scholarly journals Soil Water Studies in Oxisols and Ultisols of Puerto Rico: I. Water Movement

1969 ◽  
Vol 60 ◽  
pp. 375-385
Author(s):  
James M. Wolf ◽  
Matthew Drosdoff
Keyword(s):  
Soil Water ◽  
Water Movement ◽  
Soil Aggregates ◽  
Flow Characteristics ◽  
Field Capacity ◽  
Water Infiltration ◽  
Clay Soils ◽  
Water Release ◽  
Soil Water Tension ◽  
Free Drainage

Soil water experiments were conducted to determine the water supplying characteristics of two clayey Ultisols, a clayey Oxisol, and a sandy Oxisol. Water infiltration into all soils was very rapid, reaching 9 cm/hr after 1 hr of continuous flooding. The strong structural stability of the clay soils permitted infiltration rates in excess of that for the sandy soil. Lateral water movement, downslope, was a significant factor in observed high rates of water infiltration and may partially account for downslope movement of nitrates. Values of soil water tension after 2 to 3 days of free drainage did not exceed 20 to 80 cm of water (roughly 1/50 to 1/12 bar). Field capacity was established to be 1/15 bar for the sandy Oxisol and 1/20 bar for the clayey Oxisol and Ultisols. Two avenues of soil water movement were postulated: Capillary pores (between soil particles) and non-capillary pores (between soil aggregates). Because of water movement in non-capillary pores, flow characteristics of the clay soils resembled that of the sand. In terms of soil water release characteristics, the clays and the sand were similar.

scholarly journals Factors Determining Soil Water Repellency in Two Coniferous Plantations on a Hillslope

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 730 ◽  
Author(s):  
Moein Farahnak ◽  
Keiji Mitsuyasu ◽  
Kyoichi Otsuki ◽  
Kuniyoshi Shimizu ◽  
Atsushi Kume
Keyword(s):  
Soil Water ◽  
Overland Flow ◽  
Soil Aggregates ◽  
Aggregate Size ◽  
Water Repellency ◽  
Soil Aggregate ◽  
Water Infiltration ◽  
Soil Water Repellency ◽  
Tree Cutting ◽  
Coniferous Plantations

Soil water repellency (SWR) is a cause of low water infiltration, overland flow and soil erosion in mountainous coniferous plantations in Japan. The factors determining SWR intensity were investigated in two coniferous plantations of Chamaecyparis obtusa (Siebold et Zucc.) Endl. and Cryptomeria japonica (L.f.) D. Don, using intact tree plots and cut tree plots on the same hillslope. The SWR of Ch. obtusa plots was stronger than that of Cr. japonica plots. SWR intensity decreased after tree cutting. There were no significant differences in SWR upslope and downslope of individual trees/stumps for both tree species, though areas downslope of individual Ch. obtusa trees had higher SWR intensity than those upslope. SWR intensity and soil aggregate stability were positively correlated in the Ch. obtusa intact tree plot (r = 0.88, p < 0.01), whereas in the cut tree plot, this correlation was weak with no significance (r = 0.29, p = 0.41). Soil aggregate size had a non-significant influence on SWR intensity. These findings suggest that SWR intensity was not related to the soil aggregate size, but SWR intensity seemed have a role in soil aggregation in the Ch. obtusa intact tree plot. Destruction of soil aggregates could occur after tree cutting because of physical disturbances or increased input of different types of organic matter from other vegetation into soil. The presence of Ch. obtusa introduces a source of SWR, although uncertainty remains about how water repellency is distributed around soil aggregates. The distribution pattern of soil water content and soil hydraulic conductivity around Cr. japonica was related to other factors such as the litter layer and non-water-repellant soil.

scholarly journals Numerical Study of Macropore Impact on Ponded Infiltration in Clay Soils

2013 ◽  
Vol 1 (No. 1) ◽  
pp. 16-22
Author(s):  
Kodešova Radka ◽  
Šimůnek Josef Kozak and Jiři
Keyword(s):  
Numerical Simulations ◽  
Preferential Flow ◽  
Water Movement ◽  
Numerical Study ◽  
Water Infiltration ◽  
Clay Soils ◽  
Saturated Water ◽  
Water Recharge ◽  
Considerable Impact ◽  
Hydrus 1D

The single-porosity and dual-permeability models in HYDRUS-1D (&Scaron;imůnek et al. 1998, 2003) were used to simulate variably-saturated water movement in clay soils with and without macropores. Numerical simulations of water flow for several scenarios of probable macropore compositions show a considerable impact of preferential flow on water infiltration in such soils. Preferential flow must be considered to predict water recharge in clay soils.

