Can phosphorus application and cover cropping alter arbuscular mycorrhizal fungal communities and soybean performance after a five-year phosphorus-unfertilized crop rotational system?

Abstract

BackgroundUnderstanding diversity of arbuscular mycorrhizal fungi (AMF) is important for optimizing their role for phosphorus (P) nutrition of soybeans (Glycine max (L.) Merr.) in P-limited soils. However, it is not clear how soybean growth and P nutrition is related to AMF colonization and diversity of AMF communities in a continuous P-unfertilized cover cropping system. Thus, we investigated the impact of P-application and cover cropping on the interaction among AMF colonization, AMF diversity in soybean roots, soybean growth and P nutrition under a five-year P-unfertilized crop rotation.MethodsIn this study, we established three cover crop systems (wheat, red clover and oilseed rape) or bare fallow in rotation with soybean. The P-application rates before the seeding of soybeans were 52.5 and 157.5 kg ha−1 in 2014 and 2015, respectively. We measured AMF colonization in soybean roots, soybean growth parameters such as aboveground plant biomass, P uptake at the flowering stage and grain yields at the maturity stage in both years. AMF community structure in soybean roots was characterized by specific amplification of small subunit rDNA.ResultsThe increase in the root colonization at the flowering stage was small as a result of P-application. Cover cropping did not affect the aboveground biomass and P uptake of soybean in both years, but the P-application had positive effects on the soybean performance such as plant P uptake, biomass and grain yield in 2015. AMF communities colonizing soybean roots were also significantly influenced by P-application throughout the two years. Moreover, the diversity of AMF communities in roots was significantly influenced by P-application and cover cropping in both years, and was positively correlated with the soybean biomass, P uptake and grain yield throughout the two years.DiscussionOur results indicated that P-application rather than cover cropping may be a key factor for improving soybean growth performance with respect to AMF diversity in P-limited cover cropping systems. Additionally, AMF diversity in roots can potentially contribute to soybean P nutrition even in the P-fertilized cover crop rotational system. Therefore, further investigation into the interaction of AMF diversity, P-application and cover cropping is required for the development of more effective P management practices on soybean growth performance.

Legacy of eight‐year cover cropping on mycorrhizae, soil, and plants

“…Overall, our study showed a stimulation of AMF in the subsequent crop when fallow was replaced by barley CC but not when fallow was replaced by vetch. Our results agreed with other field experiments in which the use of grass CCs, such as winter wheat ( Kabir and Koide , ; Higo et al, ), oat and rye ( Kabir and Koide , ; White and Weil , ), and ryegrass ( Higo et al, ), increased mycorrhizal colonization from 26% to two times in the subsequent maize crop. The lack of positive effect of vetch CC on the AMF parameters is contrary to our first hypothesis and disagrees with some studies.…”

Impact of Phosphorus Fertilization on Tomato Growth and Arbuscular Mycorrhizal Fungal Communities

“…To characterize the AMF community in the tomato roots, we performed high-throughput sequencing of amplicons as described in Higo et al [15,43,48]. Briefly, three PCR products per plot were combined together (from 27 samples to 9 samples) to prepare 9 libraries.…”

“…The taste and flavor of tomatoes and their antioxidant content differ according to growing conditions, cultivation techniques, cultivars, and cultivation time [10][11][12][13]. Soil P is a well-known key nutrient for tomato production and other crops, such as maize [14] and soybean [15], and maintaining adequate levels of P in the soil is important for maximizing tomato growth and development [16][17][18]. However, the effect of different P fertilizer amounts on the growth performance of tomato plants remains unknown.…”

“…In addition, appropriate agricultural management can improve the nutritional functions of AMF [28]. A higher AMF species richness can promote plant P nutrition [15,29,30]. In general, high levels of P fertilizer input have been shown to decrease colonization by AMF [31], as well as the abundance and richness of AMF communities in the roots and soil [32,33].…”

“…In general, high levels of P fertilizer input have been shown to decrease colonization by AMF [31], as well as the abundance and richness of AMF communities in the roots and soil [32,33]. For example, high amounts of P can decrease the diversity of and change AMF communities, but moderate P fertilizer applications can enhance the diversity of AMF communities [15,34]. As mentioned above, previous reports on the impacts of P fertilization on AMF communities are contradictory.…”