Corn Fertility Research

Several studies were initiated in 2003 and were repeated in 2004 to evaluate the impact of fertility programs on corn grain yield. These studies included:

• Spring applied anhydrous, urea, urea + Agrotain, dry ammonium nitrate, 32% urea ammonium nitrate, anhydrous, dried distiller’s grain, and ESN (coated urea) was added in 2004
• In-furrow applications of calcium sources
• Fertilizer amendment mixtures and an Aerway implement
• Foliar applied Nutri-Cal at 1.25, 2.5, and 5 gal/a
• The impact of foliar applied Nutri-Cal on weed control with glyphosate.
• No-till corn planted in a spring applied anhydrous applicator zone-tilled area and between the zone-tilled area compared with conventionally tilled corn
• In-furrow starter and liquid N fertility program compared to a preplant dry fertilizer program in a no-till production system.

Anhydrous Timing and Nitrogen Source Comparison
An increase in government regulations of anhydrous ammonia and ammonium nitrate may affect the availability and price of these nitrogen sources in the future. In 2003, fall and spring applied N trials were initiated to compare the effect of nitrogen source and application timing of anhydrous on corn grain yield (Table 1). Asgrow ‘RX752YG’ was no-till planted on May 19, 2003 at 29,000 seeds/acre on a Mexico silt loam soil. This study was arranged as a randomized complete block design in plots 30 by 150 ft with four replications. Grain yield was similar amongst nitrogen sources in 2003. Late planted corn did not have the yield potential in 2003 of early planted corn.

Spring Zone Tillage
Anhydrous ammonia is one of the most common nitrogen fertilizer sources for farmers in northern Missouri. Spring applications may eliminate the need for nitrogen stabilizer and reduce production costs. Zone tillage may help soils warm quicker and encourage germination and early plant growth while reducing risk of soil erosion compared to conventional or reduced tillage systems. Extensive research has evaluated fall zone-tillage systems for corn production; however, limited research has evaluated spring zone-tillage. One of the major limiting factors in no-till production is cool, wet soils in the spring. In addition, there has been increasing interest on the impact of management decisions on corn grain quality. This study was designed to determine the effect of spring zone tillage on corn stand establishment, grain yield, and grain quality.

Research was conducted in the long-term no-till and reduced tillage crop rotation research plots at the Greenley Research Center. This study was arranged as a split-plot design with four replications in plots 15 by 295 ft. Cropping system was the main plot and zone tillage was the sub-plot. Anhydrous was custom applied with a 30 ft DMI tool bar and metered with a Raven SSC 440 controller calibrated to deliver 150 lb N/acre. A burndown application of Roundup WeatherMAX at 22 oz/a plus ammonium sulfate at 17 lbs/100 gal plus Banvel at 1 pt/a was used to control winter annuals, spring annuals, and clover. ‘DK 60-19’ was planted in 30 in. widerows at 29,000 seeds/acre on May 23, 2003 above the zone tilled anhydrous applicator strip and between the zone tilled strip. Plots were maintained weed-free with two applications of Roundup WeatherMAX at 22 oz/a plus ammonium sulfate at 17 lbs/100 gal. The center two rows were counted to determine final populations and harvested using a small plot combine. Moisture was adjusted to 15% prior to analysis. Grain samples were collected and quality determined using NIR spectroscopy. Zone-tillage did not affect corn population, grain yield, or grain quality compared to no-till or reduced tillage treatments in 2003. This trial was repeated in 2004.

Table 1. Fall and spring applied anhydrous research in 2003^a.

Trt No.	Treatment	Rate	Unit	Application Timing	(bu/acre)
1	Zone Tillage	0	LB N/A	Nov 15, 2002	93.7	a
2	Anhydrous	150	LB N/A	Nov 15, 2002	96.8	a
	N-Serve	1	QT/A
3	Anhydrous	150	LB N/A	Nov 15, 2002	93.8	a
4	Anhydrous	175	LB N/A	Nov 15, 2002	96.0	a
	N-Serve	1	QT/A
5	Anhydrous	175	LB N/A	Nov 15, 2002	107.0	a
6	Anhydrous	200	LB N/A	Nov 15, 2002	99.6	a
	N-Serve	1	QT/A
7	Anhydrous	200	LB N/A	Nov 15, 2002	98.8	a
8	Untreated	0	LB N/A		95.9	a
9	Anhydrous	175	LB N/A	April 16, 2003	100.1	a
10	Urea	175	LB N/A	May 9, 2003	103.0	a
11	Dried Distillers Grain	175	LB N/A	May 19, 2003	111.0	a
12	Ammonium Nitrate	175	LB N/A	May 9, 2003	100.2	a
13	32% Urea Ammonium Nitrate	175	LB N/A	May 9, 2003	108.0	a
14	Agrotain	1	gal/ton	May 9, 2003	107.0	a
	Urea	175	LB N/A
LSD (P=.05)					NS

Table 2. The impact of spring, zone tillage on corn population, grain yield, oil, protein, and starch following a clover cover crop, double-crop soybean, and reduced tillage in 2003.