Maximum Water-holding Capacity Research Articles

Assembly processes of rhizosphere and phyllosphere bacterial communities in constructed wetlands created via transformation of rice paddies.

Constructed wetlands are an efficient and cost-effective method of restoring degraded wetlands, in which the microorganisms present make a significant contribution to the ecosystem. In this study, we comprehensively investigated the patterns of diversity and assembly processes of 7 types of constructed wetlands at the rhizosphere and phyllosphere levels. The results showed that the rhizosphere communities of the constructed wetlands exhibited a more balanced structure than that of paddy fields, and 5 types of constructed wetland demonstrated higher potential diversity than that of paddy fields. However, the opposite trend was observed for the phyllosphere communities. Analysis of mean nearest taxon difference indicated that both deterministic and stochastic processes affected the establishment of the rhizosphere and phyllosphere communities, and stochastic processes may have had a larger effect. An iCAMP model showed that dispersal limitation was the most important factor (67% relative contribution) in the rhizosphere community, while drift was the most important (47% relative contribution) in the phyllosphere community. Mantel tests suggested that sucrase, average height, top height, total biomass, belowground biomass, maximum water-holding capacity, and capillary porosity were significantly correlated with processes in the rhizosphere community, whereas factors such as the deterministic process, average height, top height, and SOC were significantly correlated with deterministic processes in the phyllosphere community. Our results can assist in the evaluation of artificial restorations, and can provide understanding of the ecological processes of microbial communities, as well as new insights into the manipulation of microorganisms in polluted wetland ecosystems.

Release of Carbon Dioxide and Water-Soluble Carbon Amended with Rice and Wheat Residues in an Inceptisols of Varanasi

ABSTRACT Crop residues are the main organic source of nutrients in agricultural soils. The active pool of soil organic carbon plays a dominant role in crop production and soil health. Rice and wheat residues were used in 90 days incubation study under controlled conditions (25°C temperature and maximum water-holding capacity) to estimate the release of carbon dioxide and water-soluble carbon in an Indo-Gangetic alluvial soil (Inceptisols) of Varanasi. The experiment was laid out in a factorial completely randomized design with three replications. The rice and wheat residues showed a wide variation in the content of their total carbon (TC), total nitrogen (TN), total phosphorus (TP) and total sulfur (TS). Out of the two crop residues added to the soil, rice residue had higher carbon dioxide-carbon (CO2-C) release than that of the wheat residue over control. Results revealed that conjunctive application of rice residue along with urea (20 kg N ha−1) and Trichoderma viride (10 kg ha−1) had resulted in a higher content of CO2-C (7.44 mg per 100 g per day) at 90 days of the incubation period. The amount of CO2 (mg) released, increases with a combination of crop residues with urea (20 kg N ha−1) and Trichoderma viride (10 kg ha−1) up to 90 days over control. The highest release of CO2 (204.70 mg) was recorded with rice residue treated with urea (20 kg N ha−1) and Trichoderma viride (10 kg ha−1). The study also revealed that the release of water-soluble carbon decreases with an increase in the incubation period irrespective of treatment. At 90 days of the incubation period, the control without any crop residue addition has the highest water-soluble carbon content (459.75 µg/g). The present study indicates that the incorporation of rice and wheat residues along with urea and supplemental decomposers (Trichoderma viride) has the potential to release adequately active organic carbon pool parameters such as CO2 and water-soluble carbon in an Inceptisols of Varanasi region of India.

