Introduction

This proposal aligns with USB’s strategic plan to improve plant nutrition by utilizing the tools necessary to produce a healthier, more resilient plant. This proposal aims to improve the reliability of phosphorus (P) potassium (K) fertilizer recommendations with emerging climate-smart agriculture production systems to help growers adapt to extreme weather conditions. Soil testing ensure proper plant nutrition, enhanced soil productivity, and profitability with minimal environmental impact on the ecosystem. Most of the current recommendations are generated from outdated agricultural production systems. There is limited information on P and K fertilizer recommendations for soybean systems that use cover crops, which has emerged as an important approach to improve soil health and build resilience for climate-smart agricultural production. In Tennessee, P and K fertilizer recommendations are based on Mehlich I extraction. However, most growers/crop consultants send samples to laboratories that use Mehlich III extractions. So, a calibration for Mehlich III was established for West Tennessee soils. Appropriate calibration would prevent under or over application of P and K fertilizers and enhanced profitability of the fertilizer applications.  Soybean producers participating in NRCS’ Conservation Reserve Program rely on the University of Tennessee fertilizer recommendations in their production system. Image-based canopy sensing detects the real-time performance of plants. Previous work conducted in Kentucky suggests the normalized difference vegetative index can detect P and K soybean nutrient deficiencies. However, there is limited information on the use sensors to detect P and K soybean nutrient deficiencies. To address these challenges, we proposed to (1) evaluate soil test correlation and calibration from P and K fertility trials for soybean production systems with cover crops.