Corn planting strategies in the United States Corn Belt

Corn residue decomposition;Corn seeding depth;Precision agriculture;Geographic information systems (GIS)

Coronel, Eric G

关键词: Corn residue decomposition;    Corn seeding depth;    Precision agriculture;    Geographic information systems (GIS);   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/95314/CORONEL-DISSERTATION-2016.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

In Illinois, corn (Zea mays L.) producers aim to start planting operations in mid-April. Early planting allows for the use of longer-season corn varieties, which tend to yield more than shorter-season varieties. However, constraints to early planting in the U.S. Corn Belt include excessive soil moisture and low temperatures in April. Corn producers often wait for soils to dry and for temperatures to increase before starting planting operations. Meeting the potential for high corn yield requires a successful planting operation and crop establishment. Chapter 1 presents research about challenges in no-till, continuous corn production due to large amounts of corn residue, which may interfere with planting operations and contributes to keeping soils cooler and wetter, delaying field operations. A practice in Illinois is to apply post-harvest nitrogen (N) fertilizer to accelerate residue decomposition. A 2-yr study in Illinois investigated corn residue treated with liquid ammonium sulfate (AMS) and urea-ammonium nitrate (UAN) broadcast-applied post-harvest. Treatments receiving fall N applications did not show greater residue decomposition as measured by stalk strength, and carbon-to-nitrogen (C/N) ratios were not reduced compared to an untreated control. Weather conditions and the residue’s initial quality likely drove the decomposition rate of corn residues. Soil ammonium and nitrate data indicated that some of the N fertilizer applied in early and mid-fall was lost. Results indicated that applying post-harvest N fertilizer to enhance corn residue decomposition is not warranted. Chapters 2 and 3 present research about the application of variable seeding depth of corn as a way to improve yield. Sufficient soil moisture is crucial for corn germination and emergence; however, within-field soil moisture varies with topography. As a result, corn seeding depth should vary with soil moisture gradients to reach optimal moisture. Using relative elevation data, landscape (LSP) zones were delineated to partition soil moisture variability into dry, transitional, and wet LSP zones. The corn yield response to shallow, standard, and deep seeding depths in dry, transitional, and wet LSP zones was tested. It was hypothesized that shallow seeding in wet LSP zones and deep seeding in dry LSP zones would result in higher yield than the standard seeding depth. Chapter 2 describes the experiment where field-long strips were planted in 17 commercial fields in 2014 and 2015 at shallow, standard, and deep seeding depths. Corn was machine-harvested. Across years, the LSP zones were a significant predictor of the yield response in 7 fields. Two fields showed no response to seeding depth, 7 fields yielded similarly for the shallow and standard seeding depths, 4 fields yielded similarly for the deep and standard seeding depths, while 4 fields responded positively to combinations of shallow, standard, and deep seeding depths. Chapter 3 describes the experiment where corn emergence, plant growth, and grain yield were quantified in the LSP zones, along with soil moisture. Two fields in Illinois were planted with field-long strips in 2015 at shallow, standard, and deep seeding depths. Soil moisture was nearly twice as high in wet LSP zones than in dry LSP zones for one field. Seeds planted at shallow depths had earlier emergence and higher growth earlier in the season compared to seeds planted deeper. Shallow seeding in wet LSP zones in one field showed a more consistent emergence rate and less variability compared to the standard and deep seeding depths. However, these results did not translate into significant grain yield differences. The LSP zones had greater influence on grain yield than seeding depths. The data in the appendix showed considerable plant-to-plant variability from adjacent corn plants sampled within-row. This is particularly interesting as corn seeds are assumed to have nearly identical genetics, and except for spacing differences, the growing environment of corn plants along short distances could be assumed to be homogeneous.