scholarly journals Mycorrhizal fungi transfer nitrogen from tree to maize in subsistence farmers' fields

2020 ◽  
Author(s):  
Janina Dierks ◽  
Wilma Blaser-Hart ◽  
Hannes Gamper ◽  
Johan Six

Abstract Trees within farmers' fields can enhance systems' longer-term productivity e.g., via nutrient amelioration, which is indispensable to attain sustainable agroecosystems. While arbuscular mycorrhizal fungi (AMF) are known to improve plant access to soil nutrients, the potential of AMF to facilitate nutrient transfer from trees to crops is unclear. We used the 15N (nitrogen) natural abundance technique together with root and AMF exclusion plots to assess if Faidherbia albida (faidherbia) trees deliver N to maize via associated AMF in smallholder fields. We show, here, that within one cropping season, maize obtained approximately 35 kg biologically fixed N ha-1 from faidherbia and AMF significantly contribute to this transfer of N. One third of tree-derived N in maize leaves was attributed to transfer via AMF and two thirds were explained by tree leaf litter input. Thus, the faidherbia-AMF association can enhance agroecosystem functioning and as such, attain greater sustainability of low-input cropping systems.

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Walid Ellouze ◽  
Ahmad Esmaeili Taheri ◽  
Luke D. Bainard ◽  
Chao Yang ◽  
Navid Bazghaleh ◽  
...  

Soil fungi are a critical component of agroecosystems and provide ecological services that impact the production of food and bioproducts. Effective management of fungal resources is essential to optimize the productivity and sustainability of agricultural ecosystems. In this review, we (i) highlight the functional groups of fungi that play key roles in agricultural ecosystems, (ii) examine the influence of agronomic practices on these fungi, and (iii) propose ways to improve the management and contribution of soil fungi to annual cropping systems. Many of these key soil fungal organisms (i.e., arbuscular mycorrhizal fungi and fungal root endophytes) interact directly with plants and are determinants of the efficiency of agroecosystems. In turn, plants largely control rhizosphere fungi through the production of carbon and energy rich compounds and of bioactive phytochemicals, making them a powerful tool for the management of soil fungal diversity in agriculture. The use of crop rotations and selection of optimal plant genotypes can be used to improve soil biodiversity and promote beneficial soil fungi. In addition, other agronomic practices (e.g., no-till, microbial inoculants, and biochemical amendments) can be used to enhance the effect of beneficial fungi and increase the health and productivity of cultivated soils.


Agronomy ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 127 ◽  
Author(s):  
Arjun Kafle ◽  
Kevin Cope ◽  
Rachel Raths ◽  
Jaya Krishna Yakha ◽  
Senthil Subramanian ◽  
...  

Phosphorus is an essential macronutrient required for plant growth and development. It is central to many biological processes, including nucleic acid synthesis, respiration, and enzymatic activity. However, the strong adsorption of phosphorus by minerals in the soil decreases its availability to plants, thus reducing the productivity of agricultural and forestry ecosystems. This has resulted in a complete dependence on non-renewable chemical fertilizers that are environmentally damaging. Alternative strategies must be identified and implemented to help crops acquire phosphorus more sustainably. In this review, we highlight recent advances in our understanding and utilization of soil microbes to both solubilize inorganic phosphate from insoluble forms and allocate it directly to crop plants. Specifically, we focus on arbuscular mycorrhizal fungi, ectomycorrhizal fungi, and phosphate-solubilizing bacteria. Each of these play a major role in natural and agroecosystems, and their use as bioinoculants is an increasing trend in agricultural practices.


2006 ◽  
Vol 21 (4) ◽  
pp. 245-252 ◽  
Author(s):  
Jason L. De Bruin ◽  
Nicholas R. Jordan ◽  
Paul M. Porter ◽  
Sheri C. Huerd

AbstractIntegration of rye (Secale cereale L.) cover crops into the corn (Zea mays L.) soybean [(Glycine max (L.) Merr.] rotation of the upper Midwest USA can provide many agronomic and agroecological benefits. Integration is made difficult by short growing seasons, but may be facilitated by management of key agroecological interactions such as those between rye and soil microbiota. Rye growth was measured and colonization by arbuscular-mycorrhizal fungi (AMF) was determined in greenhouse experiments using soils from seven different management systems from a long-term cropping-systems experiment in southwest Minnesota. Microbial effects on rye growth were not evident before vernalization, but at final harvest (4 weeks after vernalization) soil microbial populations reduced rye shoot and root growth, relative to a pasteurized control inoculum. At final harvest, shoot biomass in 2-year rotations was 17% greater than 4-year rotations, indicating that microbial populations selected for by 4-year rotations may be more deleterious or pathogenic than those selected for by 2-year rotations. Growth of three rye cultivars was examined in all inocula; cultivars differed in their mean response to soil microbiota and their ability to host AMF. These findings suggest that management factors affect interactions between rye and soil microbiota resulting in altered rye growth.


