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1087 Jamison Rd
Washington Court House, OH 43160
(800) 321-1562
Knowledge is key to using your analytic results to their fullest. The Spectrum Agronomic Library provides you with useful information that will help you to better understand the complex science of agronomy. Our agronomists will be continually adding original and reprinted articles, so check the library regularly for new information.
Michigan researchers re-evaluated the effects of higher populations and narrow rows on the yield of some newer corn varieties developed for the Northern Belt. Their findings were published in the report “Row Width and Plant Density Effects on Corn Grain Production in the Northern Corn Belt”, William C. Widdicombe and Kurt D. Thelen, Michigan State Univ., Agronomy Journal 94:1020-1023 (2002).
During 1998 and 1999, the researchers conducted an investigation that included six different corn hybrids planted in six different Michigan locations that included maturity ranging from 93 to 108 days; ear types that included determinate, indeterminate, and flex; leaf orientation that ranged from wide to upright; and height ranging from medium-short to tall.
They found that narrower rows and higher populations improved yields as seen in the following tables.
| Table 1. Effect of row width (average across all variable, dates, and locations) | |||
|---|---|---|---|
| Row width (inches) | Yield (bushel/Ac) | % Moisture | % Lodging |
| 30 | 177.5 | 19.6 | 1.60 |
| 22 | 181.0 | 19.2 | 1.92 |
| 15 | 184.2 | 19.2 | 1.65 |
| Table 2. Effect of Plant Density (average across all variables, dates, and locations) | ||||
|---|---|---|---|---|
| Plant Density (plants/ac) | Yield (bushel/ac) | % Moisture | Test Weight (lbs/bu) | % Stalk Lodging |
| 22,672 | 168.0 | 19.7 | 57.5 | 2.15 |
| 26,316 | 177.4 | 19.5 | 57.6 | 2.22 |
| 29,555 | 181.5 | 19.4 | 57.7 | 2.21 |
| 32,794 | 184.3 | 19.3 | 57.7 | 2.40 |
| 36,437 | 186.3 | 19.2 | 57.7 | 2.67 |
Their conclusions were as follows… “Average corn grain yield increased 2 and 4% when row width was narrowed from 76 cm (30 in) to 56 and 38 cm (22 and 15 in respectively) over the 2 yr. and 11 locations of this study. Corn grain harvest moisture decreased by a factor of 2.1 when row width was narrowed similarly. The decrease in grain moisture at harvest was small but statistically significant over the scope of the study and suggests a modest potential savings in grain drying costs with narrow row corn systems. Plant density affected grain yield, moisture, test weight, and stalk lodging. The highest plant density evaluated, 90,000 plants ha-1 (36,437 plants/a), had the highest grain yield. A plant density x hybrid interaction was observed. Grain moisture decreased for early maturing hybrids as plant density increased, but moisture levels were consistently high across all plant density levels for the later maturing hybrids. A hybrid x row width interaction was not observed, indicating hybrids that yield well in conventional 76 cm (30 in) row systems will also yield well in narrow row systems. Similarly, a plant density x row width interaction was not observed, which suggests the increased yield effect observed with narrow row systems will generally occur across the range of plant densities commonly used by growers in the northern Corn Belt.”
The PSNT is a soil nitrate test that has been developed to help make an accurate nitrogen fertilizer recommendation for a corn crop that has had an application of manure, a cover crop that contributes nitrogen to the soil, or has had a previous application of nitrogen such as a row starter, weed and feed, or broadcast treatment. This test was originally developed by Dr. Fred Magdoff at the University of Vermont for field corn production. In recent years there has been research done for a number of other crops such as cotton, tobacco and sugar beets. Since its successful introduction, the PSNT has been calibrated for a small number of vegetable crops, and the work continues on other corps. Research has been done in several states that when 25 ppm nitrate-N is present in the top foot of soil, response to additional side dress N is not likely. However, if the nitrate-N level of the top foot of soil is less than 10 ppm, response to full recommended rates of N would be expected.
The purpose of this paper is to give the reader a brief overview of some of the major points related to using nitrogen fertilizer materials. Most people working in agriculture and other plant management industries should search out more detailed information on the subject. Such information is readily available from Spectrum Analytic, and many other sources.