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Being the crucial part of the forest soil's microbial pool, soil fungi in general and mycorrhizal fungi in particular are an important study object when it comes to forest ecosystems sustainability and preservation. Thus, the study of ectomycorrhizal fungi has been carried out in the Bryanskiy Les State Nature Biosphere Reserve, located in the south-eastern part of the Bryansk woodlands (European Russia). Forest types featured in the study are the local predominating types, namely green-moss-fructiculose pine forests and polydominant deciduous broadleaved nemoral-herbaceous forests with spruce. This study was aimed to assess seasonal dynamics of soil fungi' biomass overall and ectomycorrhizal fungi in particular over the course of the 2017 vegetation period (May – November) and its dependence on biotic and abiotic environmental factors, such as soil water content, temperature and vegetation. The vegetation period was divided into three periods of observation, namely an early (May – July), middle (July – September) and late (September – November) one. The method used to assess the fungal biomass was direct microscopic observation using the fluorescein diacetate staining. In order to estimate the ectomycorrhizal fungi biomass separately, trenching and in-growth mesh bags were employed. The obtained results suggest that the soil fungi biomass steadily increases over the vegetation period in both studied forest types. This is mostly affected by the forest type, available water amount and seasonal changes, while the temperature's impact is less pronounced. On average, the soil fungi biomass was higher in broadleaved forests than in pine forests (2.288 mg C × g-1 soil vs. 1.672 mg C × g-1 soil, respectively), with non-ectomycorrhizal component having comparable biomass. The dynamics of biomass differed in the two forest types. However, noticeable differences (p < 0.1) between the two forest types have only been recorded during the July – September period. The biomass of ectomycorrhizal fungi is smaller than the biomass of non-mycorrhizal fungi, but at the same time it is less affected by changes in moisture. Besides that, the study has shown that the forest litter characteristics can greatly affect the dynamics of the fungal biomass.

Under the impact of climate change, significant changes have taken place in the ecological environment and water cycle of the Yangtze River source area. Soil water is an important component of the hydrological cycle, and a correct understanding of the spatial and temporal distribution patterns and environmental response mechanisms of soil water is the basis for a deeper understanding of the hydrological cycle and ecological environment changes in the Yangtze River source area. It is also of great significance for promoting the sustainable development of the Yangtze River source area. In this paper, based on ground in-situ observation data, combined with the latest long time-series and multi-sensor combined global soil moisture dataset developed by the European Space Agency (ESA CCI SM V07.1), the spatial and temporal evolution of surface soil water in the Yangtze River source area is revealed, and the impact mechanism of structural function and permafrost type on soil water is discussed. The results show that the surface soil moisture in the Yangtze River source area is mainly concentrated between 0.15 and 0.20 m3/m3, with the highest value occurring from June to October. In the vertical direction, the soil moisture content mainly shows an increasing-decreasing-stable trend from the surface to the deep soil layer, and the deep soil water has a significant lag characteristic relative to the surface, with a lag time of generally 1−2 months. In the horizontal direction, the surface soil moisture overall shows a southeast high and northwest gradually decreasing trend. The closer to the structural fault zone, the lower the soil moisture content, and with the increasing depth, it shows a certain aggravating trend. The surface soil moisture content in the permafrost area is higher than that in the neighboring seasonal frozen soil area. The fluctuation range of the surface soil moisture content in the seasonal frozen soil area is smaller than that in the permafrost area. Over the past 40 years, the surface permafrost has shown a trend of gradual melting, and since 2000, the melting of permafrost has intensified, with a significant increase in surface soil moisture content. The results of this study are of great theoretical significance for the in-depth understanding of the hydrological cycle and ecological environment changes in the Yangtze River source area, and can provide a reference basis for the hydrological cycle and water resources management in the Yangtze River source area.

Spatiotemporal environmental heterogeneity can promote species coexistence through stabilizing mechanisms such as the storage effect. These mechanisms require low density advantages and species-specific responses to heterogeneity. Theory based on organisms, which are short-lived and capitalize beneficial patches instantaneously, suggests that in the presence of spatiotemporal heterogeneity, stabilizing mechanisms should arise more commonly in space than in time.We used an individual-based model to investigate if spatiotemporal soil water heterogeneity promotes stable coexistence among annual and perennial plant life-history strategies, and which functional traits explain the requirements. Scenarios explicitly differed in the resource benefits offered by the range of soil water used to simulate heterogeneity.Our results show that spatiotemporal heterogeneity promoted stable coexistence solely among perennial life-history strategies. Perennial life form delayed population responses to heterogeneity, which resulted in population decoupling among life-history strategies in time as well as in space. Recovery from low density could be explained by a combination of one classical trait which stores the effects of favorable environmental conditions (longevity) and, unexpectedly, a fast resource acquisition strategy evidenced by high adult growth rate and short-term dormancy. Life-history strategy-specific responses emerged from functional differences in seedling competitive ability and seed dispersal distance alone or, additionally, from differences in the hydrological niche. Interestingly, life-history strategies which functionally differed only in dispersal distance coexisted irrespective of whether they experienced a difference in resource benefits themselves or coexisted with life-history strategies experiencing this difference.We show that spatiotemporal heterogeneity in a single abiotic factor promoted stable coexistence through stabilizing mechanisms. Our study highlights the need to study stabilizing mechanisms across different life-history strategies to better understand the effectiveness and dimensions of spatiotemporal heterogeneity in promoting coexistence.

As fresh water supplies become more unreliable, variable and expensive, the water-related implications of sustainable agriculture practices such as cover cropping are drawing increasing attention from California's agricultural communities. However, the adoption of winter cover cropping remains limited among specialty crop growers who face uncertainty regarding the water use of this practice. To investigate how winter cover crops affect soil water and evapotranspiration on farm fields, we studied three systems that span climatic and farming conditions in California's Central Valley: processing tomato fields with cover crop, almond orchards with cover crop, and almond orchards with native vegetation. From 2016 to 2019, we collected soil moisture data (3 years of neutron hydroprobe and gravimetric tests at 10 field sites) and evapotranspiration measurements (2 years at two of 10 sites) in winter cover cropped and control (clean-cultivated, bare ground) plots during winter months. Generally, there were not significant differences in soil moisture between cover cropped and control fields throughout or at the end of the winter seasons, while evapo-transpirative losses due to winter cover crops were negligible relative to clean-cultivated soil. Our results suggest that winter cover crops in the Central Valley may break even in terms of actual consumptive water use. California growers of high-value specialty crops can likely adopt winter cover cropping without altering their irrigation plans and management practices.

Straw returning may be an efficient strategy to maintain agricultural sustainability. However, which straw returning strategy can effectively improve soil properties and crop yield remain unclear. A five-year (2011–2016) field experiment in sub-humid, drought-prone areas of northwestern China with uneven rainfall distribution and irrigation was conducted to evaluate the effects of nitrogen fertilizer without straw mulching (CK), with regular straw mulching (LSM), and with ammoniated straw plowing (ALSP) on soil water, soil aggregates, soil organic carbon (SOC), total nitrogen (TN), and water use efficiency (WUE) in an annual winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) rotation system. The results demonstrate that ALSP had a greater soil water content than CK in the 0–60 cm soil layer. ALSP also had substantially more soil water than LSM in the 0–100 cm layer during the wet year (2011–2012) and two dry years (2014–2015 and 2015–2016). In the normal years (2012–2013 and 2013–2014), the soil water content in ALSP was significantly lower than in LSM in the 0–20 cm soil layer. ALSP was better able to alleviate soil drought in dry years and excessive humidity in wet years. Compared to CK, SOC in the 0–20 cm soil layer in 2016 increased by 8.3% in LSM and 11.7% in ALSP, and TN in the upper soil increased by 6.6% in LSM and 10.1% in ALSP. The equivalent wheat yield and WUE increased in ALSP by 15.6% and 17.5%, respectively, relative to CK, and by 6.79% and 5.97%, respectively, relative to LSM. Thus, we concluded that plowing ammoniated straw with N fertilization is a promising strategy for improving soil fertility and crop productivity in winter wheat–summer maize rotation systems in the sub-humid, drought-prone areas of northwestern China.

