Land use and soil organic matter in South Africa 2: A review on the influence of arable crop production
The decline of soil organic matter as a result of agricultural land use was identified for a review with the ultimate aim of developing a soil protection strategy and policy for South Africa. Such a policy is important because organic matter, especially the humus fraction, influences the characteri...
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| Format: | Article |
| Language: | English |
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Academy of Science of South Africa
2011-05-01
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| Series: | South African Journal of Science |
| Subjects: | |
| Online Access: | http://archive.sajs.co.za/index.php/SAJS/article/view/358 |
| _version_ | 1811260005986336768 |
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| author | Chris C. du Preez Cornie W. van Huyssteen Pearson N.S. Mnkeni |
| author_facet | Chris C. du Preez Cornie W. van Huyssteen Pearson N.S. Mnkeni |
| author_sort | Chris C. du Preez |
| collection | DOAJ |
| description | The decline of soil organic matter as a result of agricultural land use was identified for a review with the ultimate aim of developing a soil protection strategy and policy for South Africa. Such a policy is important because organic matter, especially the humus fraction, influences the characteristics of soil disproportionately to the quantities thereof present. Part 1 of this review dealt with the spatial variability of soil organic matter and the impact of grazing and burning under rangeland stock production. In this second part of the review, the impact of arable crop production on soil organic matter is addressed. A greater number of studies have addressed the degradation of soil organic matter that is associated with arable crop production than the restoration. However, cropping under dryland has been found to result in significant losses of soil organic matter, which is not always the case with cropping under irrigation. Restoration of soil organic matter has been very slow upon the introduction of conservational practices like zero tillage, minimal tillage, or mulch tillage. Reversion of cropland to perennial pasture has also been found to result in discouragingly slow soil organic matter restoration. Although increases or decreases in soil organic matter levels have occurred in the upper 300 mm, in most instances this took place only in the upper 50 mm. The extent of these changes was dependent inter alia on land use, soil form and environmental conditions. Loss of soil organic matter has resulted in lower nitrogen and sulphur reserves, but not necessarily lower phosphorus reserves. Depletion of soil organic matter coincided with changes in the composition of amino sugars, amino acids and lignin. It also resulted in a decline of water stable aggregates which are essential in the prevention of soil erosion. Although much is known about how arable crop production affects changes in soil organic matter, there are still uncertainties about the best management practices to maintain and even restore organic matter in degraded cropland. Coordinated long-term trials on carefully selected ecotopes across the country are therefore recommended to investigate cultivation practices suitable for this purpose. |
| first_indexed | 2024-04-12T18:41:03Z |
| format | Article |
| id | doaj.art-f2357e2e4f0e4aedb0bad51a20150aaa |
| institution | Directory Open Access Journal |
| issn | 0038-2353 1996-7489 |
| language | English |
| last_indexed | 2024-04-12T18:41:03Z |
| publishDate | 2011-05-01 |
| publisher | Academy of Science of South Africa |
| record_format | Article |
| series | South African Journal of Science |
| spelling | doaj.art-f2357e2e4f0e4aedb0bad51a20150aaa2022-12-22T03:20:47ZengAcademy of Science of South AfricaSouth African Journal of Science0038-23531996-74892011-05-011075/610.4102/sajs.v107i5/6.358358Land use and soil organic matter in South Africa 2: A review on the influence of arable crop productionChris C. du Preez0Cornie W. van Huyssteen1Pearson N.S. Mnkeni2Department of Soil, Crop and Climate Sciences, University of the Free StateDepartment of Soil, Crop and Climate Sciences, University of the Free StateDepartment of Agronomy, University of Fort HareThe decline of soil organic matter as a result of agricultural land use was identified for a review with the ultimate aim of developing a soil protection strategy and policy for South Africa. Such a policy is important because organic matter, especially the humus fraction, influences the characteristics of soil disproportionately to the quantities thereof present. Part 1 of this review dealt with the spatial variability of soil organic matter and the impact of grazing and burning under rangeland stock production. In this second part of the review, the impact of arable crop production on soil organic matter is addressed. A greater number of studies have addressed the degradation of soil organic matter that is associated with arable crop production than the restoration. However, cropping under dryland has been found to result in significant losses of soil organic matter, which is not always the case with cropping under irrigation. Restoration of soil organic matter has been very slow upon the introduction of conservational practices like zero tillage, minimal tillage, or mulch tillage. Reversion of cropland to perennial pasture has also been found to result in discouragingly slow soil organic matter restoration. Although increases or decreases in soil organic matter levels have occurred in the upper 300 mm, in most instances this took place only in the upper 50 mm. The extent of these changes was dependent inter alia on land use, soil form and environmental conditions. Loss of soil organic matter has resulted in lower nitrogen and sulphur reserves, but not necessarily lower phosphorus reserves. Depletion of soil organic matter coincided with changes in the composition of amino sugars, amino acids and lignin. It also resulted in a decline of water stable aggregates which are essential in the prevention of soil erosion. Although much is known about how arable crop production affects changes in soil organic matter, there are still uncertainties about the best management practices to maintain and even restore organic matter in degraded cropland. Coordinated long-term trials on carefully selected ecotopes across the country are therefore recommended to investigate cultivation practices suitable for this purpose.http://archive.sajs.co.za/index.php/SAJS/article/view/358amino sugarconservational tillageorganic nitrogenperennial pasturesoil form |
| spellingShingle | Chris C. du Preez Cornie W. van Huyssteen Pearson N.S. Mnkeni Land use and soil organic matter in South Africa 2: A review on the influence of arable crop production South African Journal of Science amino sugar conservational tillage organic nitrogen perennial pasture soil form |
| title | Land use and soil organic matter in South Africa 2: A review on the influence of arable crop production |
| title_full | Land use and soil organic matter in South Africa 2: A review on the influence of arable crop production |
| title_fullStr | Land use and soil organic matter in South Africa 2: A review on the influence of arable crop production |
| title_full_unstemmed | Land use and soil organic matter in South Africa 2: A review on the influence of arable crop production |
| title_short | Land use and soil organic matter in South Africa 2: A review on the influence of arable crop production |
| title_sort | land use and soil organic matter in south africa 2 a review on the influence of arable crop production |
| topic | amino sugar conservational tillage organic nitrogen perennial pasture soil form |
| url | http://archive.sajs.co.za/index.php/SAJS/article/view/358 |
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