2014 ◽  
Vol 48 (3) ◽  
pp. 279-290 ◽  
Author(s):  
Tomoko KOJIMA ◽  
Norikuni OKA ◽  
Toshihiko KARASAWA ◽  
Keiki OKAZAKI ◽  
Shotaro ANDO ◽  
...  

2020 ◽  
Author(s):  
Ifeyinwa Monica Uzoh ◽  
Chukwuebuka Christopher Okolo ◽  
Akudo Ogechukwu Onunwa ◽  
Olubukola Oluranti Babalola

<p><strong>Abstract</strong></p><p>Cowpea, a food and nutrition security crop is being threatened by decline in soil fertility especially in small holder farmstead. The natural arbuscular mycorrhizal fungi in the soil could improve its ability to acquire and retain nutrients thereby leading to higher yield. This irrigated field research was conducted to determine the effect of biochar rates and cropping systems on selected soil chemical properties, soil microbial biomass carbon (SMBC), nitrogen (SMBN), phosphorus (SMBP), and vesicular-arbuscular mycorrhizal (VAM) spore count and mycorrhizal fungi colonization (AMF) of cowpea. Experimental design was 3 x 3 factorial in randomized complete block design (RCBD). Factor A was three cropping systems; sole cowpea, intercropping and intra-cropping, while factor B was three biochar rates; control (biochar at 0 t ha<sup>-1</sup> (B<sub>0</sub>)), biochar at 2.5 t ha<sup>-1 </sup>(B<sub>1</sub>) and biochar at 5 t ha<sup>-1</sup> (B<sub>2</sub>). These were replicated in three blocks to constitute 27 plots. The entire plot was cleared, ploughed and demarcated into beds with hoes and diggers. Cowpea sole or inter- or intra- cropped with maize were planted in a spacing distance of 25cm by 75cm, with intercropped cowpea being in-between the interrow spacing (75 cm), while the intracropped cowpeas was planted between the intrarow spacing (25 cm). Biochar soil amendment were applied two weeks after planting by making a groove in-between the rows in the soil and covering them with soil. The result showed that biochar soil amendment and interaction of biochar with cropping system significantly (p<0.05) affected SMBN, SMBC, total  VAM spore count and AMF colonization by cowpea, whereas cropping system significantly affected only total VAM spore count and AMF colonization by cowpea. B<sub>2</sub> amended soil had the highest SMBC content (0.028 mg kg<sup>-1</sup>) while the least was from control plot (0.021 mg kg <sup>-1</sup>), SMBN was highest in B<sub>1 </sub>amended soil (0.004 mg kg<sup>-1</sup>), followed by control plot (0.002 mg kg<sup>-1</sup>). Control had higher AMF and total VAM spore count while biochar amended soil had higher soil microbial properties. Considering the cropping systems, inter and intra-cropping had higher microbial biomass and total VAM spore count than sole cowpea whereas sole cowpea had higher AMF infection of cowpea than the intercropped cowpea. Biochar at 5 tha<sup>-1</sup> had the highest available P. Generally, this study showed superiority of the interaction of biochar with cropping systems over sole cropping in the improvement of soil properties in degraded soils of North-West province of South Africa.</p><p>Key words: Cropping systems; Chromic Luvisol; Microbial properties; Soil fertility; Soil amendment</p>


2005 ◽  
Vol 85 (1) ◽  
pp. 31-40 ◽  
Author(s):  
C. Plenchette ◽  
C. Clermont-Dauphin ◽  
J. M. Meynard ◽  
J. A. Fortin