A Simple, Affordable, Do-It-Yourself Method for Measuring Soil Maximum Water Holding Capacity

ABSTRACT There is an increasing need for accessible methods to monitor soil health. Our primary objective was to evaluate an accessible, do-it-yourself method for measuring the maximum water holding capacity – we call this the funnel, filter paper, and drainage (MWHCFFPD) method. First, we compared MWHCFFPD to the water desorption method via pressure cells (WHCPC), routinely used for generating soil water retention curves, using 10 soils from a wide range of textures (4–55% clay). Second, we tested the sensitivity of the MWHCFFPD to methodological variations likely encountered by citizen scientists. The two methods were quite comparable in precision, with mean coefficient of variances of 3.5% and 4.4% for the FFPD and water desorption method, respectively. The MWHCFFPD and WHCPC methods were comparable, with MWHCFFPD best correlating to WHCPC at −2.45 kPa (R2 = 0.98). The MWHCFFPD method is somewhat sensitive to some methodological modifications, most notably variation in water source, but with standardized protocols could be scientifically robust. Overall, MWHCFFPD can be used as a simple and affordable test of sieved soil structure and organic matter, and thus has potential to expand soil health monitoring.

Application Rates of Cricket Feces Influencing Soil Properties and Rice Yield in Soils of Different Moisture Contents

Background: Cricket feces is a potential high-quality soil amendment, but there is currently no established optimum rate for its application in paddy soils with varying moisture contents. This study therefore aimed to evaluate the effects of varied rates of cricket feces on soil properties, rice growth, and yield in paddy soils with differing moisture contents. Methods: Two study factors were evaluated: (i) the maximum water-holding capacity (WHCmax) and flooded soils, and (ii) cricket feces applied at rates of 0 (unamended), 3.125 (low), 6.25 (medium), and 12.5 (high) t/ha. Result: The total grain weight of rice in soil with WHCmax was 2.60, 4.33, 6.91, and 7.49 g/hill under the cricket feces from unamended to high rates, respectively, with no significant difference between the medium and high rates. Meanwhile, the total grain weight in flooded soil was 1.85, 4.02, 4.70, and 5.72 g/hill, respectively. Cricket feces increased the content of essential elements and decreased the acidity and toxicity of Al, Ca, and Na in the soil, thereby promoting rice growth and yield. The optimal application rates of cricket feces for rice in the WHCmax soil was determined to be the medium rate, while that in flooded soil was the high rate.

Water Availability Influences Soil Liming for the Tropical Grasses Implantation

ABSTRACT Limestone needs to react with water to correct the soil acidity. Therefore, it is expected that soil water availability interferes with limestone reaction time. The objectives of the study were (1) verify whether soil water availability alters limestone reaction time and (2) to evaluate whether the period of less than 60 days between limestone incorporation and sowing is sufficient to correct soil acidity. Two trials were carried out in a greenhouse, in a completely randomized design, in a factorial scheme. In the first trial, the BRS RB331 Ipyporã grass was grown, and the soil was subjected to the combination between the number of times the soil was raised to the maximum water retention capacity (1, 2, 3 and 9 irrigation) and two base saturation (50% and 60%). In the second trial, the Panicum maximum cv. Mombasa was grown, and six treatments were adopted in a 3 × 2 factorial scheme, consisting of the combination of three levels of water availability (50%, 75% and 100% from maximum water-holding capacity) and two limestone reaction periods (30 and 60 days). Soil water availability significantly influenced the limestone reaction time. As a result, it is possible to implant Mombasa and BRS Ipyporã grasses after 30 days of limestone incorporation, provided that the water saturation in the soil is increased to 75%.

Physico-thermal characteristics and hydration kinetics of chickpea splits: An essential ingredient for Puran preparation

