Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 9, 2006
Publication Date: September 27, 2006
Citation: Russo, V.M. 2006. Efficacy of bacterial or fungal soil amendments on peanut production and vegetables following peanuts. HortScience. 41(6):1395-1399. Interpretive Summary: Soil microorganisms can affect plants in ways that can be measured. Species of Rhizobium and abuscular-mycorrhizal fungi have been reported to be beneficial to some crops. The effects of these biotic amendments were tested in the greenhouse on peanut (Arachis hypogaea L.) in pots which were followed by bell pepper (Capsicum annuum L.) or dry bean (Phaseolus vulgaris L.). The effects of fertilizer rate were also tested in the greenhouse. Field trials using the same plants were undertaken to determine if there were differences in response found in the greenhouse and in field trials. In both cases peanut were planted first and treated with Rhizobium bacteria or abuscular-mycorrhizal fungi, added alone, or in combination. Controls were no amendments. In the greenhouse effects due to fertilizer rate, with the full rate being better than the reduced rate, was more important than effects of inoculum. The full fertilizer rate was used in the field. In the field use of inocula did not provide substantial benefits to yield or nutrient content of peanut or vegetable crops that followed, and the reasons for this require additional study.
Technical Abstract: Amendment of soil with microorganisms during the growth cycle of one crop may affect development of succeeding crops. Species of Rhizobium bacteria or abuscular-mycorrhizal fungi were added alone, or in combination, to potting soil in pots in a greenhouse. Controls were no amendments. Seed of peanut (Arachis hypogaea L.) were planted and two levels of a combination NPK fertilizer, the recommended and one-fourth the recommended rate, were applied. Following harvest of peanut and remoistening of soil, seed of bell pepper (Capsicum annuum L.) or navy bean (Phaseolus vulgaris L.) were sown in to the same planting medium in pots without additional inoculation with microbes. Dry weights of above-ground vegetative and edible portions of crops were determined. Inoculum type only affected peanut top and total dry weights. The recommended fertilizer level did not affect peanut yield, but did cause improvement in bell pepper and navy bean yield over that of the deficient fertilizer rate. In field experiments peanut was planted into soil receiving Rhizobium spp. bacteria, or arbuscular-mycorrhizal fungi alone, or in combination. Controls consisted of no amendment. Only the recommended fertilizer rate was used. In the following two years bell pepper or navy bean were established in plots without use of additional microbial amendment. Yields and nutrient contents of crops were determined. Type of inoculum did not affect yield or nutrient content in any crop. Bell pepper marketable yield was not affected by year, and navy bean seed yield was higher in 2004 than in 2005. In both years navy bean yields were below United States averages. For most nutrients in edible portions of bell pepper and navy bean concentrations were lower in 2004 than in 2005. Results of the field trials were generally similar to those of greenhouse studies. Use of inocula did not provide substantial benefits to yield or nutrient content of peanut or vegetable crops that followed.