Market globalization, demographic pressure, and environmental degradation have led us to reconsider many of our current agricultural systems. The heavy use of chemical inputs, including fertilizers and pesticides, has resulted in pollution, decreased biodiversity in intensively-farmed regions, degradation of fragile agro-ecosystems, and prohibitive costs for many farmers. Low input sustainable cropping systems should replace conventional agriculture, but this requires a more comprehensive understanding of the biological interactions within agro-ecosystems. Mycorrhizal fungi appear to be the most important telluric organisms to consider. Mycorrhizae, which result from a symbiosis between these fungi and plant roots, are directly involved in plant mineral nutrition, the control of plant pathogens, and drought tolerance. Most horticultural and crop plants are symbiotic with arbuscular mycorrhizal fungi. Mycorrhizal literature is abundant, showing that stimulation of plant growth can be mainly attributed to improved phosphorous nutrition. Although the mycorrhizal potential of its symbiosis to improve crop production is widely recognized, it is not implemented in agricultural systems. There is an urgent need to improve and widely apply analytical methods to evaluate characteristics such as, relative field mycorrhizal dependency, soil mycorrhizal infectivity, and mycorrhizal receptivity of soil. Decreased use of fertilizers, pesticides, and tillage will favour arbuscular mycorrhizal fungi. However, shifting from one system to a more sustainable one is not easy since all components of the cropping system are closely linked. Different cases, from actual agricultural practices in different countries, are analyzed to highlight situations in which mycorrhizae might or might not play a role in developing more sustainable agriculture. Key words: Cropping systems, mycorrhizae, sustainability, technical itineraries, rotation


1999 ◽  
Vol 8 (3) ◽  
pp. 309-318 ◽  
Author(s):  
M. VESTBERG ◽  
M. CARDOSO ◽  
A. MÅRTENSSON

The occurrence of arbuscule-forming fungi in different cropping systems was investigated at Cochabamba in the province of Cercado, Bolivia. The cropping systems included grain and mixed pasture systems, with or without fertilization and agrochemicals. Geographically, the soils studied were situated at 17°23'9'' southern latitude and 66°9'35'' western longitude and a mean height of 2600 m above sea level. Spores of four arbuscular mycorrhiza fungi-forming genera were observed; Glomus Tul. & Tul., Entrophospora Ames & Schneider, Sclerocystis Berk. & Broome emend. Almeida & Schenck and Scutellospora Walker & Sanders. Glomus was the dominating genus, followed by Sclerocystis; Scutellospora and Entrophospora were observed occasionally. A cropping system consisting of a native pasture without any fertilization or other plant or soil treatments had the highest numbers of spores and the highest species richness, i.e. eight out of nine species identified. The mycorrhizal diversity measured with the Shannon-Wiener index did however not differ very much between cropping systems. ;


Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 520 ◽  
Author(s):  
Thomas I. Wilkes ◽  
Douglas J. Warner ◽  
Keith G. Davies ◽  
Veronica Edmonds-Brown

Zero till cropping systems typically apply broad-spectrum herbicides such as glyphosate as an alternative weed control strategy to the physical inversion of the soil provided by cultivation. Glyphosate targets 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase in plants. There is growing evidence that this may have a detrimental impact on non-target organisms such as those present in the soil microbiome. Species of commercial importance, such as arbuscular mycorrhizal (AM) fungi that form a symbiotic relationship with plant roots are an important example. This study investigates the impact of soil cultivation and glyphosate application associated with conventional tillage (CT) and zero tillage (ZT) respectively on AM fungi populations under field and glasshouse conditions. Topsoil (<10 cm) was extracted from CT and ZT fields cropped with winter wheat, plus non-cropped control plots within the same field boundary, throughout the cropping year. Glyphosate was applied in glasshouse experiments at rates between 0 and 350 g L−1. Ergosterol, an indicator of fungal biomass, was measured using high performance liquid chromatography before and after glyphosate application. Fungal root arbuscules, an indicator of AM fungi–root symbiosis, were quantified from the roots of wheat plants. Under glasshouse conditions root arbuscules were consistently higher in wheat grown in ZT field extracted soils (P = 0.01) compared to CT. Glyphosate application however inhibited fungal biomass in both the ZT (P < 0.00001) and CT (P < 0.001) treatments. In the absence of glyphosate, the number of stained root arbuscules increased significantly. Ergosterol levels, used as a proxy for fungal biomass, remained lower in the soil post glyphosate application. The results suggest that CT has a greater negative impact on AM fungal growth than ZT and glyphosate, but that glyphosate is also detrimental to AM fungal growth and hinders subsequent population recovery.


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