Chickpea splits serve as a fundamental ingredient in the preparation of Puran, a traditional Indian sweet delicacy. To enhance the quality of Puran, understanding the physico-thermal characteristics and hydration kinetics of chickpea splits is crucial. This study aims to investigate the water absorption behavior of chickpea splits during soaking. The chickpea splits were soaked in a water bath and then cooking was carried out. The physical, thermal, and functional properties of chickpea split after soaking (30, 40, and 50 ºC for 360 min) till it softened and cooking (100 ºC) were investigated. The research involved examining the rehydration and softening of chickpea splits upon soaking, as well as changes in their size and texture. The kinetics of water absorption were analyzed to understand the rate and pattern of hydration. Results revealed that soaking significantly (p < 0.05) rehydrates chickpea splits, leading to a softening of texture and an increase in size. The kinetics of water absorption followed a non-linear trend, with an initial rapid phase followed by a gradual slowdown as the splits approached their maximum water-holding capacity. The hydration data of chickpea splits were fitted to different semi-empirical models of which, the two-term exponential model best described the absorption phenomena. The gelatinization temperature decreased but the degree of retrogradation increased with cooking time. The optimum soaking condition for the preparation of Puran was observed at 30 ºC for 135 min and a cooking time of 10–12 min at 100 ºC. By understanding the physico-thermal characteristics and hydration kinetics, Puran makers can optimize the soaking process to achieve the desired texture and flavour in the final product. Additionally, this knowledge can find applications in the development of innovative chickpea-based recipes and food processing techniques.

Seasonal Hydration Status of Common Bryophyte Species in Azorean Native Vegetation.

Bryophytes play a crucial role in the ecosystem's water compartment due to their unique ability to retain water. However, their role within temperate native ecosystems is mostly unknown. To address this knowledge gap, a study was conducted on Terceira Island (Azores), focusing on 14 bryophyte species found at different altitudes (40 m, 683 m, and 1012 m); five samples were collected monthly, per species and location, and their fresh, saturated, and dry weights were examined in the laboratory; four species were collected from more than one site. Generalized linear models (GLM) were used to assert the influence of climate factors (temperature, precipitation, and relative humidity) and environmental variables on two water indicators: field water content (FWC) and relative water content (RWC). None of the examined factors, per se, were able to explain all cases. Species appear to respond to climate according to a limiting factor effect: at lower elevations, precipitation was determinant, while at medium elevations, FWC was influenced by a combination of precipitation and relative humidity. At higher elevations, temperature was retained for seven of the nine studied species. The RWC values indicated that the 14 bryophyte species remained hydrated throughout the year but rarely reached their maximum water-holding capacity, even at the highest altitude. Understanding the mechanisms by which native bryophytes acquire, store, and release water is crucial for comprehending the resilience of native vegetation in the face of climate change. This knowledge can also enable the development of strategies to mitigate the effects of climate change and protect vital water resources.

Structural characteristics of the moss (bryophyte) layer and its underlying soil structure and water retention characteristics

The influence of the moss layer on soil structure and soil water retention is not well understood. Therefore, this study aims to investigate the changes in soil structure and soil water retention under moss layer and to reveal the influencing factors of these changes. 3D networks of moss layer and soil macropores were quantified using CT scanning and image analysis techniques, and soil water retention characteristics were explored through soil water retention curves (SWRCs) and VG model. The length densities of the soil macropores under the thin moss and thick moss layers were approximately 2.7 and 1.6 times higher than that under no moss cover. The soil water retention under the thin and thick moss layers were greater than those under no moss cover, with the highest plant-available water capacity under the thin moss layer. The maximum water-holding capacity of the moss layer was significantly positively correlated with the field water-holding capacity of the soil and negatively correlated with the equivalent diameter of the macropores, while the storage capacity of the moss layer was significantly and negatively correlated with the maximum effective water content of the soil. The field capacity (FC) and permanent wilting point (PWP) were significantly and positively correlated with the soil organic matter. The effect of the moss layer on water retention may be mainly realized by influencing the pore distribution and organic matter accumulation. The moss layer had a positive ecohydrological effect on soil water retention and even water conservation in forest soils.

Functional exploration of taro starch (Colocasia esculenta) supplemented yogurt.

