Improve Soil Water Retention Research Articles

Effect of In Situ Polymerization of Super Absorbent Polymers on the Protection of Earthen Heritage Sites in Semi-Arid Regions

As precious cultural heritage, earthen sites are susceptible to various natural factors, leading to diverse forms of degradation. To protect earthen sites, the effects of super absorbent polymers (SAPs) on soil water retention, physical properties, and color compatibility at different concentrations were studied. After applying SAP treatment to an earthen site with different degrees of weathering, we drew the following conclusions. SAP-2 improved soil water retention capacity, increased soil water content, and slowed down the precipitation of soluble salts. At the same time, SAP-2 had the least effect on soil color difference and reduced the development of cracks by filling soil pores and enhancing the cohesion between soil particles, thus giving the earthen sites better weathering resistance. Therefore, the results provide a useful reference for the surface cracking of earthen sites in semi-arid areas and the degradation caused by flaking and block spalling.

Root Influences Rhizosphere Hydraulic Properties through Soil Organic Carbon and Microbial Activity.

Processes of water retention and movement and the hydraulic conductivity are altered in the rhizosphere. The aim of this study was to investigate the physical-hydric properties of soil aggregates in the rhizosphere of annual ryegrass (Lolium multiflorum) cropped in a Kandiudalfic Eutrudox, taking into account aspects related to soil aggregate stability. Soil aggregates from rhizosphere soil (RZS) and soil between plant rows (SBP) were used to determine soil water retention curves (SWRCs) and saturated hydraulic conductivity (Ksat). In addition, properties related to soil aggregate stability, such as water-dispersible clay, soil organic carbon (SOC), and microbial activity, were also assessed. The higher microbial activity observed in the RZS was facilitated by increased SOC and microbial activity, resulting in improved soil aggregation (less water-dispersible clay). For nearly all measured matric potentials, RZS had a higher water content than SBP. This was attributed to the stability of aggregates, increase in SOC content, and the root exudates, which improved soil water retention. The increase in total porosity in RZS was associated with improved soil aggregation, which prevents deterioration of the soil pore space and results in higher Ksat and hydraulic conductivity as a function of the effective relative saturation in RZS compared to SBP.

Climate vulnerability of agroecological and conventional smallholders in Mvomero district, Tanzania: using mixed-methods to uncover local experiences and motivations of farming for the future

Changing rainfall patterns make farmers increasingly vulnerable to crop failure, income loss and food insecurity. Agroecology is proposed to reduce climate vulnerabilities of farmers, as such practices and social movement aim to create more resilient farm and food systems. It is however fairly unknown if, and to what extent, agroecological farmers are better able to cope with climate induced exposures as compared to conventional smallholders. We conducted 194 surveys with agroecological and conventional smallholders to explore the three components of climate vulnerability: exposure, sensitivity and adaptive capacity. We combined this with field observations and interviews, and an analysis of long-term rainfall data. We also followed up the initial survey analysis with additional focus group discussions. Just as climate change occurs incrementally over time, we highlight modest, yet important differences between conventional and agroecological farmers. We find that agroecological farmers are less vulnerable to short-term dry spells, due to a combination of farming practices that improve soil water retention, like mulching and the use of cover crops. However, the use of botanicals might induce new vulnerabilities, as their processing requires additional labor, and sometimes expenditures, and may not protect the crops from pests and diseases. We also find limitations to agroecology in terms of scale, as most farmers are unable to use botanicals on all their farmland. Yet, agroecological farmers process and apply botanicals for health benefits both in production and consumption of foods, and they can occasionally sell their organic farm products for a higher price than conventional famers. With this study, we emphasize that farmers’ reasons to practice agroecology is not just to boost productivity and become more climate resilient, but rather for improving the long-term health of producers, consumers, soils and the environment.

