Delaware Agronomy Blog

University of Delaware Cooperative Extension

Category: Corn (page 6 of 7)

Corn Leaf Stages and Growing Degree Days (May 20, 2019)

May 22, 2019 / / Comments Off on Corn Leaf Stages and Growing Degree Days (May 20, 2019)

With the fluctuation in temperatures since mid-April, corn emergence and growth has shifted week to week. At the research station, we have observed corn take up to ten days planted April 24th, but only five when it was planted May 8th. Rising temperatures accumulate growing degree days (GDD) in less time, so that would be expected. Looking across the region, any corn planted on May 12th should have already emerged in Sussex, or be close to emerging in New Castle (as of May 20th).

Table 1: Accumulated growing degree-days based on planting dates through May 20th.

If you planted -> April 14 April 21 Apr 28 May 5 May 12
Sussex 498 407 325 225 125
Kent 465 372 297 216 118
New Castle 441 354 274 202 112

Emergence = 120 GDD, V6 = 475 GDD. Continue reading

Growing Degree Days (GDD) and Rainfall through May 14th

May 15, 2019 / / Comments Off on Growing Degree Days (GDD) and Rainfall through May 14th

Since the rainfall this weekend, cooler temperatures have slowed the accumulation of growing degree days. Since April 14th we had observed a steady trend in GDD accumulation, keeping emergence on track between 7-10 days. Any planting done since May 6th may see delayed emergence, compared to previously planted fields. For those fields planted mid-April you may be at V4-V5. As temperatures warm back up, be prepared to sidedress between V6-V8.

Figure 1: Growing degree days in the Dover area since April 14th.

Continue reading

Starter Nitrogen Fertilizer for Corn

April 18, 2019 / / Comments Off on Starter Nitrogen Fertilizer for Corn

Amy Shober, Extension Nutrient Management Specialist, ashober@udel.edu

Jarrod Miller, Extension Agronomist, jarrod@udel.edu

University of Delaware nitrogen (N) recommendations are based on a realistic yield goal with a base rate of 1 lb N per bushel of expected yield. Increased N use efficiency has been observed when 15 to 25% of the total N is applied as starter fertilizer and the remainder of the N is applied corn plants are 12 to 15 inches tall (around V5 to V6). This is especially important for corn planted in Delaware’s sandy, low organic matter soils, as these soils are susceptible to N leaching. Ultimately, split applying N to corn will help you get more N in your crop over the growing season. Continue reading

Soil Temperature for Corn Planting

April 12, 2019 / / Comments Off on Soil Temperature for Corn Planting

Jarrod Miller, Extension Agronomist, jarrod@udel.edu

The preferred soil temperature for corn germination is 50°F, which allows the seed to begin root and shoot growth. When soils fall below this temperature, germination may be limited and seeds may rot in the ground. This past week has seen increased air temperatures across Delaware, but soils take longer to warm up.

In the past few days, we have started to see consistent temperatures for corn planting. Since April 1, average daily soil temperatures ranged from 45-58°F in Newark, 46-60°F in Dover, and 48-63°F in Georgetown. This has mostly been a linear increase in temperature, with soil temperatures consistently above 50°F the last few days. Temperatures over the next week have highs in the 70s, with a few nights in the lower 50s, so our soil temperatures may hold for corn planting.

If you are interested in daily soil temperatures in your area, check the Delaware Environmental Observing System (DEOS) website: http://www.deos.udel.edu/data/agirrigation_retrieval.php.

Corn Tissue Samples and Critical Nutrient Concentrations

December 13, 2018 / / Comments Off on Corn Tissue Samples and Critical Nutrient Concentrations

Jarrod Miller, Amy Shober, Phillip Sylvester

In the summer of 2018, we sampled tissue and soil samples from University of Maryland (Salisbury, Clarksville, Keedysville) and University of Delaware (Georgetown, Marydel) corn variety trials. The goal of the project was to observe whether corn tissue samples across the region were above critical nutrient contents as described by past literature. Two varieties each from the early, middle, and late maturity groups were sampled at each site.

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