Nitrogen Use Efficiency and Gaseous Nitrogen Losses from the Concentrated Liquid Fraction of Pig Slurries

R. P. J. J. Rietra,G. L. Velthof

doi:10.1155/2019/9283106

Abstract

Processed manure can be an alternative source of nutrients for untreated manure and mineral fertilizers. Mineral concentrates (MCs) are derived from reversed osmosis of the liquid fraction of separated pig slurries. The emissions of ammonia (NH3) and nitrous oxide (N2O) from different (processed) manures and fertilizers were tested in an incubation experiment and a greenhouse experiment with grass as a test crop. Dry matter yields and nitrogen (N) uptake were also determined in the greenhouse experiment. Incorporation into the soil decreased on NH3 emission but increased N2O emission for all nitrogen products (mineral fertilizer, untreated slurry, MC, and solid fraction of separated slurry). Incorporation of both MC, slurries, and mineral fertilizers increased N2O emission in the incubation experiment. The lowest apparent N recovery (ANR) in the pot experiment with grass was obtained for incorporated pig slurry (30–39%) and surface-applied MC (33–38%), while the highest ANRs were obtained for liquid ammonium nitrate (45–53%) and acidified MC (43–55%). It is concluded that MCs have a similar N fertilizer value as mineral N fertilizers if NH3 emission is reduced by incorporation or acidification.

Highlights

Livestock manure is a valuable source of nutrients for crops and organic matter for soil
Improved manure management based on high-technology manure processing and transport of processed manures from intensive livestock regions to regions with arable cropping systems is seen as an important measure to decrease nutrient losses to the environment and increase nutrient use efficiency in intensive livestock systems [4, 5]
Mineral Concentrates. e experiments were carried out with pig slurries, Mineral concentrates (MCs), and sold fractions of separated slurries derived from four manure processing plants (A, B, C, and D) [12]. ere was one plant in which the digestate of codigested pig slurry and maize residues was treated: plant A. e other plants (B, C, and D) treated raw pig slurry, which was not digested or codigested. e separation techniques differed between the four plants

Summary

Introduction

Livestock manure is a valuable source of nutrients for crops and organic matter for soil. High losses of nitrogen (N) and phosphorus (P) have caused environmental problems related to soil, water, and air quality in many regions with intensive livestock farming systems [1]. Lower inputs by fertilizers and manures have decreased both nitrate (NO3−) leaching to ground and surface waters and gaseous emissions to the atmosphere as ammonia (NH3) and nitrous oxide (N2O) in the EU in 2000–2008 [3]. Improved manure management based on high-technology manure processing and transport of processed manures from intensive livestock regions to regions with arable cropping systems is seen as an important measure to decrease nutrient losses to the environment and increase nutrient use efficiency in intensive livestock systems [4, 5]

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Discussion

Conclusion