality and crop production.

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The Problem It Addresses

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Soil health and crop yield depend on nutrients, structure, and water movement. Municipal waste that has been composted is a potential source of nutrients and organic matter, but it can also alter soil structure and drainage in ways that might help or hurt crops. This project investigates whether using composted waste is a safe and effective practice for improving soil properties and corn yield in temperate regions.

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Objectives of the Project

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1. Clarify how composted waste changes soil physical properties such as bulk density, porosity, and water holding capacity.
2. Assess the effect of composted waste on corn growth stages and final yield.
3. Identify any thresholds where composted waste becomes beneficial or detrimental.
4. Evaluate changes in soil nutrient availability after applying composted waste.
5. Provide practical guidelines for safe use in temperate agroecosystems.

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What You Will Do Step by Step

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1. Review relevant literature on composted waste and soil physics.
2. Design a small field or pot experiment with control and treated plots.
3. Apply defined amounts of composted waste to the treatment plots.
4. Measure soil properties (bulk density, porosity, water holding capacity) at set times.
5. Plant corn and monitor germination, growth, and yield components.
6. Analyze data to compare treatments and controls using simple statistics.
7. Interpret results in the context of temperate soils and farming practices.
8. Draft practical recommendations and identify limitations.

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Expected Outcome

The project should show whether composted municipal waste improves or harms soil structure and water relations, and whether this translates into higher, lower, or unchanged corn yield. It will provide evidence-based guidelines for safe, effective use in temperate agroecosystems and highlight any potential environmental or yield risks.