Agron. Sustain. Dev. 29 (2009) 135-142
DOI: 10.1051/agro:2008052

Integration of soil structure variations with time and space into models for crop management. A review

J. Roger-Estrade¹, G. Richard², A.R. Dexter^{2, 3}, H. Boizard⁴, S. De Tourdonnet¹, M. Bertrand⁵ and J. Caneill<sup>6

1</sup>  AgroParisTech, Département SIAFEE, Centre de Grignon, BP 01, 78850 Thiverval-Grignon, France
²  INRA UR0272 Science du Sol, Centre de Recherche d'Orléans, 2163 Av. de la Pomme de Pin, CS 40001, Ardon, 45075 Orléans Cedex 2, France
³  Associate Scientist, Le Studium, 45000 Orléans, France
⁴  INRA, US 1158, Agrosystèmes & impacts environnementaux carbone-azote, Estrées-Mons, BP 50136, 80203 Péronne, France
⁵  INRA UMR 211 INRA AgroParisTech, BP 01, 78850 Thiverval-Grignon, France
⁶  INRA, UMR Biologie et Gestion des Adventices, 17 rue Sully, BP 86510, 21065 Dijon Cedex, France

Accepted 8 September 2008 ; published online 29 November 2008

Abstract - Soil structure plays a major role in the design of new crop management systems. For instance, the transition from conventional to no-tillage changes soil structure, which, in turn, has implications on crop yield greenhouse gas emissions, and pesticide and nitrate leaching. Modelling soil structure at field scale faces two main issues: (1) the spatial variability and (2) the temporal variability. Here, we review how spatial variability of soil structure is taken into account in water transfer models at field scale. We discuss the effects of soil structure on hydraulic properties. We present options to model soil structure effects using pedotransfer functions or calculations based on pore network geometry. Then we review studies on water transfer. Here, we show the utility of one-dimensional (1-D) and 2-D models, and the range of soil profile partitions. In the second part, we study a mean to model the temporal variation of soil structure. We propose an indicator of soil structure dynamics based on the proportion of compacted clods in the tilled layer. This indicator was measured from the observation face of soil pits. We studied this indicator in a long-term field experiment involving various risks of compaction. The results showed that this indicator gave a more precise description of the time course changes in soil structure than the mean soil bulk density measured on the same experimental plots. Lastly, we discuss the principles of a model that predicts the evolution of this indicator under different soil tillage and climatic conditions. This model can be used to evaluate the effects of different crop management systems on soil structure and soil water transfer.

Key words: soil structure / crop management / tillage / water transfer / model

Corresponding author: Jean.Roger_Estrade@agroparistech.fr

© INRA, EDP Sciences 2008