Arid Climatic Conditions Research Articles

Exploring the current status of barley yield and production gap of Iran

Barley (Hordeum vulgare. L) is adapted to drought and salinity as the most critical constrained factors in Iran's crop production. Hence, the grain barley's importance is exhibited via 1.75 million hectares of harvested areas and 3.2 million tons of production in the country with arid and semi-arid climate conditions. However, the current production status meets only about 50% of Iran's barley's grain demands and is globally recognized as one of the largest barley importers in recent years. This study aimed to estimate the potential and yield gap and the potential barley grain production increase under the irrigated and rainfed conditions as the first step in schematizing the promotion of barley production. The impact of determinant climate factors on barley yields was also investigated at dominant barley productions regions over Iran. The present study approach is implemented based on the Global Yield Gap Atlas (GYGA). Accordingly, 12 and 17 designated climatic zones (DCZ), are distinguished as the dominant areas of the irrigated and rainfed barley production in the country, respectively. Afterwards, 48 and 38 reference weather stations (RWSs) within the DCZs were distributed to irrigated and rainfed barley harvested areas, respectively. The SSM-iCrop2 crop model was employed to simulate potential yield in irrigated (Yp) and rainfed (Yw) conditions by utilization of required data in each RWS through 15 barley growing seasons (2000–2014). The yield gap (the difference between simulated potential yield (Yp or Yw) and actual yield (Ya)) were calculated based on the bottom-up approach of GYGA in RWSs, DCZs and national-scale, respectively. Based on the results, the estimated potential yield varies between 5283 and 8286 kg/ha (with an average of 7090 kg/ha) in irrigated condition, and in the case of rainfed barley ranged between 1072 and 4002 kg/ha (with an average of 2723 kg/ha). In contrast, the actual yield in the DCZs was reported in the range of 1406 and 3723 kg/ha (with an average of 3009 kg/ha) for irrigated barley and ranged around 390–1510 kg/ha in rainfed conditions (with an average of 1009 kg/ha). According to the results, the DCZs that are confronted with higher temperatures and shorter growth length periods due to less total received daily solar radiation have low yields in irrigated conditions. In rainfed barley harvested areas, a significant correlation between rainfall distribution, high temperature and Yw has existed during the reproductive phase within 17 DCZs. Ultimately, the results indicated that the calculated yield gap varies between 3237 and 4697 kg/ha (50–76%) with an average of 4081 kg/ha (58%), and also between 615 and 3125 kg/ha (53–82%) with an average of 1714 kg/ha (63%) in the DCZs of irrigated and rainfed barley harvested areas, respectively. Consequently, it has been concluded that by achieving attainable yield (80% of potential yield) via improving production management, irrigated barley yield production can be increased to 5672 kg/ha and 4.17 million tons, respectively, provided that water resources are available. It can also be exploitable to increase rainfed barley's current yield and production from 1009 to 2178 kg/ha and 1.05–2.26 million tons, respectively. Finally, it makes sense to be inspired by increasing total national barley production from 3.26 to 6.43 million tons per year and bring the country closer to obtain full self-sufficiency in supplying the required barley grain.

Centennial-scale linkages between the Indian Summer Monsoon and the solar irradiation from the Gulf of Khambhat (Western India)

The Indian Summer Monsoon (ISM) is a major driver of the summer precipitation across the Indian subcontinent affecting a vast population. Yet, the limited chronological extent of the instrumental records accompanied with the control of the climatic variables on the ISM, has hampered the efforts to document the climate change for the last two millennia. The present multiproxy study reports a high-resolution sedimentary record from the Gulf of Khambhat region (Western India) which represents two alternating climatic phases representing relatively arid and humid climatic conditions that coincides with the widely reported Dark Ages Cold Period (DACP) (AD 680 – AD 920) and Medieval Warm Period (MWP) (AD 920 to ∼ AD 1400). This variability of the ISM, further tends to be modulated by the solar forcings, with the periods of solar minima coinciding well with the episodes of the reduced monsoonal strength and vice-versa. The difference in timing of DACP and MWP in the North Atlantic Region (NAR) and the present study, hints at the linkage between the ISM and NAR via an atmospheric route, driven by the solar variability.

What Collapsed in 1177?

What Collapsed in 1177?