The water footprint is an increasingly demanded environmental sustainability indicator for certifications and labels in agricultural production. Processing tomatoes are highly water-intensive, and existing studies on water footprint have uncertainties and do not consider the impact of different irrigation configurations (e.g., surface drip irrigation (SDI) and subsurface drip irrigation (SSDI)) and irrigation strategies. This study presents a two-year experimental investigation to determine the water footprint of processing tomatoes grown in southern Spain (Andalusia) and the impact of SSDI and deficit irrigation. Five irrigation treatments were established: SDI1 (surface drip irrigation without water limitation), SDI2 (surface drip irrigation without water limitation adjusted by soil moisture readings), SSDI1 (subsurface drip irrigation without water limitation and a dripline depth of 15 cm), SSDI2 (similar to SSDI1 but with mild/moderate water deficit during the fruit ripening stage), and SSDI3 (subsurface drip irrigation without water limitation and a dripline depth of 35 cm (first year) and 25 cm (second year)). Measurements included crop vegetative growth, leaf water potential, leaf gas exchange, nitrate concentration in soil solution, and crop yield and quality. The soil water balance components (actual evaporation, actual transpiration, deep drainage), necessary for determining the total crop water footprint, were simulated on a daily scale using Hydrus 2D software. Results indicated that SSDI makes more efficient use of irrigation water than SDI. The water footprint of SSDI1 was 20–35% lower than that of SDI1. SSDI2 showed similar water footprint values to SDI1 under highly demanding environmental conditions and significantly lower values (≈40%) in a year with lower evaporative demand. The dripline depth in SSDI was critical to the water footprint. With a 35 cm installation depth, SSDI3 had a significantly higher water footprint than the other treatments, while the values were similar to SSDI1 when the depth was reduced to 25 cm.

Saline soils limit plant growth due to high salinity. Straw returning has proven effective in enhancing soil adaptability and agricultural stability on saline lands. This study evaluates the effects of different straw-returning methods—straw mulching (SM), straw incorporation (SI), and straw biochar (BC)—on soil nutrients, water dynamics, and salinity in a barley–cotton rotation system using field box experiments. SM improved soil water retention during barley’s jointing and heading stages, while SI was more effective in its filling and maturation stages. BC showed lesser water storage capacity. During cotton’s growth, SI enhanced early-stage water retention, and SM benefited the flowering and boll opening stages. Grey relational analysis pinpointed significant water relationships at 10 cm and 20 cm soil depths, with SM regulating water across layers. SM and BC notably reduced soil conductivity, primarily within the top 20 cm, and their effectiveness decreased with depth. SI significantly lowered soil conductivity at barley’s jointing stage. SM effectively reduced salinity at 10 cm and 20 cm soil depths, whereas BC decreased soil conductivity throughout barley’s jointing, filling, and heading stages. For cotton, SI lowered soil conductivity at the seedling and boll opening stages. SM consistently reduced salinity across all stages, and BC decreased conductivity in the top 30 cm of soil during all growth stages. Both SM and BC significantly enhanced the total nutrient availability for barley and cotton, especially improving soil organic carbon and available potassium, with BC showing notable improvements. At barley’s heading stage, SI maximized dry matter accumulation, while SM boosted accumulation in leaves, stems, and spikes during the filling and maturation stages. Straw returning increased barley yield, particularly with SM and BC, and improved water use efficiency by 11.60% and 5.74%, respectively. For cotton, straw returning significantly boosted yield and water use efficiency, especially with SI and SM treatments, enhancing the total bolls and yield. In conclusion, straw returning effectively improves saline soils, enhances fertility, boosts crop yields, and supports sustainable agriculture. These results provide a robust scientific foundation for adopting efficient soil improvement strategies on saline lands, with significant theoretical and practical implications for increasing agricultural productivity and crop resilience to salt stress.

Soil moisture is a major limiting factor in most dryland agricultural production systems around the globe. In dryland agriculture the amount of water available to grow a crop is determined primarily by the in-season rainfall and the amount of water stored in the soil profile prior to seeding of the crop. Soil water content and water storage capacity are key parameters. Soil moisture data measurements are a compromise between the spatial scale of the investigated site, the required spatial resolution, and the depth of investigation of the applied method.A bibliographic search of the measurement of soil moisture content at field-scale was done, giving an overview of current practices available to determine the spatial variability within a field, and its applicability to farm management practices.Articles published between April 2013 and March 2023 were searched, retaining only the articles with horizontal resolution less than or equal to 100 m, minimum vertical support at a depth greater than or equal to 30 cm from the soil surface, a minimum of two vertical layer depths, and the topic of the document was associated with the measurement of soil moisture at field-scale.The results of this review highlight progress in the past decade but currently there is no one method that can achieve absolute continuous spatial soil moisture in 3D at the field level. Some areas of research show promise but is still some distance away from a reliable, timely, and accurate soil moisture mapping required for many extensive dryland farming systems.

AbstractThe change in land use and land cover (LULC) due to human activities is a major cause of hydrological process changes in watersheds. This study assesses the effects of LULC changes on the hydrological processes in the Bilate catchment, located in southern Ethiopia. Landsat images of 1986, 2002, and 2018 were used to classify LULC through supervised classification. The Soil and Water Assessment Tool (SWAT) evaluated the hydrological responses to LULC changes. Results indicate an increase in built-up areas (0.70%), water bodies (0.19%), cultivated land (10.54%), and barren land (1.265%) from 1986 to 2018. Conversely, the forest (8.52%) and grazing (3.18%) areas declined. An increase in water leaving the root zone (962.02 mm/year), potential evapotranspiration (593.85 mm/year), actual evapotranspiration (201.71 mm/year), and surface runoff (514.86 mm/year) was observed, while soil water content (1423.25 mm/year) decreased at the catchment level. The declining soil water content and increasing actual and potential evapotranspiration could result in a water shortage for crop production. The impact of LULC changes on hydrology provides vital knowledge for integrated LULC and water resource management. Water resource development planning must consider LULC changes to achieve sustainable development in the catchment.