Properties of biochars derived from different straw at 500℃ pyrolytic temperature: Implications for their use to improving acidic soil water retention

Climate change cause extreme weather effects with temperature increases and drops in humidity, such as drought and heatwaves, which will lead to more evaporation in arid and semi-arid lands. The application of biochar made from crop straw without burning to farmland can effectively improve the water retention capacity of soil. A testing program has been carried out in a climate simulation laboratory to study the effects of different straw biochars on the cracking and evaporation of soils due to drying. Biochar from wheat straw (WS), corn straw (CS) and rice straw (RS) is produced at a pyrolysis temperature of 500℃. Thermogravimetric analysis and elemental analysis are carried out to obtain the properties of the biochar. Five percent of WS, CS and RS biochar by weight is added to acidic soil. Digital camera and digital image processing technology are used to analyze the crack morphology of the samples during evaporation. The results indicate that the RS biochar has the highest ash content (32.5 %), CS biochar has the highest content of volatile solid (25.36 %) and WS biochar has the highest content of fixed carbon (55.38 %). Biochar can effectively improve the water retention capacity of soil. The final water contents of the WS, CS and RS biochar soil samples are 132.3 %, 101.0 %, and 20.7 % respectively higher than that of the soil without biochar. Moreover, biochar can effectively reduce the degree of soil cracking. The addition of WS, CS and RS biochar can reduce soil cracking by 9.21 %, 16.57 %, and 7.46 %, respectively. WS contains more total cellulose than CS and RS, so WS biochar is the best choice to improve soil water retention ability. Therefore, biochar technology helps to optimize soil water retention while avoiding environmental pollution from straw burning.

Enhancing Soil Health and Fertility Management for Sustainable Agriculture: A Review

In modern agriculture, ensuring soil health and effective fertility management are paramount for sustainable crop production and environmental stewardship. This review article comprehensively explores a spectrum of strategies aimed at enhancing soil health and fertility management within the context of sustainable agriculture. Beginning with an overview of the pivotal role soil health plays in agricultural systems, the review meticulously examines the significance of adopting sound soil fertility management practices to sustain soil productivity while mitigating adverse environmental impacts. Traditional and innovative approaches to soil management are thoroughly discussed, encompassing a range of practices such as organic amendments, cover cropping, crop rotation, reduced tillage, and integrated nutrient management. These practices, deeply rooted in agricultural traditions, are shown to enhance soil structure, foster nutrient cycling, and promote beneficial soil microbial communities, thereby contributing to long-term soil health and productivity. Furthermore, the review elucidates emerging technologies and methodologies that hold promise for revolutionizing soil health and fertility management in sustainable farming systems. Precision agriculture techniques leveraging GPS, remote sensing, and data analytics are highlighted for their potential to optimize resource use and improve crop management practices. Biochar application, a burgeoning area of research, is explored for its ability to enhance soil fertility, sequester carbon, and improve soil water retention. Additionally, manipulation of the soil microbiome through innovative techniques presents exciting opportunities for enhancing soil health and resilience, the review underscores the importance of continued research, education, and policy support in promoting sustainable soil management practices. Recommendations for future research directions are provided, emphasizing the need for interdisciplinary collaborations, long-term field studies, and farmer participatory research. Practical implications for farmers and policymakers are also delineated, emphasizing the imperative of adopting holistic approaches to soil management that integrate traditional wisdom with cutting-edge technologies. By embracing sustainable soil management practices, farmers and policymakers can safeguard soil health, enhance agricultural productivity, and ensure the long-term sustainability of our food systems and environment.

Straw Returning Proves Advantageous for Regulating Water and Salt Levels, Facilitating Nutrient Accumulation, and Promoting Crop Growth in Coastal Saline Soils

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.

