2 research outputs found
Nostoc cyanobacterial inoculation in South African agricultural soils enhances soil structure, fertility, and maize growth
13 pages, figures, and tables statistics.Many soils in South Africa have low nutrient
supply, poor structural stability and are prone to soil
erosion due to susceptibility to surface sealing and
crusting. Two crusting soils from the Eastern Cape
Province, South Africa were used to evaluate the effects
of inoculation with a strain of Nostoc on soil structure,
fertility and maize growth. The Nostoc suspension was
uniformly applied over potted soils at a rate of 6g (dry
weight) per square meter soon after maize germination.
Nostoc inoculation increased soil N by 17% and 40%
in Hertzog and Guquka soils, respectively. Soil C was
also increased significantly and this increase was
strongly associated with that of soil N (R2 = 0.838).
The highest contents of soil C, soil N and mineral N,
however, were found in non-cropped Nostoc inoculated
soils. Nostoc inoculation increased maize dry matter
yields by 49% and 40% in Hertzog and Guquka soils,
respectively. Corresponding increases in maize tissue
N were 23% and 14%, respectively. Scanning electron
microscopy (SEM) revealed that soil particles and
fragments of non-cropped inoculated soils had coatings
of extracellular polymeric substances (EPS) with other
particles enmeshed in networks of filaments, whilst by
contrast little or no EPS and/or filaments were observed
on cropped and/or non-inoculated soils. This
was consistent with chemical analysis which showed
that Nostoc caused significant increases in the EPS and
soil C contents of non-cropped soils. The proportion of
very stable aggregates was increased by inoculation
with Nostoc possibly due to the greater quantities of
soil C and EPS observed in inoculated soils. Inoculated
soils cropped with maize had a lower proportion of
stable aggregates presumably due to their low soil C
and EPS contents compared to non-cropped soils. The
results suggested that Nostoc could improve the fertility
and structural stability of the studied degraded soils.This work was part of an EU, INCODEV funded research programme in Southern Africa (Cyanosoils),
Project ICA4-CT-2001-10058.Peer reviewe