The purpose of this study was to analyze the effects of sludge biochar (BC) application (2, 5, 10, 15% w/w) on the physico-chemical and thermal properties (thermal capacity, thermal conductivity and thermal diffusivity) of loess and the mechanism of action. The results showed that the application of BC changed the soil particle size distribution, reduced the soil bulk density, increased the soil total porosity (1.19–11.51%), organic matter content (10.94–85.02%), saturated water content (1.85–7.15%) and field water capacity (0.09–13.00%), and decreased the soil thermal capacity, thermal conductivity and thermal diffusivity, with an average decreasing amplitude of 2.13, 5.45 and 7.54%, respectively. Soil bulk density and water content (<30%) were positively correlated with soil thermal capacity, thermal diffusivity and thermal conductivity. The mechanisms are mainly that the negative impact of changing soil solid composition and increasing total porosity by biochar with low density and thermal parameter values; and the positive effect of raising water content by improving soil water holding capacity. Sludge biochar shows great potential in soil improvement and can realize sludge sustainable management. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of South-Central Minzu University (Natural Science Edition) is the property of Journal of South-Central Minzu University (Natural Science Edition) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil water content (SWC) is an important but highly variable element of hydrological cycle. Understanding SWC spatial variability at the crop row-scale is critical for improving management of water, soils, and crops. This study investigated the SWC spatial variability at the row scale in corn (Zea mays L.) after the fields were treated with straw mulch (FPM) or without straw mulch (FP) in 2013 and 2014. The spatial variability in SWC was assessed from five horizontal measurement points (MPs), at 10-, 30-, 50-, and 70-cm depths using time domain reflectometry. The spatial variability in SWC among the five MPs was statistically significant for 19–75% of sampling dates and was most often different between the two treatments at 10- and 30-cm depths. Straw mulch most strongly affected the spatial variability of SWC at a 10-cm depth, but this effect differed between the two years. With respect to SWC, the FP treatment exhibited a higher range and lower maximum standard deviation and coefficient of variation compared to those of the FPM treatment. In the majority of sampling dates (more than 60%), the most representative SWC estimates were obtained at MPs positioned at one-quarter into the inter-row gap. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The WINDS (Water-Use, Irrigation, Nitrogen, Drainage, and Salinity) model uses the FAO56 dual crop coefficient and a daily time-step soil–water balance to simulate evapotranspiration and water content in the soil profile. This research calibrated the WINDS model for simulation of guayule under full irrigation. Using data from a furrow irrigated two-season guayule experiment in Arizona, this research developed segmented curves for guayule basal crop coefficient, canopy cover, crop height and root growth. The two-season guayule basal crop coefficient (Kcb) curve included first and second season development, midseason, late-season and end-season growth stages. For a fully irrigated guayule crop, the year one midseason Kcb was 1.14. The second year Kcb development phase began after the crop was semi-dormant during the first winter. The second year Kcb value was 1.23. The two-season root growth curve included a growth phase during the first season, no growth during winter, and a second growth phase during the second winter. A table allocated fractions of total transpiration to soil layers as a function of root depth. With the calibrated tables and curves, the WINDS model simulated soil moisture content with a root mean squared error (RMSE) of 1- to 3-% volumetric water content in seven soil layers compared with neutron probe water contents during the two-year growth cycle. Thus, this research developed growth curves and accurately simulated evapotranspiration and water content for a two-season guayule crop. [ABSTRACT FROM AUTHOR]

As climate change intensifies, soil water flow, heat transfer, and solute transport in the active, unfrozen zones within permafrost and seasonally frozen ground exhibit progressively more complex interactions that are difficult to elucidate with measurements alone. For example, frozen conditions impede water flow and solute transport in soil, while heat and mass transfer are significantly affected by high thermal inertia generated from water‐ice phase change during the freeze‐thaw cycle. To assist in understanding these subsurface processes, the current study presents a coupled two‐dimensional model, which examines heat conduction‐convection with water‐ice phase change, soil water (liquid water and vapor) and groundwater flow, advective‐dispersive solute transport with sorption, and soil deformation (frost heave and thaw settlement) in variably saturated soils subjected to freeze‐thaw actions. This coupled multiphysics problem is numerically solved using the finite element method. The model's performance is first verified by comparison to a well‐documented freezing test on unsaturated soil in a laboratory environment obtained from the literature. Then based on the proposed model, we quantify the impacts of freeze‐thaw cycles on the distribution of temperature, water content, displacement history, and solute concentration in three distinct soil types, including sand, silt and clay textures. The influence of fluctuations in the air temperature, groundwater level, hydraulic conductivity, and solute transport parameters was also comparatively studied. The results show that (a) there is a significant bidirectional exchange between groundwater in the saturated zone and soil water in the vadose zone during freeze‐thaw periods, and its magnitude increases with the combined influence of higher hydraulic conductivity and higher capillarity; (b) the rapid dewatering ahead of the freezing front causes local volume shrinkage within the non‐frozen region when the freezing front propagates downward during the freezing stage and this volume shrinkage reduces the impact of frost heave due to ice formation. This gradually recovers when the thawed water replenishes the water loss zone during the thawing stage; and (c) the profiles of soil moisture, temperature, displacement, and solute concentration during freeze‐thaw cycles are sensitive to the changes in amplitude and freeze‐thaw period of the sinusoidal varying air temperature near the ground surface, hydraulic conductivity of soil texture, and the initial groundwater levels. Our modeling framework and simulation results highlight the need to account for coupled thermal‐hydraulic‐mechanical‐chemical behaviors to better understand soil water and groundwater dynamics during freeze‐thaw cycles and further help explain the observed changes in water cycles and landscape evolution in cold regions. Key Points: Coupled modeling of thermal‐hydraulic‐mechanical‐chemical processes improves our understanding of the hydrological dynamics in the cryo‐subsurfaceA bidirectional exchange between saturated groundwater and unsaturated soil water can be a significant process during freeze‐thaw cyclesFreeze‐thaw can generate highly variable deformation and solute transport behavior in fine‐grained frost susceptible sediments like silt [ABSTRACT FROM AUTHOR]

The rock fragment (RF) has been widely observed in the soil solum or on the soil surface. It regulates soil hydrological processes (SHPs) and thus has great impacts on soil and water conservation. However, responses of SHPs to RF characteristics (position, content, coverage area, mulching thickness, and size) remain unclear. Based on the dataset extracted from 168 published studies, effects of RF characteristics on SHPs (soil loss rate, evaporation rate, surface runoff rate, infiltration rate, soil water content, and soil water storage) and saturated hydraulic conductivity (Ks) were discussed in this study. Results showed that RFs completely inserted into the soil solum (CO_INS) improved the Ks by 6.9%, runoff rate by 12.8%, and soil loss rate by 22.3%, while it reduced the evaporation rate by 30.7%, infiltration rate by 15.4%, and soil water content by 9.9%. With the RF content (kg kg−1) increasing, its effects on these SHPs were strengthened. The RFs resting on the surface and partially covering soil surface (PA_COV) improved the infiltration rate but reduced the evaporation rate by 36.9%, surface runoff rate by 25.4%, and soil loss rate by 59.3%. This in turn enhanced soil water content and storage. However, as the RF coverage (% in area) increasing, the cross-sectional area of water flow decreased, and thus the infiltration rate reduced. The RFs completely mulch on the soil surface (CO_MUL) reduced the evaporation rate by 59.5% and infiltration rate by 76.5% but improved the soil water content and storage. Except the infiltration rate, the effects of CO_MUL on SHPs were strengthened as mulch thickness (cm) increased. The RFs partially embedded into soil surface (PA_EMB) promoted surface runoff rate by 15.3%, soil loss rate by 34.7%, and soil water content by 24.3%, but reduce the infiltration rate. However, the surface runoff rate was reduced at high embedded coverage due to increased tortuosity of water flow. In addition, the RF size exerted weaker effects on SHPs than RF positions, content, coverage, and mulch thickness. Our findings enhanced the understanding of SHP responses to RFs characteristics, which would be important for relate soil and water modeling and management. [ABSTRACT FROM AUTHOR]

