Field Research Report: Results From The Enreec Vri Field For The 2021, 2022, And 2023 Crop Seasons, Derek M. Heeren, Ali T. Mohammed, Eric Wilkening, Christopher M. U. Neale, Alan L. Boldt, Ankit Chandra, Precious Nneka Amori, Ivo Z. Goncalves, Yeyin Shi, Guillermo R. Balboa

Department of Biological Systems Engineering: Conference Presentations and White Papers

Long-term irrigation management research has been conducted from 2014 to 2023 for corn and soybean at the Eastern Nebraska Research, Extension, and Education Center (ENREEC) Variable Rate Irrigation (VRI) Field located in subhumid east-central Nebraska (in the Lower Platte North Natural Resources District). The objective of this report was to present the overall results from the VRI Field for 2021 to 2023. Across the three growing seasons, there were the following irrigation treatments: Best Management Practice (BMP), 50% BMP, 125% BMP, rainfed, Spatial ET Modeling Interface (SETMI), SDD1, SDD2, machine-learning-based Cyber-Physical System (CPS), a student team recommended rate, and industry …

Perennializing Marginal Croplands: Going Back To The Future To Mitigate Climate Change With Resilient Biobased Feedstocks, Salvador Ramirez Ii, Marty R. Schmer, Virginia L. Jin, Robert B. Mitchell, Catherine E. Stewart, Jay Parsons, Daren D. Redfearn, John J. Quinn, Gary E. Varvel, Kenneth P. Vogel, Ronald F. Follett

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Managing annual row crops on marginally productive croplands can be environmentally unsustainable and result in variable economic returns. Incorporating perennial bioenergy feedstocks into marginally productive cropland can engender ecosystem services and enhance climate resiliency while also diversifying farm incomes. We use one of the oldest bioenergy-specific field experiments in North America to evaluate economically and environmentally sustainable management practices for growing perennial grasses on marginal cropland. This long-term field trial called 9804 was established in 1998 in eastern Nebraska and compared the productivity and sustainability of corn (Zea mays L.)—both corn grain and corn stover—and switchgrass (Panicum virgatum …

A Regional Investigation Of In-Season Nitrogen Requirement For Maize Using Model And Sensor-Based Recommendation Approaches, Laura J. Stevens

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

N management for corn can be improved by applying a portion of the total N during the growing season, allowing for adjustments responsive to actual field conditions. This study was conducted to evaluate two approaches for determining in-season N rates: Maize-N model and active crop canopy sensor. Various sensor algorithms designed for making in-season N recommendations from crop canopy sensor data were evaluated. The effects of corn hybrid and planting population on recommendations with these two approaches were considered. In a 2-yr study, a total of twelve sites were evaluated over a 3-state region, including sites in Missouri, Nebraska, and …

Evaluation Of Algorithm Thresholds For Crop Canopy Sensor-Based In-Season Nitrogen Application In Corn, Brian T. Krienke

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Nitrogen fertilizer is frequently the most limiting nutrient in corn production. Typically most nitrogen is applied before planting. Since nitrogen can leave the soil system fairly easily, the result can be an inefficient use of nitrogen fertilizer. Previous research has shown increased efficiency with no reduction in yield by applying nitrogen later in the season when the crop is actively growing, with rates regulated spatially through the use of active crop canopy sensors. This study evaluated the potential for N cutoff thresholds using a sufficiency index as the threshold value for areas with poor stand or an unrecoverable N deficiency. …

Modeling Gross Primary Production Of Irrigated And Rain-Fed Maize Using Modis Imagery And Co2 Flux Tower Data, Joshua L. Kalfas, Xiangming Xiao, Diana X. Vanegas, Shashi B. Verma, Andrew E. Suyker

School of Natural Resources: Faculty Publications

Abstract

Information on gross primary production (GPP) of maize croplands is needed for assessing and monitoring maize crop conditions and the carbon cycle. A number of studies have used the eddy covariance technique to measure net ecosystem exchange (NEE) of CO₂ between maize cropland fields and the atmosphere and partitioned NEE data to estimate seasonal dynamics and interannual variation of GPP in maize fields having various crop rotation systems and different water management practices. How to scale up in situ observations from flux tower sites to regional and global scales is a challenging task. In this study, the Vegetation …

An Integrated Crop- And Soil-Based Strategy For Variable-Rate Nitrogen Management In Corn, Darrin F. Roberts

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Nitrogen (N) management in cereal crops has been the subject of considerable research and debate for several decades. Historic N management practices have contributed to low nitrogen use efficiency (NUE). Low NUE can be caused by such things as poor synchronization between soil N supply and crop demand, uniform application rates of fertilizer N to spatially variable landscapes, and failure to account for temporally variable influences on soil N supply and crop N need. Active canopy reflectance sensors and management zones (MZ) have been studied separately as possible plant- and soil-based N management tools to increase NUE. Recently, some have …

Nitrate Production As Affected By Grain-Crop Residues On The Surface Of The Soil, T. M. Mccalla, J. C. Russel

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The purpose of this bulletin is to present the data on nitrate contents and nitrate production in tests where straw or stalk residues were left on the surface through subsurface tillage, as compared with check treatments where these residues were plowed under or were absent. Nine of these tests were at Lincoln, Nebraska, and one was at the Hastings, Nebraska, Hydrological Project. Two tests were conducted in 1939, four in 1941, and four in 1942.

Studies Concerning The Elimination Of Experimental Error In Comparative Crop Tests, T. A. Kiesselbach

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

It is apparent that many sources of error have unconsciously entered into comparative crop yield tests. The very important matter of overcoming variation in soil conditions as a source of experimental error has been quite extensively studied and reported by various investigators during the past decade. The means suggested for reducing such error have been (1) repetition of plats and (2) correction of yields according to check plats planted to a uniform variety or treatment at stated intervals. Both methods have proved of value and a combination of both may often be used advantageously. Some danger always exists of error …