TY - JOUR
T1 - Plant availability and leaching of 15N-labelled mineral fertilizer residues retained in agricultural soil for 25 years
T2 - A lysimeter study
AU - Sørensen, Peter
AU - Pedersen, Betina N.
AU - Thomsen, Ingrid K.
AU - Eriksen, Jørgen
AU - Christensen, Bent T.
PY - 2023/8
Y1 - 2023/8
N2 - Background: A high use-efficiency of fertilizer N remains essential to sustain high crop productivity with low environmental impact. However, little is known on the long-term lability of mineral fertilizer N. Aims: To quantify crop uptake and leaching of 15N-labelled mineral fertilizer that has been retained in an agricultural soil for 25–30 years in crops with variable growing season. Methods: A field plot received 15N-labelled mineral fertilizers over a period of 5 years and was then kept under arable cropping for 12 years. After relocation to 16 lysimeters, the topsoil grew set-aside grassland for the next 13 years. Then crop uptakes and leaching losses of 15N remaining in soil was tested over a 2-year period by either converting set-aside grass to production grassland, or by replacing it with spring barley (+/− autumn cover crop) or vegetation-free fallow. All treatments received unlabelled mineral N fertilizers. Results: Crop uptake and leaching of 15N were generally highest in the first test year after termination of the set-aside. The leaching of residual 15N in soil declined in the order: vegetation-free soil (4.7%), spring barley (1.9%), spring barley + cover crop (0.7%) and production grassland (0.2%). Corresponding losses for the second leaching period were 2.7%, 0.9%, 0.4% and 0.06%. There was a fixed relationship between leaching losses of 15N and total N. Conclusions: After residing in soil for 25–30 years, the lability of labelled mineral N fertilizer residues appeared slightly higher than the lability of bulk soil N. Autumn vegetation was crucial for reducing leaching losses.
AB - Background: A high use-efficiency of fertilizer N remains essential to sustain high crop productivity with low environmental impact. However, little is known on the long-term lability of mineral fertilizer N. Aims: To quantify crop uptake and leaching of 15N-labelled mineral fertilizer that has been retained in an agricultural soil for 25–30 years in crops with variable growing season. Methods: A field plot received 15N-labelled mineral fertilizers over a period of 5 years and was then kept under arable cropping for 12 years. After relocation to 16 lysimeters, the topsoil grew set-aside grassland for the next 13 years. Then crop uptakes and leaching losses of 15N remaining in soil was tested over a 2-year period by either converting set-aside grass to production grassland, or by replacing it with spring barley (+/− autumn cover crop) or vegetation-free fallow. All treatments received unlabelled mineral N fertilizers. Results: Crop uptake and leaching of 15N were generally highest in the first test year after termination of the set-aside. The leaching of residual 15N in soil declined in the order: vegetation-free soil (4.7%), spring barley (1.9%), spring barley + cover crop (0.7%) and production grassland (0.2%). Corresponding losses for the second leaching period were 2.7%, 0.9%, 0.4% and 0.06%. There was a fixed relationship between leaching losses of 15N and total N. Conclusions: After residing in soil for 25–30 years, the lability of labelled mineral N fertilizer residues appeared slightly higher than the lability of bulk soil N. Autumn vegetation was crucial for reducing leaching losses.
KW - cover crops
KW - residual N value
KW - spring barley
KW - vegetation-free fallow
UR - http://www.scopus.com/inward/record.url?scp=85161291047&partnerID=8YFLogxK
U2 - 10.1002/jpln.202200288
DO - 10.1002/jpln.202200288
M3 - Journal article
AN - SCOPUS:85161291047
SN - 1436-8730
VL - 186
SP - 441
EP - 450
JO - Journal of Plant Nutrition and Soil Science
JF - Journal of Plant Nutrition and Soil Science
IS - 4
ER -