The Effects of Different Tillage Techniques and N Fertilizer Rates on Nitrogen and Phosphorus in Dry Land Agriculture
Processes governing soil organic matter (SOM) decomposition and mineralization are important for soil fertility and ecosystem sustainability. However, in the sub-Saharan region, limited work has been conducted on SOM dynamics; therefore, there was an imperative need for this study. The objective of...
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| Format: | Article |
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MDPI AG
2022-10-01
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| Series: | Agronomy |
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| Online Access: | https://www.mdpi.com/2073-4395/12/10/2389 |
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| author | Bonginkosi S. Vilakazi Rebecca Zengeni Paramu Mafongoya |
| author_facet | Bonginkosi S. Vilakazi Rebecca Zengeni Paramu Mafongoya |
| author_sort | Bonginkosi S. Vilakazi |
| collection | DOAJ |
| description | Processes governing soil organic matter (SOM) decomposition and mineralization are important for soil fertility and ecosystem sustainability. However, in the sub-Saharan region, limited work has been conducted on SOM dynamics; therefore, there was an imperative need for this study. The objective of this study was to determine the phosphorus (P) and nitrogen (N) dynamics in soil under different tillage and fertilizer management practices. The field trial was arranged as a randomized split plot design, with tillage forming the whole plot and the fertilizer application rate being the sub-plot. The tillage techniques were no-till (NT), annual tillage (CT-ANNUAL) and conventional tillage every fifth season (CT-Y5), whereby NT was practiced for four consecutive seasons, and in the fifth season, conventional tillage was employed. For all these tillage techniques, urea fertilizer was applied in amounts of 60, 120 and 240 kg N ha<sup>−1</sup> with a control for each tillage treatment. Ammonium and nitrate levels were determined calorimetrically. Sulfuric acid, at 1 M, along with 0.057 M ascorbic acid and molybdate reagent were used to extract the organic P from the soil and extractable P. The total N, ammonium, total P, organic P and extractable P in the surface soil under NT were higher (<i>p</i> < 0.05) compared to the values of both CT-Y5 and CT-ANNUAL. The high levels of total N, N mineralization, total P, organic P and extractable P under NT, compared to CT-Y5 and CT-ANNUAL, at the depth of 0–10 cm may be attributed to the accumulation of crop residues on the surface and less soil disturbance. Furthermore, nitrate was found in higher (<i>p</i> < 0.05) concentrations under CT-ANNUAL compared to CT-Y5 at all the application rates and depths. The ploughing of soil under CT-ANNUAL improves the aeration, which accelerates the decomposition of organic material and mineralization of organic N and P into soluble forms. No-till, at 60 kg N ha<sup>−1</sup> and a 0–10 cm soil depth, had optimum total N, nitrate, ammonium, total P and organic P values, thus showing its salient impact on the maintenance of soil fertility. However, the conclusion drawn from this study is that CT-Y5, due to its average N and P pools, can be recommended to under-resourced farmers in sub-Saharan preferentially over both NT and CT-ANNUAL, because it does not require advanced technology and equipment and it sustains an average soil fertility. |
| first_indexed | 2024-03-09T20:53:45Z |
| format | Article |
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| language | English |
| last_indexed | 2024-03-09T20:53:45Z |
| publishDate | 2022-10-01 |
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| spelling | doaj.art-a05b8ae6c26c4003a5fd3072f763d6912023-11-23T22:26:18ZengMDPI AGAgronomy2073-43952022-10-011210238910.3390/agronomy12102389The Effects of Different Tillage Techniques and N Fertilizer Rates on Nitrogen and Phosphorus in Dry Land AgricultureBonginkosi S. Vilakazi0Rebecca Zengeni1Paramu Mafongoya2Department of Crop Sciences, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2790, South AfricaSchool of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal (UKZN), Private Bag X01, Scottsville 3209, South AfricaSchool of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal (UKZN), Private Bag X01, Scottsville 3209, South AfricaProcesses governing soil organic matter (SOM) decomposition and mineralization are important for soil fertility and ecosystem sustainability. However, in the sub-Saharan region, limited work has been conducted on SOM dynamics; therefore, there was an imperative need for this study. The objective of this study was to determine the phosphorus (P) and nitrogen (N) dynamics in soil under different tillage and fertilizer management practices. The field trial was arranged as a randomized split plot design, with tillage forming the whole plot and the fertilizer application rate being the sub-plot. The tillage techniques were no-till (NT), annual tillage (CT-ANNUAL) and conventional tillage every fifth season (CT-Y5), whereby NT was practiced for four consecutive seasons, and in the fifth season, conventional tillage was employed. For all these tillage techniques, urea fertilizer was applied in amounts of 60, 120 and 240 kg N ha<sup>−1</sup> with a control for each tillage treatment. Ammonium and nitrate levels were determined calorimetrically. Sulfuric acid, at 1 M, along with 0.057 M ascorbic acid and molybdate reagent were used to extract the organic P from the soil and extractable P. The total N, ammonium, total P, organic P and extractable P in the surface soil under NT were higher (<i>p</i> < 0.05) compared to the values of both CT-Y5 and CT-ANNUAL. The high levels of total N, N mineralization, total P, organic P and extractable P under NT, compared to CT-Y5 and CT-ANNUAL, at the depth of 0–10 cm may be attributed to the accumulation of crop residues on the surface and less soil disturbance. Furthermore, nitrate was found in higher (<i>p</i> < 0.05) concentrations under CT-ANNUAL compared to CT-Y5 at all the application rates and depths. The ploughing of soil under CT-ANNUAL improves the aeration, which accelerates the decomposition of organic material and mineralization of organic N and P into soluble forms. No-till, at 60 kg N ha<sup>−1</sup> and a 0–10 cm soil depth, had optimum total N, nitrate, ammonium, total P and organic P values, thus showing its salient impact on the maintenance of soil fertility. However, the conclusion drawn from this study is that CT-Y5, due to its average N and P pools, can be recommended to under-resourced farmers in sub-Saharan preferentially over both NT and CT-ANNUAL, because it does not require advanced technology and equipment and it sustains an average soil fertility.https://www.mdpi.com/2073-4395/12/10/2389conventional tillageammoniumnitrateno-tillorganic P |
| spellingShingle | Bonginkosi S. Vilakazi Rebecca Zengeni Paramu Mafongoya The Effects of Different Tillage Techniques and N Fertilizer Rates on Nitrogen and Phosphorus in Dry Land Agriculture Agronomy conventional tillage ammonium nitrate no-till organic P |
| title | The Effects of Different Tillage Techniques and N Fertilizer Rates on Nitrogen and Phosphorus in Dry Land Agriculture |
| title_full | The Effects of Different Tillage Techniques and N Fertilizer Rates on Nitrogen and Phosphorus in Dry Land Agriculture |
| title_fullStr | The Effects of Different Tillage Techniques and N Fertilizer Rates on Nitrogen and Phosphorus in Dry Land Agriculture |
| title_full_unstemmed | The Effects of Different Tillage Techniques and N Fertilizer Rates on Nitrogen and Phosphorus in Dry Land Agriculture |
| title_short | The Effects of Different Tillage Techniques and N Fertilizer Rates on Nitrogen and Phosphorus in Dry Land Agriculture |
| title_sort | effects of different tillage techniques and n fertilizer rates on nitrogen and phosphorus in dry land agriculture |
| topic | conventional tillage ammonium nitrate no-till organic P |
| url | https://www.mdpi.com/2073-4395/12/10/2389 |
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