Intercropped red beet and radish with green bean affected microbial communities and nodulation by indigenous rhizobia

Abstract

The impact of intercropping green bean (Phaseolus vulgaris L.) with red beet (Beta vulgaris L. var. rubra) and radish (Raphanus sativus L.), two non-legume plants, on the plants' yields, as well as the effect on occurrence and enumeration of microorganisms in the rhizosphere was studied. The intercrop efficacy evaluation, using Land equivalent ratio, revealed values above 1.0 for all intercropped treatments. Diversity of rhizobia from green bean nodules under different intercropping and fertilizing conditions was observed. On the basis of morphological and biochemical characteristics, 67 out of 158 isolates from green bean roots were selected as rhizobia (42.4%), confirmed by detection of 780 bp nifH gene fragments in nifH-PCR, and then clustered in 27 phenotype patterns. Production of exopolysaccharide succinoglycan was observed in 23 rhizobial isolates, while 6 were detected to solubilize tricalcium phosphate. Screening of genetic diversity using (GTG) 5 -PCR fingerprinting showed presence of six different patterns on the 92% similarity level.

Beetroot and radish root yield in organic double-cropping production system

“…Unlike for beetroot, intercropped radish yielded significantly better than as a sole crop. This confirmed the results of our previous research on intercropping other varieties of green beans and radish, where we found significantly lower intercrop efficiency in green beans, and higher in radish (Ugrinovic et al, 2014). The differences in intercrop efficiency imply radish as a strong competitor and dominant species in intercrop system which includes species from Fabaceae family.…”

“…Plant growth promoters, such as beneficial strains of some bacterial species {Azptobacter sp, Derxia sp., Bacillus sp., Rhizobium heguminosarum etc. ), contribute to the plant growth and reduce the need for additional fertilization, which refers to both organic and conventional production (Hayat et al, 2010;Sripontan et al, 2014;Ugrinovic et al 2014;Miskoska -Milevska et al 2018).…”

“…Despite the intensive research, there are still unresolved issues, which are for the most part due to the complex plantmicroorganism interactions, applied microorganisms suppression by autochthonous soil and other environmental microorganisms, insufficiently developed application design, untimely exposure to precipitation and other environmental factors, etc. Thus, the efficiency of the microbial fertilizers in different agricultural plants has not been sufficiently explored and there are still plant species with the unpredictable response to the applied treatments (Betencourt et al, 2012;Dinić et al, 2014;Ugrinovic et al, 2014;Stamenković et al, 2018).…”

Land use and season drive changes in soil microbial communities and related functions in agricultural soils

“…Huang et al (2019) and Cerecetto et al (2021) conducted research on the effects of continuous tillage of beet crops on the soil microbial community, and their results showed that conventional tillage practices reduced some aspects of microbial diversity compared with no till practices, in agreement with our findings. However, a limitation of our study is that we considered only one crop (beet) although research (Lange et al, 2015; Ugrinovic et al, 2014) shows that different crops influence soil properties, microbial structure and diversity in different ways. Further studies are therefore needed to determine the influence of different crops on soil microbial diversity.…”