Aggregation‐dependent phosphorus adsorption under different land uses of district Kupwara of Kashmir Valley

Abstract

AbstractBackgroundPhosphorus (P) is among the essential elements for plant growth and one of the main elements of fertilizers. Decreased availability of P may limit agricultural production in the coming years. The magnitude of soil aggregation influences phosphorus access to mineral surfaces.AimThe present study aims to determine phosphorus adsorption processes affected by soil aggregation under different land‐use systems.MethodsThe distribution of soil aggregates was determined in representative soil samples in the district Kupwara of Kashmir Valley in India. To predict the phosphorus fertilizer requirement of a particular soil, we used the Freundlich adsorption equation and Langmuir equation and drew a clear comparison between these two models.Results and discussionMaximum phosphorus (P) adsorption was recorded at the smallest aggregate size, 0.5–0.1 mm. However, soil aggregates >2.0 mm (the largest category) adsorbed the least amount of P. Our results revealed that increasing the addition of P to the soil decreased the percentage of adsorbed P regardless of aggregate size. The maximum P adsorption of different size aggregates varied between 1869–1924, 1872–1900, 1718–1739, and 1800–1890 mg P kg–1 in irrigated agriculture, forest, orchard and rainfed agriculture soils, respectively. The variation in P adsorption parameters across the different land uses was attributed to their mean weight diameter difference. The maximum bonding energy in the forest resulted in higher P adsorption. Langmuir and Freundlich's adsorption equations were fitted to each soil aggregate size and land‐use system.ConclusionOur results revealed that for all soil aggregate sizes and land use systems, the Freundlich adsorption equation performs better than the Langmuir equation.