scholarly journals Analiza fizikalnih lastnosti šotnega substrata

2020 ◽  
Vol 116 (2) ◽  
pp. 357
Author(s):  
Tilen ZAMLJEN ◽  
Ana SLATNAR ◽  
Vesna ZUPANC
Keyword(s):  
Water Content ◽  
Water Retention ◽  
Ornamental Plants ◽  
Field Capacity ◽  
Water Repellency ◽  
Plant Production ◽  
Water Losses ◽  
Fast Change ◽  
Water Retention Properties ◽  
Wilting Point

<p>Peat substrate is the main substrate for plant production, mainly for the cultivation of vegetable seedlings and ornamental plants. Peat has good water retention properties, low mass, low pH and is free from diseases and pests. The water retention properties are particularly important for optimizing irrigation and thus water consumption in plant production. We investigated the water retention properties of unused and used peat substrate and various mixtures with additives, as well as the occurrence of water repellency, as this influences water absorption into the substrate. Unused peat substrate and different mixtures retained between 3.4 % and 18.4 % more water than the used substrate. The daily water losses are lower for the used substrates that initially contain lower water content at full saturation. At tensions between 10 and 33 kPa, the unused peat substrate contained between 25 % and 32 % water. The wilting point (WP) for unused peat substrate (tension between 300 and 1500 kPa) was between 15 and 18 %. Peat substrate has a wide interval of field capacity and the transition from the field capacity to wilting point is fast (change in water content between 7 % and 10 %). After drying, the water repellency of both unused and used peat substrates increased.</p>

scholarly journals The use of in situ volumetric water content at field capacity to improve the prediction of soil water retention properties

2008 ◽  
Vol 88 (4) ◽  
pp. 533-541 ◽  
Author(s):  
Hassan Al Majou ◽  
Ary Bruand ◽  
Odile Duval
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Water Content ◽  
Bulk Density ◽  
Water Retention ◽  
Field Capacity ◽  
Volumetric Water Content ◽  
Organic Carbon Content ◽  
Water Retention Properties

Most pedotransfer functions (PTF) developed over the past three decades to generate water retention characteristics use soil texture, bulk density and organic carbon content as predictors. Despite the high number of PTFs published, most being class- or continuous-PTFs, the accuracy of prediction remains limited. In this study, we compared the performance of different class- and continuous-PTFs developed with a regional database. Results showed that the use of in situ volumetric water content at field capacity as a predictor led to much better estimation of water retention properties compared with using predictors derived from the texture, or the organic carbon content and bulk density. This was true regardless of the complexity of the PTFs developed. Results also showed that the best prediction quality was achieved by using the in situ volumetric water content at field capacity after stratification by texture. Comparison of in situ volumetric water content at field capacity, with the water retained at different matric potentials as measured in the laboratory, showed field capacity to approximate 100 hPa, whatever the soil texture. Finally, the lack accuracy of PTFs that do not use the in situ volumetric water content at field capacity as predictor did not appear due to the test soils being unrepresentative of the soils used to develop the PTFs, but were instead related to poor correlations between the predictors used and the water retention properties. Key words: Pedotransfer functions, root mean square error, mean error of prediction, standard deviation of prediction, texture, bulk density, organic carbon content

scholarly journals The water retention properties of biochar derived from broiler poultry litter as applied to the Botswana soil

2020 ◽  
Vol 1 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Thapelo Shomana ◽  
Daniel Botha ◽  
Paul Şerban Agachi
Keyword(s):  
Water Loss ◽  
Water Retention ◽  
Arable Land ◽  
Poultry Litter ◽  
Field Capacity ◽  
Exchange Capacity ◽  
Convincing Evidence ◽  
Similar Response ◽  
Zero Hunger ◽  
Water Retention Properties

