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Abstract The demand for reliable indicators to quantify soil health has increased recently. We propose and test the use of soil microbial functional diversity as an indicator of multifunctional performance in agriculturally important areas. Agricultural fields in the Mediterranean and semiarid regions of Israel were selected as test sites and measured in Spring and Autumn seasons. Measurements included microbial parameters, basic soil abiotic properties and biological responses to agricultural management relative to measures of a natural ecosystem. Using a canonical correlation analysis we found that soil moisture was the most important basic soil property with different responses in Spring and Autumn. In Spring, it had a strongly negative relation with microbial biomass (MB), community level physiological profiling (CLPP) and the Shannon-Weaver index H', while in Autumn it had a strong relation with CLPP. We further show a significant interaction between CLPP and climate for land-use type "orchards". CLPP measured in the autumn season was thus identified as a useful and rapid biological soil health indicator, recommended for application in semiarid and Mediterranean agricultural regions. Apart from obtaining a better understanding of CLPP as the soil indicator, the study concludes that CLPP is well suited to differentiate between soils in different climates, seasons and land use types. The study shows a promising direction for further research on characterizing soil health under a larger variety of conditions.

Context. Although both plant cover and mulch are considered for erosion control in arid and semi-arid regions, they have divergent impacts on soil ecology. Aim. We examined the effects of orchard floor management practices on the density and diversity of soil free-living nematode communities and relevant soil abiotic properties. Methods. Soils were sampled in winter in a citrus orchard in the Sharon region of Israel from plots that for 6 years had been under (1) annual native species; or (2) Avena sativa and Vicia villosa, planted between tree rows; or (3) woodchip mulching along tree rows. There were two control sites: (4) bare soil between tree rows and (5) bare soil along the tree rows (both common practice). Key results. Nematode communities and their trophic diversity were significantly impacted by floor management. Significant increases in soil moisture under plant cover, and higher organic matter and water-holding capacity for all covered orchard floors could be related to nematode changes. Shifts in nematode feeding group structure suggest a shift in the type and availability of soil carbon pools. Conclusions. There was a strong association between orchard floor management and soil free-living nematode communities, indicating a shift in the soil food-web structure and functionality. Bare soil harboured fewer nematodes, but more complex communities dominated by persisters, while seeded plant cover had a greater nematode abundance dominated by coloniser communities, indicating increased availability of resources. Implications. Results reveal the importance of integrating biological information in performance index determinations for improving soil management decisions, suggesting these relationships as sensitive bio-indicators of soil health. Keywords: cover crops, functional diversity, mediterranean, mulching, nematodes, orchard, soil degradation, soil ecology., Introduction Any agricultural practice affects the functioning of soil biota (Dunn et al. 2021). This needs to be taken into consideration when contemplating a shift from conventional, intensive agriculture, characterised [...]

Conventional, sustainable or organic farming practices are assumed to have distinct effects on soil fertility and health. This is often supported by arguments linking management and resulting soil parameters to crop yield and produce quality. Soil microbial communities are sensitive to management practices that alter soil water fluxes and the pools and fluxes of nutrients. These effects might be accentuated in arid or semiarid agriculture. Conversion to vineyard use, under Mediterranean conditions, and the subsequent application of different management types creates the conditions for divergent soil microbial communities. An off-season survey of variably managed vineyards located in a Mediterranean climate showed that both organic and conventional vineyard management had the most distinct impact on soil abiotic parameters, and on the bacterial and fungal communities; both organic and sustainable management enhanced soil organic carbon, water holding capacity and nitrogen availability. The sustainable management led to soil microbial communities most similar to the natural conditions. Fungal diversity was better than bacterial diversity at discriminating between soils under different management types. Classes of the dominant Ascomycota phylum had best discriminating power; Mucoromycota declined significantly after conversion to vineyard use and was a key taxonomic indicator for such conversion. Regarding bacterial communities, a focus on functional categories, e.g. nitrogen-fixing taxa, may be more informative than total diversity assessments. Keywords: arbuscular mycorrhizae, land-use conversion, Mediterranean, microbial diversity, nitrogen-fixing bacteria, organic, soil fertility, vineyard., Introduction Demands from consumers and policy makers for more sustainable agriculture led to the emergence of numerous sustainable vineyard programs, which are then reflected in wine labels (Viers et al. [...]

