scholarly journals Student Laboratory Exercise to Understand Air and Water Relations in Container Substrates

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 900B-900
Author(s):  
E. Jay Holcomb ◽  
Robert Berghage ◽  
William Fonteno
Keyword(s):  
Water Content ◽  
Crop Production ◽  
Moisture Retention ◽  
Retention Curve ◽  
Standard Methods ◽  
Laboratory Exercise ◽  
Column Method ◽  
Standard Soil ◽  
Student Laboratory ◽  
Water Holding

The concepts of container water-holding capacity and air-filled porosity are important yet complicated for students interested in containerized crop production; however, both of these concepts can be observed and understood more completely if students develop a moisture retention curve. Our objectives were to describe an easy-to-construct and economical apparatus for creating a moisture retention curve and then to compare this curve with one generated by standard methods. The student method (column method) is constructed from plastic pipe cut into 5-cm sections. The sections of pipe are individually packed with a substrate then stacked and taped together, resulting in a 60-cm column of the substrate. The column is saturated and allowed to drain for 24 h. Then, the column is taken apart and the water content of each section determined gravimetrically. The water content of each section is graphed against height so that the result is a moisture retention curve. Data are presented to show the curve developed from the column method is similar to the curve developed by standard soil moisture tension method. The moisture retention curve can provide a better understanding of water and air holding capacities of substrates.

Quantification of Available Water Capacity Comparing Standard Methods and a Pedostructure Method on a Weakly Structured Soil

2019 ◽  
Vol 62 (2) ◽  
pp. 289-301
Author(s):  
Amjad T. Assi ◽  
Rabi H. Mohtar ◽  
Erik F. Braudeau ◽  
Cristine L. S. Morgan
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Field Capacity ◽  
Soil Aggregate ◽  
Pedotransfer Functions ◽  
Water Retention Curve ◽  
Aggregate Structure ◽  
Standard Methods ◽  
Available Water ◽  
Water Holding

Abstract. The purpose of this study was to evaluate the use of the pedostructure concept to determine the soil available water capacity, specifically the field capacity (FC). Pedostructure describes the soil aggregate structure and its thermodynamic interaction with water. Specifically, this work compared the calculation of soil water-holding properties based on the pedostructure concept with other standard methods for determining FC and permanent wilting point (PWP). The standard methods evaluated were the FAO texture estimate (FAO method), the Saxton-Rawls pedotransfer functions (PTFs method), and the water content at predefined soil suction (330 and 15,000 hPa) as measured with a pressure plate apparatus (PP method). Additionally, two pedostructure methods were assessed: the thermodynamic water retention curve (TWRC method) and the thermodynamic pedostructure (TPC method). Undisturbed loamy fine sand soil from a field in Millican, Texas, was analyzed at both the Ap and E horizons. The results showed that the estimated water content at FC and PWP for the three standard methods and for the TWRC method were in relative agreement. However, the TPC method used characteristic transition points in the modeled contents of different water pools in the soil aggregate and was higher for the Ap horizon, but in agreement with the other methods for the E horizon. For example, for the Ap horizon of the soil analyzed in this study, the FC estimated with the standard and TWRC methods ranged from 0.073 to 0.150 m3H2O m-3soil, while the TPC method estimate was 0.221 m3H2O m-3soil. Overall, the different methods showed good agreement in estimating the available water; however, the results also showed some variations in these estimates. It is clear that the TPC method has advantages over the other methods in considering the soil aggregate structure and modeling the soil water content within the aggregate structure. The thermodynamic nature of the TPC method enabled the use of both the soil shrinkage curve and the water retention curve in a weakly structured soil. It is expected that the TPC method would provide more comprehensive advances in understanding the soil water-holding properties of structured soils with higher clay contents. Keywords: Available water, Field capacity, Pedostructure, Pedotransfer functions, Permanent wilting point.

scholarly journals Effects of water deficit on the growth and yield formation of maize (Zea mays L.)