Stabilizers are essential components of manufactured products such as yogurt. The addition of stabilizers improves the body, texture, appearance, and mouth feel of yogurt while also preventing technical defects such as syneresis. A study was conducted to optimize the concentration of taro starch in yogurt. The yogurt was fortified at different concentrations of taro starch. Taro starch levels were 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, and 3%, with different storage times (0, 14, and 28 days). The Tukey honesty test was used for mean comparison (p < .1). The results of the study showed that maximum moisture and protein content was taken by using 0.5% taro starch and stored for 0 days while maximum fat % was attained in 1.5% taro starch treatment and storage time was 0 days. The maximum water-holding capacity was increased by adding 1.5% taro starch under 14 days' storage time. Water-holding capacity started decreasing with the increasing taro concentration. The acidity of yogurt started increasing with the increasing taro starch and the maximum acidity was taken at 2.5% taro starch concentration. The viscosity of the yogurt was maximum at 2% taro starch. As far as it concerned, sensory evolution, aroma, and taste started changing with the increasing taro starch concentration and increasing storage time. The study's goals were to optimize the taro concentration for stabilizing the yogurt synthesis and to probe the impact of taro starch on the physiochemical attributes of yogurt.

Plant Traits Guide Species Selection in Vegetation Restoration for Soil and Water Conservation.

Great efforts have been made to improve the soil and water conservation capacity by restoring plant communities in different climatic and land-use types. However, how to select suitable species from local species pools that not only adapt to different site environments, but also achieve certain soil and water conservation capacities is a great challenge in vegetation restoration for practitioners and scientists. So far, little attention has been paid to plant functional response and effect traits related to environment resource and ecosystem functions. In this study, together with soil properties and ecohydrological functions, we measured the seven plant functional traits for the most common species in different restoration communities in a subtropical mountain ecosystem. Multivariate optimization analyses were performed to identify the functional effect types and functional response types based on specific plant traits. We found that the community-weighted means of traits differed significantly among the four community types, and the plant functional traits were strongly linked with soil physicochemical properties and ecohydrological functions. Based on three optimal effect traits (specific leaf area, leaf size, and specific root length) and two response traits (specific leaf area and leaf nitrogen concentration), seven functional effect types in relation to the soil and water conservation capacity (interception of canopy and stemflow, maximum water-holding capacity of litter, maximum water-holding capacity of soil, soil surface runoff, and soil erosion) and two plant functional response types to soil physicochemical properties were identified. The redundancy analysis showed that the sum of all canonical eigenvalues only accounted for 21.6% of the variation in functional response types, which suggests that community effects on soil and water conservation cannot explain the overall structure of community responses related to soil resources. The eight overlapping species between the plant functional response types and functional effect types were ultimately selected as the key species for vegetation restoration. Based on the above results, we offer an ecological basis for choosing the appropriate species based on functional traits, which may be very helpful for practitioners involved in ecological restoration and management.

Research on Cotton Field Irrigation Amount Calculation Based on Electromagnetic Induction Technology

The rapid and efficient acquisition of field-scale farmland soil profile moisture-distribution information is very important for achieving precise irrigation and the adjustment and deployment of irrigation strategies in farmland. EM38-MK2 is a portable, non-invasive device that induces electric currents in soil to generate secondary magnetic fields for the rapid measurement of apparent electrical conductivity in the field. In this study, cotton fields were used as experimental objects to obtain soil apparent conductivity data for three periods, which were combined with soil-moisture content data collected simultaneously from soil samples and measured in the laboratory to construct an apparent soil-profile moisture regression model. A simple kriging interpolation method was used to map the distribution of the irrigation volume in the field, considering only the highest irrigation volume in the field as the maximum water-holding capacity in the field. The results showed that EM38 could accurately detect the spatial variation of soil moisture in the field. The R2 of the linear fit between measured and predicted soil-water content ranged from 0.51 to 0.89; the RMSE ranged from 0.66 to 1.87; and the R2 and RPD of each soil-layer water content model of the single-period model were higher than those of the full-period model. By plotting the distribution of field irrigation, it could be seen that by comparing the predicted field irrigation with the actual irrigation, at least 160 m3 ha−1 of irrigation could be saved in all three periods at an irrigation depth of 40 cm, which is about 30% of the actual irrigation; at an irrigation depth of 60 cm, about 30% and 15% of irrigation could be reduced in July and August, respectively. There are three areas in the study area with high fixed-irrigation volumes located in the northwest corner, near 500 m in the northern half of the study area and 750 m east of the southern half of the study area. The results of this study proved that the use of EM38-MK2 to monitor and evaluate the soil-moisture content of the farmland at different periods can, to a certain extent, guide the irrigation amount needed to achieve efficient and precise irrigation in the field.

