Variation In Water Holding Capacity Research Articles

Variation in Water-Holding Capacity in Sphagnum Species Depends on Both Plant and Colony Structure.

Peatlands have become a focal point in climate mitigation strategies as these ecosystems have significant carbon sequestration capacities when healthy but release CO2 and other greenhouse gases when damaged. However, as drought episodes become more frequent and prolonged, organisms key to the functioning of some peatlands are increasingly under pressure from desiccation. The Sphagnum mosses, which tend to keep their ecosystem waterlogged and many of whom promote peat formation, are only mildly desiccation-tolerant in comparison to other mosses. The role of Sphagnum anatomy and colony structure is poorly understood in the context of desiccation resilience. Using four different Sphagnum species belonging to four different subgenera and positions along the gradient of the water table, we show that plant morphological traits and colony density are important determinants of water storage capacity. Our results show that, as previously postulated, the majority of the water is stored in an easily exchangeable form, probably extracellularly, and that plant morphological traits, specifically the type and presence of branches, are major contributors to water storage and can explain some of the interspecies variation. We also show that plant density is another important determinant for water storage capacity as higher densities hold larger quantities of water per unit of biomass for all four species, which increases resilience to desiccation. The results presented here suggest that species choice and planting density should receive more attention when considering peatland restoration strategies.

A review and analysis of particle size parameters and their relationships to physical properties of growing media

AbstractAn expanded description of particle morphology and the analysis of its relationships with physical properties may help to optimize the selection of raw materials and particle size fractions used as growing media constituents. Previous works have described the outlines of these relations based mostly on sieving procedures to characterize particle size distribution. They have shown limited and sometimes contradictory results due to the different methods used, size fractions selected, and physical properties measured. Also, sieve analysis, which separates particles based on their width, is less accurate for non‐spherical particles, which is the case for most growing media constituents. Recent works have promoted the use of dynamic image analysis (DIA) to precisely analyze both particle length and width. Five raw materials were chosen (white and black peats, coir, pine bark, and wood fiber) and sieved to obtain various particle size fractions. For each particle size fraction and the raw materials, the mean weight diameter (MWD), derived from sieving, was calculated, whereas mean particle length and width were determined using a DIA tool, the QicPic device. Also, physical properties were assessed from water retention curves established using Hyprop systems. The statement that the larger the particle size, the higher the air‐filled porosity (AFP), the lower the water holding capacity (WHC) was more precisely redefined. Large variations in WHC and AFP mainly occurred for finest particle size fractions, whereas changes were conversely very small or non‐existent for larger particle sizes. From data obtained for each particle size fractions, regression models were established to relate mean particle length and width (both determined using DIA) and MWD (determined from sieving) with WHC and AFP. Mean particle length was identified as the most relevant parameter for predicting WHC and AFP of the raw materials tested.

CHANGES IN THE WATER-HOLDING CAPACITY OF A. DIFFUSA UNDER THE DIFFERENT GRAZING INTENSITIES IN THE CONDITION OF LIVESTOCK GRAZING

Soil water holding capacity is an important indicator of its ability to retain moisture and support plant growth. This study investigated the variation in water-holding capacity (WHC) characteristics of Artemisia diffusa, a common forage plant species, under different grazing intensities under livestock grazing conditions. Four intensities of livestock grazing were defined: initial (IG), low (LG), medium (MG), and heavy (HG).

Interspecific and intraspecific variability of water use traits in macrolichen species in a fragmented landscape along a climatic ecotone area

Water use traits in lichens are important attributes that determine the duration of hydration and metabolically active periods. In this study, the water holding capacity (WHC) and specific thallus mass (STM) were measured for seven macrolichen species (Parmelia sulcata, Parmelina tiliacea, Evernia prunastri, Ramalina farinacea, Lobaria pulmonaria, Lobarina scrobiculata and Nephroma resupinatum) from a Temperate-Mediterranean fragmented landscape. Twenty Quercus forests with different environmental conditions were selected to gather therein five lichen samples of each species in order to analyse their interspecific and intraspecific variation in WHC and STM. The type of photobiont was mainly responsible for differences in the WHC and the water content per biomass among species. Lichens with cyanobacteria as the main or secondary photobiont showed the highest value for both parameters. However, particular features of species were more important in modulating STM, while growth form had a minor explanatory importance. At the intraspecific level, variation in WHC relied on climatic, microclimatic and forest structure factors, while STM variability was only dependent on the two last predictors. Future research should be focused on other drivers at the microscale to unveil the environmental conditions that shape WHC and STM in lichens.