Effect of combined soil water and external load on soil compaction

Soil Research ◽  
2011 ◽  
Vol 49 (2) ◽  
pp. 135 ◽  
Author(s):  
M. A. Hamza ◽  
S. S. Al-Adawi ◽  
K. A. Al-Hinai
Keyword(s):  
Bulk Density ◽  
Soil Water ◽  
Soil Compaction ◽  
External Load ◽  
Field Capacity ◽  
Infiltration Rate ◽  
Soil Bulk Density ◽  
Soil Strength ◽  
Water Infiltration ◽  
Soil Water Infiltration

Reducing soil compaction is now an important issue in agriculture due to intensive use of farm machinery in different farm operations. This experiment was designed to study the influence of combinations of external load and soil water on soil compaction. Four soil water levels were combined with four external loads as follows: soil water—air-dry, 50% of field capacity, field capacity, and saturation; external load using different-sized tractors—no load (0 kg), small tractor (2638 kg), medium tractor (3912 kg), and large tractor (6964 kg). Soil bulk density, soil strength, and soil water infiltration rate were measured at 0–100, 100–200, and 200–300 mm soil depths. The 16 treatments were set up in a randomised block design with three replications. Combined increases in soil water and external load increased soil compaction, as indicated by increasing soil bulk density and soil strength and decreasing soil water infiltration rate. There was no significant interaction between soil water and external load for bulk density at all soil depths, but the interaction was significant for soil strength and infiltration rates at all soil depths. The ratio between the weight of the external load and the surface area of contact between the external load and the ground was important in determining the degree of surface soil compaction. Least compaction was produced by the medium tractor because it had the highest tyre/ground surface area contact. In general, the effects of soil water and external load on increasing soil bulk density and soil strength were greater in the topsoil than the subsoil.

scholarly journals Modeling Soil Water Redistribution under Gravity Irrigation with the Richards Equation

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1581 ◽  
Author(s):  
Sebastián Fuentes ◽  
Josué Trejo-Alonso ◽  
Antonio Quevedo ◽  
Carlos Fuentes ◽  
Carlos Chávez
Keyword(s):  
Finite Difference ◽  
Numerical Solution ◽  
Soil Water ◽  
Water Movement ◽  
Soil Mechanics ◽  
Water Infiltration ◽  
Richards Equation ◽  
Water Redistribution ◽  
Irrigation Drainage ◽  
Transfer Problems

Soil water movement is important in fields such as soil mechanics, irrigation, drainage, hydrology, and agriculture. The Richards equation describes the flow of water in an unsaturated porous medium, and analytical solutions exist only for simplified cases. However, numerous practical situations require a numerical solution (1D, 2D, or 3D) depending on the complexity of the studied problem. In this paper, numerical solution of the equation describing water infiltration into soil using the finite difference method is studied. The finite difference solution is made via iterative schemes of local balance, including explicit, implicit, and intermediate methods; as a special case, the Laasonen method is shown. The found solution is applied to water transfer problems during and after gravity irrigation to observe phenomena of infiltration, evaporation, transpiration, and percolation.

scholarly journals Using Soil Water Stable Isotopes to Investigate Soil Water Movement in a Water Conservation Forest in Hani Terrace

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3520
Author(s):  
Huimei Pu ◽  
Weifeng Song ◽  
Jinkui Wu
Keyword(s):  
Stable Isotopes ◽  
Soil Water ◽  
Water Conservation ◽  
Rainy Season ◽  
Preferential Flow ◽  
Water Movement ◽  
Soil Depth ◽  
Dry Season ◽  
Water Infiltration ◽  
Soil Water Movement

