Soil & Tillage Research 77 (2004) 1–13 Review Integrating no-till into crop–pasture rotations in Uruguay Fernando Garc´ ıa-Préchac a,∗ , Oswaldo Ernst b , Guillermo Siri-Prieto b,c , José A. Terra c,d a Dep. de Suelos y Aguas, Fac. de Agronom´ ıa, Univ. de la Rep. O. del Uruguay, Montevideo, Uruguay b Dep. de Prod. Vegetal, Fac. de Agronom´ ıa, Univ. de la Rep. O. del Uruguay, Montevideo, Uruguay c Agronomy and Soils Department, Auburn University, Auburn, AL, USA d Instituto Nacional de Investigacion Agropecuaria-Uruguay, Treinta y Tres, Uruguay Received 21 February 2003; received in revised form 27 November 2003; accepted 9 December 2003 Abstract Crop–pasture rotations (CPR) are unusual around the world but have been the predominant cropping system in Uruguay since the 1960s. Uruguay has a temperate sub-humid climate, 80% of its landscape (16 Mha) is climax grasslands C 3 and C 4 species. Beef, wool, and dairy are the main commodities. Crops occupy a portion of the remaining 20% land area, primarily on Argiudolls and Vertisols, rotated with seeded grass and legume pastures. Continuous cropping (CC) with conventional tillage (CT) has proven unsustainable due to decreased soil productivity. Seeded pasture periods increased soil productivity. CPR adoption created less variable inter-annual economic results, but soil degradation remained a major concern during the crop cycle using CT. Farmers and technicians became interested in no-till (NT) to reduce erosion and production cost. Currently, approximately 52% of crop producing farms and 25% of dairy farms have adopted NT. This paper synthesizes research results (mainly from long-term experiments) contrasting CC versus CPR with CT (1960–1990) and NT (from 1990). Soil erosion was reduced more than six times with NT in CC, and almost three times in CPR compared with CC using CT; but combining the use of CPR and NT resulted in the same low erosion rate as under natural pasture. The transition from CT to NT is not always easy. The time between herbicide application to pasture and planting of the first crop of the rotation crop cycle with NT is a critical transition factor to optimize N and water availability, and soil tilth. Chiseling or paraplowing can alleviate plow-pans inherited by NT from previous CT; but higher soil strength at the soil surface under NT contributes to better forage utilization under grazing. Soil organic carbon (SOC) content in CC decreased with CT, and was maintained with NT only if grain was harvested. In CC systems with harvested forage, SOC decreased even with NT. CPR with NT maintained or increased the original SOC content. The paper concludes with a discussion on the relative sustainability of CC versus CPR with NT. Both are sustainable from the soil quality and productivity standpoints. But compared with CC, CPR is a more economically and climatically buffered system, due to higher diversity. Also, CPR systems are more environmentally sustainable since fuel and agrochemicals usage is reduced approximately 50%. © 2003 Elsevier B.V. All rights reserved. Keywords: Pastures; Crop rotations; No-till; Soil quality; Soil erosion; Soil compaction; Soil organic carbon ∗ Corresponding author. Tel.: +598-2-3561251; fax: +598-2-3593004. E-mail address: fgarciap@fagro.edu.uy (F. Garc´ ıa-Pr´ echac). 1. Introduction In temperate areas of the world, it is well known that soil quality and arable crop productivity recover after a period of perennial seeded pastures of legumes and 0167-1987/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.still.2003.12.002