Ion Gradients and Nitrification Associated with Decomposition of a Plant Material Layer in Soil

Smith, J.H. and Burns, G.R. (1965) Ion Gradients and Nitrification Associated with Decomposition of a Plant Material Layer in Soil. Soil Science Society of America Proceedings. 29(2):179-181.

PDF 40.pdf Download (208kB)

Abstract

Changes in the pH and in concentrations of ammonia, NO₂-,
NO₃-, and K⁺ with distance from layers of decomposing leguminous
plant material in Red Bay sandy loam soil were measured
after 16 days' incubation. High concentrations of ammonia
(2.7 meq/100 g) and of K⁺ (1.4 meq/100 g) were found near
the plant material layer. Nitrification was inhibited and NO₂-
was found in this zone. Farther away, NO₃- accumulated. A
change in pH from 8.9, near the layer, to 5.6, about 4 cm away,
was observed. Treatment with CaCO₃ decreased the pH range
and increased nitrification. When the decomposing plant material
layer was separated from the soil on one side by an air
space, NH₃ diffused across the air space. This resulted in segregation
of some of the NH₃ from the cations and other potentially
toxic substances and lowered the overall toxicity to nitrification.
Besides the toxicity observed, the availability of plant
nutrients as well as growth of microorganisms and plant roots
could be drastically affected by pH and cation concentration
changes found near layers of decomposing plant material.

Item Type:	Article
NWISRL Publication Number:	0040
Subjects:	Soil > Chemistry > Nitrogen Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:52
Last Modified:	15 Mar 2017 22:47
Item ID:	340
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/340