Genetic Model of Mud-Clast Conglomerates in Salt Rocks and Their Significance for Salt Mineralization in Mohei Area, Simao Basin, China: A Case Study of Well L-2.

The Simao Basin is one of the most important Mesozoic salt basins in China, and the salt rocks generally contain mud-clast conglomerates. The characteristics of mud-clast conglomerates can provide effective information indicating the evolution process of the salt deposits. A combined analysis of trace elements and clay minerals was performed to characterize the genetic model of mud-clast conglomerates in the salt rocks. The results show that the sedimentary materials are felsic rocks from the Upper Crust. Ternary plot diagrams show that the tectonic settings are between the continental margin and the continental island arc. The clay minerals in the samples mainly contain illite and illite–smectite mixed layers. A dry and hot climate prevailed during the deposition of the Mengyejing Formation, and the warm-humid climate that also occurred is interspersed in some periods. Evaporation makes the water bodies shallower, and the concentrated brine starts to precipitate salt under the arid and hot climate conditions. Redox proxies indicate that most of the samples were deposited in relatively oxic conditions. The Sr/Ba ratios (average of 0.5) and paleosalinity (average of ∼35‰) during the depositional period indicate an increase in terrigenous freshwater input and carry of clasts into the evaporation basin. Furthermore, the freshwater supply enhances the hydrodynamics; as a result, the detritus that deposited in the early stage is broken into mud-clast conglomerates and co-deposited with the salt rocks. The results provide a geochemical basis for further study of mud-clast conglomerates in the Simao Basin and supply recommendations for the origin of salt deposits in similar basins around the world.

Geochemical characteristics of terrigenous saline lacustrine shale in the Qianjiang Depression, Jianghan Basin, China: implications for controls on the formation of the inter-salt organic-rich shale

ABSTRACT The inter-salt shale of the Qianjiang Formation in Jianghan Basin is a typical and important continental saline lake shale oil system in China. To achieve a better understanding of the formation of the inter-salt organic-rich shale, the mineral, major and trace elements and organic geochemical characteristics (total organic carbon (TOC) and biomarkers) of the Eq34-10 shale (high TOC) and the Eq40-5 shale (low TOC) were studied. The results suggest that (a) the organic matter in the inter-salt shale was predominantly derived from endogenous lower aquatic organisms, algae and bacteria; (b) there was a hot arid palaeoclimate and a low degree of chemical weathering conditions during the deposition of the inter-salt shale; (c) the inter-salt shale deposited in an extreme restriction hyper-saline lacustrine and reducing environment, and the salinity of the palaeolake decreases with the increase of the input of terrigenous clastic materials; and (d) the inter-salt shale deposited under an arid and semi-arid climate condition with an intermittent warm and humid climate. In summary, lake palaeoproductivity under the control of palaeoclimate change is the key and direct factor controlling the development of inter-salt organic-rich shale of Qianjiang Formation in Jianghan Basin.

Assessing and delineation of groundwater recharge areas in coastal arid area southern Tunisia

In Gabès region (southeastern Tunisia), given the semi-arid to arid climate conditions, groundwater is an essential resource to supply the growth needs of the socio-economic development. To ensure sustainable development and preserve water resources, a careful estimation of the present day recharge amount and the delineation of the potential zones of rainfall precipitation are of required for an accurate evaluation of regional water balance. In this context, this study aims to a preliminary assessment of groundwater recharge in Gabes basin in regard to the delineation of the potential recharge areas of phreatic aquifers. Thus, a geological and hydrogeological collected database coupled with remote sensing techniques (RST) were used for the determination of the lateral variation of recharging zone, Treatment by ArcGIS and Matlab softwares and Kohonen self-organizing maps (K-SOM) approaches. The obtained results indicate that five recharge potential areas have been identified and classified as 27% very low, 23% low, 40% moderate recharge, 7% good and 3% very good potential recharge located principally on southern part of the study region. This distribution is controlled principally by the geomorphological, geologic, and hydrogeologic features of the region. Reasonable management strategies based on a perennial exploitation of these low renewable resources are required to optimize the water dependent socio-economic development. The estimated groundwater potential recharge of Gabès aquifer system using K-SOM and RST is of 11.4 Mm3 y−1. This recharging rate is very low it present 7% of the total rain, thus it must be ameliorated. K-SOM and RST approach is a useful method for groundwater potential recharge mapping and is a helpful of wells establishment and groundwater sustainable management. an isotopic analyses is recommended to ameliorate the decision maker to establish the adequate strategy.

