How binomial (traditional rainfed olive grove-Crocus sativus) crops impact the soil bacterial community and enhance microbial capacities.

Intercropping can favour the yield of the main crop. However, because of the potential competition among woody crops, this system is rarely used by farmers. To increase knowledge about the intercropping system, we have explored three different combinations of alley cropping in rainfed olive groves compared to conventional management (CP): (i) Crocus sativus (D-S); (ii) Vicia sativa/Avena sativa in annual rotation (D-O); and (iii) Lavandula x intermedia (D-L). Different soil chemical properties were analyzed to evaluate the effects of alley cropping, while 16S rRNA amplification and enzymatic activities were determined to study the changes that occurred in soil microbial communities and activity. In addition, the influence of intercropping on the potential functionality of the soil microbial community was measured. Data revealed that the intercropping systems highly affected the microbial community and soil properties. The D-S cropping system increased soil total organic carbon and total nitrogen that were correlated with the bacterial community, indicating that both parameters were the main drivers shaping the structure of the bacterial community. The D-S soil cropping system had significantly higher relative abundances of the phyla Bacteroidetes, Proteobacteria, and Patescibacteria compared to the other systems and the genera Adhaeribacter, Arthrobacter, Rubellimicrobium, and Ramlibacter, related to C and N functions. D-S soil was also related to the highest relative abundances of Pseudoarthrobacter and Haliangium, associated with the plant growth-promoting effect, antifungal activity, and a potential P solubilizer. A potentially increase of C fixation and N fixation in soils was also observed in the D-S cropping system. These positive changes were related to the cessation of tillage and the development of a spontaneous cover crop, which increased soil protection. Thus, management practices that contribute to increasing soil cover should be encouraged to improve soil functionality.

Combined Soil Microorganism Amendments and Foliar Micronutrient Nanofertilization Increased the Production of Allium cepa L. through Aquaporin Gene Regulation.

The aim of this study was to investigate the impact of changes in aquaporin expression on the growth of onion (Allium cepa L.) plants when subjected to dual applications of microorganism-based soil amendments and foliar nanoencapsulated mineral nutrients. Multiple physiological parameters related to water, gas exchange, and nutrient content in leaf, root, and bulb tissues were determined. Additionally, the gene expression of aquaporins, specifically PIP1, PIP2 (aquaporin subfamily plasma membrane intrinsic protein), and TIP2 (aquaporin subfamily tonoplast intrinsic protein), was analyzed. The findings revealed that the foliar application of nutrients in a nanoencapsulated form significantly enhanced nutrient penetration, mobilization, and overall plant growth to a greater extent than free-form fertilizers. Amendments with microorganisms alone did not promote growth but influenced the production of secondary metabolites in the bulbs. The combination of microorganisms and nanoencapsulated mineral nutrients demonstrated synergistic effects, increasing dry matter, mineral content, and aquaporin gene expression. This suggests that aquaporins play a pivotal role in the transport of nutrients from leaves to storage organs, resulting in the overexpression of PIP2 aquaporins in bulbs, improved water uptake, and enhanced cell growth. Therefore, the combined treatment with microorganisms and nanoencapsulated mineral nutrients may be an optimal approach for enhancing onion productivity by regulating aquaporins under field conditions.

Sustainable alternatives to 1,3-dichloropropene for controlling root-knot nematodes and fungal pathogens in melon crops in Mediterranean soils: Efficacy and effects on soil quality.

The control of agricultural pests is key to maintain economically viable crops. Increasing environmental awareness, however, is leading to more restrictive European policies regulating the use of certain pesticides due to their impact on human health and the soil system. Given this context, we evaluated the efficacy of three alternatives to the soil fumigant 1,3-dichloropropene (1,3-D), which is currently banned in Europe: two non-fumigant nematicides [oxamyl (OX) and fenamiphos (FEN)] and the soil fumigant dimethyl disulfide (DMDS). We analysed the efficiency of these pesticides against root-knot nematodes and soil fungal pathogens (determined by qPCR) as well as the soil biological quality after treatments application (estimated by enzyme activities). Among treatments, 1,3-D and DMDS significantly reduced nematode populations. FEN was more effective in sandy soil, while OX had no effect in any soil. OX and FEN had no effect on fungal pathogens, whereas DMDS reduced the abundance of Rhizoctonia solani and Fusarium solani at the root level in clay-loam soil. Soil quality decreased after treatment application but then recovered throughout the experiment, indicating the possible dissipation of the pesticides. Our findings support DMDS as a potential sustainable alternative for controlling root-knot nematodes and fungal pathogens due to its effectiveness in both studied soils, although its negative impact on soil biological quality in sandier soils must be taken into account. Main finding of the work. DMDS is a reliable alternative to 1,3-D for controlling agricultural pest but its inhibitory effect on soil enzyme activities varied according to the soil characteristics.