Tempo-spatial dynamics of AMF under maize soybean intercropping

A field experiment was conducted to investigate whether AMF growth and yield of spores and glomalin were influenced by planting patterns. Four systems consisting of 6 rows of maize intercropped with 6 rows of soybean (6M6S), 3 rows of maize intercropped with 3 rows of soybean (3M3S), sole maize crop (CKM), and sole soybean crop (CKS) were used to examine spatial and temporal dynamics of AMF. The results showed that mycorrhizal colonization, colonization density, and hypha density increased gradually with the symbiotic period between AMF and crops; and mycorrhizal arbuscular richness at first showed an increase, then decreased. In the milking stage of maize (the filling stage of soybean), two-year results showed that mycorrhizal colonization, colonization density, arbuscular richness of mycorrhiza, soil spore density, and glomalin content of 3M3S were significantly higher than those of monoculture. With the growth of crops, the spore density of AMF increased from 269.40 spores·(100g)^-1 to 1 484.20 spores·(100g)^-1, the content of easily extractable glomalin increased from 430.88 μg·g^-1 to 600.78 μg·g^-1, and the content of total glomalin increased from 942.59 μg·g^-1 to 1 304.03 μg·g^-1. In the milking stage of maize, the border row of intercropped maize had the highest hypha density, spore density, easily extractable glomalin, and total glomalin. In the filling stage of soybean, the border row of intercropped soybean had the highest hypha density and easily extractable glomalin, and the lowest spore density. Correlation analysis indicated that contents of easily extractable glomalin and total glomalin were significantly positively correlated with hypha density, with coefficients up to 0.71 and 0.73, respectively. The spore density and hypha density were significantly positively correlated with colonization, with coefficients up to 0.72 and 0.75, respectively. Therefore, this study showed that AMF could establish a good symbiotic relationship with crops on agricultural land and showed periodical variation with both the change of seasons and the growth of crops. Intercropping promoted the colonization of AMF and increased the production of glomalin and spores, and the symbiosis between AMF and crops showed marginal effect. The 3M3S treatment was the most lucrative planting system for AMF.