Transplantation of soil from organic field confers disease suppressive ability to conducive soil.

Organic agriculture is a sustainable method of farming, and confers disease-suppressing abilities to disease-conducive soils via specialized soil microbiomes. This study aimed at transforming a disease-conducive soil from a conventional field into disease-suppressive soil by inoculating soil from an organic field previously established as "disease-suppressive". The effectiveness of the transformed soil was established with the model plant wheat (Triticum aestivum) grown under natural conditions, with regard to its potential in inhibiting fungal phytopathogens, Rhizoctonia solani and Fusarium oxysporum. The conducive soil inoculated with the disease-suppressive soil performed better than the control conducive soil in terms of reduced disease severity in plants, improved soil nutrient content, increased activity of hydrolytic enzymes, and increased abundance of structural and functional microbial markers. The study demonstrates the efficacy of the soil microbiome under long-term organic agriculture in transforming disease-conducive soil into disease-suppressive soils. Such practises are simple and easy to implement, and could greatly improve the sustainability and crop yield in developing countries.

Role of Fungi in Imparting General Disease Suppressiveness in Soil from Organic Field.

Soil microbial communities are key players responsible for imparting suppressive potential to the soil against soil-borne phytopathogens. Fungi have an immense potential to inhibit soil-borne phytopathogens, but the fungal counterpart has been less explored in this context. We assessed the composition of fungal communities in soil under long-term organic and conventional farming practice, and control soil. The disease-suppressive potential of organic field was already established. A comparative analysis of the disease suppressiveness contributed by the fungal component of soil from conventional and organic farms was assessed using dual culture assays. The quantification of biocontrol markers and total fungi was done; the characterization of fungal community was carried out using ITS-based amplicon sequencing. Soil from organic field exhibited higher disease-suppressive potential than that from conventional farming, against the pathogens selected for the study. Higher levels of hydrolytic enzymes such as chitinase and cellulase, and siderophore production were observed in soil from the organic field compared to the conventional field. Differences in community composition were observed under conventional and organic farming, with soil from organic field exhibiting specific enrichment of key biocontrol fungal genera. The fungal alpha diversity was lower in soil from the organic field compared to the conventional field. Our results highlight the role of fungi in contributing to general disease-suppressive ability of the soil against phytopathogens. The identification of fungal taxa specifically associated with organic farming can aid in understanding the mechanism of disease suppression under such a practice, and can be exploited to induce general disease suppressiveness in otherwise conducive soil.

Elucidating the interactive impact of tillage, residue retention and system intensification on pearl millet yield stability and biofortification under rainfed agro-ecosystems.

Micronutrient malnutrition and suboptimal yields pose significant challenges in rainfed cropping systems worldwide. To address these issues, the implementation of climate-smart management strategies such as conservation agriculture (CA) and system intensification of millet cropping systems is crucial. In this study, we investigated the effects of different system intensification options, residue management, and contrasting tillage practices on pearl millet yield stability, biofortification, and the fatty acid profile of the pearl millet. ZT systems with intercropping of legumes (cluster bean, cowpea, and chickpea) significantly increased productivity (7-12.5%), micronutrient biofortification [Fe (12.5%), Zn (4.9-12.2%), Mn (3.1-6.7%), and Cu (8.3-16.7%)], protein content (2.2-9.9%), oil content (1.3%), and fatty acid profile of pearl millet grains compared to conventional tillage (CT)-based systems with sole cropping. The interactive effect of tillage, residue retention, and system intensification analyzed using GGE statistical analysis revealed that the best combination for achieving stable yields and micronutrient fortification was residue retention in both (wet and dry) seasons coupled with a ZT pearl millet + cowpea-mustard (both with and without barley intercropping) system. In conclusion, ZT combined with residue recycling and legume intercropping can be recommended as an effective approach to achieve stable yield levels and enhance the biofortification of pearl millet in rainfed agroecosystems of South Asia.

Complete Genome Sequence of Pseudomonas sp. Strain SK, Isolated from Organic Wheat Rhizosphere.

Here, we report the annotated whole-genome sequence of Pseudomonas sp. strain SK, isolated in India from organic wheat rhizosphere. This strain has proved to be a species with potential biocontrol activity against soilborne plant pathogens based on antiSMASH analysis.

Exploring the efficacy of wastewater-grown microalgal biomass as a biofertilizer for wheat.

Microalgae possess the ability to grow and glean nutrients from wastewater; such wastewater-grown biomass can be used as a biofertilizer for crops. The present investigation was undertaken to evaluate two formulations (formulation with unicellular microalgae (MC1) and formulation with filamentous microalgae (MC2); T4 and T5, respectively), prepared using wastewater-grown microalgal biomass, as a biofertilizer (after mixing with vermiculite/compost as a carrier) in wheat crop (Triticum aestivum L. HD2967) under controlled conditions. The highest values of available nitrogen (N), phosphorus (P), and potassium (K) in soil and nitrogen-fixing potential were recorded in treatment T5 (75% N + full-dose PK + formulation with filamentous microalgae (MC2). Microbial biomass carbon was significantly enhanced by 31.8-67.0% in both the inoculated treatments over control (recommended dose of fertilizers), with highest values in T4 (75% N + full-dose PK + formulation with unicellular microalgae (MC1)). Both the microalgal formulations significantly increased the N, P, and K content of roots, shoots, and grains, and the highest total N content of 3.56% in grains was observed in treatment T5. At harvest stage, the treatments inoculated with microalgal formulations (T4 and T5) recorded a 7.4-33% increase in plant dry weight and up to 10% in spike weight. The values of 1000-grain weight showed an enhancement of 5.6-8.4%, compared with T1 (recommended doses of fertilizers). A positive correlation was observed between soil nutrient availability at mid crop stage and plant biometrical parameters at harvest stage. This study revealed the promise of such microalgal consortia as a biofertilizer for 25% N savings and improved yields of wheat crop.