Effect of Biochar on Apple Yield and Quality in Aged Apple Orchards on the Loess Plateau (China)

Apples are not only a foodstuff, but also a raw material for many industrial production fields, and the market demand is constantly increasing. The Loess Plateau is one of the world’s largest apple-producing areas, with about 85% are aged orchards (more than 20 years old), facing problems such as poor soil water retention, degradation of tree strength, and declining yield and quality, etc., so do aged orchards in other regions of the world, and study on improving quality and increasing yield of aged orchards is of great significance to the sustainable development of the apple industry. Here, 6 treatments (2, 4, 6, 8, 10 and 12 kg/plant) were designed in the experiment to study the effects of biochar on yield and quality in aged apple orchards. The study showed that: biochar could improve soil water retention, but caused the soil alkalization; biochar could improve apple quality and increase yield, T3 and T4 were of better quality, and T3 had the highest yield. Comprehensive analysis, T3 is the optimal scheme. The results not only provide a reference for aged orchards worldwide, but also have great significance for the sustainable development of the apple industry.

Biochar is colonized by select arbuscular mycorrhizal fungi in agricultural soils

Arbuscular mycorrhizal fungi (AMF) colonize biochar in soils, yet the processes governing their colonization and growth in biochar are not well characterized. Biochar amendment improves soil health by increasing soil carbon, decreasing bulk density, and improving soil water retention, all of which can increase yield and alleviate environmental stress on crops. Biochar is often applied with nutrient addition, impacting mycorrhizal communities. To understand how mycorrhizas explore soils containing biochar, we buried packets of non-activated biochar in root exclusion mesh bags in contrasting agricultural soils. In this greenhouse experiment, with quinoa (Chenopodium quinoa) as the host plant, we tested impacts of mineral nutrient (as manure and fertilizer) and biochar addition on mycorrhizal colonization of biochar. Paraglomus appeared to dominate the biochar packets, and the community of AMF found in the biochar was a subset (12 of 18) of the virtual taxa detected in soil communities. We saw differences in AMF community composition between soils with different edaphic properties, and while nutrient addition shifted those communities, the shifts were inconsistent between soil types and did not significantly influence the observation that Paraglomus appeared to selectively colonize biochar. This observation may reflect differences in AMF traits, with Paraglomus previously identified only in soils (not in roots) pointing to predominately soil exploratory traits. Conversely, the absence of some AMF from the biochar implies either a reduced tendency to explore soils or an ability to avoid recalcitrant nutrient sources. Our results point to a selective colonization of biochar in agricultural soils.

Enhancing Soil Resilience to Climatic Wetting‐Drying Cycles Through a Bio‐Mediated Approach

AbstractClimatic wetting‐drying cycles exacerbated by climate change can trigger several weakening mechanisms in surface soils, potentially leading to instability and failure of slopes and earthen structures. This study proposes a bio‐mediated approach based on microbially induced calcite precipitation (MICP) to increase soil resilience to wetting‐drying cycles. To explore its viability and the underlying mechanisms, we conducted a series of laboratory tests on clayey soil that underwent six wetting‐drying cycles. The tests were conducted with different treatment methods to investigate the effect of treatment sequence and cementation solution concentration. After MICP treatment, the initial evaporation rate, surface crack ratio during drying, and total soil weight loss during rainfall erosion were reduced by up to 32%, 85%, and 90%, respectively. Spraying the cementation solution first in the MICP treatment sequence proves more effective in improving soil water retention capacity. On the other hand, initiating the sequence with the bacterial solution demonstrates a more pronounced effect in reducing soil desiccation cracks and erosion. Microstructure analysis reveals that the content and distribution of CaCO3 precipitation are the major factors controlling the effectiveness of MICP for the cementation of clayey soil. Employing MICP can minimize the carbon footprint and contribute to developing environmentally friendly solutions for soil improvement in regions affected by climatic wetting‐drying cycles.

Enhancing salt tolerance and crop growth in agricultural systems: the impact of magnetized-ionized water irrigation on soil properties, microbial communities, and cotton growth.