Big-sized trees and higher species diversity improve water holding capacities of forests in northeast China

High water-holding forests are essential for adapting to drought climates under global warming, and a central issue is which type of forests could conserve more water in the ecosystem. This paper explores how forest structure, plant diversity, and soil physics impact forest water-holding capacities. We investigated 720 sampling plots by measuring water-holding capacities from 1440 soil and litter samples, 8400 leaves, and 1680 branches and surveying 18,054 trees in total (28 species). Water-holding capacities were measured as four soil indices (Maxwc, maximum water-holding capacity; Fcwc, field water-holding capacity; Cpwc, soil capillary water-holding capacity; Ncpwc, non-capillary water-holding capacity), two litter metrics (Maxwcl, maximum water-holding capacity of litters; Ewcl, effective water-holding capacity of litters), and canopy interception (C, the sum of estimated water interception of all branches and leaves of all tree species in the plot). We found that water-holding capacity in the big-sized tree plots was 4–25 % higher in the litters, 54–64 % in the canopy, and 6–37 % in the soils than in the small-sized plots. The higher species richness increased all soil water-holding capacities compared to the lowest richness plot. Higher Simpson and Shannon-Wiener plots had 10–27 % higher Ewcl and C than the lowest plots. Bulk density had the strongest negative relations with Maxwc, Cpwc, and Fcwc, whereas field soil water content positively affected them. Soil physics, forest structure, and plant diversity explained 90.5 %, 5.9 %, and 0.2 % of the water-holding variation, respectively. Tree sizes increased C, Ncpwc, Ewcl directly (p < 0.05), and richness increased Ewcl directly (p < 0.05). However, the direct effects from the uniform angle index (tree distribution evenness) were balanced by their indirect effect from soil physics. Our findings highlighted that the mixed forests with big-sized trees and rich species could effectively improve the water-holding capacities of the ecosystem.

Influence of Watering Regimes on Physiological Traits, Growth, Yield, and Capsaicin Content of Chilies

Water stress is a major limiting factor affecting the physiological processes, growth, and productivity of crop plants, including chili. This study evaluated chili plants' responses regarding physiological traits, growth, yield, and capsaicin content under different irrigation levels. The experimental design was a 2x4 factorial in CBD. A pot experiment was conducted on two species of chilies: Capsicum annuum ‘Super-Hot 2’ and ‘Huay-Siiton’ and C. frutescent ‘Prik-Kee-Nu-Suan.’ The plants were irrigated at four watering regimes such as 100%, 80%, 60%, and 40% of maximum water holding capacity (MWHC) after the anthesis through fruit development. Midday leaf water potential (LWPmd) was ranked between -1.30 MPa in 100% MWHC to -2.11 MPa in 40% MWHC indicating the level of water stress. The 40% MWHC caused a drastic decrease in LWPmd and reduced the maximum quantum yield of PSII (Fv/Fm) and growth rate in canopy width. Observed leaf greenness was maximized at 60% MWHC. The irrigation regimes also affected the yield of chili, especially the 60% and 40% MWHC, with a reduced number of fruits/plant, fruit fresh and dry weights, and fruit sizes. In the case of 40% MWHC, the dry yield was too low, and it was impossible to analyze the capsaicin content. The reduced irrigation (80% and 60% MWHC) did not significantly induce the capsaicin content or pungency of the studied chili cultivars. Thus the capsaicin yield of studied chili cultivars was reduced considerably by severe reduction of dry fruit yield under restricted water.