Effect of Weed Management on Weed Growth, Performance, Profitability and Economics of Wheat in Transitional Plain of Luni Basin

A experiment was conducted at Agricultural Research Station, Keshwana, Jalore under arid climate conditions in Rabi season during 2018-19 with the object of effect of herbicide on weed, wheat growth, yield and economics. The data shows that the treatment 2,4 D @ 0.5 kg ha-1 at 35 DAS+ hand hoeing 45 DAS recorded lower dry matter of weeds at harvest (18.3 g), maximum growth, spike length (8.5 cm), No. of spikelet (17), No. of seeds per spike (54.7), seed yield (40.1 q) and Straw yield (59.1 q) of wheat, and at par with the treatment Metsulfuron 4 g ha-1 35 DAS + hand hoeing 45 DAS. The treatment 2,4 D @ 0.5 kg ha-1 at 35 DAS+ hand hoeing 45 DAS also produced the maximum gross return (Rs 117763 ), net return (Rs 70886 ) and B:C ratio (2.51).

Editorial Preface to Special Issue: Exploring the impact of Andean uplift and climate on life evolution and landscape modification: From Amazonia to Patagonia

• Uplift of the Northern Andes (from Peru to Colombia) took place from Late Cretaceous to Paleocene (72 and 60 Ma), and was driven by collision of the South American plate with the Caribbean Arch. This process affected drainage directions and paleogeography shaping the present Andes configuration. • Studies in the Northern Andes concur with Late Cretaceous tectonism and suggest that uplift took place in three-stages. During the final Neogene uplift stage, the Antioquia plateau (Central Cordillera, Northern Andes) is thought to have achieved altitudes higher than present. • Subsurface processes, such as slab-flattening drove uplift in Central Cordillera (Northern Andes) and caused an asymmetric topography that affected drainages and biodiversity development. • Climate as a driver of mountain uplift remains contentious, but it is clear that uplift strongly affects climate and environment, due to the orographic rain shadow effect. • Multiple studies found that Andean uplift played a key role in shaping the evolutionary history and biodiversity patterns in both plants and animals, even in mutualistic species relationships. The effect of uplift on biogeographic history is not limited to the Andes mountains, but also extends into the Amazon drainage basin with soils in the western Amazonia being most species rich. During the Neogene, eastern Amazonia gradually became species-enriched through biotic interchange. • The effects of Andean uplift on biota add to other fundamental factors, such as climate, environment and dispersal, all of which contribute to the modern biodiversity patterns in South America and their evolutionary history. • The Neotropics were hot and humid during Eocene global warming. However, paleobotanical studies in the Northern Andes suggest that during towards the end of the Eocene a shift towards arid and seasonal climatic conditions occurred. In western Amazonia the EOT is further marked by a sea level drop, and a shift from deltaic to fluvial conditions that is accompanied by a decline in species richness. • In Patagonia the Oligocene ‘icehouse’ is characterized by a species poor assemblage. Towards the MCO there is an increase in species diversity with a subsequent decline in the MMCT. The biggest paleobotanical change, however, occurs in the late Miocene and is marked by the rise in arid taxa. This coincides with the uplift of the easternmost flank of the Andes and formation of a rain shadow. Aridification and sea level drop was initiated in the MMCT and culminated in the late Miocene. In the Northern Andes this transition is recognized by a dramatic change in paleosoil profiles. • Marine incursions and fluctuating sea level played an important part in Amazonia's history and evidence of this can be found in middle and late Miocene deposits in the western Amazon. Sediment records in the large Pebas wetland system (western Amazon) indicate that orbital forcing controlled sedimentation while the towering Central and Northern Andes provided the sediment supply. • Holocene records of Amazonia suggest rainforest trees are resilient to natural drying but not to fire and deforestation. A stark warning that human influence is more devastating than climate change.

