Depletion of macro-nutrients from rhizosphere soil solution by juvenile corn, cottonwood, and switchgrass plants

• Published in: Plant and soil Vol. 270; no. 1-2; pp. 213 - 221
• Main Authors: Wang, Z.Y, Kelly, J.M, Kovar, J.L
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01-08-2007; Springer Nature B.V
• Subjects: Acid soils; Agronomy. Soil science and plant productions; Biological and medical sciences; biomass; calcium; Chemistry; Corn; Efficiency; Forest soils; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; grasses; Heterogeneity; magnesium; Nutrient concentrations; Nutrient content; Nutrient dynamics; Nutrient status; Nutrient uptake; Nutrient utilization; Panicum virgatum; phosphorus; Plant nutrition; Plant roots; Plant species; Plants; Populus; Populus deltoides; potassium; Rhizosphere; Roots; Soil chemistry; Soil nutrients; Soil solution; soil-plant interactions; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soils; Solution chemistry; Surface water; Vegetables; Zea mays; Monocotyledones; Panicum virgatum L; C4-Type; Inorganic element; Cereal crop; Populus deltoides; mini-rhizotron; Gramineae; Dicotyledones; Angiospermae; Populus deltoids L; Hardwood forest tree; Soil solution; Minirhizotron; Zea mays; Root; Nutrient recovery; root morphology; Forest tree; Woody plant; Panicum virgatum; Salicaceae; Rhizosphere; Depletion; Decrease; Morphology; Vegetative apparatus; nutrient efficiency; Spermatophyta; Fodder crop; Soil plant relation; Zea mays L
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-004-1538-z

In situ sampling of rhizosphere solution chemistry is an important step in improving our understanding of soil solution nutrient dynamics. Improved understanding will enhance our ability to model nutrient dynamics and on a broader scale, to develop effective buffers to minimize nutrient movement to surface waters. However, only limited attention has been focused on the spatial heterogeneity and temporal dynamics of rhizosphere solution, and still less is known about how rhizosphere solution chemistry varies among plant species. Nutrients in rhizosphere soil solution and changes in root morphology of juvenile corn (Zea mays L. cv. Stine 2250), cottonwood (Populus deltoids L.), and switchgrass (Panicum virgatum L.) were monitored using mini-rhizotron technology. Plants were grown for 10 days in a fine-silty, mixed, superactive, mesic Cumulic Hapludoll (Kennebec series). Micro-samples (100-200 μL) of rhizosphere and bulk soil solution were collected at 24-h intervals at a tension of -100 kPa and analyzed for P, K, Ca, and Mg concentration using Capillary Electrophoresis techniques. Plants were harvested at the end of the 10-day period, and tissue digests analyzed for nutrient content by Inductively Coupled Plasma Spectroscopy. Corn plants produced roots that were 1.3 times longer than those of cottonwood, and 11.7 times longer than those of switchgrass. Similar trends were observed in number of root tips and root surface area. At the end of 10 days, rhizosphere solution P and K concentrations in the immediate vicinity of the roots (<1 mm) decreased by approximating 24 and 8% for corn, and 15 and 5% for cottonwood. A rhizosphere effect was not found for switchgrass. After correction for initial plant nutrient content, corn shoot P, K, and Mg were respectively 385, 132, and 163% higher than cottonwood and 66, 37, and 10% higher than switchgrass. Cottonwood shoot Ca concentration, however, was 68 to 133% higher than that of corn or switchgrass. There was no difference in root P concentration among the three species. Nutrient accumulation efficiency (μg nutrient mm-1 root length) of cottonwood was 26 to 242% higher for P, 25 to 325% higher for Ca, and 41 to 253% higher for Mg than those of corn and switchgrass. However, K accumulation efficiency of corn was four to five times higher than that of the cottonwood and switchgrass. Nutrient utilization efficiency (mg of dry weight produced per mg nutrient uptake) of P, K, and Mg was higher in cottonwood than in corn and switchgrass. These differences are element-specific and depend on root production and morphology as well as plant nutrient status. From a practical perspective, the results of this study indicate that potentially significant differences in rhizosphere solution chemistry can develop quickly. Results also indicate that cottonwood would be an effective species to slow the loss of nutrients in buffer settings.