Spatial Variations in Water-Holding Capacity as Evidence of the Need for Precision Irrigation

Malaysia receives a lot of water from its two main monsoon periods. Generally, there is a lot of precipitation throughout the year, with drought periods lasting less than three months. To date, irrigation has been treated homogenously, even though soil properties can vary spatially over a field, requiring site-specific applications. The aim of this study was to establish an irrigation management zone (IMZ) covering 23.4 ha, which was previously determined under the same soil series. Soil sampling was done according to a grid system over an area of 100 m × 100 m. Three soil depth ranges were examined for every sampling point, namely 0–30, 30–60, and 60–90 cm from the soil surface. Samples were taken to a laboratory for physical analysis and determination of the available water-holding capacity (AWHC). Delineation of AWHC values was achieved using GIS software and the Kriging method. Estimated irrigation depth (EID) data for the plantation were collected for the years 2016 and 2017. Afterward, EID and total net irrigation (TNI) data were simulated in the FAO Cropwat model and compared. The results showed that clay, sand, and organic matter (OM) distributions varied with soil depth; however, no strong correlation was found between these variable with AWHC. The IMZ was classified into three areas named zones A, B, and C, ranging from 79 to 167 mm. The crop water requirement (CWR) was 667 mm in 2016 but only 260 mm in 2017. Based on the AWHC values, the EID for 2016 was found to be below the TNI requirement range of about 106 to 110 mm. In contrast, the EID range was approximately 34 to 62 mm and above TNI requirements for 2017. This study indicates that water inputs for irrigation can be optimized with knowledge of the water-holding capacity of a specific soil. Subsequently, this can be related to crop yield and the impact on sustainable agriculture.

Determination of Water-holding Capacity of Porcine Musculature Based on Released Water Method Using Optimal Load.

The purpose of this study was to evaluate the suitability of the released water (RW) method for measuring water-holding capacity (WHC) by pressure and filter-paper absorption within two thin plastic films. One hundred fifty pork loins with considerable variations in WHC (three pork qualities: PSE, pale, soft, and exudative; RFN, reddish-pink, firm, and nonexudative; and DFD, dark, firm, and dry; 50 pork loins in each pork quality group) were used to measure drip loss (DL)% and RW % after applying different loads (1.5, 2.0, 2.5, 3.0 and 3.5 kg). Percentages of DL and RW were significantly (p<0.05) different among pork quality groups. The RW % of 2.5 kg load sample was significantly (p<0.05) higher than that of 2.0 kg or 1.5 kg load sample. However, there were no significant (p>0.05) differences in RW % among 2.5 kg, 3.0 kg, and 3.5 kg load samples for all three pork quality groups. The RW % was highly and positively correlated (r>0.95; p<0.001) with DL %. The highest correlation was observed between DL % and RW % of 2.5 kg load sample (r=0.97; p<0.001). Among all RW loads within each quality groups, the highest correlation between DL % and RW % was observed for 2.5 kg load sample (r=0.43, 0.66, and 0.46 for PSE, RFN and DFD quality groups, respectively, p<0.001). These results imply that applying 2.5 kg load is the best for determination of RW %. It is recommended as a reference method to assess DL % of pork muscles.

