Irrigation and fertilization strategies have been extensively employed to enhance the growth and yield of greenhouse tomatoes. However, the impacts of divergent fertilizer application patterns on soil microbial communities under water-saving irrigation regimes in China's arid and semi-arid zones remain underexplored. In this study, a pot experiment was conducted in the greenhouse of Yuncheng University, Shanxi Province, incorporating three irrigation levels (I1, 90%-100% field capacity [Fs]; I2, 72%-80% Fs; I3, 54%-60% Fs) and four fertilization modes (C1, soluble organic-inorganic fertilizer combination; C2, sole soluble inorganic fertilizer; C3, sheep manure-inorganic fertilizer combination; C4, sole soluble organic fertilizer) to evaluate the effects of water-fertilizer management on the growth and physiological attributes of greenhouse tomatoes. Results demonstrated that irrigation regimes and fertilization patterns significantly modulated bacterial richness and diversity, as quantified by amplicon sequence variants (ASVs). The C1 treatment (soluble organic-inorganic fertilizer integration) exhibited the highest bacterial alpha diversity (Shannon index: 7.29). In beta diversity analysis, it induced the most distinct community structures, particularly under I3 (PCo1 = 17.96%) where it strongly diverged from C3. Microbial communities under I2 (PCo1 = 11.13%) showed greater homogeneity while preserving treatment-specific patterns, suggesting slight deficit irrigation balances stability and functional differentiation. The C1 treatment also elicited the most pronounced enhancement in soil enzyme activities, particularly phosphatase (PHO, 9.51 mg g ⁻ ¹) and catalase (CAT, 2.29 mL g ⁻ ¹). Conversely, reduced irrigation (I3) corresponded with decreased bacterial diversity, whereas slight deficit irrigation (I2) sustained higher microbial abundance compared to severe deficit irrigation. Additionally, I2 elevated soil pH (8.04), available phosphorus (AP: 10.39 mg kg ⁻ ¹), and soil nitrate nitrogen (SNO₃ ⁻ -N: 5.02 mg kg ⁻ ¹). These findings provide critical insights into optimizing water-fertilizer strategies to enhance microbial activity and nutrient cycling in greenhouse tomato production systems. Phylogenetic analysis identified Actinobacteriota (26.06%), Proteobacteria (25.89%), Chloroflexi (12.42%), and Acidobacteriota (11.03%) as the dominant bacterial phyla. Significant positive correlations were observed between invertase, urease, catalase, and alkaline phosphatase activities and microbial diversity indices (ASVs, ACE, Chao1, Shannon index). This study advances our understanding of how rhizosphere bacterial communities adapted to fertilization regimes under water stress, offering novel perspectives for precision management of greenhouse agroecosystems in water-constrained regions.
The present study concerns measurement of the radon concentration in drinking and irrigation waters obtained from the eastern part of Oman, in particular in regard to water quality assessment of the region. The samples were collected from different places covering most types of water sources in the region. A passive and time-integrated track etch detector (LR-115 type II) combined with a high-resolution optical microscope has been used to obtain the radon concentration in the studied samples. Values of dissolved radon in water varied among the water sources; the highest concentration of radon was found to be 363 Bq m-3 in a drinking water sample while well water used for irrigation showed the lowest value, at 140 Bq m-3. Measured data for all water sources are below the permissible limit of 11.1 kBq m-3 recommended by the US-EPA. Annual effective doses for the studied samples were in the range 0.38-0.99 μSv y-1 which is significantly less than the action level recommended by the WHO (0.1 mSv y-1), indicating that the water sources in the Jalan BBH region of Oman are safe to use. The obtained data may serve as a reference for any future radiological study of the waterbody of this region.
The option of reusing greywater is proving to be increasingly attractive to address the water shortage issue in many arid and semiarid countries. Greywater represents a constant resource, since an approximately constant amount of greywater is generated from kitchen, laundries, bathroom in every household daily, independent of the weather. However, the use of greywater for irrigation in particular for household gardening may pose major hazards that have not been studied thoroughly. In this study, a 1-year monitoring was conducted in four selected households in Perth, Western Australia. The aim of the monitoring works is to investigate the variability in the greywater flow and quality, and to understand its impact in the surrounding environments. Case studies were selected based on different family structure including number, ages of the occupants, and greywater system they used. Samples of greywater effluent (showers, laundries, bathtub, and sinks), leachate, soil, and plants at each case study were collected between October 2008 and December 2009 which covered the high (spring/summer) and low (autumn/winter) production of greywater. Physical and chemical tests were based on the literature and expected components of laundry and bathroom greywater particularly on greywater components likely to have detrimental impacts on soils, plants, and other water bodies. Monitoring results showed the greywater quality values for BOD, TSS, and pH which sometimes fell outside the range as stipulated in the guidelines. The soil analyses results showed that salinity, SAR, and the organic content of the soil increased as a function of time and affected the plant growth. Nutrient leaching or losses from soil irrigated with greywater shows the movement of nutrients and the sole impact from greywater in uncontrolled plots in case studies is difficult to predicted due to the influence of land dynamics and activities. Investigative and research monitoring was used to understand greywater irrigation in households. Greywater quality is very site specific and difficult to predetermine or control except for the use of some recommended household products when using greywater. Investigative and research monitoring was indicated that greywater quality is very site specific and difficult to predetermine or control except for the use of some recommended household products when using greywater.
Sunflower production is significantly lower in arid and semi-arid regions due to various crop management problem. Conservation of tillage provides the most excellent opportunity to reduce degradation of soil reserves and increase soil productivity. The main objective of this study was to investigate the combined effects of conservation tillage and drought stress on growth and productivity of different sunflower hybrids. Experimental treatments included two sunflower hybrids ('NK-Senji' and 'S-278'), two drought stress treatments (i.e., well-watered and drought stress at flowering and grain filling stages) and three tillage practices (i.e., conservation, minimum and deep tillage). The results indicated that morphological and physiological parameters, and yield-related traits were significantly (P≤0.05) affected by all individual factors; however, their interactive effects were non-significant. Among sunflower hybrids, 'NK-Senji' performed better for morphological, physiological, and yield-related traits than 'S-278'. Similarly, conservation tillage observed better traits compared to the rest of the tillage practices included in the study. Nonetheless, conservation tillage improved growth and yield-related traits of hybrid 'NK-Senji' under drought stress. Hence, it is concluded that conservation tillage can improve the productivity of sunflower under low moisture availability. Therefore, conservation tillage could be suggested in the areas of lower water ability to improve sunflower production. Nonetheless, sunflower hybrids or varieties need thorough testing for their adaptability to conservation tillage and low moisture availability before making recommendations.