Water conservation forests significantly contribute to the stability of mountain agricultural ecosystems in Hani Terrace. In this study, we analyzed the relationship between the stable isotopic composition of soil water and precipitation to determine the mechanisms of soil water movement in the small watershed of Quanfuzhuang. We observed significant seasonal variations in soil water sources: antecedent precipitation was the dominant supply during the dry season, and current precipitation dominated during the rainy season. The recharge ratio of precipitation to soil water in the grassland was significantly higher than that in the arbor land and shrubland. The influence of water infiltration, old and new soil water mixing, and soil evaporation on the soil water stable isotopes gradually decreased from the surface (0–20 cm) to the deep (60–80 cm) soil. We observed significant seasonal variability in average soil water δ18O in the upper 0–60 cm and lower variability at 60–100 cm. The average soil water δ18O was generally higher in the dry season than in the rainy season. The mixing of old and new water is a continuous and cumulative process that is impacted by soil structure, soil texture, and precipitation events. We therefore identified a significant time delay in soil water supply with increasing soil depth. Moreover, the piston flow of soil water co-occurred with preferential flow, and the latter was the dominant supply during the rainy season.

scholarly journals Experimental and Numerical Investigations of Influence on Overland Flow and Water Infiltration by Fracture Networks in Soil

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Lei Zhu ◽  
Dongjun Fan ◽  
Rong Ma ◽  
Yonggen Zhang ◽  
Yuanyuan Zha
Keyword(s):  
Soil Water ◽  
Water Flow ◽  
Surface Runoff ◽  
Preferential Flow ◽  
Water Movement ◽  
Water Infiltration ◽  
Two Dimensional ◽  
Soil Matrix ◽  
Soil Water Infiltration ◽  
Soil Water Movement

Preferential flow is common in clay or expansive clay soils, involving water bypassing a large portion of the soil matrix. Dye tracer experiment and numerical modeling are used to simulate the surface runoff and subsurface preferential flow patterns influenced by the soil fracture network of a relatively steep hillslope system (slope angle equals to 10 degrees). The result of the experiments indicates that part of the water is infiltrated through cracks, leading to the delay of the initial runoff-yielding time and reduction of the discharge of the surface runoff. The soil water flow is mainly in the matrix when the intensity of precipitation is low. With the increasing of precipitation, soil water movement may become in the form of preferential flow through cracks. In addition, the nonuniformity of soil water infiltration and the depth of the average water infiltration increase as the precipitation intensity increases. To this end, the complete coupling model was established by using the surface-matrix-crack (SMC) model to simulate water flow within discrete fracture as well as to simulate water flow in the soil matrix based on the concept of dual permeability using the traditional Richards’ equation. In this model, the “cubic law” of fluid motion in cracks within smooth parallel plates and the two-dimensional diffusion wave approximation to Saint-Venant equations with momentum term ignored (two-dimensional shallow water equations) were used. The model divides soil water infiltration into two forms and uses the overall method to calculate the exchange of water between the crack networks and matrix regions as well as the exchange water between surface runoff and infiltration water. Results indicate that the SMC model has better performance compared with the traditional equivalent continuum model when those models are used to simulate the surface runoff movement and the soil water movement in the presence of cracks.

Structural decline of soils, assessment and prevention

Soil Research ◽  
1991 ◽  
Vol 29 (6) ◽  
pp. 905 ◽  
Author(s):  
WW Emerson
Keyword(s):  
Structural Damage ◽  
Soil Aggregates ◽  
Total Porosity ◽  
Field Capacity ◽  
The Other ◽  
Clay Soils ◽  
Particle Bonding ◽  
Remoulded Soil ◽  
Cracking Clays

