Ilya Gelfand

Conventional low-density poly(ethylene) (LDPE) agricultural mulch films generate persistent plastic waste, which has motivated the development of biodegradable mulch films (BDMs) that can provide adequate performance during use while offering improved end-of-life options. Here, composite films containing poly(lactic acid) (PLA), poly(butylene adipate-co-terephthalate) (PBAT), microcrystalline cellulose (MCC), and hydroxyapatite (HA) were evaluated for their material properties and suitability as agricultural mulches. Correlation analysis and Elastic Net regression were used to examine composition–property relationships. PBAT primarily governed ductility and tensile performance, whereas MCC significantly increased water absorption because of its hydrophilic character. Water absorption was the most reliably modeled response (training R² = 0.893), while mechanical property models showed limited validation performance, which indicates that composition alone could not fully predict unseen formulations. Several formulations met commercial BDM mechanical requirements. Multi-objective optimization predicted a composition of 9.3/80.7/3.5/6.5 wt% PLA/PBAT/MCC/HA. The combined experimental and modeling framework clarifies composition–property relationships in biodegradable polymer composites and demonstrates how data-driven approaches can guide the formulation of biodegradable agricultural mulch films.

Ephemeral leaflets are produced on emerging daughter cladodes of Opuntia ficus-indica (prickly pear), a constitutive crassulacean acid metabolism (CAM) species of major agronomic and ecological importance. Despite their ubiquity across Cactaceae, these transient organs have never been characterized as discrete photosynthetic units. Here, we investigate whether leaflets operate via C3 or CAM photosynthesis and quantify their contribution to early cladode carbon (C) economy. Gas-exchange measurements, stomatal aperture analysis, titratable acidity assays, C isotope discrimination (δ13C), and 13CO2 pulse-labelling consistently indicated that leaflets operate via the C3 pathway: they exhibited daytime stomatal opening, minimal nocturnal acid accumulation, greater discrimination against 13CO2 (δ13C reaching −17‰ in mature leaflets compared with −10‰ to −11‰ in cladodes), and net daytime CO2 uptake at rates of ∼50% of those in mature cladodes. C-balance calculations indicated that leaflets supply ∼0.12 g C cladode−1 d−1, meeting ∼20% of the daily C demand of the expanding daughter cladode. Experimental removal of leaflets and stomatal blockage reduced daughter-cladode surface area by 28–34% and dry weight by ∼38% relative to controls at 3 weeks. These findings reveal an intra-plant co-ordination of C3 and CAM C fixation in spatially distinct organs and identify leaflets as adaptive source organs that accelerate biomass accumulation during pulsed periods of water availability in arid environments.

Salinity and drought are abiotic stresses that substantially impair growth, biomass production, and metabolic regulation. This study examined how irrigation frequency and salinity levels affect biomass production, physiological traits, and antioxidant responses in the halophytes Sarcocornia fruticosa (Megadim ecotype) and Arthrocaulon macrostachyum (AM). The plants were subjected to irrigation intervals of 2, 6, and 10 days and varying salinity levels: 50, 150, and 250 mM NaCl for Sarcocornia, and 150 and 250 mM NaCl for AM.,Frequent irrigation significantly increased both fresh and dry biomass across all salinities, with the highest biomass under high salinity and frequent irrigation in both halophytes. Moderate salinity (150 mM), combined with 6- and 10-day irrigation intervals, yielded higher production than at other salinity levels. AM showed strong antioxidant responses, with higher flavonoid, polyphenol, radical-scavenging activity (RSA), oxygen radical absorbance capacity (ORAC), and protein levels, particularly under a 6-day irrigation interval. In contrast, Sarcocornia exhibited greater RSA and ORAC levels under frequent irrigation at 150 and 250 mM NaCl, while flavonoids increased under 10-day irrigation at 50–150 mM; polyphenols, RSA, and ORAC peaked at 50 mM NaCl with 6-day irrigation.,Photosynthetic pigments, total soluble sugars, and electrical conductivity increased with irrigation every 10 days in both species, suggesting osmotic adjustment to drought. Conversely, anthocyanin, relative water content, and malondialdehyde levels peaked with more frequent irrigation. Overall, irrigation frequency significantly interacted with salinity to influence growth, osmotic adjustment, and antioxidant defense mechanisms in halophytes, highlighting their potential for sustainable cultivation in saline and water-limited environments.