Spatiotemporal environmental heterogeneity can promote species coexistence through stabilizing mechanisms such as the storage effect. These mechanisms require low density advantages and species-specific responses to heterogeneity. Theory based on organisms, which are short-lived and capitalize beneficial patches instantaneously, suggests that in the presence of spatiotemporal heterogeneity, stabilizing mechanisms should arise more commonly in space than in time. We used an individual-based model to investigate if spatiotemporal soil water heterogeneity promotes stable coexistence among annual and perennial plant life-history strategies, and which functional traits explain the requirements. Scenarios explicitly differed in the resource benefits offered by the range of soil water used to simulate heterogeneity. Our results show that spatiotemporal heterogeneity promoted stable coexistence solely among perennial life-history strategies. Perennial life form delayed population responses to heterogeneity, which resulted in population decoupling among life-history strategies in time as well as in space. Recovery from low density could be explained by a combination of one classical trait which stores the effects of favorable environmental conditions (longevity) and, unexpectedly, a fast resource acquisition strategy evidenced by high adult growth rate and short-term dormancy. Life-history strategy-specific responses emerged from functional differences in seedling competitive ability and seed dispersal distance alone or, additionally, from differences in the hydrological niche. Interestingly, life-history strategies which functionally differed only in dispersal distance coexisted irrespective of whether they experienced a difference in resource benefits themselves or coexisted with life-history strategies experiencing this difference. We show that spatiotemporal heterogeneity in a single abiotic factor promoted stable coexistence through stabilizing mechanisms. Our study highlights the need to study stabilizing mechanisms across different life-history strategies to better understand the effectiveness and dimensions of spatiotemporal heterogeneity in promoting coexistence. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The soil water regime often controls whether an ecosystem is a source of greenhouse gases such as CO2 or CH4 or is, instead, a carbon sink. The soil water regime of wetland forests is complicated by ecosystem feedback and landscape scale interactions. An in-depth understanding of these processes is needed to optimize the management of such ecosystems to balance timber production, carbon sequestration and biodiversity preservation. To investigate the soil water regime of non-riparian wetland forests, we set up a physically based Hydrus-1D soil water model for two hydric black alder Alnus glutinosa sites in a lowland hemiboreal setting informed by field observations of the soil water. Further, to gain ecohydrological insights, we explored the correlations between modeled long-term soil water parameters and local dendrochronology. We found that, at the clay soil site, the simulated root water uptake had a significant correlation (up to 0.55) with the residual tree-ring chronology. However, in the sandy soil site, the meteorological conditions—air temperature and precipitation—were better predictors for tree radial growth (correlation up to 0.42). In addition, we observed a trend towards dryer conditions during the modeling period, which might enhance the growing conditions for the considered forest stands due to a reduction in soil waterlogging. [ABSTRACT FROM AUTHOR]

The Gravity Recovery and Climate Experiment (GRACE, 2003–2017) and its Follow‐On mission GRACE‐FO (2018‐now) provide global estimates of the vertically integrated Terrestrial Water Storage Changes (TWSC). Since 2015, the Soil Moisture Active Passive (SMAP) radiometer observes global L‐band brightness temperatures, which are sensitive to near‐surface soil moisture. In this study, we introduce our newly developed Constrained Bayesian (ConBay) optimization approach to merge the TWSC of GRACE/GRACE‐FO along with SMAP soil moisture data into the ∼10 km resolution W3RA water balance model. ConBay is formulated based on two hierarchical multivariate state‐space models to (I) separate land hydrology compartments from GRACE/GRACE‐FO TWSC, and (II) constrain the estimation of surface soil water storage based on the SMAP data. The numerical implementation is demonstrated over the High Plain (HP) aquifer in the United States between 2015 and 2021. The implementation of ConBay is compared with an unconstrained Bayesian formulation, and our validations are performed against in‐situ USGS groundwater level observations and the European Space Agency (ESA)'s Climate Change Initiative (CCI) soil moisture data. Our results indicate that the single GRACE/GRACE‐FO assimilation improves particularly the groundwater compartment. Adding SMAP data to the ConBay approach controls the updates assigned to the surface storage compartments. For example, correlation coefficients between the ESA CCI and the ConBay‐derived surface soil water storage (0.8) that are considerably higher than those derived from the unconstrained experiment (−0.3) in the North HP. The percentage of updates introduced to the W3RA groundwater storage is also decreased from 64% to 57%. Key Points: A Constrained Bayesian (ConBay) optimization approach is introduced to integrate GRACE/GRACE‐FO and SMAP data into a modelThe ConBay integration of GRACE/GRACE‐FO and SMAP controls the updates assigned to the surface soil and groundwater compartmentsThe ConBay approach considerably reduced the phase shift differences between the model‐derived groundwater storage and USGS observation [ABSTRACT FROM AUTHOR]

Abstract Nowadays, infiltration tactics are widely used to manage storm water in urban areas. These techniques are used and recognized around the world due to their benefits, such as reducing the negative consequences of urbanization, reducing storm water flow in sewage systems and recharging groundwater. Richards equation is one of the most well-known equations for simulating water infiltration in soil in the unsaturated area. In the present study, a one-dimensional approach to the numerical solution of Richards equation is presented using meshless Petrov–Galerkin method and Kirchhoff transformation. The results of this modeling have been compared with analytical solution, laboratory data, and finite difference and meshless numerical methods. Given that the proposed model can provide an accurate representation of water level changes in unsaturated soil compared to analytical solution, laboratory data, finite difference method and MQ-RBF with the root mean square error equal to 0.09, 1.02, 0.7 and 0.1, it can be claimed that the model can model the flow of water infiltration in unsaturated soil.

Alternate partial root-zone drip fertigation (ADF) is a combination of alternating irrigation and drip fertigation, with the potential to save water and increase nitrogen (N) fertilizer efficiency. A 2-year greenhouse experiment was conducted to evaluate the effect of different fertigation frequencies on the distribution of soil moisture and nutrients and tomato yield under ADF. The treatments included three ADF frequencies with intervals of 3 days (F3), 6 days (F6) and 12 days (F12), and conventional drip fertigation as a control (CK), which was fertilized once every 6 days. For the ADF treatments, two drip tapes were placed 10 cm away on each side of the tomato row, and alternate drip irrigation was realized using a manual valve on the distribution tapes. For the CK treatment, a drip tape was located close to the roots of the tomato plants. The total N application rate of all treatments was 180 kg ha−1. The total irrigation amounts applied to the CK treatment were 450.6 and 446.1 mm in 2019 and 2020, respectively; and the irrigation amounts applied to the ADF treatments were 60% of those of the CK treatment. The F3 treatment resulted in water and N being distributed mainly in the 0–40-cm soil layer with less water and N being distributed in the 40–60-cm soil layer. The F6 treatment led to 21.0 and 29.0% higher 2-year average concentration of mineral N in the 0–20 and 20–40-cm soil layer, respectively and a 23.0% lower N concentration in the 40–60-cm soil layer than in the CK treatment. The 2-year average tomato yields of the F3, F6, F12, and CK treatments were 107.5, 102.6, 87.2, and 98.7 t ha−1, respectively. The tomato yield of F3 was significantly higher (23.3%) than that in the F12 treatment, whereas there was no significant difference between the F3 and F6 treatment. The F6 treatment resulted in yield similar to the CK treatment, indicating that ADF could maintain tomato yield with a 40% saving in water use. Based on the distribution of water and N, and tomato yield, a fertigation frequency of 6 days under ADF should be considered as a water-saving strategy for greenhouse tomato production.

The application of nitrogen (N) improves the winter wheat yield. Excessive N application affects winter wheat yields, leading to low net incomes and negative environmental impacts, therefore, optimizing N application is essential. In this study, the effects of N rates on crop growth yield, net income (NI), water use efficiency (WUE), and nitrogen use efficiency (NUE) in the irrigated districts of the eastern loess plateau, China, were investigated using seven N application rates (N0, N90, N180, N210, N240, N270, and N300 kg ha−1) during the 2016–2017 and 2017–2018 seasons. N application significantly increased the total water consumption at 0–200 cm during the growth period, the aboveground dry matter at maturity, the grain nitrogen accumulation, yield, NI, and WUE. However, N exceeding 240 kg ha−1 did not favor dry matter and nitrogen accumulation or translocation from the anthesis stage to the maturity stage, thus leading to reduced yield, NI, and WUE. The transpiration rate and stomatal conductance N240 was highest 21–28 day after anthesis, at 187–276 kg ha−1, which can achieve a high yield and profitability with relatively low environmental costs.