Crop farming in Botswana is very modest and of high risk compared to its neighboring countries because of significant dependency on reduced and unreliable rainfall and as a result of soils with poor water holding capacity and low cation exchange capacity. For this reason, only about two thirds of the available arable land are planted and of the planted land only about half is harvested, which translates into only one third of productive arable land. This study examines how addition of poultry litter (PL) biochar affects water retention properties of Botswana’s sandy soils. While many variables should be studied to fully comprehend this aspect, this paper exploits in detail, effects of biochar addition in reducing rate of water loss by evaporation. This work provides convincing evidence that addition of PL-derived biochar (as little as 10%) can significantly reduce water loss by evaporation, thus increasing water soil retention. It is demonstrated that water retention properties increase with increasing rate of biochar application. Two types PL-derived biochar were studied: (i) one with sunflower husks bedding and another (ii) with woodchips bedding. Though both biochars showed similar response to the test, the biochar with sunflower husks was slightly superior. Biochar also indicated significant hygroscopicity, when dried and left exposed to the atmosphere, as moisture content increased with increasing humidity. Based on initial indicators, further study should be done at laboratory and field scale to determine optimum conditions of biochar application in the quest to improve food security for Botswana, as well as improve employment and environmental goals of the country. A comprehensive further study should critically examine Field Capacity, Permanent Wilting Point, and Plant Available Water. As an ultimate goal, enhancing soil moisture retention properties of Botswana’s sandy soil enables to increase success rate in the traditional farming sector and, consequently, offers potential to accomplish “No Poverty” and “Zero Hunger” sustainable development goals.

Properties and Management of Allophanic Soils

2003 ◽  
Author(s):  
Anthony S. R. Juo ◽  
Kathrin Franzluebbers
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Water Retention ◽  
Field Capacity ◽  
High Water ◽  
Soil Porosity ◽  
Water Retention Capacity ◽  
Soil Taxonomy ◽  
Retention Capacity ◽  
High Soil

Allophanic soils are dark-colored young soils derived mainly from volcanic ash. These soils typically have a low bulk density (< 0.9 Mg/m3), a high water retention capacity (100% by weight at field capacity), and contain predominantly allophanes, imogolite, halloysite, and amorphous Al silicates in the clay fraction. These soils are found in small, restricted areas with volcanic activity. Worldwide, there are about 120 million ha of allophanic soils, which is about 1% of the Earth's ice-free land surface. In tropical regions, allophanic soils are among the most productive and intensively used agricultural soils. They occur in the Philippines, Indonesia, Papua New Guinea, the Caribbean and South Pacific islands, East Africa, Central America, and the Andean rim of South America. Allophanic soils are primarily Andisols and andic Inceptisols, Entisols, Mollisols, and Alfisols according to the Soil Taxonomy classification. Allophanic soils generally have a dark-colored surface soil, slippery or greasy consistency, a predominantly crumb and granular structure, and a low bulk density ranging from 0.3 to 0.8 Mg/m3. Although allophanic soils are apparently well-drained, they still have a very high water content many days after rain. When the soil is pressed between fingers, it gives a plastic, greasy, but non-sticky sensation of a silty or loamy texture. When dry, the soil loses its greasiness and becomes friable and powdery. The low bulk density of allophanic soils is closely related to the high soil porosity. For example, moderately weathered allophanic soils typically have a total porosity of 78%, with macro-, meso-, and micropores occupying 13%, 33%, and 32%, respectively. Water retained in the mesopores is readily available for plant uptake. Water retained in the micropores is held strongly by soil particles and is not readily available for plant use. The macropores provide soil aeration and facilitate water infiltration. The high water retention capacity is also associated with the high soil porosity. In allophanic soils formed under a humid climate, especially those containing large amounts of allophane, the moisture content at field capacity can be as high as 300%, calculated on a weight basis. Such extremely high values of water content seem misleading.