2017 ◽  
pp. 143-148
Author(s):  
Mahama Salifu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Deficit ◽  
Crop Production ◽  
Water Holding Capacity ◽  
Field Soil ◽  
The World ◽  
Soil Water Holding Capacity ◽  
Water Holding

Maize (Zea mays L.) is the most important consuming cereal crop in the world after rice and wheat. This requires an understanding of various management practices as well as conditions that affect maize crop performance. Water deficit stress during crop production is one of the most serious threats to crop production in most parts of the world and drought stress or water deficit is an inevitable and recurring feature of global agriculture and it is against this background that field study of crops response to water deficit is very important to crop producer and researchers to maximize yield and improve crop production in this era of unpredicted climatic changes the world over.A pot experiment was carried out to determine the effects of water deficit on growth and yield formation of maize. Two maize cultivars were used Xundan20 and Zhongdan5485. Three levels of soil water content were used in two stages of water control levels at two stages of the maize plant development1. The JOINTING STAGE: A. CONTROL (CK) soil water content: from 70% to 80% of soil water holding capacity at the field, soil water content: from 55% to 65% of soil water holding capacity at the field, soil water content: from 40% to 50% of the Soil water holding capacity at the field.2. The BIG FLARE PERIOD: A. CONTROL (CK) soil water content: from 75% to 85% of soil water holding capacity at the field, soil water content: from 58% to 68% of soil water holding capacity at the field, soil water content: from 45% to 55% of the soil water holding capacity at the field.This research mainly studied the effects of water deficit on physiological, morphology and the agronomical characteristics of the maize plant at the different water stress levels.The importance of these results in this experiment will enable plant producers to focus and have a fair idea as to which stage of the maize plant’s development that much attention must be given to in terms of water supply.

scholarly journals Pinhole Multistep Centrifuge Outflow Method for Estimating Unsaturated Hydraulic Properties with Small Volume Soil Samples

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1169
Author(s):  
Long Thanh Bui ◽  
Yasushi Mori
Keyword(s):  
Hydraulic Properties ◽  
Volcanic Ash ◽  
Small Volume ◽  
Clayey Soil ◽  
Soil Hydraulic Properties ◽  
Retention Curve ◽  
Volcanic Ash Soil ◽  
Equilibrium Data ◽  
Soil Hydraulic ◽  
Water Holding

If soil hydraulic conductivity or water holding capacity could be measured with a small volume of samples, it would benefit international fields where researchers can only carry a limited amount of soils out of particular regions. We performed a pinhole multistep centrifuge outflow method on three types of soil, which included granite decomposed soil (Masa soil), volcanic ash soil (Andisol soil), and alluvial clayey soil (paddy soil). The experiment was conducted using 2 mL and 15 mL centrifuge tubes in which pinholes were created on the top and bottom for air intrusion and outflow, respectively. Water content was measured at 5, 15, and 30 min after applying the centrifuge to examine the equilibrium time. The results showed that pinhole drainage worked well for outflow, and 15 or 30 min was sufficient to obtain data for each step. Compared with equilibrium data, the retention curve was successfully optimized. Although the curve shape was similar, unsaturated hydraulic conductivities deviated largely, which implied that Ks caused convergence issues. When Ks was set as a measured constant, the unsaturated hydraulic properties converged well and gave excellent results. This method can provide soil hydraulic properties of regions where soil sampling is limited and lacks soil data.

scholarly journals Evaluation of drought resistance of primocane raspberry on some parameters of water metabolism in the conditions of Bryansk region

2019 ◽  
pp. 23-27
Author(s):  
I. V. Alexeenko
Keyword(s):  
Water Content ◽  
Water Deficit ◽  
Drought Resistance ◽  
Critical Periods ◽  
Water Metabolism ◽  
Yield Data ◽  
Great Yield ◽  
Water Holding ◽  
Lower Water Content ◽  
Intensive Growth