The development of agricultural practices requires an understanding of the improvement of salt tolerance and crop growth in agricultural systems through magnetized-ionized water irrigation. This study examined the impacts of fresh water (F), brackish water (B), magnetized-ionized fresh water (MIF), and magnetized-ionized brackish water (MIB) on soil properties and the growth of cotton seedlings through microbial analysis during the cotton seedling period. The results revealed that magnetized-ionized water irrigation improved soil water retention and promoted salt leaching. In comparison with F irrigation, plant height, leaf area index (LAI), dry matter accumulation (DM), and chlorophyll content (SPAD) levels increased by 3.61%, 4.07%, 5.76%, and 1.33%, respectively, under MIF irrigation. Similarly, when compared with B irrigation, LAI, DM, and SPAD increased by 5.13%, 6.12%, and 3.12% under MIB irrigation. Magnetized-ionized water irrigation also led to a notable rise in the relative abundance of beneficial soil bacterial communities, particularly Pseudomonas and Azoarcus, as well as fungal communities like Trichoderma, while reducing the prevalence of pathogenic fungi, such as Lasionectria, Gibberella, and Alternaria. Notably, this irrigation approach induced alterations in soil properties, and partial least squares path modeling revealed significant links between soil properties and both cotton growth and fungal community structure (with path coefficients of -0.884 and 0.693, respectively). This study elucidated the distinct effects of soil properties and growth indices on cotton yield during the seedling period, providing a crucial scientific foundation for enhancing future agricultural production through the use of magnetized-ionized water irrigation. © 2024 Society of Chemical Industry.

A biochar selection method for remediating heavy metal contaminated mine tailings

Approximately 390,000 abandoned mines across the US pose considerable, pervasive risks to human and environmental health; world-wide the problem is even greater. Lime, organic materials, and other amendments have been used to decrease metal bioavailability (e.g., Cd, Cu, Mn, Ni, Zn) in contaminated mine wastes and to promote plant community establishment for tailings stabilization. Biochar properties (e.g., alkaline pH, metal sorbing capabilities, available nutrients, improved soil water retention) make it a potential amendment for remediating metal contaminated mine tailings. A three-step procedure was developed to identify biochars that were most effective at reducing heavy metal availability, retaining metals, and subsequently selecting biochars for use in a soil amendment laboratory trial to ultimately be utilized in heavy metal contaminated mine land settings: Step (1) a synthetic precipitation leaching procedure extract of mine tailings was produced, representing potentially available metals, and used to identify metal removal properties of 28 different biochars (e.g., made from various feedstocks and pyrolysis or gasification conditions); Step (2) evaluate how well biochars retained previously sorbed metals; and Step (3) laboratory evaluation of the most promising biochars that removed and did not releases metals, applied at 0, 1, 2.5, and 5% (by wt) to mine tailings for reducing metal bioavailability. The reported methodology and results from this study could be used to quickly identify specific biochars and application rates to reduce mine tailings metal availability and aid in future remediation of abandoned mine sites globally.

Towards a zero-waste sustainable biorefinery of Codium sp. seaweed: From bioactives application to soil enhancement materials

In the pursuit of sustainability and circularity, this study aimed to develop a multi-purpose biorefinery pipeline using extracts from the green seaweed Codium sp. and transforming its post-extracted biomass into biochars, emphasizing holistic resource utilization. Five extracts from Codium sp. were evaluated, testing their antioxidant potential, cytotoxicity, photoprotective effects, anti-inflammatory activity, and inhibitory capabilities against enzymes hyaluronidase, collagenase, and elastase.The ethyl acetate extract showed the highest values in the ORAC assay, indicating antioxidant activity. However, no relevant antioxidant activity was observed in the FRAP and DPPH assays for the other extracts. The hydroethanolic extract exhibited the best anti-enzymatic capacity, inhibiting elastase by 88% at 200 μg/mL. It also demonstrated a photoprotective effect and reduced ROS production (30%) induced by UVB exposure. The hydroethanolic and ethanol extracts significantly reduced the concentration of the tumour necrosis factor-alpha (TNF-α) in response to LPS stimulation, indicating anti-inflammatory activity.The hydroethanolic post-extracted biomass was converted into biochars using conventional slow pyrolysis, hydrothermal carbonization (HTC), and acid-mediated carbonization (AMC). The biochars contained 56–75% C and 22–30% O and the one synthesized by HTC had the highest textural development. The biochar obtained by AMC showed better performance in improving soil water retention capacity, suggesting that acid surface chemistry plays a more significant role than porosity.The Codium sp. extracts and biochars produced from the post-extracted biomass have demonstrated potential as a source of valuable bioactive compounds and biomaterials for a circular economy framework and biorefinery pipeline with wide-ranging applications.

