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Recovery efficiency of nitrogen from liquid and solid fractions of pig slurry obtained using different separation technologies
Author(s) -
Fangueiro David,
Coutinho João,
Borges Leandro,
Vasconcelos Ernesto
Publication year - 2015
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.201400261
Subject(s) - slurry , lolium perenne , chemistry , settling , dry matter , chromatography , nitrogen , fraction (chemistry) , zoology , analytical chemistry (journal) , agronomy , perennial plant , materials science , biology , environmental science , environmental engineering , organic chemistry , composite material
The characteristics of solid (SF) and liquid (LF) fractions resulting from solid–liquid separation of pig slurry depend on the separation technique used. It can be assumed that the separation technique will also affect the nitrogen (N) availability to plants. A pot experiment was performed with ryegrass to compare the N‐recovery efficiency of SFs and LFs obtained with four frequently used separation techniques (centrifugation [Cent], sediment settling during 20 h [Sed], enhanced settling during 20 h by addition of cationic polyacrylamide [Sed+PAM], sieving [Siev], sieving followed by treatment of the resulting liquid fraction by PAM addition [Siev+PAM]) with the untreated slurry (US) and an unfertilized control. Increases (2–17%) of ryegrass dry matter yield (DMY) were obtained in LF treatments relative to US. However, this increase was statistically significant only for the Siev+PAM‐L treatment. A significant decrease of ryegrass DMY was observed in SF treatments relative to US. All treatments with SFs led to similar values of DMY while only small differences were observed between treatments receiving LFs. A significant correlation ( R 2 = 0.968) was observed between the total DMY and the NH $ _4^+ $ ‐ N : N tot ratio of the fraction applied suggesting that this is a major parameter to be considered when comparing separation techniques. Overall, the separation techniques showed only a weak effect on the dry matter yields and on the N ‐ recovery efficiency from LF and SF although they strongly affected the nutrient concentration and speciation in each fraction.