Grass-clover response to cattle slurry N-rates: Yield, clover proportion, protein concentration and estimated N2-fixation

Henrik Thers; Johannes L. Jensen; Jim Rasmussen; Jørgen Eriksen

doi:10.1016/j.fcr.2022.108675

Grass-clover response to cattle slurry N-rates: Yield, clover proportion, protein concentration and estimated N₂-fixation

Henrik Thers^*, Johannes L. Jensen, Jim Rasmussen, Jørgen Eriksen

^*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

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Abstract

Optimal nitrogen (N) fertilization for grass-clover leys is important, since the N application affects yields and the clover and crude protein (CP) contents of the forage. Modeling of optimal N application to maximize economic output and minimize environmental consequences depends on grass-clover responses, e.g., on clover proportion, dry matter (DM) and CP yield. Thus, such parameters need to be quantified in field trials. Based on a three-year field trial (2017–2019; Foulumgaard Experimental Farm, Denmark) with four cuts of an organically managed grass-clover ley, the effect of increasing N fertilization from cattle slurry (0, 50, 100, 200 and 300 kg total N ha^-1) on DM yield, CP yield and concentration as well as on clover proportion was examined. Results were analyzed separately for four sward ages (1–4 years). Dry matter yields ranged from 5.8 to 11.8 Mg ha^-1 and the 200 and 300 kg N ha^-1 treatments showed the highest DM yield for all sward ages; the 300 kg N ha^-1 showed no significant additional yield benefit relative to the 200 kg N ha^-1. The clover proportion generally decreased with increasing N application (36–65 % for 0 N and 8–35 % for 300 kg N ha^-1). The herbage concentration of CP was either unaffected or decreased with increasing N application. The fourth-year swards showed DM yields comparable to first and third-year sward ages. In unfertilized swards, a linear relationship was found between the first cut in a given year and the fourth cut of the previous year (r² = 0.82 within a range of autumn clover proportions of 33–74 %), indicating the possibility of using last cut for predicting next year's fertilizer requirements. The comprehensive data and results may form the basis for future modeling of optimal N application in organic grass-clover leys.

Original language	English
Article number	108675
Journal	Field Crops Research
Volume	287
ISSN	0378-4290
DOIs	https://doi.org/10.1016/j.fcr.2022.108675
Publication status	Published - Oct 2022

Keywords

Crude protein
N yield
Optimized N-fertilization
Organic dairy rotation
Protein content
Sward age

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10.1016/j.fcr.2022.108675

1-s2.0-S0378429022002465-mainFinal published version, 974 KBLicence: CC BY

Cite this

@article{2976d331c2df4bc3ba6f3e7e6f5f32d2,

title = "Grass-clover response to cattle slurry N-rates: Yield, clover proportion, protein concentration and estimated N2-fixation",

abstract = "Optimal nitrogen (N) fertilization for grass-clover leys is important, since the N application affects yields and the clover and crude protein (CP) contents of the forage. Modeling of optimal N application to maximize economic output and minimize environmental consequences depends on grass-clover responses, e.g., on clover proportion, dry matter (DM) and CP yield. Thus, such parameters need to be quantified in field trials. Based on a three-year field trial (2017–2019; Foulumgaard Experimental Farm, Denmark) with four cuts of an organically managed grass-clover ley, the effect of increasing N fertilization from cattle slurry (0, 50, 100, 200 and 300 kg total N ha-1) on DM yield, CP yield and concentration as well as on clover proportion was examined. Results were analyzed separately for four sward ages (1–4 years). Dry matter yields ranged from 5.8 to 11.8 Mg ha-1 and the 200 and 300 kg N ha-1 treatments showed the highest DM yield for all sward ages; the 300 kg N ha-1 showed no significant additional yield benefit relative to the 200 kg N ha-1. The clover proportion generally decreased with increasing N application (36–65 % for 0 N and 8–35 % for 300 kg N ha-1). The herbage concentration of CP was either unaffected or decreased with increasing N application. The fourth-year swards showed DM yields comparable to first and third-year sward ages. In unfertilized swards, a linear relationship was found between the first cut in a given year and the fourth cut of the previous year (r2 = 0.82 within a range of autumn clover proportions of 33–74 %), indicating the possibility of using last cut for predicting next year's fertilizer requirements. The comprehensive data and results may form the basis for future modeling of optimal N application in organic grass-clover leys.",

keywords = "Crude protein, N yield, Optimized N-fertilization, Organic dairy rotation, Protein content, Sward age",

author = "Henrik Thers and Jensen, {Johannes L.} and Jim Rasmussen and J{\o}rgen Eriksen",

note = "Publisher Copyright: {\textcopyright} 2022 The Authors",

year = "2022",

month = oct,

doi = "10.1016/j.fcr.2022.108675",

language = "English",

volume = "287",

journal = "Field Crops Research",

issn = "0378-4290",

publisher = "Elsevier B.V.",

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Grass-clover response to cattle slurry N-rates: Yield, clover proportion, protein concentration and estimated N₂-fixation. / Thers, Henrik ; Jensen, Johannes L.; Rasmussen, Jim et al.
In: Field Crops Research, Vol. 287, 108675, 10.2022.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

