Within-field yield stability and gross margin variations across corn fields and implications for precision conservation

Authors: Adhikari, Kabindra; Smith, Douglas; Hajda, Chad; Kharel, Tulsi

Submitted to: Precision Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2023
Publication Date: 3/11/2023
Citation: Adhikari, K., Smith, D.R., Hajda, C.B., Kharel, T.P. 2023. Within-field yield stability and gross margin variations across corn fields and implications for precision conservation. Precision Agriculture. 24(4):1401-1416. https://doi.org/10.1007/s11119-023-09995-7.
DOI: https://doi.org/10.1007/s11119-023-09995-7

Interpretive Summary: Spatial-temporal yield variability can be used to identify yield stability zones in the field. Yield maps and farm economic data are used to generate field gross margin maps that help to formulate precision conservation plans with economic justification. This study used corn yield and farm economic data from 2018, 2019, and 2020 and generated gross margin maps and yield stability zones for nine corn fields in Blackland Prairie soils in Texas. It identified specific areas in the field that are constantly non-profitable during the past three years, and suggested to pull it out of production. By doing so, it could have saved over $13,800 that was used as input cost during the past three years. This approach could be an effective conservation tool helping farmers save money and contribute to environmental benefits.

Technical Abstract: Soil spatial variation is one of the major causes of within-field yield variation across farms. Spatial-temporal yield variation and its impact on yield stability can be assessed through multi-year yield monitor data and geostatistical techniques. Yield stability zones and gross margin maps based on yield and farm economic data could assist in formulating appropriate precision conservation plans with economic justification. This study employed corn yield measurements from 2018, 2019, 2020 and farm economics data to compile yield stability and gross margin maps for nine corn fields in Texas Blackland Prairie soils, and identified non profitable areas in each field that may be unsuitable for crop production. The study demonstrated that yield stability zones in the field could be efficiently delineated with average and coefficient of variation of multi-year yield maps. Approximately 57% of the area in the fields was classified as unstable zone with higher or lower yield and, nearly 14% of the area constantly produced lower yield (stability zone: D) during the study period. Average gross margin from the fields ranged between -$693 to $775/ha, field W-12 had the highest margin ($541/ha), and Y-10 had the lowest margin (-$257/ha) of all. Almost all fields under stability zone A and zone B had positive margins, and zone C and D had negative margin. Based on yield and gross margin assessment, yield stability zone D could be removed from production and used for permanent conservation cover. Further, this plan could be effectively applied in three specific fields, namely Y-8, Y-6, and W-13 as the fields had a relatively large, contiguous areas under zone D that would ease plan implementation. This could save a total amount of $5600 that was used to cover input cost for Zone D in these three fields. This approach could be an effective conservation tool helping farmers save money and contribute to environmental benefits. We believe that this methodology could be extended to other regions to improve precision conservation planning.