Predicting hydraulic properties of seasonally impounded soils

2009 ◽  
Vol 148 (2) ◽  
pp. 159-170 ◽  
Author(s):  
N. G. PATIL ◽  
G. S. RAJPUT ◽  
R. K. NEMA ◽  
R. B. SINGH
Keyword(s):  
Hydraulic Properties ◽  
Water Retention ◽  
Monsoon Season ◽  
Field Capacity ◽  
Pedotransfer Functions ◽  
Agricultural Crop ◽  
Statistical Regression ◽  
Soil Water Retention ◽  
Retention Characteristics ◽  
Wilting Point

SUMMARYAgricultural crop management decisions often require data on hydraulic properties of soils. Little information is available on hydraulic properties of clay soils that are impounded by rainwater (known as ‘Haveli’ lands) every year during the monsoon season in large tracts of Madhya Pradesh in India. Estimating hydraulic properties using global pedotransfer functions (PTFs) is one possible way to collect such information. Rules in the widely used global PTF Rosetta were executed to obtain estimates of two important hydraulic properties, namely soil water retention characteristics (SWRC) and saturated hydraulic conductivity (Ks). SWRC estimates obtained with maximum input (particle size distribution, bulk density, field capacity and permanent wilting point) in Rosetta were relatively closer to the laboratory-measured data as compared with the estimates obtained with lower levels of input. Root mean square error (RMSE) of estimates ranged from 0·01 to 0·05 m3/m3. Hierarchical PTFs to predictKsfrom basic soil properties were derived using statistical regression and artificial neural networks. Evaluation of these indicated that neural PTFs were acceptable and hence could be used without loss of accuracy.

scholarly journals Hydropedological parameters limiting soil moisture regime floodplain ecosystems of south Moravia

2005 ◽  
Vol 53 (1) ◽  
pp. 71-84
Author(s):  
Ladislav Kubík
Keyword(s):  
Soil Moisture ◽  
Water Retention ◽  
Humus Content ◽  
Field Capacity ◽  
Pedotransfer Functions ◽  
Physical Parameters ◽  
Moisture Regime ◽  
Floodplain Ecosystems ◽  
Soil Moisture Regime ◽  
Wilting Point

Soil moisture regime of floodplain ecosystems in southern Moravia is considerably influenced and greatly changed by human activities. It can be changed negatively by water management engineering or positively by landscape revitalizations. The paper deals with problems of hydropedological characteristics (hydrolimits) limiting soil moisture regime and solves effect of hydrological factors on soil moisture regime in the floodplain ecosystems. Attention is paid especially to water retention curves and to hydrolimits – wilting point and field capacity. They can be acquired either directly by slow laboratory assessment, derivation from the water retention curves or indirectly by calculation using pedotransfer functions (PTF). This indirect assessment uses hydrolimit dependency on better available soil physical parameters namely soil granularity, bulk density and humus content. The aim is to calculate PTF for wilting point and field capacity and to compare them with measured values. The paper documents suitableness utilization of PTF for the region of interest. The results of correlation and regression analysis for soil moisture and groundwater table are furthermore presented.

EFFECT OF SOIL WATER CONTENT ON THE WINTER SURVIVAL OF WINTER WHEAT, RYE AND TRITICALE

1990 ◽  
Vol 70 (3) ◽  
pp. 667-675 ◽  
Author(s):  
YVES CLOUTIER ◽  
ANDRÉ COMEAU ◽  
MICHÈLE BERNIER-CARDOU ◽  
DENIS A. ANGERS
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Winter Wheat ◽  
Soil Temperature ◽  
Water Content ◽  
Field Capacity ◽  
Winter Rye ◽  
Winter Cereal ◽  
Ice Encasement ◽  
Wilting Point

A field study was conducted to determine the effect of soil moisture on the survival of three winter cereal species. Treatments were applied by watering and weighing the soil to the desired water content. Plants were overwintered in a plastic greenhouse in 1988 and in 1989, in which the air was not heated, but the soil was slightly heated on cold days to avoid very low temperatures. Soil temperature did not fall below −16 °C. Soil temperature rate of change was dependent on moisture content. Puma winter rye and Otrastajuskaja 38 winter wheat were the hardiest, followed by Wintri winter triticale and Norstar winter wheat. Harus winter wheat was less hardy, and Champlein winter wheat was totally winter killed. The highest survival rate was obtained at moderate to high soil moisture content. The soil contained 44% water at field capacity and 19% at the wilting point. The drier the soil in the range 13–23%, the greater the mortality indicating a negative effect of long-term drought on plant survival. By contrast, the wettest treatments: 58% and partial ice encasement, did not reduce survival. However, total ice encasement killed 50–75% of the plants depending on the cultivar. There was an interaction between cultivar and moisture treatment. The data suggest that a moisture level intermediate between the wilting point and field capacity should be sought in studies of cold hardiness.Key words: Moisture, winterkill, ice encasement, wheat, rye, triticale