TY - JOUR

T1 - Grass-clover response to cattle slurry N-rates

T2 - Yield, clover proportion, protein concentration and estimated N2-fixation

AU - Thers, Henrik

AU - Jensen, Johannes L.

AU - Rasmussen, Jim

AU - Eriksen, Jørgen

PY - 2022/10

Y1 - 2022/10

N2 - Optimal nitrogen (N) fertilization for grass-clover leys is important, since the N application affects yields and the clover and crude protein (CP) contents of the forage. Modeling of optimal N application to maximize economic output and minimize environmental consequences depends on grass-clover responses, e.g., on clover proportion, dry matter (DM) and CP yield. Thus, such parameters need to be quantified in field trials. Based on a three-year field trial (2017–2019; Foulumgaard Experimental Farm, Denmark) with four cuts of an organically managed grass-clover ley, the effect of increasing N fertilization from cattle slurry (0, 50, 100, 200 and 300 kg total N ha-1) on DM yield, CP yield and concentration as well as on clover proportion was examined. Results were analyzed separately for four sward ages (1–4 years). Dry matter yields ranged from 5.8 to 11.8 Mg ha-1 and the 200 and 300 kg N ha-1 treatments showed the highest DM yield for all sward ages; the 300 kg N ha-1 showed no significant additional yield benefit relative to the 200 kg N ha-1. The clover proportion generally decreased with increasing N application (36–65 % for 0 N and 8–35 % for 300 kg N ha-1). The herbage concentration of CP was either unaffected or decreased with increasing N application. The fourth-year swards showed DM yields comparable to first and third-year sward ages. In unfertilized swards, a linear relationship was found between the first cut in a given year and the fourth cut of the previous year (r2 = 0.82 within a range of autumn clover proportions of 33–74 %), indicating the possibility of using last cut for predicting next year's fertilizer requirements. The comprehensive data and results may form the basis for future modeling of optimal N application in organic grass-clover leys.

AB - Optimal nitrogen (N) fertilization for grass-clover leys is important, since the N application affects yields and the clover and crude protein (CP) contents of the forage. Modeling of optimal N application to maximize economic output and minimize environmental consequences depends on grass-clover responses, e.g., on clover proportion, dry matter (DM) and CP yield. Thus, such parameters need to be quantified in field trials. Based on a three-year field trial (2017–2019; Foulumgaard Experimental Farm, Denmark) with four cuts of an organically managed grass-clover ley, the effect of increasing N fertilization from cattle slurry (0, 50, 100, 200 and 300 kg total N ha-1) on DM yield, CP yield and concentration as well as on clover proportion was examined. Results were analyzed separately for four sward ages (1–4 years). Dry matter yields ranged from 5.8 to 11.8 Mg ha-1 and the 200 and 300 kg N ha-1 treatments showed the highest DM yield for all sward ages; the 300 kg N ha-1 showed no significant additional yield benefit relative to the 200 kg N ha-1. The clover proportion generally decreased with increasing N application (36–65 % for 0 N and 8–35 % for 300 kg N ha-1). The herbage concentration of CP was either unaffected or decreased with increasing N application. The fourth-year swards showed DM yields comparable to first and third-year sward ages. In unfertilized swards, a linear relationship was found between the first cut in a given year and the fourth cut of the previous year (r2 = 0.82 within a range of autumn clover proportions of 33–74 %), indicating the possibility of using last cut for predicting next year's fertilizer requirements. The comprehensive data and results may form the basis for future modeling of optimal N application in organic grass-clover leys.

KW - Crude protein

KW - N yield

KW - Optimized N-fertilization

KW - Organic dairy rotation

KW - Protein content

KW - Sward age

U2 - 10.1016/j.fcr.2022.108675

DO - 10.1016/j.fcr.2022.108675

M3 - Journal article

AN - SCOPUS:85137279148

SN - 0378-4290

VL - 287

JO - Field Crops Research

JF - Field Crops Research

M1 - 108675

ER -