Multiple on-line soil sensors and data fusion approach for delineation of water holding capacity zones for site specific irrigation

Soil water holding capacity (WHC) and available water (AW) are key parameters for water management and irrigation scheduling. Measurement of within field variation in WHC should account for affecting soil properties, namely organic matter (OM) or organic carbon (OC), clay content (CC), bulk density (BD) and plasticity index (PI). The aim of this paper is to implement on-line multi-sensor and data fusion approach for the delineation of management zones of WHC for site specific irrigation. A multi-sensor platform was used, which consisted of a load cell to measure subsoiler draught, a wheel gauge to measure depth and a visible and near infrared (vis–NIR) spectrophotometer for simultaneous measurement of moisture content (MC), OC, PI, CC and BD. An electromagnetic induction (EMI) sensor was implemented separately apart from the multi-sensor platform to measure apparent electrical conductivity (ECa) in three experimental fields with vegetable crop production in East Anglia, UK. Partial least squares (PLS) regression analysis with full-cross validation was adopted to establish vis–NIR calibration models of MC, OC, PI and CC, which were validated with prediction sets. Artificial neural network (ANN) and multiple linear regression (MLR) analyses were carried out on the six named soil properties to derive maps of WHC. The validation of the on-line measurement accuracy for OC and MC were good to excellent with root mean square error of prediction (RMSEP) values of 0.06–0.72% and 0.97–2.49% and residual prediction deviation (RPD) values of 2–2.57 and 1.94–2.1, respectively. For CC and PI, the measurement was of fair to moderate accuracy with RMSEP values of 1.4–3.94% and 2.43–2.77% and RPD values of 1.41–1.77 and 1.25–1.48, respectively. Accordingly each field was divided into four classes, with normalised ranges of WHC of 0–0.25, 0.26–0.50, 0.51–0.75 and 0.76–1. These were designated, respectively, as low, medium, high and very high WHC, with the low category being the most susceptible to water changes and entitled to accommodate the largest number of moisture sensors and receive the largest amount of water. A comparison between calculated WHC and measured AWC maps showed distinguished spatial similarity, to recommend the multi-sensors and data fusion as a new approach to optimise irrigation scheduling.

2D DIGE proteomic analysis of early post mortem muscle exudate highlights the importance of the stress response for improved water‐holding capacity of fresh pork meat

Variation in water-holding capacity (WHC), which presents a major economic burden to the swine industry, is considered to be underpinned by variation at a molecular and biochemical level. High-resolution 2D DIGE followed by MS analysis and Western blot were used to unravel the proteome of muscle exudate, collected following centrifugation, in the pH 4-7 range. A first 2DE-based protein map of this substrate was produced where 89 spots were successfully characterised. Two phenotypes divergent for WHC plus one intermediate were compared with a view to deciphering the biochemical processes impacting on variation in WHC. Twenty spots were observed to be altered across the phenotypes. Of these, 14 represented sixteen proteins including metabolic enzymes, stress response proteins and structural proteins. Triosephosphate isomerase and transferrin showed a major difference between the two extreme phenotypes, and may have potential as biological markers for WHC prediction. Several members of the HSPs family were highlighted. This proteomic study makes an important contribution towards a more detailed molecular view of the processes behind WHC and will provide a valuable resource for future investigations.

Any link between integrin degradation and water-holding capacity in pork?

In order to investigate a possible relationship between integrin degradation and water-holding capacity (WHC), integrin was quantified using western blot, and water mobility and distribution was measured by proton NMR T 2 relaxometry at 24 h postmortem in pork ( n = 30) with a large variation in WHC (drip loss varying from 2.8% to 11.3%). Regression analyses revealed correlation coefficients of r = −0.32 ( P = 0.08) and r = 0.40 ( P = 0.03) for the correlations between the content of integrin determined by western blot analysis and WHC determined as either drip loss or by NMR, respectively. Water mobility and distribution was also measured in 18 meat samples upon 7 days of aging, which revealed a correlation ( r = 0.54) between integrin content determined by western blot analysis 24 h postmortem and the mobility of the myofibrillar water (T 21 relaxation time) at day 7. In contrast, no correlation could be established between integrin content 24 h postmortem and WHC at day 7 determined by NMR as the amount of extramyofibrillar water (T 22 population) ( r = −0.01). In conclusion, both visualisation by CLSM and quantification of integrin by western blot analyses of suggested that a strong link between integrin degradation and WHC in pork is questionable, whereas integrin degradation seems to have impact on the succeeding development in the mobility of the myofibrillar water.