scholarly journals MODELOS DE CURVA DE RETENÇÃO DE ÁGUA NO SOLO

Irriga ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 115 ◽  
Author(s):  
Roberto Filgueiras ◽  
Vinicius Mendes Rodrigues de Oliveira ◽  
Fernando França da Cunha ◽  
Everardo Chartuni Mantovani ◽  
Epitácio Jose de Souza
Keyword(s):  
Potential Field ◽  
Water Retention ◽  
Field Capacity ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Retention Curve ◽  
Permanent Wilting Point ◽  
Van Genuchten Model ◽  
Wilting Point

MODELOS DE CURVA DE RETENÇÃO DE ÁGUA NO SOLO  ROBERTO FILGUEIRAS¹; VINICIUS MENDES RODRIGUES DE OLIVEIRA²; FERNANDO FRANÇA DA CUNHA³; EVERARDO CHARTUNI MANTOVANI³ E EPITÁCIO JOSE DE SOUZA4 1 Doutorando em Engenharia Agrícola, Universidade Federal de Viçosa. Viçosa, MG. Email: [email protected]²    Doutorando em Engenharia Agrícola, Universidade Federal de Viçosa. Viçosa, MG³    Prof. Dr. Departamento de Engenharia Agrícola, Universidade Federal de Viçosa. Viçosa, MG4      Doutorando em Agronomia (Ciência do Solo), UNESP. Ilha Solteira, SP.  1 RESUMO  O objetivo deste trabalho foi comparar a umidade na capacidade de campo e ponto de murcha permanente obtida com os modelos de obtenção da curva de retenção de água no solo de van Genuchten e potencial e ainda comparar os valores de capacidade de campo obtidos com a tensão de 6 e 33 kPa. Para isto ajustaram-se os modelos van Genuchten e potencial para as tensões de 10, 30, 50, 100, 500 e 1500 kPa, através da câmara de Richards. Posteriormente, encontrou-se os valores de umidade para as tensões na capacidade de campo (6 e 33 kPa) e ponto de murcha permanente (1500 kPa). Ambos os modelos predisseram a umidade na capacidade de campo a 33 kPa e o ponto de murcha permanente com alta precisão, exatidão e concordância, quando comparado os dois métodos. Palavras-chave: van Genuchten, potencial, capacidade de campo.  FILGUEIRAS R.; DE OLIVEIRA V. M. R.; CUNHA F. F. DA; MANTOVANI E. C.; E. J. DE SOUZA.WATER RETENTION CURVE MODELS IN THE SOIL       2 ABSTRACT The objective of this study was to compare the moisture at field capacity and permanent wilting point obtained by the models and potential for obtaining the soil water retention curve by van Genuchten, also comparing the field capacity values with the tension of 6 and 33 kPa. Thus, it adjusted the van Genuchten model and potential for voltages of 10, 30, 50, 100, 500 and 1500 kPa through Richards chamber, subsequently finding the moisture values for the voltages at field capacity (6 and 33 kPa) and permanent wilting point (1500 kPa). Both models predicted moisture at field capacity at 33 kPa and the permanent wilting point with high precision, accuracy and harmony, when the two methods are compared. Keywords: van Genuchten , potential, field capacity. 