Leaf gas exchange characteristics, biomass partitioning, and water use efficiencies of two C4 African grasses under simulated drought

AbstractBackgroundFew studies have evaluated the effect of drought on the morpho‐physiological characteristics of African C4 grasses. We investigated how drought affects leaf gas exchange characteristics, biomass partitioning, and water use efficiencies of Enteropogon macrostachyus and Cenchrus ciliaris.MethodsThe grasses were grown in a controlled environment under optimum conditions, that is, 70% of the maximum water‐holding capacity (WHC) for the first 40 days. Thereafter, half of the columns were maintained under optimum or drought conditions (30% of maximum WHC) for another 20 days.ResultsUnder optimum conditions, C. ciliaris showed a significantly higher photosynthetic rate, stomatal conductance, and transpiration rate than E. macrostachyus. Drought decreased the photosynthetic rate, stomatal conductance and transpiration rate only in C. ciliaris. The net photosynthetic rate, stomatal conductance, and leaf transpiration of E. macrostachyus did not differ significantly under optimum and drought conditions. E. macrostachyus showed an increase in its water use efficiencies under drought to a greater extent than C. ciliaris.ConclusionsOur results demonstrate that C. ciliaris is more sensitive to drought than E. macrostachyus. The decrease in the intercellular CO2 concentration and the increase in stomatal limitation with drought in C. ciliaris and E. macrostachyus suggest that stomatal limitation plays the dominant role in photosynthesis of the studied African C4 grasses.

Covalent binding of ultrasound-treated japonica rice bran protein to catechin: Structural and functional properties of the complex

Due to the existence of many disulfide bonds in japonica rice bran protein (JRBP) molecules, their solubility is poor, which seriously affects other functional properties. To improve the functional characteristics of JRBP molecules, they were processed by ultrasound technology, and JRBP-catechin (CC) covalent complex was prepared. The structural and functional properties of indica and japonica rice bran proteins and their complexes were compared; furthermore, the changes in the structural and functional properties of JRBP-CC under different ultrasound conditions were investigated. The results showed that compared with indica rice bran protein (IRBP), the secondary structure of JRBP-CC was very different, the water holding capacity (WHC) was higher, and the emulsification performance was better. Different ultrasound conditions had different effects on the functional properties of JRBP-CC. When the ultrasound power was 200W, the λmax redshift of the JRBP-CC complex was the most significant, the particle size was the smallest, the absolute value of the zeta potential was the largest, and the hydrophobicity and microstructure of the JRBP-CC complex were the best. Concurrently, the maximum WHC and oil holding capacity (OHC) of JRBP-CC under these conditions were 7.54g/g and 6.87g/g, respectively. Moreover, the emulsifying activity index (EAI) and emulsifying stability index (ESI) were 210m2/g and 47.8min, respectively, and the scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ABTS+ were 71.96% and 80.07%, respectively.

Investigation of the effects of high hydrostatic pressure on the functional properties of pea protein isolate