Characteristics of potato (Solanum tuberosum) genotypes for resistance to abiotic environmental stress factors

The optimal variety choice for each specific region is one of the main factors influencing the productivity increase and improving the quality of the table and seed potato. It is necessary to cultivate varieties that combine the maximum adaptability to abiotic environmental factors and high field resistance or immunity to various phytopathogens. Therefore, the present study aimed to identify varieties and hybrid material of potatoes of various genetic and geographical origin with high resistance to high air temperatures and insufficient moisture. The research was conducted during April and May 2021 at the laboratory of biotechnology of agricultural plants of the Samara Scientific Research Agriculture Institute named after N. M. Tulaykov - branch of the SamSC RAS, Bezenchuk vil., Russia. The maximum average productivity was characterized by medium-early varieties Krasa Meschery (32.3 t/ha), Debut (27.8 t/ha) and Sudarynya (26.2 t/ha) and medium-ripe varieties Utro (29.4 t/ha), Siversky (32.2 t/ha) and Alaska (31.0 t/ha). It is shown that in conditions of arid climate, medium-early and medium-ripe potato varieties with genotypes of intensive and neutral type have an advantage in yield over varieties of other varieties. The interrelation of morphological features of the aboveground part of the potato plant with the yield of tubers is established. It is shown that in conditions of high air temperature and insufficient humidification, varieties with a high rate of green mass growth in the period from 50 to 60 days from planting and with a high number of stems per plant can have an advantage. he obtained results can be used in breeding work for heat resistance and drought resistance for a quick preliminary assessment of a significant amount of hybrid potato material at the initial stages of the breeding process, as well as one of the stages of a comprehensive study of new varieties.

Comparison of some evapotranspiration models using lysimeter measurements in arid climate conditions

AbstractAccurate calculation of evapotranspiration (ET) for all crops plays an important role. This study was conducted to determine the most accurate reference evapotranspiration (ETr) estimation model for arid climatic conditions using the decision support system (DSS) program for alfalfa plants in south‐east Anatolia, Turkey, in 2019 and 2020. The evapotranspiration of 12 mathematical models (ETr‐m) and the evapotranspiration of a lysimeter (ETr‐l) were used to estimate ETr. In 2 experimental years, 1133 and 1270 mm of irrigation water were applied to alfalfa plants, respectively. The actual total ET was calculated as 1288 and 1294 mm in 2019 and 2020, respectively. The root mean square error (RMSE), mean absolute error (MAE), ETr‐m/ETr‐l, and index of agreement (d) were calculated separately for each mathematical model. The RMSE, MAE, ETr‐m/ETr‐l and d values for the mathematical models had a range of 1.25–3.57 mm day−1, 0.91–1.98 mm day−1, 0.64–1.04 and 0.56–0.94, respectively. According to the results of the regression analysis with the RMSE, MAE, ETr/ETr‐m and d values obtained from the models, the Businger–Van Bavel model was the most accurate prediction model. The others were the FAO PPP‐17 Penman and the 1982 Kimberly Penman models, respectively.

Comprehensive Review on Climate Control and Cooling Systems in Greenhouses under Hot and Arid Conditions

This work is motivated by the difficulty of cultivating crops in horticulture greenhouses under hot and arid climate conditions. The main challenge is to provide a suitable greenhouse indoor environment, with sufficiently low costs and low environmental impacts. The climate control inside the greenhouse constitutes an efficient methodology for maintaining a satisfactory environment that fulfills the requirements of high-yield crops and reduced energy and water resource consumption. In hot climates, the cooling systems, which are assisted by an effective control technique, constitute a suitable path for maintaining an appropriate climate inside the greenhouse, where the required temperature and humidity distribution is maintained. Nevertheless, most of the commonly used systems are either highly energy or water consuming. Hence, the main objective of this work is to provide a detailed review of the research studies that have been carried out during the last few years, with a specific focus on the technologies that allow for the enhancement of the system effectiveness under hot and arid conditions, and that decrease the energy and water consumption. Climate control processes in the greenhouse by means of manual and smart control systems are investigated first. Subsequently, the different cooling technologies that provide the required ranges of temperature and humidity inside the greenhouse are detailed, namely, the systems using heat exchangers, ventilation, evaporation, and desiccants. Finally, the recommended energy-efficient approaches of the desiccant dehumidification systems for greenhouse farming are pointed out, and the future trends in cooling systems, which include water recovery using the method of combined evaporation–condensation, as well as the opportunities for further research and development, are identified as a contribution to future research work.

