Growth of Corn Roots and Associated Arbuscular Mycorrhizae Are Affected by Long‐Term Tillage and Phosphorus Fertilization

Abstract

Phosphorus defi ciency is a major constraint for corn (Zea mays L.) production. Cropping practices, such as tillage, modify corn P absorption, but the underlying mechanism must be assessed. A study was conducted at a long-term (18-yr) experimental site in Quebec, Canada, to evaluate the eff ects of tillage and P fertilization on arbuscular mycorrhizal (AM) fungi, soil properties, root attributes, corn growth, and corn P concentration. Soil (0-10 cm) and plant samples were collected at the 8 to 10 leaf stage from plots under moldboard plow (MP) and no till (NT) fertilized with 0, 17.5, or 35 kg P ha -1 . Tillage increased soil bulk density, vesicular colonization, shoot and root biomass, root surface area, average diameter, volume, total root length density, and the percentage of medium-sized roots; it decreased total soil C and N concentrations, specifi c root length, percentage of fi ne roots, and arbuscular and total AM fungal colonization. Phosphorus fertilization reduced total AM fungal colonization, enhanced soil Mehlich-3 P level, total root length density, and the percentage of fi ne roots. Corn shoot and root P concentrations, reduced by tillage, were positively correlated with the percentage of fi ne roots and arbuscular colonization, but negatively correlated with vesicular colonization and the percentage of medium-sized roots. Overall, P fertilization reduced total AM fungal colonization and increased root length density, and tillage decreased arbuscular development in roots and fi ne root growth in soil resulting in the low corn P concentration.

Influence of phosphorus and biofertilizers on soybean and wheat root growth and properties

“…Grain the increase of RLD with inoculation of both biofertilizers with 50% P. The enhancement of RLD with application and better nutrition of P has been widely reported (Jaidee et al, 2013;Sheng et al, 2012;Suri and Choudhary, 2013;Teng et al, 2013). Soybean crop at flower initiation stage produced roots with low average diameter in PSB + VAM and control plots, which was due to the increase in number of root hairs resulted from P deficiency (Caroll et al, 2003).…”

The long-term effects of tillage practice and phosphorus fertilization on the distribution and morphology of corn root

“…The roots recovered on the secondary sieve were selected by hand to remove the remaining mineral particles and organic debris. Next, the roots were rinsed and placed on a transparent tray with distilled water, dispersed with tweezers and scanned in black and white (400 dpi, tagged image file format [TIF], white background) using the Imagery Scan Screen (EPSON Expression 10000XL) (Sheng et al 2012 (Drouet and Pagès 2003;Sheng et al 2012). After scanning, the roots were dried with paper towels for fresh weight.…”

Field and lab conditions alter microbial enzyme and biomass dynamics driving decomposition of the same leaf litter

“…Coupled field and microcosm experiments demonstrate that field soils behave differently following disturbance (Teuben and Verhoef, 1992; Salamanca et al, 1998), primarily due to alterations in microbial community abundance, activity and composition. It is possible that soil collection decreased saprophytic fungal abundance (Coleman et al, 1988) and/or disrupted the N- and P-transporting mycelial network of mycorrhizae, likely increasing enzymatic effort to obtain nutrients from organic sources (Hart and Reader, 2004; Sheng et al, 2012). For instance, there is often an inverse relationship between total enzyme pool size and fungal biomass (Sinsabaugh et al, 2002).…”