Soil moisture is a critical variable in the hydrological cycle and the climate system, significantly impacting water resources, ecosystem functioning, and the occurrence of extreme events. However, soil moisture data are often scarce, and soil water dynamics are not fully understood in mountainous regions such as the tropical Andes of Ecuador. This study aims to model and predict soil moisture dynamics using in situ-collected hydrometeorological data for training and data-driven machine-learning techniques. Our results highlight the fundamental role of vegetation in controlling soil moisture dynamics and significant differences in soil water balance related to vegetation types and topography. A baseline model was developed to predict soil moisture dynamics using neural network techniques. Subsequently, by employing transfer-learning techniques, this model was effectively applied to different soil horizons and profiles, demonstrating its generalization capacity and adaptability. The use of neural network schemes and knowledge transfer techniques allowed us to develop predictive models for soil moisture trained on in situ-collected hydrometeorological data. The transfer-learning technique, which leveraged the knowledge from a pre-trained model to a model with a similar domain, yielded results with errors on the order of 1×10−6<ϵ<1×10−3. For the training data, the forecast of the base network demonstrated excellent results, with the lowest magnitude error metric RMSE equal to 4.77×10−6, and NSE and KGE both equal to 0.97. These models show promising potential to accurately predict short-term soil moisture dynamics with potential applications for natural hazard monitoring in mountainous regions.

Almond yields vary between rainfed and intensively irrigated systems, but how to match irrigation to potential productivity is unclear. Hence, we compared almond physiology under deficit (600 mm) and full (1300 mm) irrigation to identify stress indices and determine the production overheads of mismanaged watering. We hypothesized that trees alter their growth to conserve resources during drought and mitigate their hydraulic stress responses. Thus, we monitored stem water potential and stomatal conductance to characterize the hydraulic responses of trees to deficient and hydrated water conditions. Adapting the seasonal relationship between irrigation coefficients and tree water potential was also tested. Finally, soil water status and trunk development were considered physical stress indices for field conditions. Soil water depletion in deficit irrigation reduced stem water potential below − 2 MPa and checked stomatal conductance at 0.15 mol m-2 s-1 for most of the growing season. An empirical productivity model determined that, under deficit irrigation, almond trees suffer from chronic stress that limits their photosynthetic capacity to ∼14 µmol m-2 s-1. Consequently, nominal assimilation limitations (10%) in early summer manifested to 4 kg C tree-1 metabolic losses by autumn. The inter-annual vegetative limitations in deficit irrigation resulted in significant yield reductions (35%) by the second experimental season. Temporal changes in the correlations between stem water potential, stomatal conductance, and trunk contractions made it difficult to use water stress indices to make irrigation decisions. However, normalizing tree performance by phenology indicated a 960 mm irrigation that supported high yields. Further, integrating the variability in soil water with trunk dendrometry illustrated that trees could maintain constant growth between irrigation days under well-watered conditions. Hence, in commercial operations, variable growth rates and trunk contraction measures signal insufficient irrigation and could guide practical irrigation adaptations.

Water stress, improper fertilization practices, and agricultural waste pollution severely reduce soil fertility and limit agricultural sustainability on the Loess Plateau. Organic fertilizer application is an efficient method for improving soil water and nutrient availability and grain yield in semi-arid and arid areas. However, the impact of bio-organic fertilizer derived from agricultural waste on soil characteristics and wheat yield and the optimum bio-organic fertilizer substitution rate in semi-humid drought-prone areas remain unclear. A two-year field study was conducted to explore the effect of combined bio-organic and chemical fertilizer application on soil moisture, hydraulic properties, soil structure, soil organic carbon (SOC), total nitrogen (TN), grain yield, and water productivity (WP). Six different treatments were designed: no fertilization (CK), conventional chemical fertilization (CF), and bio-organic fertilizer treatments substituting 25% (OF25%), 50% (OF50%), 75% (OF75%), and 100% (OF100%) of the chemical N fertilizer. From the seedling to over wintering stage, the OF75% and OF100% treatments generally improved soil water storage (SWS) and soil water content (SWC) within the 0–100 cm soil layer compared to the CK and CF treatments across both growing seasons. Bio-organic fertilizer substitution significantly reduced soil bulk density by 4.0–5.6% and enhanced soil porosity by 4.2–5.9% in the 0–40 cm soil layer. Moreover, bio-organic fertilizer substitution significantly increased soil saturated hydraulic conductivity and water content, improved aggregate size distribution, and enhanced SOC and TN contents in both years. The OF75% treatment produced the highest aboveground biomass, yield components, grain yields, and WP, attributed to the improved soil physical environment and nutrient contents. Notably, the OF75% treatment increased the average wheat yield and WP by 21.1% and 24.9%, respectively, relative to the CF treatment across both growing seasons. The measured soil properties strongly correlated with wheat yield, yield components, and WP. Thus, the OF75% treatment is an appropriate and promising fertilization management strategy to alleviate water stress, improve soil properties, and promote crop production in semi-humid drought-prone regions.

The Yellow River Basin, which accommodates the second longest river in China – Yellow River, covers a total area of 795,000 km2 and plays an important role in the national agricultural production, economy, and culture. However, the Basin also faces enormous challenges related to sustainable water management in agriculture as driven by both drought and flood. In this special issue, we collected 64 articles across the Basin to improve our understanding of agricultural water management needs and demonstrate efficacies of management practices to improve the water management. The articles present exciting research on regional soil water storage and dynamics, soil moisture conservation in rain-fed agriculture, crop water demand, irrigation effects, water-nutrient coupling, water management and soil salinity, soil and nutrient losses, groundwater science and management. Findings of studies revealed: (1) the importance of mulching, drip and negative pressure irrigation, water and nutrient coupling (i.e., fertigation) in achieving both crop production and environmental protection objectives; (2) emerging research for better understanding of regional water resources and allocation of the water resources among different agricultural land uses and cropping systems, new approaches for conserving water and soil and mitigating soil salinity, system-level integrated rainfall and irrigation management, and improved knowledge on groundwater quantity and quality management; and (3) need of future research to understand processes and efficiencies of management practices in variable landscapes and cropping systems and variable and changing climates, and system-level linkages and analyses of water balance – soil water availability and conservation – water and soil losses – agricultural and environmental sustainability.

Mole channel drainage is a cost-effective and efficient way to drain slowly permeable agricultural soils. Artificial drainage has the potential to significantly influence catchment hydrology and contaminant source areas, but there is little information available about the extent, connectivity, layout, density or longevity of mole channel networks, which are commonly estimated to deteriorate within 5–20 years. Such information is important for understanding landscape hydrodynamics but, currently, there are no established techniques for calibrating estimates of mole network characteristics at the paddock or larger scale. This study characterised a 30-plus-year-old mole channel network in a small agricultural basin in Southland, New Zealand, and tested the utility of ground-penetrating radar (GPR) for identifying, mapping, and characterising mole channel drainage. A dual frequency GPR antenna (700 and 250 MHz), connected to a high-precision, real-time kinematic global positioning system, was tested and proved effective at locating mole channels and a tile drain with high lateral precision and accuracy. Surveying of six plots demonstrated that the mole network was complex in design and had a high density (1.6 m m−2) of interconnected, multidirectional mole channels. Significantly, the mole channels were predominantly in good condition and spatially well connected. Visual observations found no evidence that the blade slot and secondary soil fractures, formed by the mole plough during installation, persisted after 30 years. However, root growth and worm burrowing into the mole channels suggest they are hydraulically connected to the surrounding soil through natural macropores. Our results provide the first attempt at mapping and characterising mature, multi-generational mole channel networks in slowly permeable loess soils. The results have significance for understanding catchment-scale hydrodynamics in mole-drained landscapes, especially considering that the life span of these artificial drainage networks is shown to be considerably longer than previous estimates for loess-derived, silt loam soils.

