Volume 17, Issue 3 (10-2026)
2026, 17(3): 75-88 |
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1- Department of Soil Science, College of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran
2- Department of Soil Science, College of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran ,mhejazi@uk.ac.ir
2- Department of Soil Science, College of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran ,
Abstract: (591 Views)
Background and Objective: In calcareous soils of arid and semi-arid regions, knowledge of phosphorus (P) forms can be instrumental in optimizing the use of chemical fertilizers and reducing their detrimental effects on the environment. The aim of this study was to compare two methods of surface and subsurface application of different levels of triple superphosphate (TSP) and organic fertilizer (cow manure) on the forms of inorganic P in the subsurface layer (30–50 cm) of the soil.
Materials and Methods: The research was conducted as a randomized complete blocks design in a factorial arrangement with three replications. The fertilizer treatments included four levels of TSP (0, 200, 400, and 600 kg ha‒1) combined with two levels of cow manure (0 and 30 ton ha‒1), which were applied at two layers—surface (0–20 cm) and subsurface (30–50 cm) for four years under field conditions. At the end of the fourth year of fertilization, soil samples were taken from the 30–50 cm layer. Soil inorganic P forms were determined using the sequential extraction method, and available P was measured using NaHCO3 extraction (Olsen method).
Results: The results showed that in both fertilizer application methods, with and without cow manure, the soil available P increased with increasing fertilizer levels. Application of 600 kg ha‒1 TSP with cow manure notably increased soil available P by 41 and 42% in surface and subsurface applications, respectively. The results also indicated that in the 30–50 cm soil layer, only subsurface application caused a significant increase in labile P forms, including water-extractable P (by 70.4%) and NaHCO3-extractable P (by 78.3%) compared to the control. In contrast, in this sampling layer, surface application of TSP led to an increase in moderately labile and non-labile P forms.
Conclusion: The results of this study demonstrated that the fertilizer application method and knowledge of soil inorganic P fractions can provide a valuable tool for determining P availability for pistachio plants.
Materials and Methods: The research was conducted as a randomized complete blocks design in a factorial arrangement with three replications. The fertilizer treatments included four levels of TSP (0, 200, 400, and 600 kg ha‒1) combined with two levels of cow manure (0 and 30 ton ha‒1), which were applied at two layers—surface (0–20 cm) and subsurface (30–50 cm) for four years under field conditions. At the end of the fourth year of fertilization, soil samples were taken from the 30–50 cm layer. Soil inorganic P forms were determined using the sequential extraction method, and available P was measured using NaHCO3 extraction (Olsen method).
Results: The results showed that in both fertilizer application methods, with and without cow manure, the soil available P increased with increasing fertilizer levels. Application of 600 kg ha‒1 TSP with cow manure notably increased soil available P by 41 and 42% in surface and subsurface applications, respectively. The results also indicated that in the 30–50 cm soil layer, only subsurface application caused a significant increase in labile P forms, including water-extractable P (by 70.4%) and NaHCO3-extractable P (by 78.3%) compared to the control. In contrast, in this sampling layer, surface application of TSP led to an increase in moderately labile and non-labile P forms.
Conclusion: The results of this study demonstrated that the fertilizer application method and knowledge of soil inorganic P fractions can provide a valuable tool for determining P availability for pistachio plants.
Keywords: Inorganic phosphorus fractionation, Organic matter, Phosphorus Availability, Saline calcareous soil, Surface and sub-surface application.
Type of Article: Research |
Subject:
Availability of soil water and nutrients for plant
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Journal of Soil and Plant Interactions by http://jspi.iut.ac.ir is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
This work is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License which allows users to read, copy, distribute and make derivative works for non-commercial purposes from the material, as long as the author of the original work is cited properly.
This work is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License which allows users to read, copy, distribute and make derivative works for non-commercial purposes from the material, as long as the author of the original work is cited properly.
