Please use this identifier to cite or link to this item:
Use of Vesiucular-Arbuscular Mycorrhizal Fungi for Establishment of Effectively Nodulated Legumes on Moderately Weathered Oxisol Subjected to Simulated Erosion
|Title:||Use of Vesiucular-Arbuscular Mycorrhizal Fungi for Establishment of Effectively Nodulated Legumes on Moderately Weathered Oxisol Subjected to Simulated Erosion|
|Abstract:||The objectives of this study were to determine the influence of simulated erosion on the population and activity of vesicular arbuscular mycorrhizal (VAM) fungi, and to define the levels of chemical inputs necessary for successful establishment of effectively nodulated and mycorrhizal cowpea (Vigna unguiculata) and leucaena (Leucaena leucocephala) in a soil subjected to simulated erosion.|
Erosion was simulated by removing the top 30 cm of the Wahiawa soil (Tropeptic Eutrustox). Removal of top soil resulted in a significant decrease in the population and activity of VAM fungi. When the infectivity of soil was increased by inoculation with different strains of VAM fungus, there was no improvement in plant growth, indicating, that nutrients were, perhaps, limiting. Experiments were then conducted to determine the influence of P, lime, organic residue, Mo and inorganic Non mycorrhizal activity and plant growth.
The growth of mycorrhizal cowpea and leucaena was significantly improved when the eroded and uneroded soils were amended with phosphorus. The results showed that the level of P is very critical for the symbiosis between VAM fungi and hosts. There appear to be threshold, optimum and inhibitory levels of soil solution P for mycorrhizal activity. The optimum soil solution P level for mycorrhizal activity was found to be 0.026 mg/l. At this P level the difference in plant growth that existed between the eroded and uneroded soils in the absence of added P disappeared. Liming the eroded soil to pH 6.0 was beneficial to mycorrhizal cowpea and leucaena. Amendment of the soil samples with organic residue and Mo was not beneficial to the test legumes whereas the application of inorganic Nat the rate of 25 ppm increased the growth of mycorrhizal cowpea and leucaena in the eroded soil. Nodule dry weight and shoot N status of plants were also increased significantly by adding 25 ppm N to the soil. Maximum nodule dry weight was observed at 50 ppm N.
The nutrients (P, lime and inorganic N) were then combined at their respective optimum levels and tested for the symbiotic interaction between plants and VAM fungi. When the soil samples were amended with these nutrients, there was an increase in mycorrhizal activity and plant growth in the uneroded soil but not in the eroded soil. Inoculating the soil samples (amended with all the nutrients) with G. aggregatum, resulted in a significant increase in mycorrhizal activity and plant growth and the difference that existed between the unamended eroded and uneroded soils disappeared. Application of only basal nutrients did not influence rnycorrhizal activity.
The results of these studies demonstrate the possibility of rehabilitating eroded soils by establishing effectively nodulated legumes through VAM inoculation and chemical amendments.
|Appears in Collections:||
Ph.D. - Agronomy and Soil Science|
Please email firstname.lastname@example.org if you need this content in ADA-compliant format.
Items in ScholarSpace are protected by copyright, with all rights reserved, unless otherwise indicated.