Saturated permeability and water retention capacity in biochar-methanotrophs-clay for new landfill cover system

A new landfill cover system, biochar-methanotrophs-clay (BMC) cover is recommended for reducing methane emissions at landfills. It also contributes to decreasing soil permeability and improving soil water retention in a long time, due to highly porous structure of biochar and the growth metabolism of methanotrophs. To determine the effects of biochar content, oxidation aging times and methane-filled days on hydraulic properties, a total of 60 groups of experiments were conducted. The saturated hydraulic conductivity (ksat) was obtained by flexible wall permeameter with controllable hydraulic head pressure. The results showed that the ksat of BMC increased with increasing biochar content and oxidation aging times, while decreased with adding methane-filled days. The soil-water characteristic curves (SWCCs) were obtained with soil suction measured by the filter paper method. The results indicated the water retention capacity of MBC reduced with increasing oxidation aging times but increased with adding methane-filled days. Detected by mercury intrusion porosimetry (MIP), fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM), the differences displayed the changes of pore structures and extracellular polymeric substances (EPS). The oxidation aging of biochar increased the volume of pores, resulting in the increased ksat and the decreased water retention capacity. However, the growing of methanotrophs decreased the volume of pores, resulting in the ksat decreased and the water retention capacity increased due to EPS. No matter how many times the oxidation aging process was experienced, the BMC with longer methane-filled days exhibited relatively lower ksat and better water retention capacity. This implied a more stable barrier capacity to reduce water infiltration in the long term. By combing a series of macro and micro experiments, this paper provides theoretical guidance for the application of biochar-methanotroph-clay mixture to landfill covers.

Effect of super absorbent hydrogel on hydro-physical properties of soil under deficit irrigation

Due to water scarcity challenges, efficient management of irrigation water is becoming crucial. Water use efficiency (WUE) involves increasing crop productivity without increasing water consumption. This study was carried out to study the effect of hydrogel, deficit irrigation and soil type on WUE, soil hydro-physical properties and lettuce productivity. For this purpose, four irrigation treatments (100%, 85%, 70% and 60% of full irrigation requirements), four hydrogel concentrations (0, 0.1, 0.2 and 0.3% w/w) and three soil textural classes (clay, loamy sand, and sandy-clay soil) were conducted in pot experiment at open field during two consecutive seasons. The results revealed that crop growth parameters and soil hydro-physical properties were significantly affected by hydrogel application rates. Hydrogel addition significantly enhanced head fresh and dry weights, chlorophyll content, number of leaves and WUE. Application of hydrogel at 0.3% and 85% of irrigation requirements achieved the highest WUE without significant yield reductions. Changes in the studied hydro-physical properties of soil were more dependent on soil texture and hydrogel application rate than on the amount of irrigation water. The significant decrease in soil saturated hydraulic conductivity and bulk density confirms that super absorbent hydrogels could be recommended to improve soil water retention and enhance water use efficiency under deficit irrigation conditions.

