Soil random roughness and depression storage on coffee farms of varying shade levels Brenda B. Lin a, *, Paul L. Richards b a School of Natural Resources and the Environment, University of Michigan, 440 Church Street, Ann Arbor, MI 48109, United States b Department of Earth Sciences, SUNY Brockport, 219 Lennon Hall, Brockport, NY 14420, United States 1. Introduction 1.1. Coffee agriculture and water availability Concern for food security and water availability in agriculture has increased in areas of the world where climate variability is currently observed. Recent models of climate change show that important factors for agriculture, such as rainfall and soil moisture, may affect future production (Appendini and Liverman, 1994; Gregory and Ingram, 2000; Fischer et al., 2005). A large amount of the world’s food is grown in tropical rainfed systems (Slingo et al., 2005) where changes in precipitation and water availability may threaten both export crop production as well as subsistence agriculture in rural settings (Haile, 2005; Verdin et al., 2005). In Mexico, coffee is an important rainfed export crop for small farmers (Calo and Wise, 2005). 3.5 million farmers depend on coffee agriculture as their primary means of survival (Calo and Wise, 2005), and in Chiapas, Mexico there are few other employment opportunities outside of coffee agricultural water management 92 (2007) 194–204 article info Article history: Accepted 26 May 2007 Published on line 20 July 2007 Keywords: Soil roughness Depression storage Soil moisture Agroforestry systems Coffee agriculture Adaptive management abstract Water availability in rainfed coffee agroecosystems is an important factor in determining the production success of the crop. In this study, an estimate of soil water capture and storage was conducted in order to understand the differences of soil water availability among coffee farms or various management intensities, distinguished here by differences in shade cover level. Measurements of effective soil depression storage, leaf litter and soil moisture were taken in each of the sites. These measurements were taken to better understand how different shade coffee systems may gain or lose opportunities to keep water within the system due to contributions of shade. Three sites of varying shade were chosen in the Soconusco region of Chiapas, Mexico. The medium (30–50% cover) shade site was found to be more effective for precipitation capture when compared to the low (10–30% cover) shade site because of a larger value of effective depression storage (t-test, p = 0.05) due to increased soil roughness. This conclusion was supported by significantly higher soil moisture measurements in the medium shade site when compared to the low shade site in the dry season (repeated measure GLM, p = 0.001). The high shade (60–80% cover) site was found to have a greater slope than the other two sites, yielding smaller effective storage capacities; yet the high shade site was able to retain 15% of the available rainfall during the dry season through surface storage, possibly because of greater leaf litter and other shade contributions. Farmers may consider the use of shade trees within coffee farms as a practical method toward preserving water within the agroecosystem. # 2007 Elsevier B.V. All rights reserved. * Corresponding author at: The Earth Institute, Columbia University, 2910 Broadway, MC 3277, New York, NY 10025, United States. Tel.: +1 212 854 7807; fax: +1 212 854 6309. E-mail address: bl2249@columbia.edu (B.B. Lin). available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/agwat 0378-3774/$ – see front matter # 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.agwat.2007.05.014