AbstractThis study investigates the effects of high hydrostatic pressure (HHP) on some functional properties of pea protein isolate (PPI). HHP was combined with various temperature and pH conditions to investigate the combined effects of HHP‐based food processing conditions on the functional properties of PPI. Herein, PPI solutions prepared at different pH conditions (3.0, 5.0, and 7.0) were subjected to 300, 400, and 500 MPa HHP treatment at 25 and 50°C for 5 min. Water‐holding capacity (WHC), solubility, and emulsification activity of PPI samples were determined. Additionally, nuclear magnetic resonance (NMR) relaxometry and Fourier transform infrared spectroscopy experiments were performed for further analysis. Maximum WHC (p &lt; 0.05) was observed for the samples treated at 500 MPa‐pH 5.0‐50°C whereas maximum solubility (p &lt; 0.05) belonged to the samples subjected to 300 MPa‐pH 7.0‐50°C treatment conditions. Better emulsification activity was achieved at pH 3.0 regardless of the pressure level applied. The novelty of this study is that NMR relaxometry was introduced as a fast/nondestructive technique to investigate the changes in the functional properties of PPI samples and one of the functional parameters was correlated with NMR relaxation data. Herewith, the longest transverse relaxation time (T2) (p &lt; 0.05) belonged to the samples with maximum WHC. The results showed that HHP is able to modify the functional properties of PPI at specific temperature‐pH combinations, and NMR relaxometry technique has a high potential for such studies.Practical ApplicationsHigh hydrostatic pressure (HHP) is an emerging technology which is used for its diverse range of applications in food science and technology. Modification of physicochemical and functional properties of food ingredients is one of the latest applications of HHP treatment. This study demonstrated that HHP treatment was able to modify some functional properties of pea protein isolate (PPI) samples such as water‐holding capacity (WHC), solubility, and emulsification activity. In addition to pressure level, pH and temperature were also effective on modifying the functional properties of PPI samples. For instance, a high pressure (500 MPa) was required to improve WHC whereas lower pressures (300 MPa) improved the solubility of the samples at high pH and temperature. The results of this study could be used in model HHP studies to improve some functional properties of PPI for different purposes.

Mixed plantation regulates forest floor water retention and temperature sensitivity in restored ecosystems on the Loess Plateau, China

Ongoing warming and frequent extreme rainfall are endangering hydrological functioning in reforested ecologically vulnerable areas. The forest floor plays an important role in water conservation; however, knowledge of water retention of forest floor and its temperature sensitivity under climate change remains limited particularly in restored ecosystems. Here, we investigated and sampled litter and topsoil from three monoculture plantations, two mixed plantations, and one natural grassland on the hilly and gullied Loess Plateau. We used an artificial climate incubator to simulate different climate conditions and measure the effects on litter and topsoil water retention. Generalized additive models were used to explore the relationships between temperature sensitivity of water-retention capacity and influencing factors. The results showed that mixed plantations shortened the water retention time of litter and topsoil. In addition, mixed plantations significantly improved the maximum water-holding capacity of litter, but reduced the maximum water-holding capacity of topsoil. Litter water-retention capacity temperature sensitivity (LTS) was significantly greater than that of soil (STS). Moreover, communities with strong LTS generally had weak STS. Nonetheless, mixed plantations tend to have a more stable forest floor water-retention capacity. Soil porosity, bulk density, litter mass, and canopy openness were the key factors affecting the maximum water-holding capacity and water-retention capacity of forest floors. Overall, our results indicated that mixed plantations adjusted the water retention time of the forest floor and had a more stable water-retention capacity, which was of great significance for plantation management in arid and semi-arid regions.

Applicability of the microdialysis technique in dry soils: Impact of soil water content depends on perfusion flow rate

Plant nutrient acquisition largely depends on the availability and constant replenishment of nutrients at root surfaces. The main process providing nutrients for root uptake is diffusion which is critically affected by soil physicochemical and biological factors. The effective diffusion path length increases with decreasing soil water content thus limiting diffusive nutrient supply in dry soils. Microdialysis, an increasingly popular sampling tool for monitoring nutrient fluxes in soil in situ, could be used to measure such a limitation provided it operates reliably under dry soil conditions. However, due to its mode of operation, the performance of microdialysis could be impeded in dry soils since a significant amount of perfusate might be lost via leaching to the surrounding soil. Until now, however, no data is available on the applicability of microdialysis in dry soils. In this project, we estimated leaching losses of perfusate to eight soils with different texture maintained at 10, 20, 30, 50 and 80% (w/w) of maximum water-holding capacity in dependence of perfusion flow rate. We found that microdialysis operates reliably even in dry soils when using a high perfusion flow rate (10 μl min−1). At lower perfusion flow rates (1 or 5 μl min−1), however, significant amounts of perfusate were leaching out to soils. Diffusive fluxes of nitrate and ammonium were strongly affected by soil water content, but not fluxes of phosphate. Even at the highest flow rate (where no losses of perfusate where observed) concentrations of both inorganic N forms in dialysates decreased with decreasing soil water content. Overall, we conclude that microdialysis can be applied in dry soils without high risk of perfusate leaching when a high perfusion flow rate (10 μl min−1) is used. Further, our results highlight that microdialysis can be used in much dryer soils than previously suggested (70% MWHC) and allows monitoring the effect of soil water content on nutrient supply for root uptake via diffusion.

