Organic amendment additions to rangelands

A meta-analysis of multiple ecosystem outcomes

Kelly Gravuer, Sasha Gennet, Heather Throop

Research output: Contribution to journalArticle

Abstract

Interest in land application of organic amendments—such as biosolids, composts, and manures—is growing due to their potential to increase soil carbon and help mitigate climate change, as well as to support soil health and regenerative agriculture. While organic amendments are predominantly applied to croplands, their application is increasingly proposed on relatively arid rangelands that do not typically receive fertilizers or other inputs, creating unique concerns for outcomes such as native plant diversity and water quality. To maximize environmental benefits and minimize potential harms, we must understand how soil, water, and plant communities respond to particular amendments and site conditions. We conducted a global meta-analysis of 92 studies in which organic amendments had been added to arid, semiarid, or Mediterranean rangelands. We found that organic amendments, on average, provide some environmental benefits (increased soil carbon, soil water holding capacity, aboveground net primary productivity, and plant tissue nitrogen; decreased runoff quantity), as well as some environmental harms (increased concentrations of soil lead, runoff nitrate, and runoff phosphorus; increased soil CO 2 emissions). Published data were inadequate to fully assess impacts to native plant communities. In our models, adding higher amounts of amendment benefitted four outcomes and harmed two outcomes, whereas adding amendments with higher nitrogen concentrations benefitted two outcomes and harmed four outcomes. This suggests that trade-offs among outcomes are inevitable; however, applying low-N amendments was consistent with both maximizing benefits and minimizing harms. Short study time frames (median 1–2 years), limited geographic scope, and, for some outcomes, few published studies limit longer-term inferences from these models. Nevertheless, they provide a starting point to develop site-specific amendment application strategies aimed toward realizing the potential of this practice to contribute to climate change mitigation while minimizing negative impacts on other environmental goals.

Original languageEnglish (US)
Pages (from-to)1152-1170
Number of pages19
JournalGlobal Change Biology
Volume25
Issue number3
DOIs
StatePublished - Mar 1 2019

Fingerprint

meta-analysis
rangeland
Ecosystems
runoff
soil carbon
Soils
ecosystem
plant community
soil water
Runoff
soil
nitrogen
biosolid
compost
Climate change
fertilizer
nitrate
Nitrogen
phosphorus
Carbon

Keywords

  • arid
  • biodiversity
  • biosolids
  • climate change
  • compost
  • ecosystem services
  • grassland
  • runoff
  • savanna
  • soil carbon

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • Environmental Science(all)

Cite this

Organic amendment additions to rangelands : A meta-analysis of multiple ecosystem outcomes. / Gravuer, Kelly; Gennet, Sasha; Throop, Heather.

In: Global Change Biology, Vol. 25, No. 3, 01.03.2019, p. 1152-1170.

Research output: Contribution to journalArticle

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