The results of comparative study of productivity and some parameters of water metabolism of primocane raspberry varieties in the conditions of Bryansk region are presented. The purpose of the work was to evaluate drought-resistance of original varieties and select on her basis the most valuable genotypes. There were studied 8 primocane raspberry varieties: Bryanskoe divo, Karamelka, Podarok Kashinu, Snezhet, Pingvin, Poklon Kazakovu, Oranzhevoe chudo and Rubinovoe ozherelye. In laboratory conditions, an evaluation was made of the total water content, water deficit, and water holding capacity of the leaves during critical periods of plant water availability. It was established that the greatest amount of water in the leaves (65.63 %) is contained in the phenophase “intensive growth”; less-in the phenophase “budding” (60.73 %), even lower water content – in the phenophase “fruiting” (58.02 %).The water deficit decreased on vegetation phases, but at the same time he was on average level (11,42-16.68 %). The leaves of raspberry varieties Podarok Kashinu and Poklon Kazakovu marked a low level of water deficiency in the phenophase “fruiting” (9.2-9.8 %). The water-holding ability increased on vegetation phases. Among the studied assortment, the leaves of the varieties Poklon Kazakovu and Podarok Kashinu relatively slowly lost water after 4 hours of wilting (water loss 19.35-26.86 %). The yield data of raspberry varieties in drought conditions are presented. The varieties Poklon Kazakovu and Podarok Kashinu have been characterized by a relatively great yield. On the basis of the study of productivity and water metabolism parameters, relatively drought-resistant primocane raspberry varieties were identified: Poklon Kazakovu and Podarok Kashinu.

scholarly journals Indicators of the water regime of some varieties of chrysanthemums in the conditions of the South Ural

2021 ◽  
Vol 10 (1) ◽  
pp. 57-64
Author(s):  
Svetlana Galimullovna Denisova ◽  
Antonina Anatolyevna Reut
Keyword(s):  
Water Content ◽  
Water Deficit ◽  
Water Regime ◽  
Water Holding Capacity ◽  
Research Centre ◽  
Total Water Content ◽  
Total Water ◽  
The South ◽  
Irreversible Damage ◽  
Water Holding

In introduction studies, it is of great importance to determine how favorable the water balance of the studied species is under given environmental conditions. The aim of the research was to study the water regime of some varieties of chrysanthemums in the conditions of the Southern Ural. The study was conducted in 20182020 on the basis of the South-Ural Botanical Garden-Institute of the Ufa Federal Research Centre of Russian Academy of Sciences. The objects of the study were 23 varieties of Chrysanthemum hortorum Bailey. In the course of the research, the total water content, water-holding capacity, the content of mobile moisture, water deficit, and sublethal water deficit were determined. The analysis of water regime indicators is based on the method of artificial wilting (V.N. Tarenkov, L.N. Ivanova) and the method of saturation of plant samples (V.P. Moiseev, N.P. Reshetsky). Sublethal water deficit was determined by the method of T.K. Goryshina, L.I. Samsonova, modified by N.I. Bobrovskaya. The calculations were carried out by standard methods using statistical packages of the Microsoft Excel 2003 and the Agros 2.13 program. The studies made it possible to determine the value of the sublethal water deficit (28,4%) for the varieties of chrysanthemums in the conditions of the Bashkir Ural. It was found that the studied varieties during the growing season did not experience such a moisture deficit in the tissues that could lead to irreversible damage to the assimilating organs. Our experiments showed that chrysanthemum varieties in the Bashkir Cis-Ural under the same soil-climatic and agrotechnical conditions had the following range of indicators of total water content 70,090,4% and water-holding capacity 19,0064,6%. The analysis of variance revealed significant differences between water-holding capacity and the content of mobile moisture by varieties, the share of influence was 27,8531,71%. As a result of the correlation-regression analysis, the authors revealed a direct dependence of the indicators of mobile moisture content on the total water content, and an inverse one on the indicators of the content of mobile moisture and water-holding capacity.