Design of glucono-δ-lactone-induced pinto bean protein isolate/κ-carrageenan mixed gels with various microstructures: fabrication, characterization, and release behavior.

Protein gels are used for different purposes, such as providing good texture, serving as fat replacers, and enhancing the nutritional and functional characteristics of foods. They can also deliver controlled release agents for sensitive drugs. The objective of this study was to investigate the impact of κ-carrageenan (kcr) concentration (0, 1.5, 3, and 4.5mg g-1 ) on the morphological and physicochemical properties and release behavior of glucono-δ-lactone (GDL)-induced pinto bean protein aggregate (PBA) gels. When κ-carrageenan concentration increased from 0 to 1.5 and 3mg.g-1 , the firmness of the samples increased significantly, by 2.04 and 3.7 fold, respectively (P< 0.05). A compact and homogenous network with considerable strength and maximum water-holding capacity (97.52 ± 1.17%) was obtained with the addition of 3mg g-1 κ-carrageenan to the gel system. Further increasing the κ-carrageenan concentration to 4.5mg g-1 produced a coarse gel structure with higher storage modulus (G'), firmness (6.30-fold), thermal stability, and entrapment efficiency (85.6%). Depending on the κ-carrageenan concentration, various microstructures from protein continuous phase to κ-carrageenan continuous phase were observed. The release test indicated that 70.25% of the loaded curcumin was released in the simulated gastrointestinal tract for pure PBA gels. In contrast, for binary gels containing 4.5mg g-1 κ-carrageenan, curcumin was protected in the upper gastrointestinal tract, and 64.45% of loaded curcumin was delivered to the colon. Our study showed that κ-carrageenan/PBA gels had high entrapment efficiency and could protect curcumin in the upper gastrointestinal tract. The hydrogels are therefore very valuable for colon-targeting delivery purposes. © 2022 Society of Chemical Industry.

Effect of Dry and Flooded Rice as Cover Crops on Soil Health and Microbial Community on Histosols

Soil loss due to subsidence is a major concern in the Everglades Agricultural Area (EAA) of South Florida. Summer is typically the fallow season in the EAA, and soil loss due to oxidation and erosion is significant. Flooding and cover cropping are common practices being adopted to conserve soil, reduce weed pressure, and enhance soil health in the EAA. Cover crops also increase the microbial biomass which are the key drivers of soil function. The objective of this study was to determine the effect of (i) fallow, (ii) dry rice as a cover crop, (iii) flooded fallow, and (iv) flooded rice as a cover crop on soil health indicators and microbial community and diversity within the EAA. Baseline (pre-planting) soil samples were collected from all fields before the application of different treatments and post-harvest soil samples were collected after rice was cut and tilled into the soil surface. Microbial community composition was determined using 16S rRNA gene amplicon and fungal ITS gene amplicon sequencing. Soil bulk density decreased, and cation exchange capacity (CEC) increased in all farming practices including fallow fields. Results showed flooded fallow, flooded rice, and rice planting increased maximum water holding capacity (MWHC) and soil protein and decreased total potassium (TK). Bulk soil microbial communities responded surprisingly quickly to the applied treatments. Taxonomic composition of prokaryotic and fungal communities at the phylum level revealed visible shifts in microbial communities in response to the treatments. Instead of leaving field fallow, planting rice or flooding is a better strategy to improve soil health.