Intercropping has been known for a long time, but despite its many agronomic benefits, it still constitutes a small niche in agricultural cropping systems. It is known that this type of cropping systems improves biodiversity through several synergistic effects between plant species cultivated together. Legume-cereal intercropping, may also contribute to reducing expenditure on mineral fertilization, due to legume symbiosis with microbes that fix atmospheric nitrogen.

The assumption of this study is that intercropping creates more complex and lasting systems and interactions in the soil-plant-microbiome system. Therefore, they stimulate various part of communities, contributing to a more diverse community, which drives the processes of environmental changes resulting from various root exudates. Moreover, they also increase the co-occurrence of various bacteria and fungi, thus ensuring greater stability, health and quality of agroecosystems.

The research was carried out based on a large-scale field experiment conducted at the Experimental Station in Osiny (Lubelskie Voivodeship, Poland, N: 51°28, E: 22°4) established in 1994, the aim of which was a comparison of different agricultural production systems: organic, integrated and conventional high-input. The general design of the field experiment has been described by Feledyn-Szewczyk et al. (2019).

The aim of this study was to determine differences in the structure and activity of the microbiome of wheat and the soil under its cultivation in an organic, integrated and conventional cultivation systems of this plant, taking into account the complexity of plant communities occurring simultaneously in the field during the growing season. The organic system included intercropping of wheat with clovers and grasses, integrated wheat and clover, and conventional wheat cultivation with pure sowing. The research methods included spectrophotometric approach for enzymatic activity and EcoPlates functional diversity evaluation and next-generation sequencing was used for microbial structure determination of various ecological niches (soil, rhizosphere, roots and shoots).

The results may constitute an important link for a new vision of agriculture, including the use of a close connection between the soil-plant- microbiome for the development of sustainable crop production strategies and management practices for future resilient crop cultivations.

This work was supported in the frame of Horizon Europe Programme, agreement no. Project 101082289 — LEGUMINOSE

Feledyn-Szewczyk B., Matyka M., Staniak M., 2019, Comparison of the Effect of Perennial Energy Crops and Agricultural Crops on Weed Flora Diversity. Agronomy 2019, 9, 695; doi:10.3390/agronomy9110695

How to cite: Frąc, M., Siegieda, D., Gryta, A., Panek, J., Pylak, M., Mącik, M., Pertile, G., Oszust, K., Sisodia, P., Feledyn-Szewczyk, B., Pathan, S., and Pietramellara, G.: Relationships between the structure and activity of microbial communities in legume-cereal intercropping - new possibilities of old plant cultivation methods, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21407, https://doi.org/10.5194/egusphere-egu24-21407, 2024.

Apple orchard soils in Germany face numerous challenges, including pest and disease control and soil nutrient management, leading to the potential accumulation of potentially toxic elements (PTEs). Producing high-quality fruit requires effective management of these challenges, which is additionally intensified by the impact of changing climate and associated weather patterns. One example is bitter pit (BP) disease, a significant disorder in apple orchards that results in substantial economic loss when symptoms manifest in the fruit.

This study aimed to assess macronutrient ratios in German apple orchards and explore the relationship between BP disease incidence and variations in fruit composition across orchards with diverse locations and management practices. Soil and composite plant samples (apples, leaves, and branches) were collected from 16 apple orchard sites (a total of 32 sample sites) in the Eastern region of Germany, encompassing both conventional and organic farming systems (CFS and OFS). MP-AES was used for total macronutrients and trace element plant and soil analysis, and relevant physiochemical soil properties, such as pH, EC, OM, and carbonate content (%) or texture, were examined. Data were evaluated using bioaccumulation (BAF) and translocation (TF) factors, Pearson correlation coefficient, and principal component analysis (PCA).

The study revealed that fruits with an elevated Mg+K/Ca ratio were more affected by BP incidence. Based on PCA, a correlation between orchard location (region), management practices (CFS and OFS), and BP occurrence was observed. We conclude that macronutrient ratios, especially the Mg+K/Ca ratio, play a crucial role in BP disease development in apple orchards, and orchard location and management practices influence these ratios. Knowledge regarding these correlations can support the development of strategies for preventing and managing BP disease, leading to enhanced apple orchard productivity and reduced economic losses.

