Successive cultivation of maize and agricultural practices on root colonization, number of spores and species of arbuscular mycorrhizal fungi

Abstract

A large number of propagules and a broad spectrum of species are two important components of ecosystem (including agroecosystem) sustainability. Previous studies carried out in temperate areas showed that repeated monoculture leads to a decrease in the species abundance of arbuscular mycorrhizal fungi (AMF). This study evaluated the influence of maize monoculture and its agricultural practices on AMF during three consecutive cropping years in a Brazilian field. At the end of each cycle, soil and root samples were evaluated for species composition, spore populations and root colonization by AMF. The AMF community present during this period was scored according to the Spearman rank correlation and Principal Components Analysis. The mean percent root colonization values for the three cultivation periods were: 66.9, 60.7 and 70.5, respectively. Seven species were detected in the first year, Scutellospora persica being the most abundant (24.1% of spores) and Glomus macrocarpum the most observed (100% of samples). In the second year, Glomus etunicatum was the species with the greatest number of spores (24.7%) and, like G. macrocarpum, the most frequently observed (90%) in a community of thirteen. In the third year, twenty-three AMF species were identified, Scutellospora sp. 1 being the most abundant (17.4%), and Gigaspora decipiens and Glomus claroideum the most frequent (both with a relative frequency of 70%). The main soil factors influencing root colonization and sporulation by AMF were pH (and related properties), phosphorus and organic matter contents.

Micorriza arbuscular em plantações de Eucalyptus cloeziana F. Muell no litoral norte da Bahia, Brasil

“…De acordo com Joner & Jakobsen (1995), o desenvolvimento das hifas dos FMA pode aumentar em resposta à alta concentração da matéria orgânica, o que faz da matéria orgânica importante parâmetro nos estudos dos FMA. No entanto, são escassos os estudos sobre os efeitos da matéria orgânica na colonização radicular por FMA (Carrenho et al 2001b). Pela interferência da matéria orgânica na ecologia dos FMA, como já relatado, realizou-se análise de correlação com a colonização radicular, a qual demonstrou fraca correlação (r = 0,32; p = 0,01).…”

“…Em estudo realizado em mata de Eucaliptos, Santos (2001) observou correlação negativa (r = -0,63) entre as mesmas variáveis, no período úmido, porém, no período seco, não observou correlação. As divergências quanto à relação da matéria orgânica com o desenvolvimento intra-radical dos FMA e com a densidade de esporos são grandes, podendo-se encontrar trabalhos com correlação direta (Mohammad et al 2003) ou inversa (Carrenho et al 2001b). …”

Inoculation of Arbuscular Mycorrhizal Fungi Increase the Growth of Cocoa and Coffee Seedling Applied with Ayamaru Phosphate Rock

“…The utilization of low release P such as APR and bones powder even though in high dosage application, was effective to maintain AMF and to increase plant growth (Cardoso, 1996;Nikolaou et al, 2002). P content was reported to negatively correlated (Amijee et al, 1989;Koide & Li, 1990), no correlation (Tawaraya et al, 1996), or positively correlated (Carrenho et al, 2001) with AMF, depends on AMF species, plant species, P source and its solubility (Cardoso, 1996;Tawaraya et al, 1996;Nikolaou et al, 2002;Bhadalung et al, 2005). Maximum AMF symbiotic was achieved if soil P content was not more than 50 mg·kg -1 (50 ppm) (Ishii, 2004).…”

Mycorrhizal colonization and diversity and corn genotype yield in soils of the Cerrado region, Brazil

“…Moreover, the HS 83 × E3 hybrid and the parent lines (HS 83 and E3) were colonized by 10, 7, and 9 species, respectively (Table 2). Carrenho et al (2001) observed the presence of 25 species in areas with successive corn crops. In the present study, the number of species differed from that reported by other authors; however, it was similar to those described by Trufem and Bononi (1985) and Siqueira et al (1989), who found nine and ten species in soils from the Cerrado region, respectively.…”