Semester of Graduation

Fall 2025

Degree

Master of Science (MS)

Department

School of Plant, Environmental, and Soil Sciences

Document Type

Thesis

Abstract

Sustainable agriculture practices promote cover cropping, which enhances nutrient management and impacts subsequent crop productivity in field crop rotations. Precision agriculture technology, particularly Unmanned Aerial Vehicle (UAV) remote sensing, enables a detailed evaluation of crop management. The studies were conducted in a maize-soybean rotation system with winter cover cropping and fallow management. The maize experiment investigated the effect of nitrogen application rates and cover cropping, using UAV-derived Normalized Difference Red-Edge (NDRE) to monitor crop performance. NDRE effectively captured the N response and the effect of cover cropping across growth stages, particularly during mid-season (55-81 DAP), where it showed a strong correlation with yield. Fertilization up to 170 kg N ha⁻¹ increased maize yield, beyond which additional application produced diminishing returns. In the soybean experiment, the Red-Green-Blue (RGB) sensor on board of the UAV captured high-resolution imagery for soybean plant stand assessment. Soybean stand count classes were predicted using vegetation indices and RGB quantile values with different machine learning models. Pixel-level information summarized as RGB quantiles was an informative predictor, and the Neural Network was able to capture complex patterns in RGB data to predict stand class with high accuracy. Cover crop biomass was predicted using UAV-derived spectral and canopy height data with machine learning, comparing different neural network architectures, optimizers, and activation functions. The neural network model implemented with the Keras TensorFlow library, using the Adam optimizer and the sigmoid activation function, best predicted biomass with an RMSE of 96 g m−2. These findings underscore the potential of UAV remote sensing for nutrient management, crop establishment, and biomass prediction to support precision agriculture and sustainable crop production.

Date

11-3-2025

Committee Chair

Setiyono, Tri

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