Drought Adaptation Strategies Research Articles

Rocky soils alter the diurnal photosynthetic behavior of xerophytic species by regulating hydraulic properties

Functional relationships between photosynthetic behavior and hydraulic properties are essential to characterize plant drought adaptation strategies. However, little is known about such relationships in response to varying rock fragment content (RFC), which could induce severe soil water deficit. We evaluated the leaf hydraulic properties and the timing of diurnal depression of photosynthesis in three xerophytic shrub species grown under different RFC levels (0, 25, 50, 75 % v v−1). We found that studied species grown in 25 % RFC soil conditions had higher leaf hydraulic conductance (Kleaf) and reached maximum photosynthetic rate (Amax) in the morning, while those grown in 75 % RFC soil conditions had lower Kleaf, but reached their Amax in the afternoon. In addition, species in 75 % RFC soil conditions also exhibited low leaf hydraulic vulnerability and narrow leaf hydraulic safety margins. Our results indicate that RFC modifies the diurnal gas exchange dynamics of xerophytic species by decreasing leaf hydraulic vulnerability and hydraulic safety margins. Specifically, species surviving in 75 % RFC soils are less vulnerable to drought induced water loss, and carbon assimilation depression were later than in 25 % or 0 % RFC soil conditions. However, when faced with severe drought, these species with latter CO2 uptake depression are at higher risk of hydraulic failure, because their safety margins are relatively narrow. Our results contribute to the knowledge of drought adaptation strategies in xerophytic species native to dry-hot rocky mountains.

Understanding drought adaptation mechanisms from a gender perspective in modogashe ward, Kenya

Droughts have severely affected the pastoral production system resulting in hunger, massive loss of livestock, acute water shortages, and drought-related conflicts. This study aimed to understand the drought adaptive mechanisms from a gender perspective in Modogashe Ward, Kenya. To achieve this, the study investigated the impacts of droughts and the various ways in which men and women cope and adapt to the impacts. Due to the homogeneousness in sociocultural and economic activities in the Ward data was obtained from 60 respondents comprising 30 males and 30 females through a stratified random sampling method. One respondent, either the husband or wife, was chosen per household. Both men and women rely on pastoralism as the main source of livelihood. Thus, the impacts and adaptation mechanisms were similar for both genders. However, due to the attachment of men to livestock, the impacts and adaptation mechanisms revolved around environmental factors while those of women revolved around the provision of household basic needs. Furthermore, the study area had limited adaptation mechanisms options resulting in similar coping and adaptation strategies among men and women but with minor variations in the preferred strategies. The variations in the preferred strategies were a reflection of the existing gender roles within the social construct of the community. Men were inclined toward measures that promote livestock keeping while women preferred measures that enhanced the provision of household basic needs. The findings from this study highlight the significant role of gender dimensions driven by the local socio-cultural settings in influencing the uptake of drought adaptation practices and strategies among communities.

Depiction of Drought Over Africa in the Light of Changing Climate from CMIP6 Models

Drought stands as a prevalent weather-related natural climatic disaster on a global scale. This study employs twenty GCMs from CMIP6 to investigate hydrological drought characteristics (frequency, duration, and intensity) across Africa under four SSPs (shared socioeconomic pathway) scenarios: SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 spanning three designated periods: 2021–2040 (near-term), 2041–2060 (mid-term), and 2081–2100 (long-term). The (SPEI) at a 12-month scale and employs bias correction on the multi-model ensemble mean extracted from GCMs of the CMIP6 project via cumulative distribution function (CDF). Mann–Kendall approach was implemented for trend and the SPEI-12-based drought trend from 1979 to 2014 displays a negative trajectory of − 0.05/a for Africa, with similar figures for specific regions: Northern Africa (NAF) at − 0.06/a, Sahara (SAH) at − 0.05/a, Western Africa (WAF) at − 0.01/a, Central Africa (CAF) at − 0.02/a, Eastern Africa (EAF) at − 0.06/a, and Southern Africa (SAF) at − 0.03/a. Notably, the severe drought characteristics are manifested as a 6-month duration, 12 occurrences, and an intensity of − 1.9 events over Africa. The highest duration and frequency are observed over NAF at 7.5-month and 15.1 occurrences, respectively, while the most extreme intensity of − 2.3 events is noted over SAH. In addition, future droughts are expected to be lower frequency, extended duration, and more intense. Extreme scenarios indicate values of − 2.1, − 2.2, and − 2.6 events for Africa in the periods 2021–2040, 2041–2060, and 2081–2100, respectively, compared to − 1.99 in the historical period. The intensity of the drought is expected to increase across all sub-regions, with SAH and NAF projecting the worst conditions with − 2.4, − 2.8, and − 3.0 events respectively for SAH and − 2.2, − 2.7, and − 3.0 events for NAF. Africa’s droughts are predicted to last 6, 8, and 13 months, significantly longer than the usual 4-month period. As the historical events of 17 times is anticipated to drop to 6, 5, and 3 times, respectively. The insights derived from this study could provide a foundational basis for devising effective drought adaptation strategies in Africa. Given the anticipated severity of drought events, prioritizing plans to cope with such challenges is of paramount importance.