Two extreme textural types of cultivated surface soils are mainly considered here, non-shrinking red-brown earths and highly shrinking cracking clays. Total porosity is used to assess the structural status of the former. Values are compared with the highest and lowest values found in the field. For the latter, the criterion used is the porosity of dry aggregates or clods. Values here are taken from the literature. To find out why inter-particle bonding in soil aggregates is insufficient to stop structural decline, a scheme has been developed which includes a modified version of Emerson's (1967) classification of soil aggregates. Slaking is carefully assessed. The bulk density of a cube made from soil at 'field capacity' is measured as well as testing another for dispersion. Class 3 is now divided into 3a and 3b, according to the degree of dispersion of remoulded soil in water. Also apart from soils which disperse spontaneously from dry, classes 1 and 2, the dispersion of all soils is assessed after remoulding at 'field capacity'. It has been found that the red-brown earth site which had the best visual structure also had the largest total porosity and aggregates in class 4. At the worst site, aggregates were in class 3a and the porosity had been reduced to that of the soil cube. For cracking clays, porosity is appreciably higher where the aggregates are in class 4 rather than class 3a. Water content/dispersion curves are presented for the clays showing the extent of the increase in OD apparently associated with the presence of carbonate. Dispersion of sheared, class 3a soil immersed in water is only an outward sign of the structural damage caused when the soil is sheared too wet. If the soil is dried instead, porosity is still lost. Mechanisms are suggested by which the structure of class 3a clay soils are improved by adding carbonate. The slumping of red-brown earths and the use of surface dressings of gypsum to prevent severe dispersion after cultivation wet are discussed. The structural stability of aggregates in the other five classes is briefly considered. Classes 1 and 2 require an ameliorant to be added, the rest pose few problems.

Evapotranspiration and simulation of soil water movement in small area vegetation

2013 ◽  
Vol 27 (4) ◽  
pp. 445-453 ◽  
Author(s):  
C. Paraskevas ◽  
P. Georgiou ◽  
A. Ilias ◽  
A. Panoras ◽  
C. Babajimopoulos
Keyword(s):  
Soil Water ◽  
Water Movement ◽  
Crop Coefficient ◽  
Water Dynamics ◽  
Small Areas ◽  
Close Proximity ◽  
Free Drainage ◽  
Crop Coefficients ◽  
Bare Soils ◽  
Oasis Effect

Abstract In Greece, crops are frequently cultivated in small isolated areas in close proximity to roads and bare soils and therefore evapotranspiration is affected by local advection. Under these circumstances, oasis effect conditions are present and evapotranspiration is higher than what is expected. In this paper, the evapotranspiration and soil water dynamics of a cotton crop cultivated in small areas under the oasis effect is studied. To this end, two isolated free-drainage lysimeters cultivated with cotton in the year 2007 were used. Soil moisture of the soil profile of both the lysimeters was monitored with two capacitance water content probes. The soil water balance method was used to estimate crop evapotranspiration and corresponding crop coefficients in one of the two lysimeters. These coefficients were 75% larger than the FAO-56 crop coefficients at the mid-season stage. The FAO-56 and the derived crop coefficients were used for the simulation of the water dynamics in the second lysimeter by the SWBACROS model. The derived crop coefficients for these conditions produced much better results than the FAO-56 crop coefficients. The results were improved when crop coefficient value equal to 2.5 was used for the mid-season stage.

scholarly journals GERENCIAMENTO DA IRRIGAÇÃO DO FEIJOEIRO BASEADO EM CRITÉRIOS TÉCNICOS E ECONÔMICOS NO CERRADO

Irriga ◽  
2008 ◽  
Vol 13 (3) ◽  
pp. 378-391 ◽  
Author(s):  
Sebastião Francisco Figuerêdo ◽  
Eder João Pozzebon ◽  
José Antonio Frizzone ◽  
Juscelino Antonio de Azevedo ◽  
Antônio Fernando Guerra ◽  
...  
Keyword(s):  
Soil Water ◽  
Field Experiments ◽  
Soil Depth ◽  
Irrigation Management ◽  
Maximum Yield ◽  
Field Capacity ◽  
Irrigated Agriculture ◽  
Economic Return ◽  
Soil Water Tension ◽  
Water Tension

