The contribution of shrinkage cracks to bypass flow during simulated and natural rainfall experiments in northeastern Mexico

Abstract

. 2002. The contribution of shrinkage cracks to bypass flow during simulated and natural rainfall experiments in northeastern Mexico. Can. J. Soil Sci. 82: 65-74. Understanding the spatial and temporal dynamics of desiccation cracks and related hydro-geomorphologic processes is a key component for the sustainable management of water resources in Vertisols. The contribution of shrinkage cracks to infiltration of runoff and sediments was studied during natural and simulated rainfall experiments in Vertisols of the semi-arid plains of northeastern Mexico during the summer of 1998. Surface runoff amounted to 10.7% of the total applied rainfall, but it increased from 2.3 to 18.3% during the first and last applied rainfall. Soil cracks partially filled with transported sediments in surface runoff, but never sealed by swelling or by sedimentation during the sprinkling of 180 mm of rainfall applied in three installments during 1 wk. However, cracks observed in 1999 closed during natural rainfalls with a total depth of 450 mm, distributed in 10 storms during 3 mo. The development of soil cracks and their contribution to promote short-circuit flow are highly variable processes in time and space. Pour gérer de façon durable les ressources hydriques dans les vertisols, il est capital de comprendre la dynamique spatiale et temporelle des crevasses causées par la sécheresse et des processus hydro-géomorphologiques connexes. Les auteurs ont étudié comment les fentes de retrait modifient l'infiltration des eaux de ruissellement et des sédiments dans les vertisols lors de précipitations naturelles et artificielles. Les expériences se sont déroulées dans les plaines semi-arides du nord-est du Mexique durant l'été 1998. Le ruissellement représente 10,7 % des précipitations artificielles totales, mais passe de 2,3 % à 18,3 % entre la première et la dernière précipitation. Les crevasses dans le sol se remplissent partiellement de sédiments charriés par les eaux de ruissellement, mais elles ne sont jamais obturées par gonflement ou sédimentation quand on déverse 180 mm d'eau sur le sol en trois étapes, réparties sur une semaine. En 1999, les fentes se sont néanmoins refermées jusqu'à une profondeur de 450 mm après des précipitations naturelles correspondant à 10 orages survenus en 3 mois. L'apparition de crevasses dans le sol et la contribution de ces dernières à un écoulement limité sont des processus qui varient considérablement dans l'espace et le temps.

Threshold behaviour in hydrological systems as (human) geo-ecosystems: manifestations, controls, implications

“…Likewise, if the soil again wets up above a certain threshold value, the cracks begin to shrink and eventually close, and the local infiltration capacity is then substantially reduced. This has been observed in vertisols in a catchment of northern Mexico (Navar et al, 2002), the Tannhausen catchment in Germany (Lindenmaier et al, 2006) (compare Sect. 4), and the Riesel Y-2 catchment in Texas (Allen et al, 2005).…”

Measurement Tool for Dynamics of Soil Cracks

“…The field results indicate that crack closure can become temporally decoupled from the bulk soil moisture. Assuming that the observed changes in crack volumes are primarily due to changes in the crack width, the temporal trends seen in Installations 1 and 2 are consistent with the results of Návar et al (2002), who measured crack dimensions during and after simulated rainfall events and observed that the majority of the cracks demonstrated significant closure during the first hour of irrigation (up to 50% decrease in width) but that complete closure did not happen for three more months (until 0.450 m of cumulative rainfall had been applied).…”

“…Surface‐based methods to monitor crack evolution include surface image analysis (Flowers and Lal, 1999; Abou Najm, 2009), observing a soil's natural foaming (Mitchell and van Genuchten, 1993), and soil surface elevation monitoring (Wells et al, 2003; Arnold et al, 2005), which can be used to estimate the evolution of the crack network by assuming isotropy of shrinkage. Examples of labor‐intensive methods include a variety of crack‐tracing techniques utilizing thin flexible metal probes for depth detection and simple geometric assumptions for volume estimation (El Abedine and Robinson, 1971; Ringrose‐Voase and Sanidad, 1996; Deeks et al, 1999; Bhushan and Sharma, 2002; Bandyopadhyay et al, 2003; Kishné et al, 2009) and calipers for measuring crack geometry (Návar et al, 2002).…”

Impact of conservation agriculture on catchment runoff and soil loss under changing climate conditions in May Zeg-zeg (Ethiopia)

“…Of course, well-known errors of rainfall measurement (such as incidence angle and splash drift) are possible. Furthermore, subsurface flow between plots could occur due to vertic cracking (Návar et al, 2002). Finally, the experimental plots treated with plain tillage do not fully correspond to real-world conventional agriculture, since livestock was not allowed within the experimental station.…”