THE RELATIONSHIP BETWEEN COLOR AND WATER‐HOLDING CAPACITY IN POSTRIGOR PORCINE LONGISSIMUS MUSCLE

ABSTRACTA total 264 pork loins were selected to represent a wide range of pork quality of the longissimus thoracis et lumborum. CIE L*C*h color space showed a closer relationship to the subjective color score than L*a*b*color space. Lightness (L*) was the best measure to predict water‐holding capacity (WHC). There were highly significant (p &lt; 0.001) correlations between the measures of color and WHC, and curvilinear relationships between either WHC and color or pHu were observed. In normal muscle color range (reddish‐pink), there was considerable variation in WHC. Within the RSE + RFN groups of muscles, less variation of WHC could be accounted for by variations in color measurements. Color and WHC were not closely related and suggest that the RSE (reddish‐pink, soft, exudative) condition should be classified as a separate quality category of pork muscle.

Measuring water-holding capacity in pork musculature with a tensiometer

The water-holding capacity (WHC) of post-mortem porcine musculature is an important quality trait, and it is desirable for the industry to assess its variations ,for purposes of evaluating and processing pork products. There are several procedures to accurately determine WHC, but most are either too slow, too expensive or are impractical for commercial application. Since WHC is also important when examining the characteristics of soil, scientists routinely use an instrument called a tensiometer for this measurement. Therefore, we explored the potential application of this technique for assessing WHC in post-rigor pork muscle. The cost, potential speed and invasive application of the tensiometer in muscle were attractive characteristics. A sample (29) of pork loins, representing considerable variation in WHC were used to test the applicability of a commercial tensiometer. When tensiometer measurements were compared to 48 h drip loss, the results indicated the tensiometer could accurately detect the variations in free fluids expressed in muscle and that the procedure could be applied quickly and invasively without altering the commercial value of the product. However, particles (primarily protein and fat) in the muscle fluid became imbedded in the pores of the tensiometer ceramic tip, thus impairing the repeated use of the instrument. A plastic filter was developed to prevent clogging, but it could not be molded adequately to permit rapid insertion and removal for on-line measurements of WHC. Therefore, despite the various desirable features of the tensiometer, it failed to meet some requirements considered essential for further testing as a potential commercial, on-line procedure. First, the clogging problem must be resolved The study also indicated that the filter paper test would be more appropriate than the tensiometer for use in field tests to predict WHC when limited numbers of samples were to be tested.

Variations in water-holding capacity due to changes in the fibre diameter, sarcomere length and connective tissue morphology of some beef muscles under acidic conditions below the ultimate pH

The water-holding capacities (WHC) of six different beef muscles were measured over the pH range 5·7 to 4·0. Corresponding changes in the morphology of muscle fibres and connective tissue were observed by light microscopy. WHC increased over the pH range 5·1 to 4·0 in all muscles, with the M. longissimus dorsi (LD) having significantly higher (p < 0·05) swelling ratios than the other muscles at pH 4·3 and pH 4·0. In all muscles, swelling increased across and along the muscle fibre axis between pH5·1 and pH4·4. However, towards pH4·0, increased muscle fibre swelling occurred in predominantly ‘white’ fibre-type muscles, in particular the LD, whereas muscle fibre shrinkage occurred in predominantly ‘red’ fibre-type muscles. Increased swelling of perimysial collagen and endomysial reticulin was observed in all muscles between pH4·5 and pH4·0, while the appearance of elastin was unaffected by pH. Consequently, interactions between muscle fibre swelling and connective tissue swelling determined the extent of total muscle swelling in different muscles between pH 4·5 and pH 4·0.