Enhancing soil water retention and plant growth with thermal crosslinked silk sericin-based hydrogel

In this study, a simple and clean crosslinking method was evaluated as a novel strategy to improve the structural stability of sericin-based hydrogels for soil water retention. The hydrogels were prepared by casting a polymer mixture of silk sericin (SS), carboxymethylcellulose (CMC), and polyvinyl alcohol (PVA). The films (HF) were heated at 90 °C for 4 h to obtain a thermally crosslinked hydrogel (HFT). The HFT was evaluated using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM). The changes in water absorption, gel fraction, and swelling behavior after crosslinking were also analyzed. The biodegradability of the HFT and its performance as a soil conditioner were evaluated through burial tests and in vivo assays using Chilli plants (Capsicum annuum), respectively. According to the results, the thermal crosslinking of HF is the result of the formation of microcrystals in the SS and PVA fractions, as well as the development of a dense network of H-bonds. Both mechanisms promoted the formation of a more stable pore structure in the HFT, which proved to be potentially biodegradable and suitable for improving soil water retention and supporting plant growth. Regarding HFT biodegradability, rapid weight loss was noted during the first 14 days of the soil burial test. On the other hand, HFT improved the availability of soil water and nutrients, favoring leaf growth and likely chlorophyll production.

Grafting seedling rootstock strengthens tolerance to drought stress in polyploid mulberry (Morus alba L.)

The economically adaptable mulberry (Morus alba L.) has a long history of grafting in China, yet the physiological mechanisms and advantages in drought tolerance remain unexplored. In our study, we investigated the responses of self-rooted 2X (diploid), 3X (triploid), and 4X (tetraploid) plants, as well as polyploid plants grafted onto diploid seedling rootstocks (2X/2X, 3X/2X, and 4X/2X) under drought stress. We found that self-rooted diploid plants exhibited the most severe phenotypic damage, lowest water retention, photosynthetic capacity, and the least effective osmotic stress adjustment compared to tetraploid and triploid plants. However, grafted diploid and triploid plants showed effective mitigation of drought-induced damage, with higher relative water content and improved soil water retention. Grafted plants also improved the photosystem response to drought stress through elevated photosynthetic potential, closed stomatal aperture, and faster recovery of chlorophyll biosynthesis in the leaves. Additionally, grafted plants altered osmotic protective compound levels, including starch, soluble sugar, and proline content, thereby enhancing drought resistance. Absolute quantification PCR indicated that the expression levels of proline synthesis-related genes in grafted plants were not influenced after drought stress, whereas they were significantly increased in self-rooted plants. Consequently, our findings support that self-rooted triploid and tetraploid mulberries exhibited superior drought resistance compared to diploid plants. Moreover, grafting onto seedling rootstocks enhanced tolerance against drought stress in diploid and triploid mulberry, but not in tetraploid. Our study provides valuable insights for a comprehensive analysis of physiological effects in response to drought stress between stem-roots and seedling rootstocks.

Influence of Date Palm-Based Biochar and Compost on Water Retention Properties of Soils with Different Sand Contents

Generally, soils of arid and semi-arid regions have low water retention properties due to high sand and low organic carbon contents. This study aimed at quantifying the effect of date palm-based organic amendments (OAs) on the water retention properties of two soils (sandy loam and silty loam), as well as the influence of sand supplementation (0.5–2 mm) on the magnitude of the effect of OAs. Different grain size distributions were obtained by adding sand to natural soils. For this purpose, sand was added to the two soils (1/3 and 2/3) and different soil-OA combinations were tested at a dose of 3% by mass: compost alone, biochar alone and a mixture of biochar and compost (50:50 in mass), in addition to unamended control soils. Soil water contents were measured at nine matric potentials ranging from the saturation to the permanent wilting point. Biochar was more efficient than compost at improving soil water retention. The effect of organic amendments on water retention increased with sand content. In most cases, soil water content values were significantly higher for biochar-amended soils than for unamended or compost-amended soils. The weakness of the effect of compost addition (if alone) was probably due to its properties and notably its high mineral content and electrical conductivity. Soil sand supplementation led to higher differences between the OA-amended soils and unamended soils. Changes in available water capacity reached +26% and +80% in a sandy loamy soil enriched with 2/3 sand and amended with compost and with biochar, respectively, compared to the unamended soil. These results show that sand content (and more generally, soil texture) influences the effect of OA application. Thus, the application of biochar from date palm residues in soil seems to be an effective solution to improve the water retention properties of coarse textured soils and contribute to optimizing the use of water resources in irrigated areas.

