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- Title
Rhizosphere dynamics under nitrogen-induced root modification: The interaction of phosphorus and calcium.
- Authors
Makhani, Mitalie; Isaac, Marney E.
- Abstract
Optimizing root phosphorus (P) acquisition to reduce intensive fertilizer use is a crucial pathway for sustainable agriculture, particularly as P is an important plant macronutrient, often limiting in a majority of soils worldwide. Although many studies have assessed plant growth and P acquisition, few studies have investigated the interactive effects of nitrogen (N)-induced root modification on soil P processes or the understudied effects of soil calcium (Ca) dynamics on soil P bioavailability. In this study, we investigate soil P and Ca response in the rhizosphere of durum wheat ( Triticum turgidum L. spp. durum). Wheat grown under controlled conditions preloaded for 20 d with two N treatments [preloaded low N (1 mmol KNO3 plant−1) and preloaded high N (2 mmol KNO3 plant−1)] were transferred to rhizoboxes for 12 d [days after transfer (DAT)]. Shoot and root biomass, P and Ca concentration, and plant-available P and extractable Ca were determined every three days (0, 3, 6, 9, 12 DAT). Significantly higher root mass ( P = 0.7%), root length ( P = 1.8%) and total biomass ( P = 2.2%) were found at the end of the experiment but exclusively for high N preloaded wheat. This greater root biomass was associated with lower root P concentration, suggesting a dilution response, while little difference was observed in shoot P concentration over the 12 d. However, Ca accumulated in both roots and shoots under both preloading N levels. Concurrently, soil-extractable Ca declined, and plant-available P increased ( r = -0.62; P = 0.03%), presumably due to a promoting effect of Ca uptake on soil P availability; lower soil Ca in turn increased the repulsive forces between P ions and the negatively charged soil surface, resulting in an increased P availability in the soil solution. This study contributes to the understanding of the complex interplay between multi-nutrient dynamics within the rhizosphere.
- Subjects
RHIZOSPHERE; PLANT roots; PLANT growth; CALCIUM in soils; PHOSPHORUS in soils
- Publication
Journal of Plant Nutrition & Soil Science, 2014, Vol 177, Issue 4, p624
- ISSN
1436-8730
- Publication type
Article
- DOI
10.1002/jpln.201300381