Halophyte bio-saline agriculture can supplement conventional farm methods in salinized soils and salty water. The current study compares the yield and nutritional value of new Sarcocornia fruticosa ecotypes (Shikmona, Megadim, Naaman, and Ruhama) to those of the current ecotype (VM). Additionally, Arthrocaulon macrostachyum, phenotypically similar to Sarcocornia, was compared to Sarcocornia ecotypes, and the effects of the harvesting regime and irrigation water salinity on yield and nutritional value were studied. At both salinity levels (50 and 150 mM NaCl), 30-day harvesting intervals over a 210-day growth period increased plant yield compared to a 21-day regime. It also tended to improve electrical conductivity (EC) and total soluble sugars (TSS), lower malondialdehyde levels (a marker of toxic stress), and enhance radical inhibition activity in most ecotypes. Compared to VM, the Sarcocornia ecotypes Ruh and Naa exhibited much higher biomass with similar radical inhibition activity but lower total protein content. Higher salinity improved fresh biomass, shoot diameter, relative water content, chlorophyll level, TSS, and EC and tended to increase anthocyanin and carotenoid levels. In contrast, lower salinity tended to increase total flavonoids, polyphenols, and radical inhibition activity. In the 30-day harvest regime, A. macrostachyum exhibited the highest and second-highest yields at high and low salinity, respectively; the highest shoot diameter, total flavonoids, and radical inhibition activity; and one of the lowest malondialdehyde levels. The current study highlights the importance of optimizing harvest frequency and the advantages of employing A. macrostachyum and the Sarcocornia ecotypes Ruhama, Naaman, and Megadim with a 30-day harvesting regime under higher-salinity conditions.

Nitrous oxide (N ₂ O) emissions from agricultural soils contribute ∼4% of total anthropogenic greenhouse gas emissions globally. Events known as “hot moments” can occur following environmental changes that favor N ₂ O production, which contribute disproportionately to annual cumulative emissions. Despite their significance, hot moments and their impact have not been statistically well defined, particularly on a global scale. We collected 13,787 soil N ₂ O flux measurements from 42 publications and evaluated 14 methods of statistical anomaly detection for their ability to identify hot moments within data sets. Two methods achieved the highest overall performance by Matthews correlation coefficient (MCC): median absolute deviation (MCC: 0.80) and minimum covariance determinant (MCC: 0.80), the latter of which also performed evenly across highly dissimilar data sets and identified more contextually important minor hot moments (39%) that other methodologies may misidentify. Interquartile range, which has previously been used and recommended, performed poorly when hot moments were either very rare or very common within a data set and identified few local hot moments (14%). Overall, hot moments comprised ∼19% of measurements while contributing ∼75% of cumulative emissions. The median background N ₂ O emission reported in all data sets was 2.2 g N ha ⁻¹ day ⁻¹ , whereas the median hot moment emission was 10‐fold higher, ranging from 23 to 25 g N ha ⁻¹ day ⁻¹ . These findings advance knowledge of how to accurately define and identify hot moments globally—a crucial task to investigating and mitigating these critical biogeochemical events.

Deserts cover ~50% of Earth’s surface but are poorly studied regarding their methane (CH ₄ ) fluxes. Current theory suggests that dry soils act as CH ₄ sinks, with higher soil carbon (C) content enhancing oxidation. To test this, we measured CH ₄ fluxes in 12 field plots with increasing C content in Israel’s Negev Desert over three summer and three winter months using automated chambers. We hypothesized that well-aerated soils would oxidize CH ₄ , and the oxidation rate will increase with more organic matter. Contrary to our hypothesis, CH ₄ was emitted ~75% of the time, with average effluxes of 0.222 ± 0.007 nmol m ⁻² s ⁻¹ in summer and 0.081 ± 0.004 in winter. We propose that CH ₄ emissions were driven by abiotic processes related to solar radiation, not microbial activity. A shading experiment reduced CH ₄ efflux by 51%, supporting this idea. The newly identified CH ₄ source of at least 89.8 ± 2.2 mg CH ₄ m ⁻² yr ⁻¹ equals ~30% of the modelled CH ₄ sink (~300 mg CH ₄ m ⁻² yr ⁻¹ ) for the same region. Synopsis: Our field measurements in Israel’s Negev Desert show that dry desert soils can emit methane, challenging current models that assume these soils consistently act as atmospheric methane sinks.