Greater Nitrogen Availability, Nitrous Oxide Emissions, and Vegetable Yields with Fall-Applied Chicken Relative to Horse Manure

Gabriel Maltais-Landry,Brianna Thompson,Sean M Smukler,Zoran Nesic,Nicholas Grant

doi:10.3390/agronomy9080444

Gabriel Maltais-Landry, Brianna Thompson + Show 3 more

Open Access

https://doi.org/10.3390/agronomy9080444

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Abstract

Optimal manure management can maximize agronomic benefits and minimize environmental impacts. Field experiments were conducted in the Pacific Northwest (Vancouver, Canada) to determine how chicken and horse manures that were fall-applied to meet nitrogen crop demand affect soil ammonium (NH4+) and nitrate (NO3−), apparent net mineralization (ANM) and nitrification (ANN), crop biomass and nutrient concentration, and fluxes of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4). Relative to horse manure, chicken manure increased soil NH4+ by 60-fold, ANM by 2-fold, and ANN by 4-fold. Emissions of N2O (+600%) and CO2 (+45%) were greater and growing season CO2 emissions (−40%) were lower after application of chicken than horse manure. Productivity of cover crop (+30%), legume cover crop (−25%), and squash cash crop (+20%) were affected by chicken relative to horse manure. Overall, fall-applied chicken manure increased yields, N availability, and environmental impacts relative to horse manure.

Highlights

Proper management of manures in agricultural systems recycles nutrients, maintains crop productivity, and increases soil organic matter (SOM), which improves water holding capacity and reduces soil erosion [1]
The fraction of manure N that is plant-available N (PAN) is key to manure management because most N in solid manures consists of organic forms that must be converted to ammonium (NH4 + )
Emissions were six-fold greater with chicken relative to horse manure. These results are consistent with high soil NH4 + [33] and nitrous oxide (N2 O) emission [13] reported after chicken manure application

Summary

Introduction

Proper management of manures in agricultural systems recycles nutrients, maintains crop productivity, and increases soil organic matter (SOM), which improves water holding capacity and reduces soil erosion [1]. Manure applications can lead to excessive nitrogen (N) inputs that increase N leaching and/or runoff [2], greenhouse gas (GHG) emissions [3], and potentially soil salinity [4]. Nitrate (NO3 − ) prior to crop uptake [5]. This can be estimated with the carbon to nitrogen (C:N). As N release from organic sources is often decoupled from plant N demand [7], total N inputs typically exceed crop N requirement to maintain yields, which increases the potential for N losses [2]. Applying manures to match crop N demand can lead to P overfertilization [8] and soil P loss [1] because manures are enriched in P relative to crop N needs [9]

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