Suat Irmak - UNL Extension Water Resources Engineer

Harold W. Eberhard Distinguished Professor of Biological Systems Engineering

Suat Irmak

(faculty)
Work Chase Hall (CHA) 239
Lincoln NE 68583-0726
US
Work 402-472-4865 On-campus 2-4865

Faculty Bio

Chart of N research treatments

Feasibility of Sensor-Based Nitrogen Fertigation Management in Corn May 7, 2018

Averaged across two years, the sensor-based N fertigation treatment consistently resulted in higher profit and nitrogen use efficiency. The use of fertigation offers the unique capability to minimize N losses by reacting to slight N deficiencies in corn by applying N multiple times throughout the season with lower application rates.

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Soil moisture sensor only partially installed due to dry ground

Determining Beginning Soil Moisture for Planning Decisions April 12, 2018

Soil moisture sensors installed now can provide valuable information for dryland producers who want to determine existing soil moisture level and adjust cropping or planting plans accordingly. The authors installed and will be monitoring soil moisture readings at six sites in south central Nebraska.

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soybean field

Planting Soybean after Soybean (Part 1): Planting Considerations April 13, 2017

Farmers are increasing their soybean plantings for 2017, which likely means some are shifting to soybeans-after-soybeans. This article looks at what you should be considering at planting time as you consider changing your cropping sequence.

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Center pivot irrigated soybeans
Management in a successful soybean-after-soybean cropping system may require growers to make some slight adjustments in their practices, including irrigation, seed selection, and pest management.

Planting Soybean after Soybean (Part 2): In-Season Management Considerations April 13, 2017

In Part 1 of this article, we look at considerations for planting soybean after soybean. In this article, Part 2, we share considerations for in-season management.

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Field trials comparing early and late planted rye cover crop
Field trials comparing early and late planted rye cover crop

Implementation of Cover Crops in Corn and Soybean Systems in Nebraska November 29, 2016

A short review of cover crop research conducted at four University of Nebraska research fields (two irrigated, two dryland) to study the feasibility and impact of winter cover cropping on soil quality, soil water, and crop yields in corn-soybean systems. Objectives were to quantify cover crop emergence, fall and spring biomass production, soil water changes, soil chemical and physical property changes, and crop yields.

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Harvest 2016 — When Corn Yields are Below Expectations October 14, 2016

A review of 2016 growing conditions across Nebraska sheds light on a number of factors that may have contributed to reduced yield in individual fields. An understanding of these factors may be helpful when selecting seed for 2017.

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Figure 1: Early-planted rye (left) and late-planted rye before corn at Concord, April 22, 2016.
Figure 1: Early-planted rye (left) and late-planted rye before corn at Concord, April 22, 2016.

Biomass Production of Winter Annual Cover Crops in Corn and Soybean August 11, 2016

Rye was the leading biomass producer in the first two years of a four-year study exploring whether winter cover cropping in no-till corn and soybean systems in Nebraska can benefit soil quality despite their short growing season.

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Corn leaf rolling
Figure 1. One indicator of heat stress is when corn leaves roll in the early morning in areas where there is adequate soil moisture.

Impacts of Extreme Heat Stress and Increased Soil Temperature on Plant Growth and Development June 21, 2016

Both corn and soybean are susceptible to extreme heat (and water) stress during early vegetative stages as well as later critical growth stages (pollination for corn and flowering for soybean). Extreme heat stress can reduce plant photosynthetic and transpiration efficiencies and negatively impact plant root development, which collectively can negatively impact yield. The author recommends that during an extended heat wave (air temperature equal to or greater than 90 F for 7-10 days), applying 0.25-0.40 inch of water can be very beneficial.

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