Film mulching is widely used as an agronomic practice to counteract water scarcity in arid and semi-arid areas. Although crop models have emerged as powerful tools for system studies and scenarios analysis, they have been rarely used in areas with severe drought and salinization and where mulching is being used as a management practice. An earlier study shown great modelling potential under severe salinity in southern Xinjiang, China. The model is WAVES (the WAter Vegetation Energy and Solute), while evaporation was overestimated in the earlier study without considering the mulching effect. In this study, we used a modified WAVES model by incorporating three functions working on potential evaporation, underlying surface albedo, and soil resistance into it to represent the mulching effect. Calibration and validation were conducted using cotton field experiments from 2 different years. Of the 3 functions evaluated, the one representing potential evaporation reduction exerted the highest modification effect on soil water status. The modified model better simulated evaporation, soil-water content, soil-salt content, leaf area index (LAI), and yield than the original model, decreasing normalized root mean square error (NRMSE) by 173%, 15%, 14%, 9%, and 35%, respectively. The modification effects were most significant during the seedling stage. In addition, the modified model produced a higher realistic evaporation (E)/evapotranspiration (ET) under the film mulching environment. These findings suggest that the modified WAVES model can be applied for crop management under film mulching, particularly in areas with low rainfall and high salinization.

Link for citation: Raudina T.V., Smirnov S.V., Istigechev G.I., Pokrovsky O.S. Photochemical transformation of dissolved organic matter and behavior of metals in the waters of the southern taiga bog complex, Western Siberia. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 182-193. In Rus. The relevance. Dissolved organic matter is one of the largest biologically available sources of carbon in terrestrial and aquatic ecosystems, and its dynamics are critical to local and global carbon cycles. Destruction of organic matter during migration determines the biological cycle of elements and their stability. Important processes that lead to the transformation or removal of the dissolved organic matter are bio- and photodegradation. To date, enough research has been carried out to study the composition of humic substances, forms of metals, and the processes of migration of organo-mineral compounds in natural waters of the taiga zone, Western Siberia. Work is underway to study the dissolved organic carbon bioavailability, but the mechanisms of its photochemical transformations in different seasons of the year have not been studied. At the same time, photochemical mineralization of dissolved organic compounds largely regulates the biogeochemical cycles of elements by changing their bioavailability, the intensity of carbon dioxide emission from surface waters into the atmosphere, and the removal of dissolved trace elements through precipitation and coagulation. The main aim is to assess changes in the chemical composition and the rate of the dissolved organic matter and dissolved metals removal in the waters of the southern taiga bog complex (Western Siberia) under the sunlight exposure on a spatio-temporal scale. Objects: soil waters within different bog landscapes (open sedge-sphagnum fen, tall ryam (pine-shrub-sphagnum phytocenosis with high pine trees), and waterlogged mixed forest) of the Bakchar bog complex located in the southeastern part of the Ob-Irtysh interfluves, the Vasyugan plain. The waters were taken at a depth by digging a pit (40´40 cm area, 40 cm depth), which allowed the surrounding gravitational water to fill it up to the depth of 10–20 cm. The sampling took place during two field period in 2020 (June and October). Methods. pH, water temperature, specific conductivity (Cond) and dissolved oxygen were measured using a multiparameter instrument (WTW MULTI 3430 SET). The dissolved organic carbon was measured by a high-temperature thermic oxidation method using a Shimadzu TOC-LCPN analyzer, with an uncertainty of 2 %. The absorbance was measured at wavelengths up to 800 nm, 1 nm step using quartz 10 mm cuvette on a Cary-50 spectrophotometer. Major cations (Ca, Mg, Na, K), Si, and trace metals were determined with an ICP-MS Agilent CE 7500 with In and Re as internal standards and three various external ones. In the photodegradation experimental design, we followed the methodology which is sunlight exposure of sterile filtered (0,2 μm) samples in quartz reactors in the outdoor pool. Results. The authors revealed the influence of photodegradation on the qualitative and quantitative composition of dissolved organic substances and the behavior of metals in water samples of bog landscapes of the taiga zone of Western Siberia on spatiotemporal scales. It was established that from 3 to 30 % of the dissolved organic carbon can be removed from soil water under the influence of sunlight with maximum values in early June. At the same time, in autumn, despite the decrease in the amount of solar radiation, the photodegradable DOC can also reach 10–12 %. In general, there is a decrease in the percentage of the dissolved organic carbon loss in the waters in the row fen>ryam>forest. The dissolved organic carbon removal can be associated both with the transition of a part into an inorganic form, and with the destruction of high-molecular organic substances. A significant change (p

This study aimed to determine how within-plot soil heterogeneity combined with yearly climate variability can promote the heterogeneity of vine growth at plot level, and which soil-climate parameters influence final yield and berry composition the most. An 8-year experiment was conducted on grapevine in two zones of a vineyard (1 ha) differentiated according to grapevine vigour as determined by NDVI: high vigour (HV) and low vigour (LV). The heterogeneity of the soil properties (depth, texture and composition), plant growth (shoots and roots) and plant production (yield components and berry composition) were determined at plot level. Compared to the LV zone, the HV zone was associated with deeper soils, higher soil water and nitrogen availability, CEC and montmorillonite/illite ratio. More extended root systems, higher vegetative growth and higher yield were observed in the HV zone compared to the LV zone. Drier and warmer vintages increased the difference in heterogeneity of vine growth and yield between the two zones. Berry composition (primary and secondary metabolites) also differed between HV and LV zones but seemed unconnected to vigour and mainly depended on soil-climate-plant interactions over the years. The heterogeneity of plant vigour within the vineyard mainly resulted from differences in root exploration, soil profile and composition (notably montmorillonite/illite ratio). The present study identified soil and crop factors that, depending on weather conditions, can be drivers for reducing the heterogeneity of plant development and improving productivity at vineyard level.

Extreme high temperature (EHT) events are becoming more frequent and prolonged due to global climate change. Predicting the effects of EHT events on agricultural soil fauna remains a major challenge. In order to assess the response of community composition and vertical distribution of soil fauna to EHT events, this study investigated the soil macrofauna communities in facility agricultural farmlands at the end of an EHT event in East China in 2022 and eighteen days after. The results showed that the taxonomic richness and abundances of the soil macrofauna community were reduced eighteen days after the EHT event. However, changes in abundance were taxonomically dependent: individuals of ants (Pheidole indica), centipedes (Himantariidae) and crickets decreased significantly, while Enchytraeidae and earthworms increased. Soil water content was an important factor determining taxonomic richness at the end of the EHT event and the abundance of earthworms eighteen days after the EHT event. The maximum values of taxonomic richness and abundance of the soil macrofauna community were observed in the surface layer (0–10 cm) at the end of the EHT event and eighteen days after. Earthworms burrowed into the deeper layer at the end of the EHT event, but moved to the surface layer eighteen days after the EHT event. These results showed that most soil fauna taxa experienced adverse effects posed by EHT events, while the earthworm and Enchytraeidae had abilities to increase their abundances rapidly by EHT events. This study suggests that soil water content and vertical distribution should be considered when assessing the impact of an EHT event on soil biodiversity.

