Applicability of Darcy’s law for predicting irrigation head: what are the limits?

Soil Research ◽  
2013 ◽  
Vol 51 (1) ◽  
pp. 10
Author(s):  
V. K. Phogat ◽  
R. Horn

Modelling soil water movement has increased the demand for accurate measurements of soil physical and hydraulic properties. Data on saturated hydraulic conductivity (K), which was measured by using different hydraulic heads, are presented for artificially packed soil columns and for different soil layers of undisturbed soil cores taken from a long-term experiment on conservation tillage. In the majority of the samples in both artificially packed soil columns and undisturbed soil cores, increasing hydraulic head caused significant deviation (i.e. significant positive correlation coefficient between hydraulic head and the measured values of K) from the conventional criterion for Darcy’s law that flux remains linear with hydraulic gradient. The study, therefore, emphasis the need to define the hydraulic head for measuring K values to be used for studying water movement in soils, to facilitate efficient utilisation of water resources for irrigating field crops in different soils and under different planting systems and irrigation methods.

Agronomie ◽  
2000 ◽  
Vol 20 (3) ◽  
pp. 297-307 ◽  
Author(s):  
Pierre Benoit ◽  
Enrique Barriuso ◽  
Philippe Vidon ◽  
Benoit Réal

2018 ◽  
Vol 50 (1) ◽  
pp. 77-92 ◽  
Author(s):  
Kenneth Miller ◽  
Brenna J. Aegerter ◽  
Nicholas E. Clark ◽  
Michelle Leinfelder-Miles ◽  
Eugene M. Miyao ◽  
...  

Author(s):  
MA Islam ◽  
MA Khan ◽  
MA Rouf

The objectives of this study were to determine the nutrient losses through the soil columns with the variation of soil and fertilizer. The experiment was conducted in a net house of Sher-e-BanglaAgriculturalUniversity, Dhaka, Bangladesh during July–November to study the effect of fertilizer and manure on the growth and yield of T. aman rice and leaching loss of nutrients through undisturbed soil columns. The experiment consists of 2 factors i.e. soils and fertilizer plus manure. Two soils (S1= SAU Soil and S2= Sonargaon Soil) with 4 levels of fertilization, as F0: Control, F1: 100% N120P20K45S20 (FRG 2012), F2: 50% NPKS + 5 t/ha cowdung, F3: 50% NPKS + 2.1 t/ha poultry manure were used in the experiment. T. Aman (BR11) rice was grown in the soil cores. Altogether, there were 8 treatment combinations and the treatment combinations were replicated 3 times. Twenty four undisturbed soil cores collected in PVC pipes were placed at the bottom of the perforated plastic containers and two holes of each plastic container were connected to a conical flask that was used to collect column leachate.  Leachates were collected at 25, 35, 45, 55, 65 and 75 DAT (Days after transplanting) and analyzed for N, P, K and S. The leachate N, P, K and S concentration varied with different soil, fertilizer and time. The higher N and S concentrations were found in the leachate of SAU soil and higher leachate K concentrations were obtained in Sonargaon soil. The higher amounts of N leaching were observed during 45–55 DAT and higher leachate N concentrations were found in F1 treatment. Higher leachate K concentrations were found in 100% chemical fertilizer treatment and higher leachate K concentrations were found at 35DAT in all fertilizer treatments. The leachate P concentration increased at 35 DAT and then decreased. Results revealed that soil had no significant effect on the yield and yield parameters. The yield contributing characters and yields were significantly affected by fertilizer and manure application. The highest effective tillers/core (17.0), plant height (105.6 cm), panicle length (23.70 cm), grain yield (0.046 kg/core) and straw yield (0.053 kg/core) of T. Aman rice were found from F1 (RDCF) treatment. The highest 1000-grain wt. (23.70 g) was obtained from F2 and filled grain/panicle (121.8) from T3 treatment and the lowest in F0 treatment. The highest grain yield was found by the application of recommended dose of chemical fertilizer which was statistically similar to F3 (50% NPKS + 2.1 ton poultry manure) treatment. The combined effects of soil and fertilizer were not significant but the highest grain (0.049 kg/core) and straw yields (0.056 kg/core) were recorded from S2F1 (Sonargaon Soil + 100% NPKS) treatment combination.J. Bangladesh Agril. Univ. 15(2): 199-205, December 2017


1999 ◽  
Vol 63 (6) ◽  
pp. 1530-1543 ◽  
Author(s):  
Johan Perret ◽  
S. O. Prasher ◽  
A. Kantzas ◽  
C. Langford

Soil Research ◽  
2017 ◽  
Vol 55 (7) ◽  
pp. 682 ◽  
Author(s):  
D. Moret-Fernández ◽  
C. Peña-Sancho ◽  
B. Latorre ◽  
Y. Pueyo ◽  
M. V. López

Estimation of the soil–water retention curve, θ(h), on undisturbed soil samples is of paramount importance to characterise the hydraulic behaviour of soils. Although a method of determining parameters of the water retention curve (α, a scale parameter inversely proportional to mean pore diameter and n, a measure of pore size distribution) from saturated hydraulic conductivity (Ks), sorptivity (S) and the β parameter, using S and β calculated from the inverse analysis of upward infiltration (UI) has been satisfactorily applied to sieved soil samples, its applicability to undisturbed soils has not been tested. The aim of the present study was to show that the method can be applied to undisturbed soil cores representing a range of textures and structures. Undisturbed soil cores were collected using stainless steel cylinders (5cm internal diameter×5cm high) from structured soils located in two different places: (1) an agricultural loam soil under conventional, reduced and no tillage systems; and (2) a loam soil under grazed and ungrazed natural shrubland. The α and n values estimated for the different soils using the UI method were compared with those calculated using time domain reflectometry (TDR) pressure cells (PC) for pressure heads of –0.5, –1.5, –3, –5, –10 and –50kPa. To compare the two methods, α values measured with UI were calculated to the drying branch of θ(h). For each treatment, three replicates of UI and PC calculations were performed. The results showed that the 5-cm high cylinders used in all experiments provided accurate estimates of S and β. Overall, the α and n values estimated with UI were larger than those measured with PC. These differences could be attributed, in part, to limitations of the PC method. On average, the n values calculated from the optimised S and β data were 5% larger than those obtained with PC. A relationship with a slope close to 1 fitted the n values estimated using both methods (nPC=0.73 nUI+0.49; R2=0.78, P<0.05). The results show that the UI method is a promising technique to estimate the hydraulic properties of undisturbed soil samples.


Soil Science ◽  
2011 ◽  
Vol 176 (8) ◽  
pp. 399-406 ◽  
Author(s):  
Anders Lindblad Vendelboe ◽  
Per Moldrup ◽  
Goswin Heckrath ◽  
Yan Jin ◽  
Lis Wollesen de Jonge

2012 ◽  
Vol 11 (1) ◽  
Author(s):  
Andreas H. Kristensen ◽  
Chisato Hosoi ◽  
Kaj Henriksen ◽  
Per Loll ◽  
Per Moldrup

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