Drought Adaptation Strategies Among Smallholder Cereal Farmers In Makueni County, Kenya

Increasing frequency and severity of drought increase vulnerability of smallholder cereal farmers globally. Arid and Semi-Arid Lands cover 80% of Kenya and location around the equator are major factors in drought development in the country. Frequent droughts result in fluctuations in cereal yields hence food insecurity in Makueni County. This study evaluated community-based and indigenous knowledge drought adaptations practiced by smallholder cereal farmers in Makueni County, Kenya. This study adopted explanatory sequential mixed methods research design. Household surveys (N=225) and key informant interviews (N=16) were used. Descriptive techniques were used in data analysis. The study found that frequent droughts in Makueni County resulted in adoption of small farm sizes for production of maize, sorghum and finger millet. Majority of the farmers produced between 1 and 10 bags of cereals. Majority (50.2%) of the smallholder cereal farmers who adopted community-based adaptations and indigenous knowledge-based drought adaptations strategies recorded an in increase in cereal yields in Makueni County. Early planting (66.7%), timely weeding (61.4%), manure application (57.0%), improving land tillage (56.1%), seed spacing (55.3%) and planting droughtresilient seeds (44.7%) led to the high annual cereal yields ranging between 1 and 10 bags in Makueni County. The drought adaptation strategies are commendable for upscaling in agro-ecological zones with similar climatic conditions in order to improve food production in the country. Information and data generated by this study is expected to result in improvement in drought adaptation policy formulation and adaptive capacity of smallholder cereal farmers hence, improvement in food production and security.

Welfare impacts of drought adaptation strategies in John Taolo Gaetsewe district, Northern Cape Province, South Africa

Drought is a global problem that presents a negative impact on the welfare of millions of people in both industrialized and developing nations. In South Africa, poor rural households, who depend on rain-fed subsistence agriculture for their livelihoods are the most susceptible to drought, and have the least ability to absorb its impacts. The primary goal of this study was to analyse the effects of drought adaptation strategies on rural households’ welfare and to compute the welfare enhancement impacts that are associated with each adaptation method. The study was conducted in John Taolo Gaetsewe district, Northern Cape province. Multistage sampling technique was used to sample 360 rural households, who were affected by drought. The results showed that the average age of households’ heads was 52 years. Only 41% of the households’ heads had an education level between Grades 8 and 12, and about 63% were male. Average farming experience was 7.67 years and pensioners made up about 47%. Also, 65% of households’ heads depended on government assistance, while 85% lacked access to formal credit. The 2SLS results showed that household income, household size, pension, grant, and use of crop diversification significantly influenced per capita consumption expenditure. The results showed that average treatment effect (ATE) from crop diversification was R497.16 and statistically significant (p<0.05). It was concluded that many drought adaptation methods are not influencing households’ welfare, and efforts to promote adaptation should focus on crop diversification with specific assistance given to social grant holders. Res. Agric. Livest. Fish. Vol. 11, No. 2, August 2024: 185-196