How to cite: Sut-Lohmann, M., Grimm, M., Raab, T., and Heinrich, M.: Conventional vs. organic soil management practices in German apple orchards: Correlation between bitter pit disease incidence and nutrient status, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16731, https://doi.org/10.5194/egusphere-egu24-16731, 2024.

A third of the world’s arable land has been lost since the 1950’s largely attributed to the rise of industrialised conventional agriculture, since its practices severely deplete the soil of essential organic matter, nutrients, and crop diversity, increasing its vulnerability to disease, drought, and flooding. Therefore, there is a pressing need to develop regenerative methods of cultivation to enrich soil fertility. Permaculture is a form of agroecology adopting holistic management to create a set of principles and design frameworks enriching soil based on a whole ecosystem approach. To date, there is little scientific evidence on the influence permaculture management has on soil fertility and subsequently microbial abundance and diversity. This study investigates the effect of permaculture management on soil fertility by comparing two mature permaculture managed allotment soils with a conventional arable soil. Soil fertility was assessed by microbial biomass and diversity (measured by phospholipid fatty acid analysis), soil nutrient (nitrate, ammonium and phosphate) and soil organic carbon contents. The greenhouse gas emission potential of soils was also measured with an in vitro incubation and gas chromatography analysis. Both bacterial and fungal abundance were 3-4 times higher under permaculture managed soils (with the more mature site showing higher fungal abundance) compared to conventionally managed soils. Furthermore, the bacterial/fungal ratio significantly varied between sites, with the arable soil showing a much lower abundance of fungi compared to its bacterial biomass. The greater soil microbial abundance and diversity under permaculture management was attributed to the use of organic amendments, crop rotation and diversity and no till practices promoting symbiotic relationships between the soil microbes and crop, exchanging essential nutrients and minerals. Consequently, permaculture soils had significantly higher organic matter, organic carbon, and nutrient contents as well as soil moisture compared to the arable soil. Regarding greenhouse gas emissions, the permaculture soils had 2-3 times higher soil respiration rate measured as carbon dioxide, which was explained by a multiple linear regression combination of soil nitrogen, organic carbon and moisture (77.34 % variance explained). Nitrous oxide (N₂O) and methane (CH₄) emissions were not statistically different between soil types due to high variability between replicates. However, N₂O from permaculture soils was marginally higher representing soil conditions at the time of sampling (October), which did not include fertilisation effects of the arable soil. This study found permaculture management of soils leads to increased fertility compared to conventionally managed arable soil, as expressed by the soils’ higher microbial abundance, nutrient, and organic carbon contents. The management of permaculture focused on mimicking the natural recycling of an ecosystem with addition of organic amendments, little disturbance to the soil using no dig raised beds, and crop diversity and rotation to aid microbial activity and synergy with the plant, creating a dense network of hyphae within the soil that contributes to enriched carbon and nutrient content.

How to cite: Williamson, R., Reay, M., and Sgouridis, F.: Permaculture management of arable soil increases soil microbial abundance and diversity, nutrient and carbon stocks compared to conventional arable agriculture, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19083, https://doi.org/10.5194/egusphere-egu24-19083, 2024.

Maize (Zea mays L.) is a major crop worldwide, commonly used as monoculture and with high nitrate leaching losses. Diversified maize rotations can improve the environmental problems of maize monoculture without reducing yields and soil nutrients. Previous research focused on maize-legume or maize-cereal rotations, with limited exploration of rotations with industrial crops for biorefining. Furthermore, long-term field trials are rare, hindering our understanding of the crop performance and nutrient dynamics over time. In a four-year rotation system of maize, hemp (Cannabis sativa L.), beet (Beta vulgaris L.), and triticale (Triticosecale) established in 2012 on a sandy soil in Denmark, quadruplicated for maize to appear each year, we examined dry matter yield, yield stability, biomass nitrogen (N) and biomass N stability of maize in rotation compared to monoculture across two rotation cycles. We also quantified nitrate leaching, soil carbon (C) and N stocks in the root zone of 0-100 cm. Moreover, the period between the main crops was covered with “secondary crops”- winter rye (Secale cereale L.), winter rape (Brassica napus L.), grass/clover (Festuca rubra L. – Trifolium repens L.). The results showed that in the initial four years, the aboveground biomass yield of maize in rotation (15.5 Mg ha^-1) was significantly lower (by 7%) than that in monoculture (16.6 Mg ha^-1), but this difference disappeared in the following four years (17 and 16.5 Mg ha^-1). The maize biomass N yield in rotation (194.5 kg ha^-1) was similar to that in monoculture (196.6 kg ha^-1) in the first cycle and was significantly higher (by 8%) in the second cycle (195.5 and 165.7 kg ha^-1). Nitrate leaching showed interannual variability affected by double-cropping, being almost halved by the diverse rotation compared to the monoculture at the start of the rotation, but increasing at the onset of the second cycle when the preceding winter rape did not survive in the winter. Also, winter rye following maize reduced nitrate leaching, except when the preceding secondary crop was grass-clover or poorly thriving winter rape. During the whole period, the rotation system can increase both soil C and N stocks. This study shows that several of the benefits of diverse crop rotations in comparison to monoculture require several years to take place, and that the management of the secondary crops is particularly vital for reducing nitrateleaching.

