Analysis of Generation of Linear Inter-row Cracks Using Numerical Model

Abstract

Cracks play important roles in drainage efficiency in clayey agricultural fields. Controlling location, depth width of cracks has a substantial meaning in utilizing clayey paddies for cultivating various crops. Many researchers pointed out that cracking pattern in the agricultural fields is determined by many factors. Among them, effect of transpiration from cultivated crops is one of the most important determinants of cracking patterns when we aim to control them as farming operations. The present study clarified the effect of transpiration from row-planted crops on the location of linear inter-row cracks using numerical simulations based on two-dimensional elastic consolidation model. The model describes bidirectional movement of water induced by transpiration, and predicts the locations where tensile effective stress is generated. The validity of the model was tested by laboratory experiment. The experiments revealed occurrence of cracks induced by bidirectional water movement, and correspondence between the locations of cracks and predicted distribution of tensile stress as well. Further numerical simulations demonstrated that the distribution of tensile effective stress has single or double peaks depending on the row spacings, which possibly account for the number of linear cracks at inter-row spacing.