Information about soil hydraulic properties and changes in them brought about by agricultural practices is essential in the development and use of models of catchment hydrology. The objectives of this study were to examine the extent to which different tillage practices affect the magnitude and variability of the hydraulic properties of a clay loam and to evaluate the effectiveness of a laboratory inverse method employed for characterizing the soil from the hydraulic point of view. The field work was conducted at an experimental farm located in the Agri River basin (Italy), selected as a target area for application of recently developed distributed models at basin scale. Undisturbed vertical soil samples (cores) were collected from the top layer of no-till and conventional-till field plots. The laboratory inverse method simultaneously determined relationships of water retention, ??(h), and hydraulic conductivity, k(??), from an evaporation experiment using a parameter estimation technique. This method was developed with the aim of reducing experimental efforts without significantly lowering accuracy in parameter estimates. A Crank-Nicolson type finite-difference solution of Richards' equation was coupled with a non-linear optimization problem to estimate unknown parameters in the closed-form analytical relations employed in this study for describing soil hydraulic properties. Comparisons with laboratory-measured saturated hydraulic conductivity and soil water retention data obtained for a group of soil cores by a sand-kaolin box apparatus demonstrate the applicability and accuracy of the proposed inverse method. Overall, the results of hydraulic-property characterization for the soil at the experimental farm reveal no significant differences among tillage treatments. In addition, as a general rule, a progressive annulment of tillage effects on structure and hydraulic properties of soil is observed with time.
Evaluation of a laboratory inverse method for determining unsaturated hydraulic properties of a soil under different tillage practices / Santini, Alessandro; Romano, Nunzio; Ciollaro, G.; Comegna, V.. - In: SOIL SCIENCE. - ISSN 0038-075X. - 150:5(1995), pp. 340-351. [10.1097/00010694-199511000-00003]
Evaluation of a laboratory inverse method for determining unsaturated hydraulic properties of a soil under different tillage practices.
SANTINI, ALESSANDRO;ROMANO, NUNZIO;
1995
Abstract
Information about soil hydraulic properties and changes in them brought about by agricultural practices is essential in the development and use of models of catchment hydrology. The objectives of this study were to examine the extent to which different tillage practices affect the magnitude and variability of the hydraulic properties of a clay loam and to evaluate the effectiveness of a laboratory inverse method employed for characterizing the soil from the hydraulic point of view. The field work was conducted at an experimental farm located in the Agri River basin (Italy), selected as a target area for application of recently developed distributed models at basin scale. Undisturbed vertical soil samples (cores) were collected from the top layer of no-till and conventional-till field plots. The laboratory inverse method simultaneously determined relationships of water retention, ??(h), and hydraulic conductivity, k(??), from an evaporation experiment using a parameter estimation technique. This method was developed with the aim of reducing experimental efforts without significantly lowering accuracy in parameter estimates. A Crank-Nicolson type finite-difference solution of Richards' equation was coupled with a non-linear optimization problem to estimate unknown parameters in the closed-form analytical relations employed in this study for describing soil hydraulic properties. Comparisons with laboratory-measured saturated hydraulic conductivity and soil water retention data obtained for a group of soil cores by a sand-kaolin box apparatus demonstrate the applicability and accuracy of the proposed inverse method. Overall, the results of hydraulic-property characterization for the soil at the experimental farm reveal no significant differences among tillage treatments. In addition, as a general rule, a progressive annulment of tillage effects on structure and hydraulic properties of soil is observed with time.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