Carbon sequestration in soil has been suggested as a means of reducing the rate of increase of atmospheric C[O.sub.2]. Most soil science research has been on soil organic carbon (SOC) sequestration but in arid and semiarid climates, soil inorganic carbon (SIC) may offer another option for C sequestration. A field study was conducted in Bakersfield, CA, to determine if irrigation water quality (fresh water [FW] vs. treated effluent [TE]) affected the distribution and amount of SIC and SOC in the upper 4 m of soil and parent material compared to a nonirrigated (NI) field. Significant carbonate depletions were found in the upper 2 m in both irrigated fields compared with the NI. Differences in carbonate content between irrigated fields were also related to soil texture. Total carbonate and clay-size carbonate were more abundant at the sites irrigated with TE than at the sites irrigated with FW, indicating that the TE had inhibited carbonate dissolution. Based on stable isotope analyses ([sup.13]C and [sup.18]O) and radiocarbon dating, we estimated that irrigation for >75 yr sequestered about 7.15 kg [m.sup.-2] [(4 m).sup.-1] of SIC under FW and between 0.9 and 2.4 kg [m.sup.-2] [(4 m).sup.-1] under TE, if carbonate dissolution is C sequestration. Adding C loss due to SOC decomposition to the SIC sequestration, the fields may be a source for 8.8 and 17.4 to 15.9 kg [m.sup.-2] [(4 m).sup.-1] of C under FW and TE, respectively. This study provides some of the first evidence of how water quality affects the C budget in an arid region. Abbreviations: FW, freshwater; NI, nonirrigated; PSD, particle size distribution; SIC, soil inorganic carbon; SOC, soil organic carbon; TE, treated effluent.

Halophytes are able to thrive in salt concentrations that would kill 99% of other plant species, and identifying their salt-adaptive mechanisms has great potential for improving the tolerance of crop plants to salinized soils. Much research has focused on the physiological basis of halophyte salt tolerance, whereas the elucidation of molecular mechanisms has traditionally lagged behind due to the absence of a model halophyte system. However, over the last decade and a half, two Arabidopsis (Arabidopsis thaliana) relatives, Eutrema salsugineum and Schrenkiella parvula, have been established as transformation-competent models with various genetic resources including high-quality genome assemblies. These models have facilitated powerful comparative analyses with salt-sensitive Arabidopsis to unravel the genetic adaptations that enable a halophytic lifestyle. The aim of this review is to explore what has been learned about halophytism using E. salsugineum and S. parvula. We consider evidence from physiological and molecular studies suggesting that differences in salt tolerance between related halophytes and salt-sensitive plants are associated with alterations in the regulation of basic physiological, biochemical, and molecular processes. Furthermore, we discuss how salt tolerance mechanisms of the halophytic models are reflected at the level of their genomes, where evolutionary processes such as subfunctionalization and/or neofunctionalization have altered the expression and/or functions of genes to facilitate adaptation to saline conditions. Lastly, we summarize the many areas of research still to be addressed with E. salsugineum and S. parvula as well as obstacles hindering further progress in understanding halophytism. [ABSTRACT FROM AUTHOR]

Non-photochemical quenching (NPQ) plays a major role in photoprotection. Anastatica hierochuntica is an annual desert plant found in hot deserts. We compared A. hierochuntica to three other different species: Arabidopsis thaliana, Eutrema salsugineum and Helianthus annuus, which have different NPQ and photosynthetic capacities. Anastatica hierochuntica plants had very different induction kinetics of NPQ and, to a lesser extent, of photosystem II electron transport rate (PSII ETR), in comparison to all other plants species in the experiments. The major components of the unusual photosynthetic and photoprotective response in A. hierochuntica were: (1) Low NPQ at the beginning of the light period, at various light intensities and CO2 concentrations. The described low NPQ cannot be explained by low leaf absorbance or by low energy distribution to PSII, but was related to the de-epoxidation state of xanthophylls. (2) Relatively high PSII ETR at various CO2 concentrations in correlation with low NPQ. PSII ETR responded positively to the increase of CO2 concentrations. At low CO2 concentrations PSII ETR was mostly O2 dependent. At moderate and high CO2 concentrations the high PSII ETR in A. hierochuntica was accompanied by relatively high CO2 assimilation rates. We suggest that A. hierochuntica have an uncommon NPQ and PSII ETR response. These responses in A. hierochuntica might represent an adaptation to the short growing season of an annual desert plant. [ABSTRACT FROM AUTHOR]

The article discusses a study which examined the long-term in situ accumulation of copper (Cu), chromium (Cr), nickel (Ni) and zinc (Zn) in the soil profile of an effluent recharge basin at a wastewater reclamation plant in Israel. The study was designed to quantify the accumulation of metals in the soil profile of the basin, explain retention mechanisms and determine material balances and metal removal efficiency in relation to metal load increase. Study researchers concluded that the low long-term removal efficiency of the metals may be due to the low concentrations of metals in the recharged effluent and low adsorption affinity and retention capacity of sandy soil.