How to cite: Zong, M., Manevski, K., Liang, Z., Abalos, D., Jabloun, M., Lærke, P. E., and Jørgensen, U.: Diversifying maize rotation with industrial crops can improve maize yield, soil nutrient stocks, and nitrate leaching losses depending on time since adoption and crop species, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8996, https://doi.org/10.5194/egusphere-egu24-8996, 2024.

Climate change effects on agriculture is already a major threat for global crop production in terms of yields and quality of grains. In particular, sustainability of rainfed agriculture in semiarid regions is severely affected by warming and prolonged drought periods. Exploring new soil amendments such as biochar, which holds in countering climate change effects may be a sustainable method aimed at storing carbon, increasing soil quality and buffering the warming and drought stresses on soil and crops. However, we still need to better understand the effects of biochar application on crop yields, particularly under climate change conditions.

To fill this knowledge gap, in a long-term field experiment, we investigated how cumulative biochar addition (20 t ha^-1 year^-1) under climate change conditions affected a barley crop. Rainout shelters and open-top chambers were set up to simulate a 30% rainfall reduction combined with an increase of 2°C in soil temperature. Unamended soils for both ambient conditions and climate change manipulation were used as a control. Our findings revealed that the barley yield was greatly impacted by climate manipulation reducing the grain yield by 74-81%. However, the application of biochar did not lead to improvements in crop yield under these altered conditions. Moreover, grain quality parameters (specific grain weight and weight of 1000 grains) were not enhanced by the application of biochar nor the simulated climate change conditions.

Acknowledgments: this work was supported by the research projects TED2021-132342B-I00 (Spanish MICINN) and TUdi (Horizon 2020, GA 101000224).

How to cite: Benavente-Ferraces, I., Carpio Espinosa, M. J., Perciun, V., Panettieri, M., García-Gil, J. C., and Plaza, C.: Biochar application on a rainfed barley crop under a climate change scenario does not improve grain yield and quality, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20475, https://doi.org/10.5194/egusphere-egu24-20475, 2024.

Tunisia is facing twin challenges, namely, food and water security, which are pressing now and likely to increase in the future mainly due to climate change. To face this alarming situation, the implementation of conservation agriculture (CA) remains crucial for facing interannual variability in climatic conditions that impact durum wheat production. The current study aims to assess the effect of tillage systems on grain yield (YLD), above-ground biomass (AGB), and crop water productivity. The experiment was conducted at the Bourabia experimental station of the National Institute of Agricultural Research of Tunisia, located in a semi-arid zone of Tunisia, during cropping seasons (2013-2014 and 2014-2015). At harvest, above-ground biomass, yield, and yield components of durum wheat (Maali cultivar) were determined. Tillage practices included no-tillage (CA) and conventional tillage (CV). Preceding crops were either common vetch or bread wheat. The N rates applied were: 0, 75, 100, 120, and 140 kg N ha⁻¹. The experiments were laid out in a ‘Split-Plot’ design with three replications. The results show that the relationship between water productivity (quantity of water used to produce a ton of grain) and grain yield illustrated a better water valorization in CA system. For yields lower than 2 t ha^-1, more water was needed in AC than in CV to produce the same amount of grain; Whereas for yields greater than 2 t ha^-1, the opposite was revealed. On the other hand, grain yield and above-ground biomass were higher under CA compared to CV (+806 and +2468 kg ha⁻¹ for YLD and AGB respectively) in the dry growing season (year2), while in the favorable growing season (year1), the opposite was observed (-315 and -604 kg ha⁻¹ for YLD and AGB respectively). This feature illustrates the positive effect of CA in low-rainfall growing season due to good soil infiltration and reduction of evapotranspiration. Therefore, these findings provide evidence of the positive impact of CA on rainfed durum wheat under semi-arid Mediterranean conditions.

