Environmental Impact of Rotationally Grazed Pastures at Different Management Intensities in South Africa
Nitrogen fertilization, irrigation and concentrate feeding are important factors in rotational pasture management for dairy farms in South Africa. The extent to which these factors affect environmental efficiency is subject to current and intense debate among scientists. A three-year field study was...
Main Authors: | , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2021-04-01
|
Series: | Animals |
Subjects: | |
Online Access: | https://www.mdpi.com/2076-2615/11/5/1214 |
id |
doaj-4edc20a4c834404d814fcb988c2f418b |
---|---|
record_format |
Article |
spelling |
doaj-4edc20a4c834404d814fcb988c2f418b2021-04-22T23:07:01ZengMDPI AGAnimals2076-26152021-04-01111214121410.3390/ani11051214Environmental Impact of Rotationally Grazed Pastures at Different Management Intensities in South AfricaHendrik P. J. Smit0Thorsten Reinsch1Pieter A. Swanepoel2Ralf Loges3Christof Kluß4Friedhelm Taube5Institute of Crop Science and Plant Breeding, Grass and Forage Science/Organic Agriculture, Christian-Albrechts-University Kiel, D-24118 Kiel, GermanyInstitute of Crop Science and Plant Breeding, Grass and Forage Science/Organic Agriculture, Christian-Albrechts-University Kiel, D-24118 Kiel, GermanyDepartment of Agronomy, Stellenbosch University, Stellenbosch 7600, South AfricaInstitute of Crop Science and Plant Breeding, Grass and Forage Science/Organic Agriculture, Christian-Albrechts-University Kiel, D-24118 Kiel, GermanyInstitute of Crop Science and Plant Breeding, Grass and Forage Science/Organic Agriculture, Christian-Albrechts-University Kiel, D-24118 Kiel, GermanyInstitute of Crop Science and Plant Breeding, Grass and Forage Science/Organic Agriculture, Christian-Albrechts-University Kiel, D-24118 Kiel, GermanyNitrogen fertilization, irrigation and concentrate feeding are important factors in rotational pasture management for dairy farms in South Africa. The extent to which these factors affect environmental efficiency is subject to current and intense debate among scientists. A three-year field study was conducted to investigate the yield response of different N-fertilizer treatments (0 (N0), 220 (N20), 440 (N40), 660 (N60) and 880 (N80) kg N ha<sup>−1</sup> year<sup>−1</sup>) on grazed pastures and to calculate the carbon footprint (CF) of milk produced. Excessive N-fertilization (N60 and N80) did not increase herbage dry matter and energy yields from pastures. However, N80 indicated the highest N-yield but at the same time also the highest N surpluses at field level. A maximum fertilizer rate of 220 kg ha<sup>−1</sup> year<sup>−1</sup> (in addition to excreted N from grazing animals) appears sufficient to ensure adequate herbage yields (~20 t DM ha<sup>−1 </sup>year<sup>−1</sup>) with a slightly positive field-N-balance. This amount will prevent the depletion of soil C and N, with low N losses to the environment, where adequate milk yields of ~17 t ECM ha<sup>−1</sup> with a low CF (~1.3 kg CO<sub>2</sub> kg ECM<sup>−1</sup>) are reached. Methane from enteric fermentation (~49% ± 3.3) and N<sub>2</sub>O (~16% ± 3.2) emissions from irrigated pastures were the main contributors to the CF. A further CF reduction can be achieved by improved N-fertilization planning, low emission irrigation techniques and strategies to limit N<sub>2</sub>O emissions from pasture soils in South Africa.https://www.mdpi.com/2076-2615/11/5/1214farm-N-balancecarbon footprintdairygreenhouse gassustainable agriculture |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Hendrik P. J. Smit Thorsten Reinsch Pieter A. Swanepoel Ralf Loges Christof Kluß Friedhelm Taube |
spellingShingle |
