Within-field variability in nutrients for site-specific agricultural management in irrigated cornfield

Authors: KUMAR, HEMENDRA - Auburn University; SRIVASTAVA, PUNEET - University Of Maryland; LAMBA, JASMEET - Auburn University; ORTIZ, BRENDA - Auburn University; Way, Thomas - Tom; SANGHA, LALJEET - Virginia Tech; TAKHELLAMBAM, BIJOYCHANDRA - Auburn University; MORATA, GUILHERME - Alabama Cooperative Extension Service; MOLINARI, ROBERTO - Auburn University

Submitted to: Journal of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2022
Publication Date: 5/16/2022
Citation: Kumar, H., Srivastava, P., Lamba, J., Ortiz, B., Way, T.R., Sangha, L., Takhellambam, B., Morata, G., Molinari, R. 2022. Within-field variability in nutrients for site-specific agricultural management in irrigated cornfield. Journal of the ASABE. 65(4):865-880. https://doi.org/10.13031/ja.15042.
DOI: https://doi.org/10.13031/ja.15042

Interpretive Summary: Phosphorus (P) is an important nutrient for agricultural crop production. Variations in the soil P content across a field affect crop yield. We investigated variability in soil P in a corn field during the crop growing season. Three irrigation management zones were delineated. Two irrigation zones received an average of 1.12 times the irrigation amount of the third zone, and those two had higher soil P concentrations than the average whole-field soil P. This variation in soil P was determined to occur as a result of terrain attributes, differences in soil properties, and surface runoff losses within the field. Crop yield showed a significant positive correlation with soil total P. Thus, soil P was found to be an important factor influencing corn yield.

Technical Abstract: Understanding spatial and temporal variation of phosphorus (P) in agricultural fields is challenging. Variation in P levels across a field can impact crop yield. The aim of this study was to investigate soil P variability in a corn field during the 2019 crop growing season in the Tennessee Valley Region (TVR) of North Alabama. Three different irrigation management zones (IRs) were delineated based on 10 years of historical records of crop yield, soil texture, and measured topography. Multiple locations were selected in these management zones for soil sampling at 0-15, 15-30, and 30-60 cm depth increments at different crop growth stages. Soil samples (n = 360) at four different locations in each IR with three replicates for each depth were collected for analysis. Classical statistics were used to understand the spatial and temporal variation in P during the growing season. The normalized data approach was adopted to distinguish three IRs for P. The IR1 and IR2 zones which received an average of 1.12 times the irrigation amount of the IR3 zone, had higher P concentrations than the average P in the field for various crop growth stages. Similarly, IR3 was deficient in P concentration as compared to average P in the field. This P variation in these IRs was found due to terrain attributes, differences in soil properties, and surface runoff losses within the field. A significant difference was recorded in the crop yield in the IR1 and IR3 zones of the same field. The low yield was recorded in IR3 and high yield in IR1 and IR2 as compared to average yield of the field during the 2019 growing season. The crop yield showed a significant positive correlation with soil total P. Therefore, it can be concluded that soil P was found to be one of the main causes that influenced the crop yield, and farmers need to adopt different management practices within the same cropland during the growing season.