How to cite: Souissi, A., Bahri, H., Cheikh M’hamed, H., Benyoussef, S., and Annabi, M.: Conservation Agriculture to increase water productivity of durum wheat under semi-arid Mediterranean conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20791, https://doi.org/10.5194/egusphere-egu24-20791, 2024.

Pea (Pisum sativum L.) is a leguminous plant that is cultivated for its nutritional value and advantageous effects on soil fertility when used as a preceding crop. Its symbiotic nitrogen fixation and phosphorus solubilization properties thanks to the association with rhizospheric bacteria make it crucial component in cereal-based cropping systems. In Tunisia, the upscaling of pea cultivation faces numerous challenges, including low yields attributed to soil fertility depletion and the low abundance or ineffectiveness of specific rhizobia for achieving optimal pea nodulation.

The current study aims to assess the diversity and plant growth promoting traits of pea endophytic bacteria in order to select effective inoculant strains. For this purpose, 166 bacterial strains were isolated from root nodules of pea plants, collected from 46 regions in Tunisia. The strains were subjected to thorough in vitro assays, involving morphological, functional, and genetic characterization.

The results demonstrated that 153 strains were tested Gram-negative and 13 strains Gram-positive. Among the Gram-negative isolates, 44 strains induced nodule formation on pea plants of the 'Lincoln' variety, but mostly produced low nodule number and biomass and poor plant growth. The assessment of phosphorus solubilization among the whole isolates collection revealed a highly significant difference in the halo diameter formed on Pikovskaya medium and the phosphorus solubilization index. One hundred thirteen isolates were capable of solubilizing inorganic phosphorus.

The analysis of functional diversity of pea microsymbionts showed that Rhizobium strains (Oued Bj0.16, BjD, KalAM, MzBrg, Jbn, Morg15, Jed3, Sbit1, and Sb4), that were originated respectively from Beja, Kalaat Andalous, Menzel Bourguiba, Jbeniana, Morneg, Jedaida, Sbitla, and Sbiba sites, presented the highest efficiency in regards of nitrogen fixation. Furthermore, the strain Oued Bj0.16 demonstrated a moderate ability to solubilize phosphorus whereas the strain SoliL stands as the most efficient phosphorus-solubilizing bacteria (PSB). Concerning non-nodulating bacteria, BsM, Mat3L, MzelTM, and Mok4 were identified as a highly efficient PSB. In addition, the Gram-positive strain TebkL, originated from Beja, was identified as the most efficient P-solubilizer. The 16S gene sequencing revealed that pea nodular microsymbionts were attributed to 6 different genera: Rhizobium sp., Rhizobium leguminosarum, Parabulkolderia fungorum, Pantoea sp., Pseudomonas fluorescens, Pseudomonas baetica, Bacillus subtilis, Paenibacillus polymyxa, and Rhizobium nepotum. The exploration of pea microsymbionts diversity demonstrated extensive functional and genetic variations associated with the isolates origin.

In a nutshell, the application of single or mix of these beneficial bacteria as inoculant is an eco-friendly option that provides nitrogen and phosphorus to the crops and gets rid of chemical fertilizer, thereby promoting plant growth and preserving the environment in a Mediterranean context.

How to cite: Hachana, A., Hemissi, I., Souissi, A., Riahi, A., Abdi, N., Bouraoui, M., Arfaoui, H., Ouzari Cherif, I., Ferjani, R., and Sifi, B.: Functional and genotypic diversity of pea (Pisum sativum L.) microsymbionts in several geographical sites in Tunisia: Selection of inoculant strains for biofertilizer formulation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6722, https://doi.org/10.5194/egusphere-egu24-6722, 2024.