Determination of the tensile strength of unsaturated tailings using bending tests

2015 ◽  
Vol 52 (11) ◽  
pp. 1874-1885 ◽  
Author(s):  
Bibiana Narvaez ◽  
Michel Aubertin ◽  
Faustin Saleh-Mbemba
Keyword(s):  
Tensile Strength ◽  
Water Content ◽  
Water Retention ◽  
Water Retention Curve ◽  
Initial Water Content ◽  
Ambient Conditions ◽  
Initial Water ◽  
Bending Tests ◽  
Retention Curve ◽  
Apparent Cohesion

Bending tests were conducted on specimens of unsaturated tailings from three hard rock mines to evaluate their tensile strength. Saturated samples were prepared at an initial water content, w0, of 40% and then naturally dried under ambient conditions to pre-selected degrees of saturation, Sr, which can be related to the corresponding suction using the water retention curve. The basic interpretation of the bending tests results is based on an elastic–brittle behavior. The results show how the tensile strength, σt, of unsaturated tailings varies with water content, w (and Sr). The experimental data are also used to evaluate Young’s modulus in tension, Et, and to estimate the apparent cohesion, capp, as a function of Sr. Predictive equations are also applied to estimate the values of σt of unsaturated tailings using the water retention curve.

Functional Properties of Adlay Flour (Coix lacryma-jobi L. var. Ma-yuen) Resulting from Modified Durations of Fermentation Using Rhizopus oligosporus

2021 ◽  
Vol 2 (2) ◽  
pp. 1-6
Author(s):  
Ardiyan Dwi Masahid ◽  
Maria Belgis ◽  
Helyas Vintan Agesti
Keyword(s):  
Protein Content ◽  
Water Content ◽  
Functional Properties ◽  
Fat Content ◽  
Ash Content ◽  
Carbohydrate Content ◽  
Water Holding Capacity ◽  
Rhizopus Oligosporus ◽  
Swelling Power ◽  
Water Holding

Adlay is a nutritious grain that has the potential as an alternative food because it has a high protein and fat content of 14.10% and 7.90%, respectively. The use of Adlay as flour still has a weakness, namely the functional properties of Adlay flour such as low swelling power. One way to improve the characteristics of Adlay flour is by fermentation using Rhizopus oligosporus. The fermentation duration is the time that allows changes in the characteristics of the flour due to the fermentation. This study aims to determine the effect of differences in fermentation duration using Rhizopus oligosporus on the physical, chemical, and functional characteristics of Adlay flour produced from fermented Adlay seeds. This study used one factor, namely the lengths of fermentation for 0, 12, 24, 30, 36 and 48 hours. The analysis in this study included whiteness, yield, pH, water content, ash content, protein content, fat content, carbohydrate content, swelling power and solubility, oil holding capacity (OHC) and water holding capacity (WHC). The results have shown that the longer the fermentation duration the lower rate of whiteness, pH, yield, water content, fat content, and carbohydrate content will become, while some functional properties of Adlay flour become better with increasing values of ash content, protein content, swelling power, solubility, Oil Holding Capacity (OHC), and Water Holding Capacity (WHC).

scholarly journals A Novel Frequency Domain Impedance Sensor with a Perforated Cylinder Coaxial Design for In-Situ Measuring Soil Matric Potential

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2626 ◽  
Author(s):  
Chao Chen ◽  
Xiaofei Yan ◽  
Qiang Xu ◽  
Song Yu ◽  
Yihan Ma ◽  
...  
Keyword(s):  
Water Content ◽  
Water Retention ◽  
Soil Samples ◽  
Environmental Research ◽  
Water Retention Curve ◽  
The Novel ◽  
Soil Matric Potential ◽  
Matric Potential ◽  
Retention Curve

Soil matric potential is an important parameter for agricultural and environmental research and applications. In this study, we developed a novel sensor to determine fast and in-situ the soil matric potential. The probe of the soil matric potential sensor comprises a perforated coaxial stainless steel cylinder filled with a porous material (gypsum). With a pre-determined gypsum water retention curve, the probe can determine the gypsum matric potential through measuring its water content. The matric potential of soil surrounding the probe is inferred by the reading of the sensor after the soil reaches a hydraulic equilibrium with the gypsum. The sensor was calibrated by determining the gypsum water retention curve using a pressure plate method and tested in three soil samples with different textures. The results showed that the novel sensor can determine the water retention curves of the three soil samples from saturated to dry when combined with a soil water content sensor. The novel sensor can respond fast to the changes of the soil matric potential due to its small volume. Future research could explore the application for agriculture field crop irrigation.

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