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Salinity is one of the main challenges to sustainable agriculture and is a plant abiotic stress of growing global concern. Arbuscular mycorrhizal fungi (AMF) symbiosis aids plants in overcoming stress. In this study, the efficacy of inoculation with locally isolated species using a quick colonizing method, and a commercially available AMF product were compared for enhancing growth and the physiological responses of two varieties of cucumber (‘Diva’ and ‘Safaa’) exposed to increasing soil salinity stress. Plants were irrigated with four levels of saline water of 0.64 (control), 2, 4 and 6 dS m-1 ) and evaluated. Three mycorrhizal treatments were used: uninoculated control, native AMF quick root colonizer containing 3 species and a commercial inoculum with 5 species of the Glomeraceae, Glomerales. Salinity stress significantly reduced the plant growth, ion homeostasis potassium/sodium ratio (K/Na), and mycorrhizal root colonization percentage. However, salinity increased proline content, chlorophyll content (SPAD) and leaf chlorophyll fluorescence, Na concentration in leaves and malondialdehyde (MDA) content. The application of both native and commercial AMF inoculants proved partially beneficial in alleviating the detrimental effects of salinity stress. Both inoculants improved plant growth parameters, as indicated from the improvement in plant height, plant biomass, and K and P uptake, enhancing the K/Na ratio, and optimizing nutrient availability under saline conditions. The AMF inoculation improved SPAD and photosynthetic efficiency. The AMF inoculation also promoted the accumulation of proline, and enhanced catalase activity, while the impact on MDA content exhibited fluctuation in response, with lower levels observed with native and higher levels with commercial AMF inoculants. Native AMF showed an overall higher root colonization percentage compared to commercial AMF. The findings highlight the complex role and interaction between plant-fungal symbioses in regulating salinity tolerance. The native AMF species may possess specific traits that enhance their effectiveness under local soil and climatic conditions. Overall, the use of AMF was found to be partially beneficial for cucumber plants under salinity stress, and can be integrated into a pool of sustainable farming practices that improve vegetable production under high salinity conditions, contributing to a more resilient and productive agricultural future. [ABSTRACT FROM AUTHOR]

Drought stress is one of the most serious abiotic stresses that cause significant reductions in plant growth and yield in many areas around the world. Arbuscular mycorrhizal fungi (AMF) improve plant drought tolerance by extending the root zone through extraradical hyphae exploration of soil micropores. This study evaluated the combined application of AMF and potassium silicate (PS) to improve the drought tolerance of cucumber plants. Cucumber plants were grown under two watering regimes: droughtstressed 60% water holding capacity (WHC) and unstressed 80%WHC, and three mycorrhizal inoculation treatments (control, native AMF: quick root colonizer species, and commercial AMF) with or without potassium silicate application (100 mL/pot, con. 40 mL/L). Drought stress significantly reduced plant height, biomass, and photosystem II efficiency, while it increased the content of leaf glycine betaine and catalase activity. Generally, AMF inoculation significantly improved plant growth, SPAD, photosystem II efficiency, concentration of proline, glycine betaine, and catalase activity, and the native species exhibited comparable effects to commercial species for most variables studied. Contrary to our expectations, PS application alone did not improve plant growth, except for increased photosystem II efficiency, but root fresh and dry weights were reduced. Under drought stress, combination of PS and AMF significantly improved plant height, shoot fresh weight, SPAD value, glycine betaine, and catalase activity compared to PS alone. Our results highlight that the combined application of PS and AMF inoculants can protect cucumber seedlings from drought stress; however, further research is needed to optimize the PS application method and dosage and to investigate their long-term effects on plant growth and yield under field conditions. [ABSTRACT FROM AUTHOR]

Locally produced soil amendments can play a vital role in sustainable agriculture, enhancing soil quality and crop plant growth. This study investigated the impact of locally sourced biochar (BC) and ash, obtained from Maerua crassifolia Forssk. (wood), and Saccharum kajkaiense, Melderis (grass) on soil properties and okra (Abelmoschus esculentus) biomass. We assessed different application rates (10% and 20%), either separately or combined with the potting soil/peat (Biomix). Biomix application reduced soil pH (7.9),and increased soil organic mater (OM) (51.9%), NO3-1 (17.5%) levels, water holding capacity (WHC) (22.9%), and dry biomass (37.7%) of okra compared no Biomix application. Among BC and ash amendments, grass ash excelled, increasing okra biomass by 132.7%, followed by wood BC and grass BC. However, wood ash had a slight negative effect on okra dry weight and also increased the soil EC (6.12 dS m-1). Wood ash had higher K levels (758 mg kg-1) but lower Na (159 mg kg-1) compared to control (51 mg kg-1 K and 235 mg kg-1 Na). Both BC amendments raised soil organic matter (OM) by 7.63-8.69%, while wood and grass ash slightly increased soil P (57.7-64.6 mg kg-1). However, wood and grass BC reduced soil P to 44 mg kg-1. Grass ash raised NO3 levels (25.5%) compared to the control. The interaction of Biomix with wood and grass amendments decreased soil EC, increased soil OM, NO3 level and plant dry weight of okra. Wood and grass BC (20%) with Biomix enhanced the soil OM by 11%. The combination of 10% grass ash and Biomix resulted in the highest NO3 levels at 170 mg kg-1. Furthermore, the combination of Biomix and 10% grass ash produced the most significant increase (204.3%) in plant dry weight compared to the control. In conclusion, locally sourced biochar and ash amendments, particularly grass ash in combination with potting soil/peat (Biomix), demonstrated significant potential to enhance soil quality and crop biomass, offering valuable insights for sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