Evaluation of sensitive physical parameter combinations for determining the uncertainty of fire simulations and predictions in China

AbstractFires are fundamental and natural phenomena that affect terrestrial ecosystems and the global climate change. However, uncertainties in fire modeling still exist. It is important to improve the ability to simulate fires by tuning model parameters. In this study, a sensitivity analysis (SA) approach based on the conditional nonlinear optimal perturbation related to parameters (CNOP‐P) is employed to find the most sensitive parameter subset. First, the maximum uncertainty in modeling fire is estimated, and it is found that the degrees of uncertainty in modeling fire are different in different regions of China. The extents of the uncertainties in modeling fire in northeastern China and northern China with arid and semiarid climate conditions are greatest, and the magnitude of the uncertainty in southern China is the smallest. The uncertainty in modeling fires in northern China with a semihumid climate condition is between the above values. Second, we find that the most sensitive parameter combination with the number of elements determined by the SA method based on the CNOP‐P approach are different from the top five parameters combination via a sensitivity test using a traditional method (such as the one‐at‐a‐time [OAT] method). The most sensitive parameter combination includes not only the parameters in the fire module (e.g., ) but also the parameters that could cause variations in biomass and soil moisture. The prediction skill of fire by reducing the errors of the sensitive parameter combination using the SA method based on the CNOP‐P method are higher than those using the OAT method. The above results suggest that not only the parameters in the fire module but also the parameters of other physical processes (e.g., biomass and soil moisture) should be corrected and calibrated to improve simulation and prediction of fire.

From fragility to sustainability: Geoarchaeological investigations within the Maltese Archipelago

The Maltese Archipelago is a microcosm of long-term Anthropocene human manipulation of the environment spanning the last 8000 years. Despite their apparent fragility, the islands continue to sustain an increasing population. This paper summarises the geoarchaeological methods employed by the ERC-funded FRAGSUS Project and an associated PhD project which explored the terraced landscapes of these islands. Our projects employed archaeological excavation, sediment coring, palynology, soil survey, micromorphology, geochemistry, and absolute dating to obtain a new understanding of long-term landscape change. These scientific analyses are combined with historical data in the form of 19th Century land value assessments which offer new insights into folk concepts of agricultural viability. Landscape changes in the islands began with Neolithic agricultural activities from 5500 cal BC. These caused soil thinning which was further exacerbated by increasingly arid climatic conditions. Soil management strategies are then evident from the late 2nd millennium BC, persisting through medieval times, when the protection of red soils became enshrined in law, and into the present day, when agricultural terraces are the dominant landform in the rural landscape. The combined efforts of these projects exemplify the value of geoarchaeology in providing an environmental narrative that contextualizes the human history of landscapes. Our account of longue durée landscape use, abuse, and change is a fitting case history for the present state of the environment in Malta and beyond. Persistent development is now expanding urban sprawl into the managed, yet still fragile, rural landscape, resulting in a piecewise erasing of valuable historic agriscapes in the Mediterranean region.

Изучение адаптивного потенциала кормовых кустарниковых растений для использования в восстановлении деградированных полупустынных пастбищных экосистем

Abstract. Purpose. The study is aimed at carrying out an adaptation assessment of arid fodder shrubs for the restoration of degraded pasture ecosystems in the semi-desert zone of southern Russia in the modern conditions of climate aridization. Methods. An assessment is given of the adaptive capabilities, including the field germination of seeds, the response to drought, the yield of fodder shrubs of leafless Calligonum aphyllum, Eurotia ceratoides, and Kochia prostrata in modern climatic conditions on light chestnut soils. Results. The studies were carried out in severe arid climatic conditions (lack of productive moisture in the soil throughout the summer period) on infertile soils (humus content – 0.68–0.74 %). Field germination of seeds was 24.9 (Calligonum aphyllum), 32.6 (Kochia prostrata), 75.6 (Eurotia ceratoides). For the selected shrubs, the best sowing dates were determined – November – January. By the third year of the growing season, the height of the plants was 84–110 cm, which will contribute to the retention of snow in the pasture. All studied fodder shrubs, from May to September, had a yield higher than the natural grass stand of the pasture by 1.8–4.5 times. Scientific novelty. All the shrubs under study showed a high adaptive life potential in the arid semi-desert conditions of the study region, including high drought resistance, low demands on soil fertility and a long growing season (140–270 days), high productivity, which exceeded the natural herbage. The use of these shrubs in the restoration of degraded pastures will not only increase their productivity by 43–79 %, but also the nutritional value in terms of feed units by 1.3 times, in terms of digestible protein – by 1.7 times. All this will make it possible to increase the forage capacity of the restored pastures.