Synthesis and characterization of agarose-bacterial cellulose hydrogel for promoting seed germination by improving soil water retention

Synthesis and characterization of agarose-bacterial cellulose hydrogel for promoting seed germination by improving soil water retention

Biocrust-reduced soil water retention and soil infiltration in an alpine Kobresia meadow

Abstract. Biocrust is a key component of ecosystems and plays a vital role in altering hydrological processes in terrestrial ecosystems. The impacts of biocrust on hydrological processes in arid and semi-arid ecosystems have been widely documented. However, the effects and mechanisms of biocrust on soil hydrological processes in alpine ecosystems are still poorly understood. In this study, we selected two meadow types from the northern Qinghai–Tibet Plateau: normal Kobresia meadow (NM) and biocrust meadow (BM). Both the soil hydrological and physicochemical properties were examined. We found that, in the 0–30 cm soil layer, soil water retention and soil water content in NM were higher than those in BM, whereas the 30–40 cm layer's soil water retention and soil water content in NM were lower than those in BM. The topsoil infiltration rate in BM was lower than that in NM. Furthermore, the physicochemical properties were different between NM and BM. The 0–10 cm soil layer's clay content in BM was 9 % higher than that in NM, whereas the 0–30 cm layer's soil capillary porosity in NM was higher than that in BM. In addition, the 0–20 cm layer's soil total nitrogen (TN) and soil organic matter (SOM) in NM were higher than those in BM, implying that the presence of biocrust may not favor the formation of soil nutrients owing to its lower soil microbial biomass carbon and microbial biomass nitrogen. Overall, soil water retention was determined by SOM by altering the soil capillary porosity and bulk density. Our findings suggest that the establishment of cyanobacteria crust biocrust may not improve soil water retention and infiltration, and the soil in cyanobacteria crust meadows could be more vulnerable to runoff generation and consequent soil erosion. These results provide a systematic and comprehensive understanding of the effects of biocrust on the soil hydrology of alpine ecosystems.

Mitigating soil water deficit using organic waste compost and commercial water retainer: a comparative study under semiarid conditions

Semiarid regions have particularly been confronted with climate change effects reflected by the consistent decrease of rainfall and increase of evapotranspiration. This drought stress constitutes the main constraint for agricultural production improvement, which is aggravated by the fact that strategic (field) crops are mostly grown under rainfed systems. Therefore, the objective of this field study was to improve soil water retention by the application of two conditioners namely, an organic waste compost (DS) and a synthetic water-retaining hydrogel (WS). These amendments were applied to an agricultural soil for the cultivation of fodder maize under normal and deficit irrigation regimes. Advanced analysis showed a general disruption of plant growth parameters under water stress. However, both amendments attenuated this negative effect with respect to control by improving soil water status. More precisely, the measured soil water tension at the start of the dry season was the lowest in presence of DS (48 centibars), followed by WS (61 centibars), then unamended soil (83 centibars). Besides, compost application resulted in higher moisture (13.3%), nitrogen (0.36%), and organic matter (0.56%) in soil than the synthetic hydrogel at the end of the field experiment. Soil and plant characterization highlighted the combined effect of water deficit and conditioner type. Indeed, the consistent increase of soil water content in the presence of DS and WS improved all the addressed plant parameters when compared with untreated soil. Infrared thermal imaging showed that canopy temperature was lower in presence of both amendments while dry biomass yield increased by 38% when water supply was limited. Nevertheless, the long-term sustainability of the soil system appears to be better maintained in the presence of the organic waste compost. The latter has the added advantage of improving soil fertility in contrast to inert polymers.