Drought Disaster Causes and Their Proposed Adaptation Strategies around Karst Areas in Gunungkidul Regency, Indonesia : A Review

Gunungkidul Regency, one of Indonesia's karst regions, frequently experiences droughts. This study aims to investigate the causes of drought disasters and provide adaptation strategies for disasters that may occur near karst areas in Gunungkidul Regency. We used Google Scholar to identify drought causes on the study site. The next stage is making appropriate adaptation strategies using a qualitative and comparative analysis technique. The three main components that cause drought disasters in Gunungkidul Regency include climate characteristics, hydrogeological characteristics, and anthropogenic factors. Some proposed adaptation strategies to address the impacts of drought disasters include planting crops with low water requirements, adopting conservation agriculture and utilizing organic farming, applying structural adaptation strategies, developing agroforestry, giving farmers financial assistance, paying compensation to drought-affected families, distributing knowledge about drought adaptation strategies, reducing family food demand, suggesting seasonal migration, and reducing livestock. Working with multiple stakeholders is essential to putting these adaptation strategies into action.

Temporal and Spatial Analysis for Precipitation Trend and Homogeneity in Semi-Arid Area, Northwestern Iraq as a Case Study

Detecting the trends and homogeneity in precipitation records is fundamental in climate change and hydrological studies. This study investigates the homogeneity and trends of precipitation time series at four stations in north-west Iraq. The analysis encompasses the annual, seasonal, and monthly time scale at a significant level of 5%. Four tests were employed to assess the homogeneity analysis of the precipitation time series: Standard Normal Homogeneity, Buishand, Pettitt, and Von Neumann Ratio. Then two methods were applied to detect the trend from 1970–2020. Sequential Mann- Kendall and Innovative trend tests were employed to track the significant trend changes and to find the magnitude, tendency, and significance of the trend during this period for precipitation. Microsoft Excel was utilized to achieve the concepts of homogeneity and trend for the precipitation time series. The results of the homogeneity test confirmed the suitability and homogeneity of the precipitation for further analysis. The trend analysis showed that there is an annual increasing (positive) trend in precipitation at Duhok and Rabia stations by 14 mm/decade and 0.25 mm/decade, respectively. Conversely, Mosul and Tal-Afer stations exhibited a decreasing (negative) trend by 21 mm/decade and 8.9 mm/decade, respectively. Spring precipitation exhibited a statistically significant decreasing trend in all Northwestern stations. The most substantial value in the Mosul station by 11mm/decade. This study highlights the importance of investigating drought and flood adaptation strategies to address the impact of climate changes impacts at the mentioned area.

Leaf Trait Variations and Ecological Adaptation Mechanisms of Populus euphratica at Different Developmental Stages and Canopy Heights

The ability of plants to alter specific combinations of leaf traits during development and in response to abiotic stress is crucial for their success and survival. While there are numerous studies on the variation of leaf traits within the canopies of Populus species, the application of network analysis to understand the variation and combinations of these traits across different growth stages is rare. The leaves of Populus euphratica, a dominant species in arid regions, exhibit notable morphological variations at different developmental stages and canopy heights in response to water scarcity and climate change. In this study, 34 leaf traits (morphological, chemical, photosynthetic, and hydraulic) and their roles in drought adaptation were investigated in 60 Populus euphratica plants at five developmental stages and five canopy heights using leaf trait network (LTN) analysis. The aim was to analyze adaptive strategies to arid environments at different developmental stages and canopy heights through the interdependence of leaf traits. The results showed that the internal coordination capacity of leaf trait networks decreased and then increased with each developmental stage, while the functional modules of leaf trait networks were loosely connected and aggregated with the increase in tree diameter at breast height. With increasing canopy height, the coordination linkage’s ability between leaf traits showed an increasing then decreasing trend, and the traits of the leaves in the canopy at 6 m were more closely connected, less modular, and simpler in topology compared with those in the other layers. Leaves form functional modules by coordinating specific traits that promote growth and resist drought. Leaf photosynthesis, water transport, and nutrient traits were central to different developmental stages, whereas leaf morphology, nutrient metabolism, and drought-resistance-related traits were central to the canopy height. Leaf morphology and osmoregulatory traits play key roles in leaf trait network regulation, including leaf length and width, leaf shape index, soluble sugars, and soluble proteins, which are important “intermediary traits” in the Populus euphratica leaf network. Further analysis revealed that structural traits were important at different developmental stages and canopy heights. When resources are limited, the leaf preferentially maintains a stable connection between structural traits to enhance photosynthesis, and these traits and their combinations might confer drought resistance. During the rapid development stage, the connection between chemical traits becomes important, and the leaf grows by rapidly accumulating nutrients. In summary, this study provides new perspectives and insights into the drought adaptation strategies of P. euphratica at different developmental stages and canopy heights by analyzing leaf trait networks.