[Objective] Exploring the effects of different types of Pisha Sandstone and different land use patterns on soil water, organic carbon and total nitrogen content plays an important guiding role in the further development of Pisha Sandstone area. [Methods] 13-year-old Seabuckthorn (Hippophae rhamnoides) woodland, 6-year-old Seabuckthorn woodland, natural grassland in the soil-covered Pisha Sandstone area of Jungar banner of Inner Mongolia, natural grassland in the exposed Pisha Sandstone area, and natural grassland, Caragana korshinskii woodland, farmland and 5-year-old abandoned farmland in the sand-covered Pisha Sandstone area, a total of eight sample plots were used as the research objects. By measuring the soil water content, organic carbon and total nitrogen content of different soil layer at a depth of 0—100 cm, the contents and variation of soil water, organic carbon and total nitrogen in different soil layers were studied and compared. [Results]: The soil water storage in 0—100 cm soil layer in the soil-covered Pisha Sandstone area (13-year-old Seabuckthorn woodland (152.36 mm), 6-year-old Seabuckthorn woodland (165.16 mm), natural grassland (160.97 mm)) was higher than that of the sand-covered Pisha Sandstone area (natural grassland (73.03 mm) and Caragana korshinskii woodland (66.56) mm), farmland (79.70 mm), and 5-year-old abandoned farmland (107.03 mm)). Soil organic carbon content of grassland in the exposed Pisha Sandstone area was lower than that in the soil-covered and sand-covered Pisha Sandstone area. Soil organic carbon storage in the 0—100 cm soil layer (1.97 kg/m²) was lower than that of the natural grassland, 6-year-old and 13-year-old Seabuckthorn woodland in the soil-covered Pisha Sandstone area, natural grassland, Caragana korshinskii woodland, farmland and 5-year-old abandoned farmland in the sand-covered Pisha Sandstone area by 2.24 kg/m², 2.36 kg/m², 1.74 kg/m², 1.23 kg/m², 0.66 kg/m², 2.58 kg/m² and 1.21 kg/m², respectively. Compared with each type of Pisha Sandstone area, the total nitrogen storage of the grassland in the exposed Pisha Sandstone area was the lowest (0.18 kg/m²), which was lower than that of the natural grassland in the soil-covered Pisha Sandstone area and the natural grassland in the sand-covered Pisha Sandstone area by 0.22 kg/m². [Conclusion] To sum up, the soil water storage, organic carbon and total nitrogen storage in the 0—100 cm soil layer of the 13-year-old Seabuckthorn woodland in the soil-covered Pisha Sandstone area and the Caragana korshinskii woodland in the sand-covered Pisha Sandstone area were all lower than those of the natural grassland in the same type of area. Caragana korshinskii and Seabuckthorn planting after a certain period of years, comprehensively considering the benefits of water conservation, it should be thinned to reduce the competition with understory herbss, thereby accelerating the natural succession of the understory vegetation and ensuring the sustainable development of the ecological environment in the Pisha Sandstone area. [ABSTRACT FROM AUTHOR]

The spatial variation characteristics of the hydrogen and oxygen isotopic composition of soil water are of great significance to the study of the water cycle and the relationship between different water bodies. This study took the Shaliu River Basin of Qinghai Lake as the research object to collect the data of soil water hydrogen and oxygen stable isotope composition (δ² H, δ18O) from July and August of 2018 to 2019 in the watershed and obtain the spatial changes of soil water δ² H and δ18O by using the method of ArcGIS spatial interpolation. The results showed that the δ² H and δ18O of soil water varied from –126.53‰ to –16.13‰ and from –16.48‰ to –1.26‰ respectively in the Shaliu River Basin of Qinghai Lake in July and August, 2018-2019. During the study period, the soil water lines of the average values of δ² H and δ18O of 0-30 cm soil water were: SWL2018.07 (δ² H=5.83δ18O–8.36, R² =0.93), SWL2018.08 (δ² H=6.28δ18O–8.35, R2 =0.93), SWL2019.07 (δ² H=6.53δ18O–5.70, R² =0.94), SWL2019.08 (δ² H=6.86δ18O–1.37, R² =0.92). On the whole, the slope of SWL increased first and then decreased with the change of depth, while the intercept increased gradually with the increase of depth. In August 2019, the slope of SWL decreased gradually with the increase of depth, with a small difference in the change of intercept. Precipitation was an important source of soil water, and evaporative enrichment caused the slope of SWL at different depths to be smaller than that of the local atmospheric precipitation line (LWML). In terms of spatial distribution, the altitude effect of soil water stable hydrogen and oxygen isotopes in the Shaliu River Basin of Qinghai Lake was not obvious, but it was still affected by the intensity of local evaporation, topography, vegetation coverage, and water vapor sources, appearing patchy partitions on the watershed surface. The research results can provide data support and theoretical reference for further research on the water cycle of the watershed and the mechanism of soil water replenishment. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of soil water and nitrate in response to typical agricultural crops in dryland ecosystems are crucial for assessing ecological consequences and informing land use planning. This study was conducted in the Changwu tableland, a representative area for agricultural crop cultivation in the Loess Plateau of China. Fifteen soil profiles, including grassland, farmland, and young, mature, and old apple orchards, were sampled to investigate the effects of different land uses on soil water and nitrate dynamics using a "space-for-time" substitution approach. The results showed that the soil water content and nitrate content in farmlands were comparable to those in wild grassland. However, significant differences in soil water were observed below a depth of 2 m in apple orchards, with mature and old orchards experiencing water deficits compared to grassland of 624.9 mm and 690.0 mm, respectively. Moreover, a dried soil layer formed below a depth of 5 m in these orchards. In terms of soil nitrate, the concentration in the 0–5 m depth of apple orchards was significantly higher than that in agricultural land and grassland, and it increased with the age of the orchards. However, below 5 m, the residual nitrate stock per unit depth in apple orchards decreased to levels comparable to grassland and farmland, primarily due to the inhibitory effect of the dried soil layer on downward migration and leaching processes. Furthermore, the relationship between nitrate and soil water at 0–5 m soil depths differed during the conversion from grassland to farmland and apple orchard, with positive and negative correlations observed, respectively. This indicates that water plays a key role in influencing nitrate movement, and distinct hydrological processes occur for soil water and nitrate nitrogen under different land use change conditions. In conclusion, converting grassland and farmland to apple orchards can lead to soil water decline and nitrate accumulation in the vadose zone, posing potential threats to ecosystem sustainability and security in dryland regions. Therefore, implementing appropriate water-fertilizer management practices is crucial for promoting sustainable land use in loess drylands, with potential implications for similar areas worldwide. [ABSTRACT FROM AUTHOR]

Agricultural systems face several challenges that threaten their capacity to feed the world while maintaining a healthy and functional environment. Climate change, together with soil degradation, biodiversity loss, resource scarcity and invasive species, is a major threat to agricultural systems worldwide. In this context, new practices have been proposed to circumvent or minimize these threats. Yet, these mostly focus on the farm or plant level (e.g., breeding for stress‐tolerant species), while frequently overlooking belowground components (e.g., soil organic carbon accrual). By interlinking above‐ and below‐ground components, the likelihood of limiting the negative effects of current threats to agricultural systems can be maximized. This review explores current knowledge regarding agroforestry and its effects on belowground components as a key property in the reducing effects of climate change. We first review tree effects on key soil properties of agricultural systems. We synthesize evidence regarding agroforestry systems response to current environmental threats that are related to climate change. We continue by discussing how soil processes play a fundamental role in the capacity of agroforestry systems to cope with climate change. We conclude by proposing options on how resilience of agroforestry systems could be further enhanced. [ABSTRACT FROM AUTHOR]

Non-growing season irrigation and farmland subsurface drainage play a crucial role in salt leaching and salinization control in arid irrigation areas. This study aimed to investigate the reduction of autumn irrigation quotas and drainage discharge while maintaining soil moisture retention and reducing soil salinization. Field experiments were conducted with different autumn irrigation quotas (160 mm for SD1, 180 mm for SD2, and 200 mm for SD3) combined with subsurface drainage (1.5 m drain depth and 45 m spacing). A control treatment (referred to as CK) without subsurface drainage received 200 mm of irrigation. The results showed that, after 31 days of autumn irrigation, the groundwater depth in all three subsurface drainage plots stabilized to 1.5 m, with the CK being 0.2–0.3 m shallower compared to the SD plots. The mean soil water content in the 0–150 cm soil layer of the SD1, SD2, SD3, and CK after autumn irrigation was 0.36, 0.39, 0.41, and 0.42 cm3cm−3, respectively. The combination of autumn irrigation and subsurface drainage significantly reduced the soil salt content. The mean desalination rates in the root zone (0–60 cm) soil layer were 57.5%, 53.7%, 51.9%, and 45.1% for the SD3, SD2, CK, and SD1, respectively. The mean desalination rate of 60–150 cm was not significantly different between the SD2 and SD3 (p > 0.05), and both were significantly higher than that of the SD1 and CK (p < 0.05). The drainage discharge was 31, 36, and 40 mm in the SD1, SD2 and SD3, respectively. The amount of salt discharge through the drain pipe increased with increasing irrigation quota, which was 1.22 t/ha, 1.41 t/ha, and 1.50 t/ha for the SD1, SD2, and SD3, respectively. Subsurface drainage is an effective way to prevent salt accumulation in the soil, and an autumn irrigation quota of 180 mm is recommended for leaching of salinity in the Hetao Irrigation District. These findings provide valuable insights into optimizing irrigation practices and managing soil salinization in arid regions. [ABSTRACT FROM AUTHOR]

