Improving soil fertility through dual inoculation with arbuscular mycorrhizal fungi and Rhizobium on a eutric cambisol cultivated with forage legumes in a semi-arid region
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Date
2024
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Journal ISSN
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Publisher
ScienceDirect
Abstract
The Sub-Saharan region of southern Africa is characterized by high temperatures, low rainfall,
and poor land-use management practices such as continuous cropping without replenishment of
soil nutrients. The combination of these factors has resulted in nutrient depletion and land
degradation. The current study aimed at investigating the effect of arbuscular mycorrhizal fungi
(AMF) and Rhizobium bacteria inoculation on soil chemical properties in field-grown forage le gumes, namely, Mucuna pruriens (mucuna), Lablab purpureus (lablab) and Vigna unguiculata
(cowpea), in the semi-arid region of the Eastern Cape Province (South Africa). Forage legumes
were inoculated with the AMF species Paraglomus occulum and the Rhizobia bacteria species
Bradyrhizobium strain and grown for 120 days. Soil samples were collected in the following
sequence: prior to planting, before flowering and after harvesting the forage legumes in each of
the two seasons (2017/2018 and 2018/2019) and soil chemical properties were determined using
standard procedures. The results showed that the addition of dual inoculation over time greatly
improved soil chemical properties when compared to the control treatment. This was advocated
by the significant (P ≤ 0.05) increase in soil pH, soil organic carbon, soil organic matter, total
nitrogen, phosphorus, calcium, potassium, magnesium, sodium, sulfur and iron in soils. The
concentration of cation exchange capacity was significantly (P ≤ 0.05) higher in cowpea treated
with Rhizobium as compared to other treatment combinations. The control treatment of mucuna
forage greatly improved the concentrations of manganese, boron, copper, molybdenum, and zinc
over other treatment combinations only before the flowering stage. However, the concentrations
of micronutrients were significantly higher on the treatment combination of lablab and single
inoculation of AMF after harvesting. Generally, dual inoculation with AMF and Rhizobia enhanced
soil properties when compared to a single inoculation or untreated control
Description
The present study assessed the effect of AMF and Rhizobium
inoculation on soil chemical properties in field-grown forage legumes in the Eastern Cape Province of South Africa. It is hypothesized
that the application of AMF and Rhizobium inoculation will improve soil chemical characteristics
Keywords
Arbuscular mycorrhizal fungi, Biofertilization, Legumes, Chemical properties, Rhizobium, Namibia, University of Namibia