Water uptake patterns and rooting depths of Tamarix ramosissima in the coppice dunes of the Gurbantünggüt Desert, China: a stable isotope analysis.

Tamarix ramosissima has an important role in stabilizing sand dunes in desert ecosystems. Understanding the water use strategies of T. ramosissima is essential to understand its adaptations on coppice dunes. We utilized the stable isotopes δ2H and δ18O in soil water, groundwater, and xylem water to identify monthly differences in water sources. Additionally. we explored rooting depth using 2H2O as an artificial tracer. In May, T. ramosissima derived 75% of its water from shallow and middle soil layers. In July, it absorbed 90% water from middle and deep soil layers. In August and September, it acquired approximately 80% of its water from deep soil layers. The labelling using 2H as an artificial tracer indicated that the root system of T. ramosissima could reach depths >500 cm in the coppice dunes. 2H absorption was observed at depths of 100, 200, 300 and 400 cm. Soil water is the dominant water source for T. ramosissima in the coppice dunes because groundwater is at depths >30 m. The flexible water-use strategies of T. ramosissima enable it to effectively utilize different available water sources to adapt to the arid environment. These findings improve our understanding of water uptake patterns and drought adaptation strategies of T. ramosissima in the coppice dunes of desert ecosystems.

Dynamic physiological response of tef to contrasting water availabilities.

Global climate change is leading to increased frequency of extreme climatic events, higher temperatures and water scarcity. Tef (Eragrostis tef (Zucc.) Trotter) is an underutilized C4 cereal crop that harbors a rich gene pool for stress resilience and nutritional quality. Despite gaining increasing attention as an "opportunity" crop, physiological responses and adaptive mechanisms of tef to drought stress have not been sufficiently investigated. This study was aimed to characterize the dynamic physiological responses of tef to drought. Six selected tef genotypes were subjected to high-throughput whole-plant functional phenotyping to assess multiple physiological responses to contrasting water regimes. Drought stress led to a substantial reduction in total, shoot and root dry weights, by 59%, 62% and 44%, respectively (averaged across genotypes), and an increase of 50% in the root-to-shoot ratio, relative to control treatment. Drought treatment induced also significant reductions in stomatal conductance, transpiration, osmotic potential and water-use efficiency, increased chlorophyll content and delayed heading. Tef genotypes exhibited diverse water-use strategies under drought: water-conserving (isohydric) or non-conserving (anisohydric), or an intermediate strategy, as well as variation in drought-recovery rate. Genotype RTC-290b exhibited outstanding multifaceted drought-adaptive performance, including high water-use efficiency coupled with high productivity under drought and control treatments, high chlorophyll and transpiration under drought, and faster drought recovery rate. This study provides a first insight into the dynamic functional physiological responses of tef to water deficiency and the variation between genotypes in drought-adaptive strategies. These results may serve as a baseline for further studies and for the development of drought-resistant tef varieties.

