Tillage Effect on Soil Water Content and Soybean (Glycine max) Yield in a Strip Intercropping System

Soybean [Glycine max (L.) Merr.] response to strip-intercropping with corn (Zea may L.) and oat (Avena Jativa L.) interseeded with nondormant alfalfa (Medicago Jativa L.) may be affected by soil moisture. A three-crop strip-intercropping system of corn, soybean and oat interseeded with nondormant alfalfa was established to determine the effect of tillage system and row position on soil water content and grain yield in the soybean strip. The experiment was a split-plot design with three tillage treatments (conventional, CT; reduced, RT; and minimum tillage, MT) as main plot effects and three row positions (both edge rows and the center row) as subplot effects. In 1989 (a dry year), MT resulted in greater soil water content and soybean yield than other tillage treatments. The row bordering the oat-alfalfa strip had a lower soil water content and soybean yield than did the other two positions. Tillage did not have a significant effect in 1990 (a wet year) on soil water content or soybean yield. The 1990 soybean yield was lower in the soybean row bordering corn, but water availability did not differ significantly between row positions. MT was the most suitable tillage system for soybean production with the three-crop strip intercropping on this soil for both the wet and dry year in which this study was conducted

The ‘Palo a Pique’ Long-Term Research Platform: First 25 years of a Crop-Livestock Experiment in Uruguay

Mixed crop-livestock long-term experiments (LTE) are critical to increase the understanding of sustainability in complex agroecosystems. One example is the ‘Palo a Pique’ LTE which has been running for 25 years in Uruguay (1995 to present) evaluating four pasture-crop rotations under livestock grazing with no-till technology in soils with severe limitations. Results demonstrate that cropping systems reduced soil organic carbon (SOC) compared with permanent pastures, and that perennial pastures rotating with crops were critical to mitigate SOC losses. Data from the ‘Palo a Pique’ LTE has contributed to establish new national policies to secure sustainability of agricultural-based systems. Although the original purpose of the LTE was oriented to crops and soils, a demand for sustainable livestock intensification has gathered momentum over recent years. As a result, the current approach of the ‘Palo a Pique’ LTE matches each pasture-crop rotation with the most suitable livestock strategy with the common goal of producing 400 kg liveweight/ha per year. General approaches to the pursuit of sustainable livestock intensification include: shortening the cycle of production, diversifying animal categories, increasing liveweight gain and final animal liveweight, and strategic livestock supplementation. Prediction of trade-offs between environmental, economic, and production indicators can be addressed through monitoring and modelling, enabling timely anticipation of adverse sustainability issues on commercial farms. The ‘Palo a Pique’ LTE serves as a framework to address contemporary and future questions dealing with the role of ruminants on climate change, competition for land, nutrient dynamics, and food security