Background and Objectives: In order to identify the possibility of supplying food to the world's population, given the need for continued production in sustainable agriculture, it is necessary to correctly predict the yield of crops. For this purpose, modeling of growth stages and yield of rice based on meteorological statistics of Iran, was studied in Gorgan University of Agricultural Sciences and Natural Resources. The purpose of this study was to use the simple model SSM-iCrop2 to simulate rice growth and yield to investigate the effects of climatic factors, soil, agronomic management and to determine the genetic coefficients of rice in Iran. Due to the appropriate ability of the model in rice simulation, it can be used as a suitable tool for better planning and management of rice fields in the country. Materials and Methods: In this study, the SSM-iCrop2 model was used to simulate the potential yield. In this model, the amount of potential yield is calculated based on meteorological data, soil conditions, management and plant parameters. The model needs a series of inputs to run, which is made to perform the simulation of the collected model. The most important processes to be simulated in the model are plant phenology, leaf area changes, dry matter production and distribution, and soil water balance. For parameterization and evaluation of the model, the values of performance and day to maturity of the simulated were compared with those observed. According to the statistics of the Ministry of Agriculture, 2001-2016, the main areas of rice cultivation and production in Iran were identified. In this study, to compare the deviation of the simulated values from the observed squared error mean (RMSE), coefficient of variation (CV), correlation coefficient (r) and the deviation of the simulated results from line 1:1 with a range of 20% difference. Between the simulated and observed values was used to test the model results. Results: In parameterization of SSM-iCrop2 model for rice, the comparison of observed and simulated days to maturity with RMSE, CV and r values of respectively 12 days, 11 percent and 0.61, respectively, and for grain yield of 56 g m-2, 21 percent and 0.80 indicated the accuracy of the used parameters. Furthermore, in evaluation the model, RMSE, CV and r values for days to maturity were 9 days, 10 percent and 0.95 and for grain yield were 43 g m-2, 14 percent and 0.77 and in simulation evapotranspiration were 44 mm, 9 percent and 0.79 respectively, which confirms the precision of the model simulation. Application of SSM-iCrop2 model is simple and acceptably precise simulation is possible with minimal parameters and inputs. Conclusion: The results of parameterization and evaluation of SSM-iCrop2 model, which was (RMSE), (r) and (CV), showed that this model includes phenological stages and grain yield in the history of different plantings in the climatic conditions of Iran simulates with great accuracy, which indicates the appropriate structure of the model in the simulation. Therefore, considering the appropriate accuracy of SSM-iCrop2 model in simulating rice phenology and yield, it can be used as a suitable tool to study cropping systems and interpret the results in different environmental and management conditions to plan and improve the management of rice fields in the country. [ABSTRACT FROM AUTHOR]

Soil moisture has a profound influence on life on Earth, and this vital water resource varies across space and time. Here, we explored soil moisture variations in boreal forest and tundra environments, where comprehensive soil moisture datasets are scarce. We installed soil moisture sensors up to 14 cm depth at 503 measurement sites within seven study areas across northern Europe. We recorded 6,138,528 measurements to capture soil moisture variations of the snowless season from April to September 2020. We described the spatio‐temporal patterns of soil moisture, and test how these patterns are linked to topography and how these links vary in space and time. We found large spatial variation and often less pronounced temporal variation in soil moisture across the measurement sites within all study areas. We found that throughout the measurement periods both univariate and multivariate models with topographic predictors showed great temporal variation in their performance and in the relative influence of the predictors within and across the areas. We found that the soil moisture‐topography relationships are site‐specific, as the topography‐based models often performed poorly when transferred from one area to another. There was no general solution that would work well in all the study areas when modeling soil moisture variation with topography. This should be carefully considered before applying topographic proxies for soil moisture. Overall, these data and results highlight the strong spatio‐temporal heterogeneity of soil moisture conditions in boreal forest and tundra environments. Plain Language Summary: Water is fundamental for all life on Earth. Here, we investigated soil moisture of northern environments, which is an important component in the global carbon cycle. We found large spatial and temporal variations in soil moisture across the measurement sites within the seven study areas. We found that the predictive power of the statistical soil moisture models varied from site to site and week to week, which highlights the complexity of modeling soil moisture in boreal forest and tundra environments. Key Points: Soil moisture was measured with 503 sensors in seven areas from April to SeptemberWe found more spatial than temporal variation within the seven areasSoil moisture‐topography relationships were time‐ and site‐specific [ABSTRACT FROM AUTHOR]

Recent articles from the Agricultural Experiment Station campuses and UC ANR's county offices, institutes and research and extension centers.

The need for potable water is becoming growing drastically and different methods of freshwater production are explored theoretically and experimentally. Meanwhile, water harvesting from soil is a method through which soil water is attempted to be extracted as much as possible in form of vapor and condensed on the inner surface of a plastic cover and collected in a container. In the present study, the maximum amount of harvested water from soil is theoretically calculated and a parametric study is conducted to find the effects of contributing parameters on the highest level of harvested water from soil. Soil of interest is located under a plastic cover which absorbs solar rays and get heated. Therefore, its water turns into vapor and the condensate is collected afterwards. In fact, such a small harvesting water structure resembles a solar greenhouse. So, the governing equations seem roughly the same. Based on the results of the theoretical and parametric study, increases in difference between temperatures of trapped air under the plastic cover and soil surface brought about lower levels of harvested water as a increase led to a 13% decrease in harvested water. In contrast, solar radiation intensity, area of soil under the plastic cover and soil absorptivity were all directly proportional to the quantity of harvested water. Moreover, it was concluded that solar radiation intensity acts as a marginally (around 5%) more significant parameter in comparison to area of soil in the amount of harvested water.

Soil sorption properties can influence the bioavailability of substances and consequently the toxicity for soil organisms. Current standardised laboratory testing for the exposure assessment of pesticides to soil organisms uses OECD artificial soil that does not reflect the high variation in chemical-physical soil properties found in natural agroecosystems. According to guideline OECD 222, earthworm reproduction tests with Eisenia fetida and the pesticide carbendazim were performed in four natural soils and OECD artificial soil. By using pF 1.6, which ensures a uniformity in actual soil water availability, the control reproduction performance of E. fetida in all natural soils was at the same level as OECD artificial soil. In a principle component analysis, the variation in toxicity between the tested soils was attributable to a combination of two soil properties, namely total organic carbon content (TOC) and pH. The largest difference of 4.9-fold was found between the typical agricultural Luvisol with 1.03% TOC and pH 6.2 (EC10: 0.17 (0.12–0.21) mg a.i. kg−1 sdw, EC50: 0.36 (0.31–0.40) mg a.i. kg−1 sdw) and OECD artificial soil with 4.11% TOC and pH 5.6 (EC10: 0.84 (0.72–0.92) mg a.i. kg−1 sdw, EC50: 1.07 (0.99–1.15) mg a.i. kg−1 sdw). The use of typical agricultural soils in standardised laboratory earthworm testing was successfully established with using the measure pF for soil moisture adjustment. It provides a more application-oriented approach and could serve as a new tool to refine the environmental risk assessment at lower tier testing or in an intermediate tier based approach. [ABSTRACT FROM AUTHOR]