Drought shocks, adaptive strategies, and vulnerability to relative poverty

Drought shocks, adaptive strategies, and vulnerability to relative poverty

Agro-climatic zone-wise drought hazards in Karnataka under historical and future climate scenarios

This study performed the spatio-temporal analysis of drought hazards across the agro-climatic zones (ACZs) of Karnataka under historical and future climate scenarios. The India Meteorological Department’s high-resolution gridded data for1989-2019 was used for historical drought occurrence analysis. Coordinated Regional Climate Downscaling Experiment ensemble data of the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios were used for analysing future drought hazards in the near (2031-2060) and end term (2061-2099) periods. The standardised precipitation index (SPI) was used to calculate the frequency of droughts at different accumulation periods of 1, 3, 6, 9, and 12 months. Subsequently, the ACZ-wise drought hazard index (DHI) was calculated and mapped geospatially using ArcGIS. The results indicated that moderate drought events have the highest frequencies of occurrence, followed by severe and extreme drought events for all accumulation periods. During 1989-2019, 54.8%, 28.3% and 16.7% of droughts were moderate, severe, and extreme, respectively. An increase of 2.6% and 2.4% in the frequency of moderate droughts is projected under the RCP4.5 and 8.5 scenarios, respectively, in the end term. Under both historical and future climate scenarios, a high frequency of extreme droughts was observed in the long accumulation periods (SPI-9 and SPI-12), whereas the frequency of moderate droughts was observed to be high in the short accumulation periods (SPI-1 and SPI-3). Under the historical scenario, the frequency of droughts in the extreme category was high in the southern transition, central dry, and north eastern dry zones, severe category in the northern dry, southern transition, and coastal zones, and moderate category in the north transition, hill, and southern dry zones. Among the 30 districts of Karnataka, Chitradurga, Udupi, Tumakuru, Ballari, Koppala, Raichuruand Gadaga districts have very high DHI. This study sheds light on the potential consequences of climate change on drought scenarios in the Karnataka state’s agro-climate zones and urges for zone specific drought adaptation and mitigation strategies to strengthen the State resilience.

VULNERABLITY OF RURAL LIVELIHOODS IN NINH THUAN PROVINCE TO DROUGHT

The risk of drought poses a significant challenge to agricultural production in Ninh Thuan Province. Therefore, this study aims to identify the factors that influence farmers’ livelihood outcomes due to the impact of drought. Data were collected from a survey of 231 farmers randomly selected from the districts of Thuan Nam, Thuan Bac, and Ninh Hai. In addition to descriptive statistics, a Tobit regression model was used to identify the factors influencing livelihood outcomes during mild and severe droughts. The results showed that farmers’ livelihood outcomes were generally low. The regression identified the financial (β=0.230 and 0.205), social (β=0.200 and 0.291), and human capital (β=0.195 and 0.196) impacts on farmers’ livelihood outcomes from both mild and severe droughts. During mild drought years, seasonal adjustment (β=-0.009) and migration (β=0.013) were found to significantly influence livelihood outcomes. In severe drought years, government support (β=-0.030) negatively affected livelihood outcomes. There is a need to establish an early warning system for climate change and extreme weather events while simultaneously disseminating information widely to farmers so that they can take timely measures to cope. Enhancing human capital by raising awareness and skills in adapting to drought and developing comprehensive abilities to implement drought adaptation strategies is needed.

Biological and environmental controls on nighttime water-use behaviors in Populus simonii in semi-arid areas of the Chinese Loess plateau

Recent studies have revealed that the active nighttime water-use behaviors by trees have critical physio-ecological significance in survival and growth in adversity. However, the characteristics and biophysical control of nighttime water-use of silvicultural trees are not clear. We continuously monitored sap flow and leaf water potential (predawn and midday) of Populus simonii of different tree sizes as well as environmental factors during the 2021 and 2022 growing seasons (May-September) in a semi-arid area of Loess Plateau. Our results showed that both nighttime water-use (WUn) and the ratio of nighttime to daily water-use (WUn%) increased significantly with tree size, and had larger values in the drought year than in the normal year. The WUn% of different tree sizes ranged from 10.24 to 13.01% and can reach up to 36.49% during prolonged soil drought. Besides, the WUn% of different tree sizes were significantly positively and negatively correlated with nighttime vapor pressure deficit (VPDn) and soil water content, respectively. By partitioning the components of WUn, we found that as tree size increased, the stem water refilling (RE) and nighttime transpiration increased obviously, but the ratio of RE to WUn (RE%) did not change. The RE of different tree sizes constituted the major part of WUn with an average RE% of 65.7–68.0%, and the RE% was larger in the drought year than in the normal year. Additionally, the RE% of different tree sizes increased with decreasing predawn leaf water potential (Ѱpd) during the soil dry stage and with increasing VPDn during the soil wet stage. Given the increased risk of atmospheric drought and soil drought, it can be expected from our findings that the nighttime water-use behaviors of trees become more active in the future, which represents a significant performance of drought adaptation strategies of silvicultural species.