In a previous study, we isolated four antagonistic bacterial strains viz., Pseudomonas aeruginosa B1-SQU, Pseudomonas indica B2-SQU, Serratia marcescens B3-SQU and Pseudomonas brenneri B4-SQU from the rhizosphere of cabbage which suppressed damping-off in cabbage caused by Pythium aphanidermatum. In this study, potential of these bacterial isolates to produce antimicrobial volatile organic compounds (VOCs) against P. aphanidermatum was tested. The results of the two-sealed-base-plates assay revealed that all four bacterial strains produced VOCs against P. aphanidermatum with the maximum inhibition with P. brenneri B4-SQU followed by S. marcescens B3-SQU, P. aeruginosa B1-SQU and P. indica B2-SQU. Solid-phase microextraction coupled with gas chromatography-mass spectrometry was used to profile the VOCs of bacteria. A total of 20 VOCs were detected in P. aeruginosa B1-SQU and the major compounds identified were Carbon dioxide, 1-Butanol, 3-methyl- and Disulfide, dimethyl. The main volatile compounds detected in P. indica B2-SQU were 1-Butanol, 3-methyl-, Disulfide, dimethyl and 1,2-Propanediamine. Disulfide, dimethyl and 1,2-Propanediamine were the predominant compounds identified in S. marcescens B3-SQU among others. The major compounds detected in P. brenneri B4-SQU were 1-Butanol, 3-methyl-, 1,2-Propanediamine and Disulfide, dimethyl. Dimethyl disulfide, a well-known antimicrobial compound, was detected in the volatile profiles of all four antagonistic bacterial isolates. These results suggest that VOCs of antagonistic bacteria may be involved in the suppression of P. aphanidermatum and these antagonistic bacterial strains may be used as biofumigants for controlling damping-off of cucumber. [ABSTRACT FROM AUTHOR]

Organic soil amendments have been used in Oman since prehistoric agriculture began and are still being used today. Recently, interest in certified organic farming, and the use of organic soil amendments to enhance soil quality has motivated more research on traditional and new diverse soil amendment products. In addition, the arid climate of Oman combined with sandy soils benefit from non-traditional soil amendments and nutrient sources, such as treated human waste and wastewater. These two are not allowed in certified organic farming but offer sustainable solutions to building soil health for non-certified crops. This review will cover studies of soil quality in Oman related to the comparison of these various amendments, including manures, composts, organic mulch materials, biochar, ash, and others. In general, most of these amendments improve the soil by adding organic carbon, increasing the water holding capacity, improving infiltration rate, and stimulating or providing habitat and food sources for diverse soil microbiological communities. Some amendments can also help crops overcome some of the stresses of agriculture in Oman, such as soil salinity, heat and drought. Most also provide macro and micronutrients for crop growth. Some anti-quality factors may be present however, such as a high carbon to nitrogen ratio in some mulches, or high heavy metal content, human pathogens, and pharmaceutical residues in treated waste or wastewater. Biochar may have a positive or negative effect on soil microbes, depending on the source material and temperature of combustion can result in byproducts that inhibit microbes. The value of soil microorganisms has been shown in organic cropping systems, and several new species have been discovered in Oman. Some of these provide possibilities for biocontrol of pathogens, and increased salt tolerance in crops like tomato. Though much valuable research has been done in Oman and the rest of the world, there is much left to be done to determine the effects of these organic amendments over the long term, and also the interactions among various amendments, soil conditions, soil microbes, and on crops grown with different irrigation methods and cropping systems. [ABSTRACT FROM AUTHOR]

Survey responses of producers and institutional buyers in northeastern Kansas (United States) were analyzed to understand barriers and opportunities for sustainable food systems in the region where their emergence has been limited. Producers and buyers identified barriers previously noted regarding mismatches of available quantities and prices. Producers' enthusiasm to supply locally exceeded buyers' interest to source locally. Transportation was identified as one of the major concerns by producers, and their responses to choice tasks revealed producers' preferences to sell locally while pricing their products to secure sales revenue and to cover their logistics expenses at least partially. [ABSTRACT FROM AUTHOR]

This study evaluated germination and establishment characteristics of native legumes, which may hold potential for development as water-efficient cover crops in Kansas. Twenty-three species were subjected to hot water scarification, cold-moist stratification, and no pretreatment and allowed to germinate on moist filter paper under ambient laboratory conditions for 16 days. 1n the field, I m- plots were plantedwith 1.1 grams of seed of each of 23 native species and five introduced species at three planting dates, two in the fall and one in earlyspring. Seedlings were counted in late June. The effect of seed treatment on germination in the lab was highly species dependent. Hot water scarification had positive (4 species), neutral (16 species), or negative (3 species) effects on early germination (day 2), though fewer differences were seen can day 16. Stratification rarely had significant negative consequences and also affected both the rate and total amount of germination. Both species and planting date had significanteffects on establishment in field plots. Establishment of all species was most successful with spring planting. Because of extremely dry conditions, this trend could be attributable to moisture availability. Though these results are preliminary, the lack of germination inhibition and Successful establishment of some of the species in the field indicates that this is a promising direction of future research tier new cover crops for harsh conditions. [ABSTRACT FROM AUTHOR]

Summarizes a report on ecosystem analysis at a watershed level, as presented during a conference sponsored by the Soil and Water Conservation Society in Athens, Georgia in April 1997. Education, research and policy needs; Development of the direction for integrated natural resource systems management; Interagency cooperation and communication.