Gerenciamento da irrigação do feijoeiro baseado em critérios técnicos e econômicos no Cerrado  Sebastião Francisco Figuerêdo1; Eder João Pozzebon2; José Antonio Frizzone3; Juscelino Antonio de Azevedo1; Antônio Fernando Guerra1;Euzébio Medrado da Silva11Embrapa Cerrados, Brasília, DF,  [email protected]ência Nacional de Águas (ANA), Brasília, DF3Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP  1 Resumo O conhecimento sobre o manejo da irrigação sob condições de escassez de água é essencial para o aperfeiçoamento da agricultura irrigada. Nesse sentido, este trabalho foi realizado objetivando definir níveis de tensão de água no solo, mais adequados para o início das irrigações do feijoeiro no Cerrado, baseado em critérios técnicos e econômicos. Foram conduzidos experimentos na Embrapa Cerrados-DF, durante três anos, em blocos ao acaso, testando, como tratamentos, as seguintes tensões: 33kPa, 50kPa, 70kPa, 100kPa, 500kPa e 1000kPa, na profundidade de 10cm. As irrigações foram aplicadas até a capacidade de campo, na camada de 0-40cm. No intervalo37 a967kPa, o rendimento de grãos reduziu-se, em forma logarítmica, com o aumento da tensão e, quadrática, com as lâminas totais. Os maiores rendimentos foram obtidos quando a irrigação era feita na tensão de água em torno de 37kPa. Entretanto, ao se considerar uma situação média estudada de custo da água e de preço do feijão, o nível de tensão mais adequado, para maior lucratividade, passou para 61kPa. As análises mostraram que baixos custos da água e altos preços do feijão levam aos pontos de máximo rendimento de grãos e de lucratividade a se aproximarem. Numa situação contrária, esses pontos se distanciam, resultando em economia de água.   UNITERMOS: Tensão da água no solo, análise econômica, manejo da irrigação, otimização da irrigação.  Figuerêdo, S. F.; Pozzebon, E.J.; Frizzone, J. A. ;  Azevedo, J. A. de; Guerra, A.F.;   Silva, E. M. da.  MANAGEMENT OF DRYBEAN IRRIGATION BASED ON TECHNICAL AND ECONOMICAL CRITERIA IN CERRADO  2 abstract The knowledge on irrigation management under deficit conditions is essential to improve irrigated agriculture. Thus, this work was developed in order to define the most adequate soil-water tensions to begin irrigating drybean crop in Cerrado, based on technical and economical criteria. Field experiments were conducted in Embrapa/Cerrados-DF,Brazil, during three years in a randomized block scheme using as treatments the following soil-water tensions: 33kPa, 50kPa, 100kPa, 500kPa and 1000kPa, ate a 10-cm depth. The irrigations were applied until field capacity filled the 40-cm soil depth. In the interval from 37 to 96kPa, grain yield decreased logarithmically with the increase of soil-water tension and, quadratically with total applied water. The highest yields were obtained when the irrigations were conducted with soil-water tension around 37kPa. However, after considering the water irrigation costs and the grain dry bean price, the best soil-water tension for getting larger economic return was 61kPa.The analysis showed that the combination of low irrigation costs and high grain drybean prices makes the breakeven points of total water applied for maximum yield and maximum economic return to similar. In an opposite situation, those costs are very different, resulting in larger water economy. Key words: Soil-water tension, economical analysis, irrigation management, optimizing irrigation.

scholarly journals Soil Water Studies in Oxisols and Ultisols of Puerto Rico: II. Moisture Retention and Availability

1969 ◽  
Vol 60 ◽  
pp. 386-394
Author(s):  
James M. Wolf ◽  
Matthew Drosdoff
Keyword(s):  
Puerto Rico ◽  
Soil Water ◽  
Sandy Soil ◽  
Soil Profile ◽  
Field Capacity ◽  
The Other ◽  
Clayey Soils ◽  
Moisture Retention ◽  
Water Release ◽  
Available Water

The two Oxisols studied, one very sandy (Bayamón) and the other high in clay (Catalina), tended to dewater at low tensions, whereas soil water release in the Ultisols extended over a wider range of tensions. The sandy soil failed to release appreciable water above 1 bar of tension. Field capacity was established at 1/15 bar for the sandy soil and 1/20 bar for the clayey soils. The available water stored in the top 30 cm of the soil profile was determined to be 3.6, 5.0, 5.5, and 6.0 cm for Bayamón, Humatas, Torres, and Catalina, respectively. For Bayamón and Catalina, the two Oxisols, the bulk of the water was released between field capacity and 1 bar. In contrast to the Oxisols, a high proportion of the water in the Ultisols, Humatas and Torres, was available only at tensions above 1 bar. The Catalina soil was by far the best in terms of water supplying characteristics, while Humatas and Bayamón were the worst.

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