Agronomic and financial benefits of direct Minjingu phosphate rock use in acidic humic nitisols of Upper Eastern Kenya
A major constraint to crop production in Sub-Saharan Africa is nutrient deficiency, especially phosphorus (P) deficiency. Phosphorus plays a crucial role in photosynthesis but is usually deficient in acidic soils since it is converted to less available forms, affecting crop yields. There is a need t...
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| Autores principales: | , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Elsevier
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/a163960e58d2468987fac4df5a913a64 |
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| Sumario: | A major constraint to crop production in Sub-Saharan Africa is nutrient deficiency, especially phosphorus (P) deficiency. Phosphorus plays a crucial role in photosynthesis but is usually deficient in acidic soils since it is converted to less available forms, affecting crop yields. There is a need to improve phosphorus availability to crops for maximum production. This study assessed Minjingu phosphate rock fertilizer's impact on maize yields, soil chemical composition, and cost-effectiveness in acidic humic nitisols of Tharaka Nithi County, Upper Eastern Kenya. A field experiment in a randomized complete block design (RCBD) was set during long rains (SR2017) and Short rains (LR2018) seasons. The treatments were Minjingu phosphate rock, manure, Tithonia diversifolia, Minjingu phosphate rock + manure, Tithonia diversifolia + Minjingu phosphate rock, Calcium Ammonium Nitrate (CAN) + Triple Superphosphate (TSP), and a control. Soil samples were collected at a depth of 0–20 cm before and at the end of the experiment for pH, P-sorption, and other soil nutrient determinations. Other auxiliary data collected included labor and input costs besides output prices. The CAN+TSP treatment had significantly higher grain yields (6.86 Mg ha-1), while Minjingu phosphate rock on its own had the second-lowest than the control treatment (3.0 Mg ha-1). Also, a similar trend in the stover yields was observed. Minjingu phosphate rock combined with either manure or Tithonia diversifolia led to a significant increase (over 100%) in the phosphorous levels. Sole application of Minjingu phosphate rock increased soil iron levels while magnesium, copper, and zinc levels decreased significantly. Other than the control, all treatments significantly lowered the P-sorption levels. However, CAN+TSP had the highest P-sorption (913 mg kg−1)while Tithonia diversifolia had the lowest (744 mg kg−1). During the LR2018 season, all treatments reached a break-even point, and the net benefit was significantly higher at P < 0.05. Conclusively, the use of phosphate rock, either solely or in combination with organic elements, improved yields, soil chemical composition, P-sorption and was very cost-effective. |
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