Regional differences in influence of intermediate cover permeability on perched leachate in landfill

Intermediate cover may act as impervious layers in landfill and form perched leachates, which have adverse effects on the safe operation of landfill. The formation rules of perched leachate mound in different climate regions are not the same and still unclear. To solve this problem, a finite difference method that took account of climate boundaries was conducted. Four typical cities' climate data standing for Chinese climate and 4 permeability parameters of intermediate cover were used in the simulation. The results showed that key to the formation of perched leachate is that the infiltration rate of the leachate is greater than the ks of the intermediate cover. Under arid climate conditions, the infiltrates of the leachate are generally lower than the infiltration capacity of the intermediate cover, and it is not easy to form a perched leachate mound. In humid regions, when the ks of the intermediate cover is lower than 10−5 cm/s, perched leachate forms easily in rainy seasons. The result can be useful to determine the permeability parameters of intermediate cover, especially in humid climate.

Assessment of Water Stress in Vineyards Using On-The-Go Hyperspectral Imaging and Machine Learning Algorithms

<b>Highlights</b> <list list-type=bullet><list-item> Many vineyards are located in arid and semi-arid climatic conditions with dry summers. </list-item><list-item> Optimal water supply is crucial to avoid any yield or quality loss due to under-irrigation or over-irrigation, respectively. </list-item><list-item> Hyperspectral images, weather data, and machine learning models were used to classify water stress into three categories. </list-item><list-item> Optimal random forest classifier (RFC) and artificial neural network (ANN) models had accuracies of 73% and 70%, respectively. </list-item></list> <b>Abstract</b>. Efficient use of scarce water resources for optimum crop yield and quality is a major concern in dry lands. Traditionally, in-situ methods such as measurements of leaf water potential (ΨL) or soil moisture have been used for estimating plant water stress in vineyards. However, these methods are time, labor, and cost-intensive, and limited to point measurements of water stress that do not offer much spatial resolution. In this study, hyperspectral images acquired from a ground-based utility vehicle were analyzed to evaluate the applicability of hyperspectral data in classifying plant water stress measured as ΨL into three classes: no to mild water stress (ΨL > −0.8 MPa), moderate water stress (-0.8 MPa ≤ ΨL ≤ -1.2 MPa) and severe water stress (ΨL < -1.2 MPa). A field trial was carried out in an experimental vineyard in arid southeastern Washington, USA. Grapevines were subjected to either full irrigation (FI) or regulated deficit irrigation (RDI). Several vegetative indices (VIs) derived from hyperspectral reflectance information were assessed to estimate the level of water stress. Linear relationships between VIs and ΨL, and relative variable importance based on Gini impurity in different test models were evaluated to select optimal VIs for vine water stress classification. Green Normalized Difference Vegetation Index (GNDVI), Photochemical Reflectance Index (PRI), and Anthocyanin Index (ANT) showed consistently good trends in the data obtained over two growing seasons and were selected as the optimal VIs. In addition, air relative humidity, evapotranspiration, minimum soil temperature, and solar radiation demonstrated high significance in model development and were included in the final optimized random forest classifier (RFC) and artificial neural network (ANN) models. The RFC model had an accuracy of 73% while the ANN model had an accuracy of 70% in classifying plant water condition into three classes. Both models demonstrated good classification abilities and can be applied to analyze vine water stress and developing decision support tools for precision irrigation in vineyards.

