Water Regime Modulates Extractable Phosphorus Redistribution Under Liquid and Solid Phosphorus Fertilization in High-P Alkaline Calcareous Soil
Year: 2026
Type: article
Abstract: In alkaline soils rich in residual phosphorus, phosphorus availability to plants depends not only on the existing reserve, but also on the redistribution of the extractable fraction within the root-explored zone. This study evaluated the effects of water regime, fertilizer treatment, and wheat presence on the distribution of ammonium lactate-extractable phosphorus (P-AL) within the 2–8 cm layer of an alkaline calcareous Chernozem with high initial P availability (P-AL = 178.1 mg kg−1). The pot experiment compared plant-free soil (S0) and wheat-planted soil (SP), four water regimes (H0–H150; 0–150 L m−2), and four fertilization treatments: an unfertilized control (F0), a solid NPK fertilizer (FS), and a liquid NP fertilizer applied at low and high rates (FL1 and FL2). These treatments represented practical fertilization options and were not equivalent in P input, supplying 51.8, 13.9, and 27.9 mg P pot−1 for FS, FL1, and FL2, respectively. Soil and plant samples were collected at BBCH 21–22, 20 days after fertilization. Water regime was a major factor shaping P-AL redistribution, significantly affecting P-AL at all three analyzed soil depths (p < 0.001), with its effect depending on vegetation condition and fertilization treatment. Wheat presence reduced P-AL relative to S0, and apparent P-AL depletion (ΔP-AL = S0 − SP) was greatest under H0, ranging from 83 to 99 mg kg−1. FL2 produced the largest S0–SP contrasts under H0–H100, whereas under H150 the largest difference was associated with FS. Under high water input, the higher-input solid NPK treatment (FS), which supplied the largest P input and was the only treatment supplying K, was associated with the highest shoot biomass (16.7 g), root biomass (6.92 g), and root P accumulation (25.2 mg pot−1). The results indicate that P fertilization in high-P alkaline soils should be adapted to water regime, fertilizer input and application method, without allowing for direct conclusions regarding phosphorus use efficiency, total plant P uptake, or leaching losses.
Source: Agronomy
Language: English
Subfield: Soil Science
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W7204112075