Application of calcium nitrate with phosphorus promotes rhizosphere alkalization in acid subsoil

作者：Zhe Weng, Guangdi Li, P. W. G. Sale, Caixian Tang · 发表于：European Journal of Soil Science · 年份：2021 · DOI：10.1111/ejss.13153 · 被引用次数：14 · 研究领域：Plant nutrient uptake and metabolism、Clay minerals and soil interactions、Aluminum toxicity and tolerance in plants and animals

Abstract Combatting subsoil acidity is a challenge as the incorporation of lime in subsurface layers may not be economically feasible. The use of nitrate to facilitate plant excess anion uptake has shown the potential to increase soil pH. A column experiment was carried out to demonstrate this root‐induced alkalization in various depths in an acid soil with pH 4.28 (0.01 M CaCl 2 ). It consisted of two types of nitrogen (N) fertilizers (urea and Ca(NO 3 ) 2 , both at 5 atom% 15 N enrichment) banded at a depth of 0–10 cm, 10–20 cm or 20–30 cm, with phosphorus (P) fertilizer (NaH 2 PO 4 ) at 150 mg P per column either applied to the N layers (N+P) or evenly mixed into the remaining layers without N addition (N‐P). Aluminium‐tolerant wheat (ET8) was used as test plants, receiving an initial N dose of 60 mg kg −1 soil at sowing and an additional dose of 30 mg kg −1 every 10 days from 40 days after sowing. Plants had a total N supply of 90 mg N kg −1 at 50 days and 180 mg N kg −1 at 80 days after sowing. The N+P treatments increased plant N uptake and increased rhizosphere and bulk soil pH. Nitrate placement increased pH of treated layers by up to 0.4 and 0.2 units in the rhizosphere and bulk soils, respectively, compared with the control at Day 80. Rhizosphere alkalization was greater with deeper N+P treatments as these encouraged the proliferation of deeper roots in the treated layer. The form of N and the application method of P fertilizer had no effect on shoot biomass over 80...