Abstract
Corn (Zea mays L.) grain is a major commodity crop in Illinois and its production largely relies on timely application of nitrogen (N) fertilizers. Currently, growers in Illinois and other neighboring states in the U.S. Midwest use the maximum return to N (MRTN) decision support system to predict corn N requirements. However, the current tool does not factor in implications of integrating cover crops into the rotation, which has recently gained attention among growers due to several ecosystem services associated with cover cropping. A two-year field trail was conducted at the Agronomy Research Center in Carbondale, IL in 2018 and 2019 to evaluate whether split N application affects nitrogen use efficiency (NUE) of corn with and without a wheat (Triticum aestivum L.) cover crop. A randomized complete block design with split plot arrangements and four replicates was used. Main plots were cover crop treatments (no cover crop (control) compared to a wheat cover crop) and subplots were N timing applications to the corn: (1) 168 kg N ha−1 at planting; (2) 56 kg N ha−1 at planting + 112 kg N ha−1 at sidedress; (3) 112 kg N ha−1 at planting + 56 kg N ha−1 at sidedress; and (4) 168 kg N ha−1 at sidedress along with a zero-N control as check plot. Corn yield was higher in 2018 than 2019 reflecting more timely precipitation in that year. In 2018, grain yield declined by 12.6% following the wheat cover crop compared to no cover crop control, indicating a yield penalty when corn was preceded with a wheat cover crop. In 2018, a year with timely and sufficient rainfall, there were no yield differences among N treatments and N balances were near zero. In 2019, delaying the N application improved NUE and corn grain yield due to excessive rainfall early in the season reflecting on N losses which was confirmed by lower N balances in sidedressed treatments. Overall, our findings suggest including N credit for cereals in MRTN prediction model could help with improved N management in the Midwestern United States.
Highlights
Corn is a major agricultural crop in Illinois, with a total planted area around 4.2 million hectares in 2018, and an estimated economic value of $7.4 billion in 2017 that represented a 43.5% of the total market value of agricultural products in that year [1]
The maximum return to N (MRTN) for Illinois is developed based on data from 69 site-years for corn–corn rotation and 65 site-years for soybean–corn rotation mainly when no cover crop was present
Studies to look at N recommendation following cover crops are not as abundant as no cover crop N
Summary
Corn is a major agricultural crop in Illinois, with a total planted area around 4.2 million hectares in 2018, and an estimated economic value of $7.4 billion in 2017 that represented a 43.5% of the total market value of agricultural products in that year [1]. Nitrogen is the most limiting nutrient in most crops [2,3,4,5,6,7], including corn and N management decisions are often difficult due to uncertain weather conditions [8]. Illinois uses maximum return to N (MRTN) decision support system to determine the corn N requirement [9]. The MRTN N predictions for corn are often accurate when no cover crop is planted prior to corn. Studies to look at N recommendation following cover crops are not as abundant as no cover crop N trials, and, it is important to evaluate the effect of cover crops, especially non-leguminous species, on corn yield and it’s N requirement
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