Gamma-aminobutyric acid modulates antioxidant and osmoprotective systems in seedlings of Triticum aestivum cultivars differing in drought tolerance

The stress-protective effects of plant neurotransmitters, including gamma-aminobutyric acid (GABA) have been intensively examined in recent years. However, studies on the GABA influence on stress protective systems in bread wheat cultivars with different drought adaptation strategies are still lacking. The aim of this work was to estimate the GABA effect on the state of antioxidant and osmoprotective systems in etiolated seedlings of two wheat cultivars differing significantly in drought tolerance, namely Doskonala (non-drought-resistant) and Tobak (drought-resistant) under model drought induced by PEG 6000. Two-day-old seedlings were transferred to 15% PEG 6000 and incubated for two days in the absence or presence of GABA. Treatment with 0.1 and 0.5 mM GABA significantly reduced the growth-inhibitory effect of PEG 6000 on the roots and shoots of both cultivars, but to a greater extent on those of non-resistant Doskonala. It was shown that GABA treatment reduced drought-induced accumulation of H2O2 and MDA, stabilized SOD and GPX activity, the level of sugars, anthocyanins and flavonoids in seedlings of both cultivars. Meanwhile GABA treatment enhanced the stress-induced increase in proline content in the Doskonala cultivar, but decreased it in the Tobak, completely prevented stress induced decrease in anthocyanins and flavonoids level in the Tobak and only partially in Doskonala cultivar. Thus, the stabilization of the stress-protective systems functioning in the wheat cultivars and variety-dependent differences in response to GABA were revealed. Keywords: anthocyanins, antioxidant system, drought resistance, gamma-aminobutyric acid, oxidative stress, proline, Triticum aestivum

Resilience of rainfed agriculture in northern part of Cyprus: a comprehensive drought severity level impact analysis and adaptive strategies

Resilience of rainfed agriculture in northern part of Cyprus: a comprehensive drought severity level impact analysis and adaptive strategies

Patterns, timing, and environmental drivers of growth in two coexisting green-stemmed Mediterranean alpine shrubs species.

The Mediterranean alpine is one of the most vulnerable ecosystems under future environmental change. Yet, patterns, timing and environmental controls of plant growth are poorly investigated. We aimed at an improved understanding of growth processes, as well as stem swelling and shrinking patterns, by examining two common coexisting green-stemmed shrub species. Using dendrometers to measure daily stem diameter changes, we separated these changes into water-related shrinking and swelling and irreversible growth. Implementing correlation analysis, linear mixed effects models, and partial least squares regression on time series of stem diameter changes, with corresponding soil temperature and moisture data as environmental predictors, we found species-specific growth patterns related to different drought-adaptive strategies. We show that the winter-cold-adapted species Cytisus galianoi uses a drought tolerance strategy combined with a high ecological plasticity, and is, thus, able to gain competitive advantages under future climate warming. In contrast, Genista versicolor is restricted to a narrower ecological niche using a winter-cold escape and drought avoidance strategy, which might be of disadvantage in a changing climate. Pregrowth environmental conditions were more relevant than conditions during growth, controlling the species' resource availability. Thus, studies focusing on current driver constellations of growth may fail to predict a species' ecological niche and its potential future performance.

Two common, often coexisting grassland plant species differ in their evolutionary potential in response to experimental drought.

