Environmental and economic trade‐offs of using composted or stockpiled manure as partial substitute for synthetic fertilizer

Abstract

Manure generated from livestock production could represent an important source of plant nutrients in substitution of synthetic fertilizer. To evaluate the sustainability of partially substituting synthetic fertilizer with soil organic amendments (OA) in horticulture, an economic and greenhouse gas (GHG) budget was developed. The boundary for analysis included manure processing (stockpiling versus composting), transport and spreading of manure and compost (feedlot and chicken) in intensively cultivated horticultural fields. The OA field application rates were calculated based on the nitrogen supplied by OA. The GHG budget based on directly measured emissions indicates that the application of composted manure, in combination with reduced fertilizer rate, was always superior to stockpiled manures. Compost treatments showed from 9 to 90% less GHG emissions than stockpiled manure treatments. However, higher costs associated with the purchase and transport of composted manure (3 times higher) generated a greater economic burden compared to stockpiled manure and synthetic fertilizer application. However, the plant nutrient replacement value of the OA was considered only for the first year of application and if long term nutrient release from OA is taken into account, additional savings are possible. As the income from soil carbon sequestration initiatives in response to OA application are unlikely to bridge this financial gap, particularly in the short-term, this study proposes that future policy should develop methodologies for avoided GHG emissions from OA application. The combined income from soil carbon sequestration and potentially avoided GHG initiatives could incentivize farmers to adopt OA as a substitute for synthetic fertilizers, thereby promoting more sustainable farming practices.

A Comprehensive Analysis of Agricultural Non-Point Source Pollution in China: Current Status, Risk Assessment and Management Strategies

“…Most of the farms do not have a corresponding fecal treatment system, especially those small farmers who choose the way of stocking for breeding. Animal waste is an important source of AGNPS pollution, its output is huge and pollution is widespread, but the corresponding pollution prevention countermeasures are relatively weak [78]. The discharge of livestock and poultry feces is large and highly random, then the direct or indirect discharge of eutrophic substances such as nitrogen and phosphorus into the water bodies, causing serious pollution to water quality [79].…”

Envisioning the manureshed: Toward comprehensive integration of modern crop and animal production

“…In a study of the environmental outcomes of substituting manure products for commercial fertilizers, De Rosa et al. (2022) compared composted and stockpiled manure as a substitute for commercial fertilizer. They found that a program of composted manure and judicious N fertilizer use resulted in 9–90% less greenhouse gas emissions than one relying upon unprocessed, stockpiled manure.…”

Phosphorus availability and speciation in soils amended with upcycled dairy-waste nutrients

“…Utilization of dairy manure as a nutrient source for agricultural production is a potential way to sustainably use dairy waste products (De Rosa et al, 2022). However, the application of raw dairy manure to agricultural fields often leads to nitrogen (N) and phosphorus (P) leaching that threatens water quality (Cao and Harris, 2010;Ghezzehei et al, 2014;Pagliari et al, 2020).…”

“…Manures are typically applied to soils at rates needed to meet plant N requirements, thus exceeding P requirements by up to six times (Carey et al, 2011), which may lead to legacy P accumulation in the soil (McDowell and Sharpley, 2001). Due to the widespread threat from dairies to surface water quality (US EPA, 2013;Femeena et al, 2023), there is a major imperative to develop nutrient recycling technology from dairy waste that will reduce nutrient leaching and improve the dairy bioeconomy, soil health, and nutrient resource sustainability (Adhikari et al, 2005;Van Zanten et al, 2019;Bach et al, 2021;Muscat et al, 2021;De Rosa et al, 2022). Meeting this imperative requires research to develop technology to recover P and N from dairy waste and test its efficacy as a beneficial soil amendment (Kushwaha et al, 2011;Kolev, 2017;Ahmad et al, 2019).…”