Hendrik P. J. Smit Thorsten Reinsch Pieter A. Swanepoel Ralf Loges Christof Kluß Friedhelm Taube Environmental Impact of Rotationally Grazed Pastures at Different Management Intensities in South Africa Animals farm-N-balance carbon footprint dairy greenhouse gas sustainable agriculture |
author_facet |
Hendrik P. J. Smit Thorsten Reinsch Pieter A. Swanepoel Ralf Loges Christof Kluß Friedhelm Taube |
author_sort |
Hendrik P. J. Smit |
title |
Environmental Impact of Rotationally Grazed Pastures at Different Management Intensities in South Africa |
title_short |
Environmental Impact of Rotationally Grazed Pastures at Different Management Intensities in South Africa |
title_full |
Environmental Impact of Rotationally Grazed Pastures at Different Management Intensities in South Africa |
title_fullStr |
Environmental Impact of Rotationally Grazed Pastures at Different Management Intensities in South Africa |
title_full_unstemmed |
Environmental Impact of Rotationally Grazed Pastures at Different Management Intensities in South Africa |
title_sort |
environmental impact of rotationally grazed pastures at different management intensities in south africa |
publisher |
MDPI AG |
series |
Animals |
issn |
2076-2615 |
publishDate |
2021-04-01 |
description |
Nitrogen fertilization, irrigation and concentrate feeding are important factors in rotational pasture management for dairy farms in South Africa. The extent to which these factors affect environmental efficiency is subject to current and intense debate among scientists. A three-year field study was conducted to investigate the yield response of different N-fertilizer treatments (0 (N0), 220 (N20), 440 (N40), 660 (N60) and 880 (N80) kg N ha<sup>−1</sup> year<sup>−1</sup>) on grazed pastures and to calculate the carbon footprint (CF) of milk produced. Excessive N-fertilization (N60 and N80) did not increase herbage dry matter and energy yields from pastures. However, N80 indicated the highest N-yield but at the same time also the highest N surpluses at field level. A maximum fertilizer rate of 220 kg ha<sup>−1</sup> year<sup>−1</sup> (in addition to excreted N from grazing animals) appears sufficient to ensure adequate herbage yields (~20 t DM ha<sup>−1 </sup>year<sup>−1</sup>) with a slightly positive field-N-balance. This amount will prevent the depletion of soil C and N, with low N losses to the environment, where adequate milk yields of ~17 t ECM ha<sup>−1</sup> with a low CF (~1.3 kg CO<sub>2</sub> kg ECM<sup>−1</sup>) are reached. Methane from enteric fermentation (~49% ± 3.3) and N<sub>2</sub>O (~16% ± 3.2) emissions from irrigated pastures were the main contributors to the CF. A further CF reduction can be achieved by improved N-fertilization planning, low emission irrigation techniques and strategies to limit N<sub>2</sub>O emissions from pasture soils in South Africa. |
topic |
farm-N-balance carbon footprint dairy greenhouse gas sustainable agriculture |
url |
https://www.mdpi.com/2076-2615/11/5/1214 |
work_keys_str_mv |
AT hendrikpjsmit environmentalimpactofrotationallygrazedpasturesatdifferentmanagementintensitiesinsouthafrica AT thorstenreinsch environmentalimpactofrotationallygrazedpasturesatdifferentmanagementintensitiesinsouthafrica AT pieteraswanepoel environmentalimpactofrotationallygrazedpasturesatdifferentmanagementintensitiesinsouthafrica AT ralfloges environmentalimpactofrotationallygrazedpasturesatdifferentmanagementintensitiesinsouthafrica AT christofkluß environmentalimpactofrotationallygrazedpasturesatdifferentmanagementintensitiesinsouthafrica AT friedhelmtaube environmentalimpactofrotationallygrazedpasturesatdifferentmanagementintensitiesinsouthafrica |
_version_ |
1721513654128476160 |