For terrestrial plant communities, the increase in frequency and intensity of drought events is considered as one of the most severe consequences of climate change. While single-species studies demonstrate that drought can lead to relatively rapid adaptive genetic changes, the evolutionary potential and constraints to selection need to be assessed in comparative approaches to draw more general conclusions. In a greenhouse experiment, we compare the phenotypic response and evolutionary potential of two co-occurring grassland plant species, Bromus erectus and Trifolium pratense, in two environments differing in water availability. We quantified variation in functional traits and reproductive fitness in response to drought and compared multivariate genetic variance-covariance matrices and predicted evolutionary responses between species. Species showed different drought adaptation strategies, reflected in both their species-specific phenotypic plasticity and predicted responses to selection indicating contrasting evolutionary potential under drought. In T. pratense we found evidence for stronger genetic constraints under drought compared to more favourable conditions, and for some traits plastic and predicted evolutionary responses to drought had opposing directions, likely limiting the potential for adaptive change. Our study contributes to a more detailed understanding of the evolutionary potential of species with different adaptive strategies in response to climate change and may help to inform future scenarios for semi-natural grassland ecosystems.

Addressing the effects of soil organic carbon on water retention in US Pacific Northwest wheat–soil systems

Soil organic carbon (SOC) is considered a significant contributor to soil water retention. However, generalizations about the role of SOC in available water-holding capacity (AWHC) may have inaccurately portrayed this relationship. We aim to reexamine the relationship between SOC and water retention using the National Cooperative Soil Survey (NCSS) Database. We focus on regional soil groups within the Pacific Northwest wheat production region, including Haploxerolls, Argixerolls, Haplocambids, and Durixerolls. We evaluated 77 sites based on SOC, total nitrogen (TN), pH, texture, bulk density (BD), field capacity (FC), permanent wilting point (PWP), and AWHC. Our findings indicate that texture and BD were the most significant contributors to AWHC variation, while SOC played a secondary role in explaining this variation. Mid-infrared (MIR) spectroscopy coupled with a random forest (RF) algorithm was used to evaluate the importance of spectral bands in determining changes in FC and PWP. This analysis identified mineral bands related to inner-surface hydroxyl groups in kaolinite (3700 cm −1) and Si-O-Si overtones (1870 cm −1) as the most important spectral contributors to PWP. The water retention at FC was associated with organic absorbances relevant to soil aggregation, such as polysaccharide C–O (~1035 cm −1), while mineral bands were relatively less influential. This study highlights the need to reexamine the impact of SOC as well as the interaction between soil texture and compaction on soil water retention to elucidate the underlying mechanisms responsible for AWHC, thus providing insight into future drought adaptation strategies.

Agricultural drought severity in NE Italy: Variability, bias, and future scenarios

This study investigated the variability of agricultural drought severity, as depicted by vegetation indices, and the bias in identifying drought events when considering a stationary vs nonstationary climate reference. The work leveraged gridded climate data (NCEP CFSv2, CHIRPS 1981–2022), soil properties (OpenLandMap), satellite imagery (Sentinel2/Landsat, 2000–2022), and future climate projections (NEX-GDDP, 2050) together with local knowledge of selected farms, to augment drought monitoring techniques and identify potential issues for agriculture. For the study domain, significant differences were observed when comparing drought characteristics using stationary and nonstationary drought indexes, with biases being not ubiquitous in either space or time of year. When developing sustainable drought mitigation and adaptation strategies, decision-makers should carefully address this uncertainty to avoid a possible underestimation of drought magnitude. Results showed a drought increase (∼50%) by the mid and late twenty-first century. Projection of future climate highlighted an even more significant impact (∼80%) with a wide variability of risk across the domain. As drought impact was also related to soil organic carbon (SOC), our results suggest that improving SOC content could be a sustainable strategy for enhancing soil drought resilience, especially in areas commonly characterized by low concentrations of organic carbon and nutrients. The analysis highlighted that drought impacts were also modulated by investment in irrigation infrastructure and irrigation efficiency. Researchers and land managers could apply the proposed analysis design to address historical, current and future indicators of vegetation conditions within irrigated regions. By providing spatio-temporal information on the patterns of drought impacts and their bias, this study supports identifying priority regions for targeted drought risk reduction and adaptation options, including water resources and soil management sustainability criteria, to move towards more resilient agricultural systems.