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Fluid Journal : Fluid Journal 1999-2001
1 Fluid Journal Summer 2001 Summary: To date, we have observed that attainable yield potential varied significantly in the two years of this study. It appears that only 75 to 85 percent of the yield potential (220 to 260 bu/A) is likely to be the most efficient and profitable yield target for high-yielding systems. However, intensification of management is essential to increased productivity. Currently recommended fertilizer management programs may not be sufficient to meet the nutrient demands of higher plant populations. We have observed that maximum attainable yields require higher plant densities as well as greater amounts of N (and especially K) per bushel of yield. Low commodity prices and environ- mental concerns about global climate change caused by carbon dioxide enrichment of the atmosphere provide strong justification for increasing both farm profits and the storage of carbon (C) in agricultural soils. The working hypothesis of this project is that achieving increased profit and C storage will require innovative new crop management practices that improve soil quality, increase yields and decrease production costs. To do so will require exploitation of the existing yield potential of modern hybrids and varieties. Although greater inputs will be required to achieve these goals, we hypothesize that nutrient-use efficien- cies (and therefore profit) will be enhanced. There is a need to develop scientific understanding of the relationship between soil productivity, crop yield potential, input use efficiency and C- sequestration in corn-based cropping systems. To address these issues requires an initial focus on quantifying crop growth rates and dry matter distribution among various plant organs, nutrient uptake rates, optimal Drs. Tim Arkebauer, Ken Cassman, Achim Dobermann, Rhae Drijber, John Lindquist, Lenis Nelson, William Powers, Ken Russell, James Specht and Daniel Walters Are Currently Recommended Fertilizer Management Programs Sufficient? Probably not, Nebraska researchers' observations suggest if maximum attainable yields are goal. MANAGEMENT LEVEL PLANT POPULATION DENSITY (pl/A) Figure 1. Population and management effects on corn grain yield, 1999. CORN GRAIN YIELD (bu/A) 30,000 37,000 44,000 300 250 200 150 100 CONTROL RECOMMENDED INTENSIVE PLANT POPULATION DENSITY (pl/A) Figure 2. Population and management effects on percent of barren stalks, 1999. 30,000 0 1 2 BARREN PLANTS (%) 3 4 5 6 7 8 37,000 44,000 CONTROL RECOMMENDED (M1) INTENSIVE (M2) PLANT POPULATION DENSITY (pl/A) Figure 3. Population and management effects on stover yield, 1999. 30,000 0 2 CORN STOVER YIELD (ton/A) 4 6 8 37,000 44,000 CONTROL RECOMMENDED (M1) INTENSIVE (M2)
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