Sign up for email alerts of new Fluid Journal issues!
Fluid Journal : Spring 2011
6 The Fluid Journal Spring 2011 Dr. Gentry is a soil scientist and research assistant professor, and Dr. Below is a Professor of Crop Physiology in the Department of Crop Sciences at the University of Illinois, Champaign-Urbana. Table 3. Traditional vs. high-tech, two years. Traditional High-tech Factor Yield * Yield ** Bu/A-1 None or all 193 245 Fertility 197 +4 236 -9 Nitrogen 198 +5 232 -13 Genetics 202 +9 225 -20 Population 187 -6 238 -7 Fungicide 198 +5 218 -27 Data from Champaign and Dixon Springs * Difference when changed to high-tech level ** Difference when changed to traditional level *** Adapted from Ruffo, Henninger, and Below. A new experimental design to analyze the value of management factors contributing to high corn yield. Am. Soc. Ag. Mtg. Oct 31-Nov 4, 2010. Expanding study Based on the data collected from two years of high-yield studies, we propose to expand the study design to include conservation practices and sustainability measurements. In 2011, we will add three additional factors to the omission plot experimental design: crop rotation, partial stover removal, and tillage intensity. Research and conventional wisdom provide evidence that corn following soybean produces greater yields than following corn. Research by the CPL has indicated that the primary agent of yield reduction in corn-corn rotations is corn residue, although the mechanism is not fully understood. A number of studies have shown that with proper management and additional organic inputs, stover removal can be performed without degrading soil quality or reducing soil organic matter content. We propose that partial stover removal in the high- yield corn environment cannot only be performed in a sustainable manner, but that the use of stover for biofuel or animal feed is a more environmentally sustainable application for corn stover than allowing it to slowly decompose at the soil's surface. Another benefit of partial stover removal is that less corn residue greatly facilitates strip tillage activities from a mechanical perspective, thus promoting conservation tillage in the high-yield environment. We will assess the effects of removing corn stover for reducing soil organic matter and for reducing the continuous corn yield penalty. We will also conduct plant tissue analyses of removed stover to estimate soil carbon and plant nutrients removed at various stover harvest rates. This will result in information that can be used to create appropriate fertilizer recommendations based on how much stover is removed. Strip tillage is a relatively new reduced tillage system that protects soil from erosion, retains plant-available water later in the growing season, and allows banding of fertilizers for more efficient plant uptake and reduced erosional losses associated with broadcast fertilization. Although strip tillage has been used exclusively in single-row cropping systems to date, we propose that strip tillage can also be used with twin-row corn systems and that pairing strip tillage with twin-row technologies will result in improved plant nutrient uptake, reduced soil erosion, and increased soil organic matter retention. Anticipated results Yield results. In the previously described high-yield study investigating the individual and combined use of five "high-tech" factors versus "traditional" practices, the combined "high-tech" treatment yielded 14 to 66 bu/A more grain than the treatment combining only "traditional" inputs and practices (Table 3). Although there was variation in the data set influenced by site and weather, in all cases the value of a given high-yield factor was more influential on yield when combined with other high-yield factors, rather than provided alone. These trials show that single production factors used alone do not guarantee high corn yields; rather, it is the positive interaction among multiple complementary factors that will optimize the production potential of each plant and result in higher corn yields. We will implement the same treatment design using combinations of complementary high-yielding management practices to assess the effect of the practices both on yield and sustainability metrics. Environmental results. We define agricultural sustainability as a system of crop and animal production that, over the long term: • Satisfies human, food, fiber, forage, and fuel needs • Sustains the economic vitality of farm operations • Maintains or improves soil organic matter, soil structure, and water quality (modified from the 1990 Farm Bill). Looking ahead We propose to maintain or improve soil organic matter by reducing tillage and increasing plant populations, thus creating more below ground root biomass and exudates. We will maintain and improve soil structure both with strip tillage and the addition of below ground plant biomass to increase soil organic matter. Finally, we will maintain or improve water quality by optimizing the use of every agricultural input that is applied to the crop. Specifically, we will achieve this by improving N uptake efficiency with split N application, slow-release N inputs, and optimum placement of inputs by banding P and S fertilizer with the strip tiller. Finally, by creating a favorable rooting environment with strip tillage, banding nutrients, and using the most advanced suitable crop hybrids, we will optimize the corn root system for maximal fertilizer recovery and increased below ground carbon sequestration. We will evaluate sustainability in a number of ways, primarily focusing on nutrient uptake efficiency and the validity of removing corn stover based on additional root production in the high-yield environment. Less tangible and quantifiable sustainable outcomes (e.g., improved water availability and soil structure, reduced soil erosion, and fossil fuel combustion) will be observed and recorded whenever possible. From an environmental perspective, the outcome of this project will be highly beneficial, resulting in preservation of our soil and water resources for future generations.
Early Spring 2011