Soil Water Retention in the Semiarid Region of Brazil

2018 ◽  
Vol 10 (9) ◽  
pp. 105
Author(s):  
Antonio Carlos da Silva ◽  
Jeane Cruz Portela ◽  
Rafael Oliveira Batista ◽  
Rutilene Rodrigues da Cunha ◽  
Joaquim Emanuel Fernandes Gondim ◽  
...  
Keyword(s):  
Soil Structure ◽  
Water Retention ◽  
Field Capacity ◽  
Water Retention Curve ◽  
Soil Water Retention ◽  
Retention Curve ◽  
Available Water ◽  
Permanent Wilting Point ◽  
Physical Attributes ◽  
Wilting Point

From the physics point of view, soil structure is a dynamic attribute that is affected by genetic conditions and anthropogenic changes and requires an integrated approach. Soil water retention curve is one of the main tools used in soil structure evaluations. The objective of this work was to evaluate the structural and chemical attributes of soils of different classes and agroecosystems in the Terra de Esperança Settlement (Governador Dix Sept Rosado, Rio Grande do Norte, Brazil) to distinguish these environments. Disturbed and undisturbed soil samples were collected in horizons of 10 soil profiles of the soil classes: Cambissolo Háplico (Haplustepts), Latossolo Vermelho-Amarelo (Eutrustox), Chernossolo Rêndzico (Calciustolls), and Neossolo Flúvico (Usticfluvents). The soil physical attributes evaluated were granulometry, soil density, total porosity, aeration porosity, macroporosity, microporosity, field capacity, permanent wilting point, available water, and water retention curve. The results were expressed in averages of four replicates per horizon (in laboratory) by multivariate analysis, which detected the most sensitive attributes for the distinction of the environments. The soil physical attributes of the different classes and its inorganic fractions, especially silt and clay, were determinant to distinguish the environments; they affected the microporosity; aeration porosity; and available water. The source material of the Chernossolo Rêndzico, which is rich in calcium and magnesium, affected its physical attributes, characterized by the predominance of the silt fraction. Clay was the determinant fraction of the Cambissolo Háplico, and Neossolo Flúvico; and the sand fraction on the surface layer, and clay fraction in the Bw horizon were determinant of the Latossolo Vermelho-Amarelo. The more expressive physical attributes were soil density, sand content, macroporosity (Latossolo Vermelho-Amarelo), microporosity, field capacity, available water, permanent wilting point, total organic carbon, mass-based moisture, volume-based moisture, clay, aeration porosity (Cambissolo Háplico, and Neossolo Flúvico), and silt (Chernossolo Rêndzico).

scholarly journals Application of k-Nearest code to the improvement of class pedotransfer functions and countrywide Field Capacity and Wilting Point maps

2014 ◽  
Vol 9 (No. 1) ◽  
pp. 1-8 ◽  
Author(s):  
M. Miháliková ◽  
S. Matula ◽  
F. Doležal
Keyword(s):  
Czech Republic ◽  
Soil Water ◽  
Water Retention ◽  
Field Capacity ◽  
Pedotransfer Functions ◽  
Land Resource ◽  
Nearest Neighbour ◽  
Soil Water Retention ◽  
The Czech Republic ◽  
Wilting Point

The database of soil hydrophysical properties in the Czech Republic (HYPRESCZ) which contains the data needed for derivation of pedotransfer functions for soil water retention curves was used for the estimation of field capacity and wilting point of agricultural land resource on a countrywide scale. The results were combined with the existing Soil Texture Map of the Czech Republic to create four new maps, namely the Map of Field Capacity and the Map of Wilting Point for the topsoil and subsoil separately. From the total number of 1048 relevant database entries, only about a half included reliable wilting point data. The k-Nearest computer code employing the k-Nearest neighbour technique was used for estimation of the missing wilting points, which made it possible to use all entries. The estimation uncertainty was assessed in terms of standard deviations and the root mean square error. Finally, two sets of class pedotransfer functions were derived and found sufficiently comparable: (i) the functions estimating the soil water retention curve in the whole range, derived solely from the database entries containing the measured wilting points, and (ii) the functions estimating the field capacity and wilting point only, derived from all database entries, including the k-Nearest neighbour estimated data.

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