Dry Bean (Phaseolus vulgaris L.) Crop Water Production Functions and Yield Response Factors in an Arid to Semi-Arid Climate

HighlightsDeficit irrigation negatively affected dry bean yield and yield components.Excess irrigation increased crop ETc but not dry bean yield.Soil moisture fluctuation was greater in the top 0.3 m of the soil profile compared to deeper depths.Crop water production function had a slope of 18.9 kg ha-1 mm-1 and threshold crop evapotranspiration of 171 mm.Dry bean crop was found to be sensitive to water stress (yield response factor Ky = 1.94).Abstract. Under changing climate conditions and declining water resources, understanding crop response to water stress is critical for effective irrigation management. The objectives of this study were to quantify dry bean (Phaseolus vulgaris L., cv. Othello) soil moisture dynamics, crop evapotranspiration (ETc), and yield response factor and to develop dry bean irrigation and crop water production functions (IWPF and CWPF). Five irrigation treatments, i.e., full irrigation (FIT), 75% FIT, 50% FIT, 25% FIT, and 125% FIT, were evaluated using a randomized complete block design (RCBD) with three replications for three years (2017, 2018, and 2019) in the arid to semi-arid intermountain region of Powell, Wyoming. The results showed a significant influence of irrigation on dry bean soil moisture dynamics and ETc. The dry bean crop showed a greater soil moisture fluctuation in the top 0.3 m of the soil profile compared to 0.6 m and at 0.9 m. ETc ranged from 187 to 438 mm, from 190 to 409 mm, and from 217 to 398 mm in the 2017, 2018, and 2019 growing seasons, respectively. A positive two-segment relationship was observed between dry bean seed yield and cumulative irrigation water applied. The average cumulative seasonal irrigation of 310 mm resulted in maximum seed yield. For all three years, the seed yield increased linearly with ETc. Combining the data from the three years resulted in a CWPF with a slope of 18.9 kg ha-1 mm-1 and an offset of 171 mm of ETc (i.e., the ETc required for crop establishment before any seed yield is produced, or threshold ETc). Moreover, the dry bean crop was found to be sensitive to water stress (Ky = 1.94). These results indicated that under the typical semi-arid to arid climate conditions of the intermountain region of Wyoming, deficit irrigation of dry bean may not be a viable strategy because the yield loss outweighs water-saving benefits. Keywords: Dry bean, Crop evapotranspiration, Crop production function, Irrigation water production function.

Evaluation of Seasonal, Drought, and Wet Condition Effects on Performance of Satellite-Based Precipitation Data over Different Climatic Conditions in Iran

The Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Mission (GPM) are the most important and widely used data sources in several applications—e.g., forecasting drought and flood, and managing water resources—especially in the areas with sparse or no other robust sources. This study explored the accuracy and precision of satellite data products over a span of 18 years (2000–2017) using synoptic ground station data for three regions in Iran with different climates, namely (a) humid and high rainfall, (b) semi-arid, and (c) arid. The results show that the monthly precipitation products of GPM and TRMM overestimate the rainfall. On average, they overestimated the precipitation amount by 11% in humid, by 50% in semi-arid, and by 43% in arid climate conditions compared to the ground-based data. This study also evaluated the satellite data accuracy in drought and wet conditions based on the standardized precipitation index (SPI) and different seasons. The results showed that the accuracy of satellite data varies significantly under drought, wet, and normal conditions and different timescales, being lowest under drought conditions, especially in arid regions. The highest accuracy was obtained on the 12-month timescale and the lowest on the 3-month timescale. Although the accuracy of the data is dependent on the season, the seasonal effects depend on climatic conditions.

The Bessarabian (Sarmatian) serpulid bioherms – an indicator of specific climatic conditions (Topola Formation, Northeastern Bulgaria)

Eight Bessarabian (Sarmatian) serpulid bioherms located among aragonite sediments of the Topola Formation in section Zelenka (Northeastern Bulgaria) have been studied to elucidate their macro- and microscopic characteristics. It is concluded that these bioherms were formed under identical arid climatic conditions as the associated aragonite sediments.

Influence of humic preparations on productivity increase of cucurbits in arid farming conditions

The paper presents the results of studying the influence of liquid humic fertilizer produced from milled lowland peat on biological activity, the dynamics of nutrients in brown semi-desert soils in arid climate conditions with leaf fertilization of cucurbits. In arable farming of the Astrakhan region most of the harvest is formed by mobilizing soil fertility without compensation for the elements of nutrition carried out with the harvest, which leads to a negative balance of humus and nutrients, as a consequence, the soil is depleted, its fertility becomes lower. It is shown, that application of humates promotes increase of the content of humus in soil in arable horizons and reception of higher harvests of an early ripe watermelon that is caused by activization of biochemical processes in soil and increase of nutrients availability that has accelerated development and ripening of fruits of studied crop.